# 51st Rencontres de Moriond EW 2016

Europe/Paris
,
Description

The 51st Rencontres de Moriond session devoted to ELECTROWEAK INTERACTIONS AND UNIFIED THEORIES will be held in La Thuile from Saturday March 12th to Saturday March 19th, 2016.

This year we will celebrate the Rencontres de Moriond 50th anniversary!

La Thuile is a pleasant winter sport resort located in the Italian Alps, at 1450 m alt., about 120 km from Geneva. The nearest international airport is Geneva (Switzerland).

Since its foundation in 1966 by Jean Tran Thanh Van, the Rencontres de Moriond bring together theorists and experimentalists for in-depth discussions on recent findings and new ideas in elementary particle physics in a pleasant, relaxed and intimate atmosphere.

The meeting is intended to promote fruitful collaboration between experimentalists and theorists and between various institutions by bringing together a limited number of physicists and astrophysicists in beautiful and inspiring surroundings.

This session is devoted to electroweak interactions and to unified theories.
The Rencontres de Moriond are sponsored by

Support
• Sunday, March 13
• Heavy Flavours: (morning)
• 1
$\overline{B} \rightarrow D^{(\ast)}\tau\overline{\nu}_{\tau}$ decays with hadronic and semileptonic tagging at Belle
The ratio of the measured $\overline{B} \to D^{(\ast)} l \overline{\nu}$ decay rates for $l=\tau$ vs. $e,\mu$ from BaBar, Belle, and LHCb together show a significant deviation from the Standard Model. Belle's 2015 result of $\overline{B} \rightarrow D^{(\ast)} \tau^{-}\overline{\nu}_{\tau}$ with hadronic tagging and the current world average will be discussed. Furthermore, Belle's preliminary new measurement of $\overline{B^{0}} \rightarrow D^{\ast+} \tau^{-} \overline{\nu}_{\tau}$ with the semileptonic tagging method will be introduced along with compatibility studies with selected New Physics models.
Speaker: Dr Pablo Goldenzweig (KIT)
• 2
During Run 1 of the LHC, the LHCb experiment has collected a large sample of beauty-hadrons that corresponds to an integrated luminosity of 3.0 fb$^{-1}$ at $pp$ centre-of-mass energy of 7 and 8 TeV. This talk gives an overview of the rare decay measurements the LHCb collaboration performed using Run 1 data, with an emphasis on Flavour Changing Neutral Current processes of the type $b \rightarrow s \ell^+ \ell^-$. Anomalies in the branching fractions and angular distributions of these decays are discussed and connected with tests of Lepton-Flavour-Universality.
Speaker: Johannes Albrecht (TU Dortmund)
• 3
Global analysis of b-->sll anomalies
Recently, the LHC has found several anomalies in exclusive semileptonic b --> s l l decays with a combined significance of more than 4 sigma. After a brief discussion of the hadronic uncertainties entering the theoretical prediction for the relevant decays, I present an interpretation of the data in terms of new physics. Based on model-independent global fits of the effective Wilson coefficients to the data, the discrimination between high-scale new physics and low-energy QCD effects as well as the possibility of lepton-flavour universality violation are discussed.
Speaker: Dr Lars Hofer (UB Barcelona)
• 4
$CP$ violation in b-hadrons at LHCb
Latest LHCb measurements of $CP$ violation in the decays of b-hadrons are presented based on $pp$ collision data collected in Run 1, corresponding to an integrated luminosity of 1 fb$^{-1}$ at centre-of-mass energy 7 TeV and 2 fb$^{-1}$ at 8 TeV. New decays, $\Lambda_b\to \Lambda \pi^-K^+$ and $\Lambda_b\to \Lambda K^+K^-$, are identified and the associated $CP$ asymmetries are measured. The $\Lambda_b\to \Lambda \phi$ decay is observed for the first time and novel $T$-odd triple product asymmetries are measured.
Speaker: Dr Sean Benson (CERN)
• 9:55 AM
break
• 5
B->sll SM contributions
Speaker: Gudrun Hiller (Dortmund)
• 6
Charm mixing and CP violation
LHCb collected the world's largest sample of open charm decays during Run 1 of the Large Hadron Collider. This has permitted many precision measurements of charm mixing and $CP$ violation parameters, the most precise of which being $\Delta A_{CP}$, a measurement of the relative strength of direct, time-integrated $CP$ asymmetries between two singly-Cabibbo suppressed $D^{0}$ decays. This measurement has recently been updated using promptly-produced $D^{0}$ mesons with the full Run 1 dataset, and has a precision below the permille level. In addition, LHCb has recently made the first observation of $D^{0}$ mixing in a multibody $D^{0}$ decay, also measuring associated coherence parameters which can be used as input to measurements of the CKM angle $\gamma$. LHCb has also measured the mixing parameters $x$ and $y$ with a model-independent analysis of $D^{0} \to K_{S}^{0}\pi^{+}\pi^{-}$ decays, and the size of direct $CP$ violation in $D^{0} \to K_{S}^{0}K_{S}^{0}$ decays. These four analyses will be presented, along with a brief overview of the prospects for Run 2.
Speaker: Mr Alex Pearce (University of Manchester)
• 7
Studies of the rare decays of B mesons to muon pairs with the ATLAS detector at LHC Run 1
The study of the rare decays $B^0_s \to \mu^+\mu^-$ and $B^0 \to \mu^+\mu^-$ has been performed using 25 fb$^{-1}$ of integrated luminosity collected with the ATLAS detector during LHC Run 1. The analysis and the results are presented.
Speaker: Dr Sandro Palestini (CERN)
• 8
Lepton flavour non-universality in b -> s l l processes
TBA
Speaker: Dr Nejc Kosnik (Jozef Stefan Institute)
• Heavy Flavours: (afternoon)
• 9
Recent hot results (including semileptonic b hadrons decays)
The LHCb experiment has collected large samples of heavy flavoured hadrons during Run 1, corresponding to an integrated luminosity of 3.0 fb$^{-1}$ at $pp$ centre-of-mass energy of 7 and 8 TeV. Interesting results using semileptonic $B$ decays have been published, amongst which are a novel measurement of $|V_{ub}|$ and an enhanced branching ratio of semitauonic $B^0$ decays. The latter is possibly hinting for new physics. LHCb has also reported the most precise measurements of the $B^0-\bar{B^0}$ mixing frequency and of $CP$ violation in $B^0-\bar{B^0}$ and $B_s^0-\bar{B_s^0}$ mixing. A new measurement of $CPT$ violation in $B^0-\bar{B^0}$ and $B_s^0-\bar{B_s^0}$ mixing (using hadronic $B$ decays) will also be presented.
Speaker: Dr Jeroen van Tilburg (Nikhef)
• 10
The CKM angle gamma
Latest results will be presented from the analysis of open charm B-decays, sensitive to the CKM angle gamma, from the Run 1 LHCb dataset. This includes new results using the ADS, GLW and GGSZ techniques applied to B→DX decays. The talk will conclude with a discussion on the determination of gamma from these tree-level decays, as well as the associated hadronic parameters.
Speaker: Dr Malcolm John (University of Oxford)
• 11
Rare B decays at ATLAS and CMS
Speaker: Sanjay Swain (NISER, India)
• 12
Weak matrix elements from Lattice QCD
Speaker: Dr Nicolas Garron (university of Edinburgh)
• 6:30 PM
break
• 13
Neutral pion form factor and search for K+ to pi+ nu nu at NA62
The NA62 experiment at CERN SPS collected a large sample of charged kaon decays with a highly efficient trigger for decays into electrons in 2007 using the experimental setup of the earlier kaon experiment at CERN NA48/2. The kaon beam represents a source of tagged neutral pion decays in vacuum. A measurement of the electromagnetic transition form factor slope of the neutral pion in the time-like region from ~1 million fully reconstructed $\pi^0$ Dalitz decay is presented. The limits on dark photon production in $\pi^0$ decays from NA48/2 are also reported. The $K^+\rightarrow\pi^+\nu\bar{\nu}$ decay is one of the theoretically cleanest meson decay where to look for indirect effects of new physics complementary to LHC searches. The new experimental setup used by the NA62 experiment at CERN SPS since 2014 is designed to measure the branching ratio of this decay with 10% precision. NA62 took data with the new setup in pilot runs in 2014 and 2015 reaching the final designed beam intensity. The quality of data acquired in view of the final measurement will be presented.
Speaker: Dr Giuseppe Ruggiero (CERN)
• 14
Searches for lepton number violation and resonances in the $K^{\pm}\rightarrow \pi \mu \mu$ decays at the NA48/2 experiment
The NA48/2 experiment at CERN collected a large sample of charged kaon decays into final states with multiple charged particles in 2003-2004. A new upper limit on the rate of the lepton number violating decay $K^{\pm} \rightarrow \pi^{\mp} \mu^{\pm} \mu^{\pm}$ obtained from this sample is reported: $8.6 \times 10^{-11}$ at 90% CL, which improves by more than an order of magnitude upon the previous measurements. Searches for two-body resonances in the $K^{\pm}\rightarrow \pi \mu \mu$ decays (including heavy neutral leptons and inflatons) in the accessible range of masses and lifetimes are also presented.
Speaker: Karim Massri (University of Liverpool)
• 15
Lepton number symmetry as a way to testable leptogenesis
We propose a minimal and motivated extension of the Standard Model characterised by an approximated lepton number conservation, which is able both to generate neutrino masses and to account for a successful baryogenesis via leptogenesis. The sterile fermions involved in the leptogenesis process have masses at the GeV scale. We determine the viable parameter space that complies with both the neutrino and baryogenesis phenomenology, and analyse the different regimes for the generation of a lepton asymmetry in the early Universe (weak and strong washout) in order to determine their testability in future experimental facilities.
Speaker: Dr Michele Lucente (Centre for Cosmology, Particle Physics and Phenomenology - CP3)
• Young Scientist Forum: #1
• 16
Precision Measurement of B(B0->D*-pi+pi-pi+) at BABAR
Using a sample of $(470.9 \pm 2.8) \times 10^6$ B meson pairs, we measure the decay branching fraction ${\mathcal{B}(B^0\to D^{*- }\pi^+ \pi^- \pi^+) = (7.26 \pm 0.11 \pm 0.31) \cdot 10^{-3}}$, where the first uncertainty is statistical and the second uncertainty is systematic. The measurement is 2.4 times more precise than the current world average value. This branching fraction includes singly-charmed $B^0$ decays only and is obtained by removing the dominant doubly-charmed $B^0$ decay contribution from the contaminated branching fraction of $(7.37 \pm 0.11 \pm 0.31) \cdot 10^{-3}$.
Speaker: Dr Rocky So (University of British Columbia)
• 17
Status and prospects of the Belle II experiment
The Belle II experiment at the SuperKEKB $e^+e^-$ collider will start its operation in 2018, with the goal of collecting 50 $ab^{-1}$ of data. This will allow for high precision measurements in the quark flavor sector, opening a window into physics at the energies beyond achievable at the high energy frontier experiments. In the talk we present the recent status of the SuperKEKB and Belle II detector construction, along with some physics prospects.
Speaker: Luka Santelj (KEK - High Energy Accelerator Research Organization)
• 19
Global constraints on heavy neutrino mixing
We derive constraints on the mixing of heavy Seesaw neutrinos with the SM fields. We explore and compare both a completely general scenario where the heavy neutrinos are integrated out and the more constrained case of only 3 extra heavy states. The latter assumption implies non-trivial correlations that do not allow to saturate all model-independent bounds.
Speaker: Mr Josu Hernandez-Garcia (IFT)
• Monday, March 14
• Neutrinos: (morning)
• 20
Latest results from IceCube on neutrino properties and flux types
The IceCube Neutrino Observatory is a cubic kilometer ice Cherenkov neutrino detector, located at the geographic South Pole, detecting neutrinos down to energies of about $10\,\textrm{GeV}$. Thanks to its size, IceCube can probe small fluxes of high-energy neutrinos $(\gt 10\,\textrm{TeV})$ and in the last couple of years it has established the existence of a high-energy astrophysical neutrino flux at the level of $0.5-2.5 \cdot 10^{-18} (E/100\,\textrm{TeV})^{-\gamma}\,\textrm{GeV cm}^{-2}\textrm{s}^{-1}\textrm{sr}^{-1}$ per flavor and a spectral index $\gamma$ of $2.0-2.7$ depending on the energy range of the specific analysis. DeepCore, a region of denser instrumentation at the lower center of the detector, detects low-energy atmospheric neutrinos $(\lt 100\,\textrm{GeV})$, which are used to study neutrino oscillations with a precision comparable to that of the leading experiments in the field. The latest results on both of these topics are discussed.
Speaker: Dr Jan Auffenberg (RWTH Aachen University)
• 21
Searching for Sterile Neutrinos with MINOS
Over the last couple of decades physicists across the world have obtained model-independent evidence for neutrino oscillations, with the majority of experiments confirming the compatibility with a three-favour model i.e three neutrino mass and flavour states. However, there have been a few anomalous results in the community which among other explanations, can be explained by the existence of additional neutrinos known as sterile neutrinos. This talk will discuss the latest results for a 3+1 sterile neutrino search using the MINOS experiment data set from 2005 - 2012. MINOS is a two-detector on-axis experiment based at Fermilab. The NuMI neutrino beam encounters the MINOS Near Detector 1 km downstream before travelling 734 km through the Earth's crust, to reach the Far Detector located at the Soudan Underground Laboratory in Northern Minnesota. By searching for oscillations driven by a large mass splitting, MINOS is sensitive to the existence of sterile neutrinos through looking for any energy dependent perturbations using a charged current sample, as well as looking at any relative deficit between neutral current events between the far and near detectors. This talk will discuss the novel analysis that enabled a search for sterile neutrinos covering five orders of magnitude in the mass splitting and setting a limit in the previously unexplored regions in the parameter space $\Delta m^{2}_{41} - \theta_{24}$. This talk will show results of a search for sterile neutrinos that is sensitive to the parameter space suggested by LSND and MiniBooNE. This MINOS search for muon neutrino disappearance complements other previous experimental searches for sterile neutrinos in the electron neutrino appearance channel.
Speaker: Mr Ashley Timmons (University of Manchester)
• 22
First results of the NOvA experiment
NOvA recently released its first oscillation physics results announcing that it is primed to make significant contributions to our understanding of the neutrino sector. NOvA is a long-baseline neutrino experiment that consists of two functionally identical detectors; a 330 ton Near Detector located 100m underground at Fermilab,1 km from the source, and a 14 kton Far Detector located 810 km north in Ash River, MN. I will present NOvA’s first neutrino oscillation results, namely the first NOvA measurements of electron neutrino appearance and muon neutrino disappearance. The observation of muon-neutrino disappearance will allow for precision measurements of one of the mass-squared splitting values and determining its sign will answer the question of which neutrino mass eigenstate is the lightest. Measurement of the electron neutrino appearance rate will provide NOvA with sensitivity to the neutrino mass ordering and the amount of CP violation in the neutrino sector.
Speaker: Dr Jeff Hartnell (University of Sussex)
• 23
Latest Oscillation Results from T2K
The T2K long baseline neutrino oscillation experiment is composed of a near detector at 280m and a far detector at Super-Kamiokande, located 295 km from the neutrino beam source. The 30GeV proton beam at JPARC is used to produce $\sim~$1 GeV muon neutrinos which are detected in the Cherenkov detector at Super-Kamiokande for oscillation measurements, such as electron neutrino appearance and $\theta_{23}$ measurements from muon neutrino disappearance. By reversing the beam polarity antineutrino oscillations may also be studied. Combined measurements of neutrino and antineutrino oscillations constrain the CP-violating Dirac phase of the PMNS matrix. This talk will present the most recent oscillation results from T2K.
Speaker: Ms Christine Nielsen (University of British Columbia)
• 9:50 AM
break
• 24
Reactor neutrino fluxes (update)
In this talk I will present a review of the anti-neutrino spectra emitted from reactors. Knowledge of these and their associated uncertainties are crucial for neutrino oscillation studies. The spectra used to-date have been determined by either conversion of measured electron spectra to anti-neutrino spectra or by summing over all of the thousands of transitions that makeup the spectra using modern databases as input. The uncertainties in the sub-dominant corrections to beta-decay plague both method. Improving on current knowledge of the anti-neutrino spectra from reactors will require new experiments. Such experiments would also address the so-called reactor neutrino anomaly and the possible origin of the shoulder observed in the anti-neutrino spectra measured in recent high-statistics reactor neutrino experiments.
Speaker: Dr Anna Hayes (Los Alamos National Laboratory)
• 25
Recent Results from Daya Bay Reactor Neutrino Experiment
A new spectral measurement of electron antineutrino disappearance using the fully constructed Daya Bay Reactor Neutrino Experiment was reported in 2015. The final two of eight antineutrino detectors were installed in the summer of 2012. Including the 404 days of data collected from October 2012 to November 2013 resulted in a total exposure of 6.9 × $10^{5}$ $GW_{th}$ ton days, a 3.6 times increase over our previous results. Direct prediction of the antineutrino signal in the far detectors based on the measurements in the near detectors explicitly minimized the dependence of the measurement on models of reactor antineutrino emission. We gave a measurement of the neutrino oscillation parameters of $\theta_{13}$ and $|\Delta m_{ee}^2|$ in the three-neutrino framework. We also reported a measurement of the flux and energy spectrum of electron antineutrinos from the reactors. It was consistent with previous short-baseline reactor antineutrino experiments, and compared to the flux predicted with the Huber+Mueller (ILL+Vogel) fissile antineutrino model. An improved independent measurement of neutrino mixing angle $\theta_{13}$ with signals from the neutron captured by hydrogen is going to be published.
Speaker: Mr Yiming ZHANG (Tsinghua University)
• 26
New Results of Double Chooz
At Rencontres de Moriond, Double Chooz (DC) collaboration will present the first $\theta_{13}$ measurement with two detectors. DC is a reactor neutrino experiment running at Chooz nuclear power plant in France. In 2011, DC first reported indication of non-zero $\theta_{13}$ in reactor neutrino oscillation by a single detector at around oscillation maximum (far detector, FD). Until then only the upper limit was given by the CHOOZ experiment. A robust observation of $\theta_{13}$ was followed in 2012 by the Daya Bay and RENO experiments with multiple detectors. $\theta_{13}$ is most precisely measured by the reactor experiments with the systematic uncertainties at per mille level and the value is used as reference in current and future projects which aim to search for CP violation and mass hierarchy in neutrino sector. Therefore, precision and accuracy of the reactor $\theta_{13}$ is a critical matter and validation by multi-experiments based on different systematic uncertainty compositions are essential. In the latest analysis of DC, precision of $\theta_{13}$ is dominated by the reactor flux uncertainty after suppression of background and detector related systematic uncertainties, and hence significant improvement is expected with two detectors. DC finished construction of the second detector close to the reactor cores (near detector, ND) and has accumulated about 1 year of data with two detectors as of February 2016. In addition to that, about 2 years of data with only FD can be used in analysis to improve the precision. Thanks to nearly iso-flux experimental layout in DC, reactor flux uncertainties are strongly suppressed to the lowest level in the world.
Speaker: Dr Masaki Ishitsuka (Tokyo Institute of Technology)
• 27
The search for right handed neutrinos
Speaker: Alain Blondel (UNIGE)
• Neutrinos: (afternoon)
• 28
Recent MicroBooNE Results
MicroBooNE is a new 170-ton liquid argon time projection chamber that began collecting data in Fermilab’s Booster neutrino beam in October 2015. Physics goals of the experiment include investigating the MiniBooNE low-energy excess, and measuring cross sections for neutrino interactions. The experiment additionally is a platform for the research and development needed for future planned LArTPC experiments. This talk will report the status and early results of the experiment.
Speaker: Dr Sarah Lockwitz (Fermilab)
• 29
Recent results from MINER$\nu$A
The MINER$\nu$A experiment makes precision neutrino-nucleus cross section measurements with neutrinos and anti-neutrinos from the Fermilab NuMI beamline. These measurements probe both nuclear effects which modify the initial neutrino-nucleon cross sections via nucleon-nucleon correlations and propagation of particles through the nuclear medium. Updates to previous charge-current cross sections as a result of an improved flux prediction will be presented. In addition, results from an inclusive sample measuring a proxy for transferred energy versus three-momentum transfer will be shown. A direct measurement of electron neutrino induced charge current quasi elastic scattering, an important neutrino oscillation signal channel, will be presented. Finally, cross section results from resonant pion production will be presented.
Speaker: Dr Daniel Ruterbories (University of Rochester)
• 30
The effect of sterile neutrinos on long-baseline experiments
A variety of anomalies in short-baseline neutrino experiments hint at the possible existence of light sterile neutrinos. We show that these sterile neutrinos, if real, could very substantially affect the interpretation of future long-baseline measurements, such as those of the Deep Underground Neutrino Experiment (DUNE). In particular, interpretations that do not take the sterile neutrinos into account could lead to grossly incorrect conclusions concerning leptonic CP violation. We explore the degree to which future short-baseline experiments, should they prove to be negative, need to constrain sterile-active mixing to ensure that long-baseline experiments can safely disregard the possibility that light sterile neutrinos exist.
Speaker: Dr Boris Kayser (Fermilab)
• 31
Recent results from Borexino
Speaker: Sandra Zavatarelli (INFN Sezione di Genova)
• 6:20 PM
break
• 32
Results from OPERA
The OPERA experiment was designed to investigate muon to tau neutrino oscillations in appearance mode. Physics data were collected from 2008 to the end of 2012 in the CERN Neutrinos to Gran Sasso (CNGS) $\nu_\mu$ beam and neutrino interactions have been studied on an event-by-event base. Five tau neutrino candidate events have been detected in the analyzed data sample, assessing the discovery of the appearance of tau neutrino in the CNGS beam with a significance larger than 5 sigma. Limits on muon to tau and muon to electron neutrino oscillations induced by additional neutrino states have also been derived. In this talk, we will present an overview of the OPERA experiment and its latest results.
Speaker: Dr Alessandra Pastore (Bari University &amp; INFN)
• 33
SoLid: a new short baseline neutrino experiment
The SoLid neutrino detector concept is currently one of the most compact and most finely segmented neutrino detectors. Its use is most effective near compact and intense neutrino sources, such as the Belgian high-power BR2 research reactor, where it will operate from 2016 onwards to search for sterile neutrinos. In this talk we will review the design, the operation characteristics, and the performance of a 300 kg full-size detector module that was deployed and operated at 5m distance from the BR2 reactor core in 2015. The plan is to improve upon the current design and gradually extend the sensitive mass in order to complete a 1.5 tonne detector later in the year. The sensitivity of SoLid is sufficient to exclude a significant part of the sterile neutrino parameter space by 2018.
Speaker: Prof. Nick Van Remortel (University of Antwerp)
• Young Scientist Forum: #2
• 34
First observation of Lb -> Lambda K+ pi- and Lambda K+ K- decays at LHCb
The physics potential for b-baryon decays has been relatively untapped until the advent of the LHC, and as such important questions still exist of their fundamental properties, such as whether their decays exhibit CP violation. Presented here are observations of the decays $\Lambda_b^0 \rightarrow \Lambda K^+ \pi^-$ and $\Lambda_b^0 \rightarrow \Lambda K^+ K^-$, made at a significance level of 8.1 and 15.8 Gaussian standard deviations, respectively, and measurements of their branching fractions. The phase-space integrated CP asymmetries of these decays are also measured and found to be consistent with zero. Limits are set on the branching fractions of other $\Lambda_b^0$ and $\Xi_b^0$ decays to $\Lambda h^+h^{-}$ (where '$h$' is a kaon or pion).
Speaker: Daniel O'Hanlon (University of Warwick)
• 35
Neutrino Oscillation Physics Potential of A Possible Extension of The T2K Experiment
T2K (Tokai to Kamioka) is the world's first off-axis designed long-baseline experiment that was built for precision measurement of neutrino oscillations. The T2K experiment uses a high intensity, highly pure beam of muon (anti)neutrinos produced at J-PARC in Tokai, Japan. A Near Detector complex, 280 m downstream of the target, is operated to monitor and characterize the (anti)neutrino beam before the neutrinos oscillate. Neutrino oscillation patterns are observed at the Super-Kamiokande detector, which is located 295 km away from the neutrino production point at an angular offset of 2.5 degrees from the average beam direction. In 2013, with $6.6\times10^{20}$ protons-on-target (POT), just $8.4\%$ of the total approved proton exposure, $\nu_{\mu}\rightarrow \nu_e$ appearance, a primary goal of T2K, was discovered with $7.3\sigma$ significance. This result leads us to re-evaluate the physics potential and possibility for extension of the T2K experiment. In this report, T2K neutrino oscillation sensitivities are studied with a total exposure of $20\times10^{21}$ POT, which can be achieved by 2026 with a possible upgrade of the J-PARC beam power. This amount of data exposure, along with T2K hardware upgrades and analysis improvement, allows us to intensively explore CP violation in the lepton sector, to precisely measure neutrino oscillation parameters, and to positively search for unknown physics.
Speaker: Dr Son Cao (Kyoto University)
• 36
The scientific programme of LHCb includes a large number $CP$ violation measurements in $b$-hadron decays. To perform such measurements, one needs to disentangle the physical asymmetry from others spurious effects, such as production asymmetries arising from the flavour-asymmetric proton-proton collisions. Using an integrated luminosity of 1 fb$^{-1}$ collected at a centre-of-mass energy of 7 TeV, the $B^0$ and $B^0_s$ production asymmetries, within the LHCb acceptance, are measured. The production asymmetries, integrated over $p_T$ and $\eta$ in the range $4 < p_T < 30$ GeV/$c$ and $2.5 < \eta < 4.5$, are determined to be $A_{\rm P}(B^0) = (-0.35 \pm 0.76 \pm 0.28)\%$ and $A_{\rm P}(B^0_s) = (1.09 \pm 2.61 \pm 0.66)\%$, where the first uncertainties are statistical and the second systematic. Updates of these measurements using 2 fb$^{-1}$ of data collected at a centre-of-mass energy of 8 TeV, together with the measurement of $B^+$ and $\Lambda^0_b$ production asymmetries, are under way.
Speaker: Mr Fabio Ferrari (INFN - Sezione di Bologna)
• 37
Opportunities with (semi)leptonic rare charm decays
We study (semi)leptonic rare charm decays and its opportunities in searches for physics beyond the Standard Model (BSM). In particular, we analyze the impact of potential BSM physics in $c\to ull'$ transitions, notably branching ratios, angular observables, asymmetries and Lepton Flavor Violating decays. Testable effects are worked out model-independently and within Leptoquark models supplemented by flavor patterns to link $K$/$B$ decays.
Speaker: Stefan de Boer (TU Dortmund)
• 38
Neutron EDM and its implications for HEP
The quest for a non-zero electric dipole moment (EDM) of simple systems such as the electron, the neutron or atoms / molecules is a powerful way to search for physics beyond the standard model in particular for new sources of CP violation, complementary to LHC experiments. So far, no EDM signal was observed and the upper limit on the neutron EDM, established by the RAL/Sussex/ILL collaboration, is |dn| < 3 x 10-26 e cm (90% C.L.). This limit was set with an apparatus using ultra cold neutrons stored in a vessel at room temperature. The nEDM collaboration at the Paul Scherrer Institute in Switzerland aims at reaching a sensitivity in the 10-27 e cm range soon. I will present the current status of the experiment and discuss the prospects for the future on behalf the nEDM collaboration.
Speaker: Mr Yoann Kermaidic (LPSC)
• 39
On the study of solar flares with neutrino observatories.
Since the end of the eighties, in response to a reported increase in the total neutrino flux in the Homestake experiment in coincidence with solar flares, neutrino detectors have searched for signals of neutrinos associated with solar flare activity. The acceleration of protons in the magnetic structures of such flares produce mesons in collisions with the solar atmosphere which subsequently decay, resulting in neutrinos at O(MeV-GeV) energies. The study of such neutrinos would provide a novel window on the underlying physics of the acceleration process. The sensitivity of the IceCube Neutrino Observatory, located at the geographical South Pole, to solar flares is currently under study. I will introduce a new approach for a time profile analysis based on a stacking method of selected solar flares likely to be connected with pion production. An initial approach towards a neutrino search using the current IceCube as well as first efforts to improve the detection efficiency in the future will be presented.
Speaker: Mrs Gwenhaël de Wasseige (Vrije Universiteit Brussel)
• Tuesday, March 15
• Neutrinos: (cntd)
• 40
Review of Nuclear Matrix Elements for Neutrinoless Double-Beta Decay
Computing reliable matrix elements for processes such as neutrinoless $\beta\beta$ decay that have never before been observed is a challenging task. So far, all calculations involve approximations and phenomenology that introduce unquantifiable uncertainty. Fortunately, ab initio nuclear-structure theory, based on innovative many-body techniques plus nuclear interactions and currents that come from first principles, has made rapid progress in recent years. I describe several ab initio schemes, all in development, for computing the matrix elements and estimating uncertainty. These approaches promise dramatic improvement in the accuracy with which we can compute the the matrix elements for neutrinoless $\beta\beta$ decay, particularly when combined with more phenomenological work that is also underway. Structure theorists around the world are organizing to attack the matrix-element problem. In the US, the effort has led to a Department-of-Energy sponsored collaboration, which I will briefly describe.
Speaker: Jonathan Engel (University of North Carolina)
• 41
The searches for neutrinoless double beta decay and other physics with EXO-200
EXO-200 is a single phase liquid xenon detector that is one of the most sensitive searches for neutrinoless double beta decay in the world. The experiment uses enriched liquid xenon (110 kg in the active volume) in an ultralow background time projection chamber installed at the Waste Isolation Pilot Plant (WIPP), a salt mine with a 1600 m water equivalent overburden near Carlsbad, NM, USA. The detector has demonstrated excellent energy resolution and background rejection capabilities to set a limit of 1.1 $\times$ 10$^{25}$ yr at 90% C.L. Recently, the experiment has restarted data taking after a two year hiatus due to unforseen WIPP incidents. I will talk about the latest EXO-200 physics results, in particularly the search for the decays of $^{136}$Xe to the excited state of $^{136}$Ba, and how the imminent upgrades to EXO-200 can help with the planning of tonne-scale next generation experiment, nEXO.
Speaker: Dr Yung-Ruey Yen (Drexel University)
• 42
Neutrinoless double beta decay results from CUORE-0 and status of the CUORE experiment
The Cryogenic Underground Observatory for Rare Events (CUORE) is a 1-ton scale bolometric experiment whose detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. CUORE-0 is the CUORE demonstrator: it has been built to test the performance of the upcoming CUORE experiment and represents the largest 130Te bolometric setup ever operated. CUORE-0 has been running in the Gran Sasso National Laboratory (Italy) from March 2013 to July 2015 and CUORE is now in its final construction and commissioning phase. In this talk we will present the final CUORE-0 analysis on neutrinoless double beta decay and the corresponding detector performance. We will also discuss the status of the CUORE experiment: the final results from the commissioning of the cryostat, the installation of the towers and the early commissioning of the experiment.
Speaker: Dr Paolo Gorla (Laboratori Nazionali del Gran Sasso - INFN)
• Standard Model: (morning)
• 43
Prospects for W-mass measurements at the LHC
A precise O(10 MeV) measurement of the W boson mass is a stringent test of the standard model. The talk will discuss the experimental and theoretical challenges that need to be faced in order to achieve this level of precision. In addition, the status of various experimental studies, calibrations and state-of-the-art simulations related with this measurement will be presented.
Speaker: Mariarosaria D'Alfonso (CERN)
• 10:00 AM
break
• 44
Double Gauge Boson Production at 7/8/13TeV
LHC measurements of multi-boson production processes involving combination of up to three W, Z and isolated photons are summarized. The cross sections are measured inclusively and differentially as a function of different kinematic quantities. First measurements of di-boson cross sections at center of mass energy 13TeV are presented. Production processes sensitive to vector-boson fusion and vector-boson scattering are also presented and compared to Standard Model expectations. Limits on anomalous triple and quartic gauge couplings have been derived.
Speaker: Tiesheng Dai (Research Engineer)
• 45
Inclusive single gauge boson production at 7/8/13 TeV
We report the LHC measurements of single W and Z boson production at different centre-of-mass energies. Together, the ATLAS, CMS and LHCb detectors provide precision coverage over an absolute rapidity range from 0 to 4.5, enabling precision studies of Standard Model physics across different kinematic regions. We report both differential cross-sections and ratios of W boson and Z boson measurements. These results allow tests of the performance of different parton distribution functions (PDFs), and can be used to further constrain the PDFs. In addition, the results are compared to predictions from different Monte Carlo generators, testing different approaches to modelling QCD effects. We also report measurements of the forward-backward asymmetry in Z boson decays, and measurements of angular coefficients, which provide sensitivity to the electroweak mixing angle.
Speaker: Dr William Barter (CERN)
• 46
Precision Measurements of Electroweak Parameters with Z Bosons at the Tevatron
We report on the extraction of sin2θ_eff(MZ) and an indirect measurement of the mass of the W boson from the forward-backward asymmetry of dilepton events in the Z boson mass region at the Tevatron. The data samplesof e+e− and μ+μ− events collected by the CDF detector correspond to the full 9.4 fb−1 run II sample and yield an effective electroweak mixing angle sin2θ_eff(MZ)=0.23222±0.00046. The corresponding result reported by the D0 collaboration with the full 9.4 fb−1 e+e− sample is sin2θ_eff(MZ)=0.23146±0.00047. The CDF collaboration also extracts the on-shell electroweak mixing angle sin2θW=0.22401±0.00044 which corresponds to an indirect measurement of the W boson mass MW(indirect)=80.327±0.023GeV. The quoted uncertainties include both statistical and systematic contributions.
Speaker: Prof. Arie Bodek (University of Rochester)
• 47
Top quark physics from Tevatron
An overview over recent measurements of top quark properties from the CDF and D0 experiments at the Tevatron proton-antiproton collider is given. We focus on results that are complementary to measurements at the LHC. The results are presented in a systematic way analzsing the top quark pair production mechanism. The presented results involve a new ttbar cross section measurement, a top quark pole mass extraction, top quark polarization measurements, new measurements of the forward-backward ttbar asymmetry and a new analysis of ttbar spin correlation. Special emphasis is given to the question about how these high precision measurements can be used to perform sensitive searches for new physics. Most of the results are Tevatron legacy measurements.
Speaker: Dr Christian Schwanenberger (University of Manchester)
• Standard Model: (afternoon)
• 48
LHC performance in 2015 and prospects for future
In 2015 LHC started operation at a beam energy of 6.5 TeV. After two month beam commissioning period, first collisions were delivered in June 2015. To reach nominal performance with a bunch spacing of 25 ns, the first main hurdle was the conditioning of the vacuum chamber in under to suppress the phenomenon of electron clouds. The conditioning lasted for the rest of 2015 run, the LHC was operated at the limit of stability of the beams and of the cryogenic system. In November 2015 2244 bunches were stored in the machine, just 20% short of the nominal filling. This presentation will discuss and explain the challenges that had to be mastered in 2015. From the state of the LHC at the end of the 2015 run, projections for the performance for the period 2016-2018 will be presented.
Speaker: Dr Jorg Wenninger (CERN)
• 49
Top quark production at the LHC
Twenty years past its discovery, the top quark continues attracting great interest as we continue to unveil its properties. An overview of measurements performed by the ATLAS and CMS experiments at the CERN LHC, in the domain of top physics will be presented. The latest measurements of top quark production rates via strong and electroweak processes are reported and compared to different perturbative QCD predictions. Fundamental properties, such as mass or couplings of the top quark, as well as re-interpretations seeking for beyond the standard model contributions in the top quark sector, are extracted from the measurements reported. In each case we attempt to highlight the main prospects to be expected for the on-going Run 2 of the LHC.
Speaker: Pedro Ferreira da Silva (CERN)
• 50
Top properties at LHC@13 TeV in ATLAS and CMS
The top quark, heaviest known fundamental particle, is the only quark that decays before hadronization. This gives us a unique view on bare quarks properties. Probing top quark couplings with the other fundamental particles open a window to physics beyond the Standard Model. Measuring its properties is therefore of utmost importance. This talk will focus on recent top quark measurements by the ATLAS and CMS collaborations with a highlight on the recent 13 TeV measurements using data from the 2015 LHC Run 2.
Speaker: Emmanuel Monnier (CPPM)
• 6:20 PM
break
• 51
Precise measurement of the top mass at proton and electron colliders
Speaker: Andre Hoang (University of Vienna, Faculty for Physics)
• 52
New methods for top mass measurement at LHC
Speaker: Benjamin Stieger (University of Nebraska, Lincoln)
• 53
Probing the Atomic Higgs Force
The interaction strength of the Higgs boson to the building blocks of matter, the electron and up and down quarks, are essentially unknown. Probing these coupling is an important test of the SM which could lead not only to the establishment of new physics but also to an alternative understanding of the flavor puzzle. We propose a novel approach based on isotope shift measurements in atomic clock transitions in order to probe the Higgs-to-light-fermion couplings. Assuming state-of-the-art accuracy in frequency measurements in these systems, the sensitivity of the proposed method surpasses that of the LHC experiments.
Speaker: Dr Cedric Delaunay (LAPTH)
• Young Scientist Forum: #3
• 54
Measurements of Zgamma and Zgammagamma Production in pp Collisions at 8 TeV with the ATLAS Detector
The production of Z bosons with one or two isolated high energy photons is studied using pp collisions at 8 TeV. The analyses use a data sample with an integrated luminosity of 20.3 $fb^{-1}$ collected by the ATLAS detector during the 2012 LHC data taking. The $Z\gamma$ and $Z\gamma\gamma$ production cross sections are measured with leptonic (ee, $\mu\mu$, $\nu\bar{\nu}$) decays of the Z boson, in extended fiducial regions defined in terms of the lepton and photon acceptance. They are then compared to cross-section predictions from the Standard Model where the sources of the photons are bremsstrahlung from the initial state quarks or final state charged leptons. The yields of events with photon transverse energy $E_T$ > 250 GeV from $ll\gamma$ events and with ET > 400 GeV from $\nu\bar{\nu}\gamma$ events are used to search for anomalous triple gauge-boson couplings $ZZ\gamma$ and $Z\gamma\gamma$. The yields of events with diphoton invariant mass $m_{\gamma\gamma}$ > 200 GeV from $ll\gamma\gamma$ events and with $m_{\gamma\gamma}$ > 300 GeV from $\nu\bar{\nu}\gamma\gamma$ events are used to search for anomalous quartic gauge-boson couplings $ZZ\gamma\gamma$ and $Z\gamma\gamma\gamma$. No deviations from Standard Model predictions are observed and limits are placed on parameters used to describe anomalous triple and quartic gauge-boson couplings.
Speaker: Mr Evgeny Soldatov (National)
• 55
Confronting the improvements to track reconstruction algorithms for the ATLAS Inner Detector with Run-2 data from the LHC
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Speaker: Mr Roland Jansky (University of Innsbruck)
• 56
Totally asymptocally free trinification
Reinterpreting the naturalness principle, we address the hierarchy problem, proposing a phenomenologically interesting extension of the SM with a gauge group $SU(3)_L\otimes SU(3)_R\otimes SU(3)_c$, such that all the gauge, Yukawa and quartic couplings can be extrapolated up to infinite energy. We analyze which set of scalar or fermionic particles are needed to accomplish this goal. Finally, we consider the predictions of these models about the recently measured diboson and diphoton anomalies.
Speaker: Mr Giulio Maria Pelaggi (Università di Pisa &amp; INFN)
• 57
Vertex identification in the search for the Higgs boson decaying to two photons
A search for a Higgs boson decaying to two photons has been performed by the CMS Collaboration at the LHC experiment using pp collisions at a center-of-mass energy of 13TeV with an integrated luminosity of 2.6/fb. In the decay of the Higgs boson into two photons, the unconverted final state photons are not detected in the tracker, so the determination of the associated primary vertex is not trivial. Moreover, the CMS ECAL has no longitudinal segmentation, it is thus not a pointing calorimeter. The information from the recoiling tracks, and, when at least one of the photons is converted in the tracker, from the conversion tracks can be used to determine the primary vertex. The vertex identification algorithm used in the search for the Higgs boson decaying to two photons is described in this presentation, together with its performance.
Speaker: Ms Inna Kucher (CEA Saclay)
• 58
Probing Neutrino Mass Models with Trilepton Events at the LHC
In this work, we search for lepton flavor violation (LFV) interactions in the final $\ell_{\alpha}^{\pm }\ell_{\beta}^{\pm}\ell_{\gamma}^{\mp}+E_{miss}$ where ${\alpha}$, ${\beta}$, ${\gamma}$= $e,\mu,\tau$. This final state can be achieved via the production of singlet charged scalar $S^{\pm}$ in many neutrino mass models taking into account the allowed regions of masses and Yukawa couplings for the charged scalar. Our work is performed at both $\sqrt{s}$= 8 TeV and $\sqrt{s}$ = 14 TeV at the hadron collider LHC.
Speaker: Ms DOUNIA CHERIGUI (USTO)
• Wednesday, March 16
• The Scalar Sector
• 59
QCD corrections at N3LO review
Speaker: Giulia Zanderighi (University of Oxford)
• 60
BEH scalar @ 13 TeV in gamgam, ZZ, WW final states
The latest studies on the decays of the recently discovered BEH Scalar into bosons are presented: to pairs of W's, Z's, and photons. These results include the latest data from the CMS and ATLAS experiments, collected from 13 TeV LHC Run 2 in 2015. Although data collected is thus far limited, the continuation and extension of these studies through the rest of Run 2 will allow detailed comparisons of the BEH Scalar's properties with those predicted by the Standard Model.
Speaker: Dr Seth Zenz (Imperial College London)
• 61
BEH fermionic decays and combination at LHC@13TeV
Since the discovery of a Higgs-like boson by the ATLAS and CMS experiments at the LHC, the emphasis has shifted towards measurements of its properties and the search in the less sensitive channels in order to determine whether the new particle is the Standard Model (SM) Higgs boson. Of particular importance is the direct observation of the coupling of the Higgs boson to fermions. In this presentation a review of ATLAS and CMS results in the search for the Higgs boson in muon, tau-lepton, b-quark pair decay channels will be given. Moreover, the searches for lepton flavor violating decays will be presented.
Speaker: Dr Lidia Dell'Asta (Boston University)
• 62
H Effective Theory: Signs of deviations from the SM
Speaker: Aneesh Manohar (University of California, San Diego)
• 10:05 AM
break
• 63
Flavour violating couplings of the Standard Model scalar boson
We discuss the possibility that the Standard Model scalar boson $H$ couples to quarks and leptons in a flavour violating manner. Such flavour off-diagonal couplings can arise for instance in Two Higgs Doublet Models, or more generally in any model with more than one source of electroweak symmetry breaking. In the first part of the talk, we summarize constraints from low-energy experiments, in particular from rare decay searches and neutral meson oscillations. In the second part, we discuss LHC searches, focusing in particular on the final state $H \to \mu \tau$, in which CMS has observed a $2\sigma$ fluctuation, on the related decay $H \to e \tau$, and on couplings of the form $Htc$ and $Htu$ in the quark sector. We propose search strategies for several novel signatures associated with flavour changing $H$ couplings and estimate their sensitivity.
Speaker: Mr Joachim Kopp (University of Mainz)
• 64
Results and prospects for ttH at CMS
First 13 TeV results on the searches for the production of the Higgs boson in association with a top quark pair in the CMS experiment are presented.
Speaker: Dr Johannes Hauk (DESY)
• Beyond SM: (morning)
• 65
Long-Lived Colour-Triplet Scalars from Unnaturalness
Long-lived, colour-triplet scalars are a prediction of unnatural, or split, composite Higgs models where the spontaneous global-symmetry breaking scale f≳10 TeV and an unbroken SU(5) symmetry is preserved. Since the triplet scalars are pseudo Nambu-Goldstone bosons, they are split from the much heavier composite-sector resonances and are the lightest exotic, coloured states. Due to discrete symmetries and the large suppression scale f, the triplet scalar is often metastable. We show that existing searches for collider-stable R-hadrons from Run-I at the LHC forbid triplet scalars below 845 GeV. In the future with 300/fb at 13 TeV, triplet scalar masses up to 1.4 TeV can be discovered, whereas for shorter lifetimes displaced-vertex searches provide a discovery reach of up to 1.8 TeV. Just like the role of long-lived gluinos in supersymmetry, long-lived color-triplets will therefore provide a sign of unnaturalness in composite Higgs models.
Speaker: Tony Gherghetta (University of Minnesota)
• 66
Extended scalar search @13TeV in ATLAS and CMS
The search for extended scalars is an important aspect of the search for physics beyond the Standard Model. New scalar particles are predicted in models with extended Higgs sectors, such as Two-Higgs-Doublet Models, among others. This presentation will feature the latest results for ATLAS and CMS in the search for new scalar particles, including searches with a variety of production mechanisms and final states.
Speaker: Dr Allison McCarn (University of Michigan)
• Beyond SM: (afternoon)
• 67
Nonconventional final states at 13 TeV
A review of the nonconventional final-states searches performed by both ATLAS and CMS experiments is presented. Detailed results based on data collected during pp collisions at sqrt(S) = 13 TeV are shown, as well as a brief summary of the currently under-construction searches with sqrt(S) = 8 TeV data runs conclusions.
Speaker: Dr Revital Kopeliansky (Indiana University)
• 68
Non-universal Z' models with protected flavour-changing interactions
We define a new class of Z′ models with neutral flavour-changing interactions at tree level in the down-quark sector. They are related in an exact way to elements of the quark mixing matrix due to an underlying flavoured U(1)′ gauge symmetry, rendering these models particularly predictive. The same symmetry implies lepton-flavor non-universal couplings, fully determined by the gauge structure of the model. Our models allow to address presently observed deviations from the SM and specific correlations among the new physics contributions to the Wilson coefficients $C^{(\prime)\ell}_{9,10}$ can be tested in $b\to s\ell^+\ell^-$ transitions. We furthermore predict lepton-universality violations in Z′ decays, testable at the LHC.
Speaker: Dr Martin Jung (TUM Excellence Cluster Universe)
• 69
High-pT multi-jet final states at ATLAS and CMS @13 TeV
The increase of the centre-of-mass energy of the Large Hadron Collider (LHC) to 13 TeV has opened up a new energy regime. Final states including high-momentum multi-jet signatures often dominate beyond standard model phenomena, in particular as decay products of new heavy particles. While the potential di-photon resonance currently receives a lot of attention, multi-jet final states pose strong constraints on what physics models this observation could actually be. In this presentation, the latest results of the ATLAS and CMS collaborations in high-momentum multi-jet final states are presented. This includes searches for heavy resonances and new phenomena in the di-jets mass spectrum, di-jet angular distributions, and the sum of transverse momenta in different event topologies. Furthermore, results on leptoquark pair production will be shown. Particular focus is laid on the different background estimation methods.
Speaker: Clemens Lange (University of Zurich)
• 70
Vacuum stablility and SUSY at high scales with 2 H doublets
In this talk I consider two-H doublet models (THDMs) with a supersymmetric UV completion. Contrary to the Standard Model, THDMs can be embedded in high-scale supersymmetry with a SUSY breaking scale as high as the scale of grand unification. The stability of the electroweak vacuum and experimental constraints point towards low values of tan(beta) < 2 and a pseudoscalar mass of at least about a TeV. If the higgsino superpartners of the H fields are also kept light, the conclusions are similar and essentially independent of the higgsino mass. However, if all gauginos are also given electroweak-scale masses (split supersymmetry with two H doublets), the predicted Standard Model-like H boson mass is always too large. Light neutral and charged higgsinos emerge as a promising signature of minimal theories with supersymmetric UV completions at high scales, and can be searched for at colliders.
Speaker: Dr Felix Bruemmer (LUPM Montpellier)
• 6:20 PM
break
• 71
0-lepton SUSY Searches from ATLAS and CMS
Recent searches for Supersymmetric particles using the ATLAS and CMS experiments in channels requiring jets and missing transverse energy will be described.
Speaker: Dr Christopher Young (CERN)
• 72
High pt lepton final states @13TeV in ATLAS and CMS
Speaker: James Catmore (University of Oslo)
• 73
SUSY and the ATLAS Missing Et Excess
We demonstrate that the 3σ excess observed by ATLAS in the Z+MET channel at 8 TeV can be explained within the context of the MSSM. Using the freedom inherent in the pMSSM, we perform a detailed analysis of the parameter space and find a scenario that describes the excess while simultaneously complying with all other search constraints from the Run I data at 7 and 8 TeV, including the Z+MET analysis by CMS. We generate a small sample of simplified models, using promising models from our existing pMSSM sample as seeds, and study their properties. The successful region is described by the production of 1st/2nd generation squark pairs, followed by their decay into a bino-like neutralino which in turn decays into a Higgsino-like LSP triplet by emitting a Z boson, i.e., ˜q → B˜ → h˜ with ˜q = Q˜L, u˜R, or ˜dR. The sweet spot for the sparticle spectrum is found to have squark masses in the 500-750 GeV range, with bino masses near 350 GeV with a mass splitting of 150-200 GeV with the Higgsino LSP. If this excess holds, then this scenario predicts that a signal will be observed in the 0l+jets and/or 1l+jets searches in the early operations of Run II. Further implications of this scenario will be discussed.
Speaker: Dr Thomas Rizzo (SLAC)
• Young Scientist Forum: #4
• 74
Search for A to Zh(bb) in ATLAS at 13 TeV
A search for a heavy, CP-odd Higgs boson, A, decaying into a Z boson and a CP-even Higgs boson, h, with a mass of 125 GeV is performed using the ATLAS detector at the Large Hadron Collider. The search uses proton–proton collision data at a centre-of-mass energy of 13 TeV corresponding to an integrated luminosity of 3.2 /fb. Decays of h bosons to bb pairs, where the resulting hadronic jets can be resolved or are merged in the detector, are both considered. Final states of the Z boson decaying to a pair of charged leptons, Z → e+e− and Z → μ+μ−, or into neutrinos, Z → νν, are considered. The data are used to determine 95% confidence level upper limits on the product of production cross-sections and branching fractions, σ(pp → A)·BR(A → Zh)·BR(h → bb) for mA = [200,2000] GeV assuming gluon-fusion or b-quark-associated exclusive production. Results are also interpreted in the context of benchmark models for a two-Higgs doublet extension of the Standard Model.
Speaker: Mr Carlo Pandini (LPNHE)
• 75
Linear sigma model for the composite H -- experimental tests
In order to explore a possible dynamical nature for the Higgs field (such as its being a pseudogolsdtone boson) we develope a renormalizable Lagrangian based on the minimal SO(5) linear σ-model with the symmetry softly broken to SO(4), including gauge bosons and fermions. We then present the phenomenological implications and constraints from precision observables and the impact on present and future LHC data.
• 76
Search for heavy fermionic top partners decaying to same-sign dileptons at 13 TeV
With the discovery of the Higgs Boson during Run 1, one of the most important questions to answer during Run 2 is the naturalness problem. Composite Higgs theories answer the naturalness problem by regulating the quadratic divergences to the mass of the Higgs boson via fermionic top partners. Often predicted in such models is a top partner with charge 5e/3 which can decay to the extremely clean same-sign dilepton final state. Further, such a particle is typically the lightest of the top partners predicted and hence represents a very well motivated search. Results using 2.2 /fb of data from the CMS experiment at 13 TeV will be presented.
Speaker: Mr Clint Richardson (Boston University)
• Thursday, March 17
• Beyond SM: (cntd morning)
• 77
Final states with 3rd generation quarks @13 TeV in ATLAS and CMS
Speaker: Pieter Everaerts (University of California, Los Angeles)
• 78
An elementary Goldstone Higgs
We show, via a careful analytical and numerical analysis, that a pseudo Goldstone nature of the Higgs is naturally embodied by an elementary realization that also serves as ultraviolet completion. Renormalizability married to perturbation theory allows to precisely determine the quantum corrections of the theory while permitting to explore the underlying parameter space. By characterising the available parameter space of the extended Higgs sector we discover that the preferred electroweak alignment angle is centred around θ ≃ 0.02, corresponding to the Higgs chiral symmetry breaking scale f ≃ 14 TeV. The latter is almost 60 times higher than the Standard Model electroweak scale. However, due to the perturbative nature of the theory, the spectrum of the enlarged Higgs sector remains in the few TeV energy range. We also analyse precision constraints and the relevant phenomenological aspects of the theory.
Speaker: Dr Aurora Meroni (CP3-Origins, SDU)
• 79
H Effective Theory and the Geometry of Scalar Field Space
A geometric formulation of Higgs Effective Field Theory (HEFT) is presented. Experimental observables are given in terms of geometric invariants of the scalar sigma model sector such as the curvature of the scalar field manifold.
Speaker: Elizabeth Jenkins (UCSD and CERN)
• 80
Searches for supersymmetry in events with one or more leptons using the ATLAS and CMS experiments
Recent results from searches for supersymmetry in final states with one or more leptons by the ATLAS and CMS collaborations are reported. The data for these results have been recorded in 2015 at √s = 13 TeV and amount to an integrated luminosity of 2.2 − 2.3 fb−1 for the CMS experiment and 3.2 fb−1 for the ATLAS experiment. The results are interpreted in simplified models.
Speaker: Henning Kirschenmann (CERN)
• 9:55 AM
break
• 81
Searches for Boosted Di-Bosons Resonances with the ATLAS and CMS detectors
Resonant production of two electroweak gauge bosons (WW, WZ, ZZ) is an important signature for physics beyond the Standard Model and various possibilities resulting in such signatures have been proposed, e.g, Extended Gauge Models with heavy charged/neutral bosons (W’, Z’), bulk Randall-Sundrum excitation of the graviton (G*) in extra dimensions. Similarly the resonant production of a W or Z gauge boson with a SM Higgs boson or of two Higgs bosons is predicted in various new physics scenario. Searches for such high-mass resonances can obtain a significant sensitivity gain by exploiting techniques to identify hadronic decay of boosted W, Z or Higgs bosons. This presentation summarizes the ATLAS and CMS searches for di-bosons resonances in final states including hadronic jets and leptons with boosted boson tagging techniques.
Speaker: Dr Massimiliano Bellomo (University of Massachusetts Amherst)
• 82
Scalar Hint from the Diboson Excess?
The diboson resonant excesses reported by both ATLAS and CMS Collaborations in Run 1, can be interpreted a new weak singlet pseudoscalar particle η_WZ which may decay into two weak bosons while being produced in gluon fusion at the LHC. The couplings to the gauge bosons can arise from a Wess-Zumino-Witten anomaly term and thus we study an effective model based on the anomaly term as a well motivated phenomenological model. In models where the pseudoscalar particle arises as a composite state, the coefficients of the anomalous couplings can be related to the fermion components of the underlying dynamics. We provide an example to test the feasibility of the idea.
Speaker: Prof. Aldo Deandrea (IPNL)
• 83
LR models and dibosons
Speaker: JoAnne Hewett (SLAC National Accelerator Laboratory)
• 84
Combination of Run1 anomalies @ high mass and summary of Run2 observations
In this talk, a few examples of anomalies in the ATLAS & CMS Run I searches will be discussed, in connection with the corresponding preliminary results at 13 TeV. The agreement between the two experiments will be assessed, and the compatibility with the new results will be discussed. The talk will serve as an opportunity to stimulate a discussion on where the search for new physics at the LHC stands, in view of the 2016 Run and the perspective of integrating up to 15 times more data.
Speaker: Maurizio Pierini (CERN)
• Beyond SM: (cntd afternoon)
• 85
Diphoton searches in ATLAS
Diphoton searches in ATLAS
Speaker: Marco Delmastro (LAPP)
• 86
Diphoton Searches in CMS
Speaker: Pasquale Musella (ETH Zurich - Institute for Particles Physics)
• 87
Interpreting the 750 GeV digamma excess: a review
I review studies of theoretical implications of the new possible resonance at 750 GeV.
Speaker: Alessandro Strumia (Pisa Univ & INFN & CERN)
• 6:30 PM
break
• Celebrating the 50th Moriond
• 88
Moriond 50th anniversary
Speaker: Jacques Lefrançois (LAL Orsay)
• 89
Moriond 50th anniversary
Speaker: Prof. JEAN ILIOPOULOS (LPTENS)
• Friday, March 18
• DM & Cosmology: (morning)
• 90
Dark Matter Overview
The **complementarity of direct, indirect and collider** searches for dark matter has improved our understanding concerning the properties of the dark matter particle. We will **review the basic concepts** that these methods rely upon and highlight what are the most important information they provide when it comes down to interpret the results in terms of Weakly Interacting Massive Particles (WIMPs). Later, we go over some of the latest results emphasizing the implications to dark matter theory in a broad sense. Lastly, we point out **recent developments and prospects in the field**.
Speaker: Dr Farinaldo Queiroz (Max Planck Institute for Nuclear Physics)
• 91
Recent nucleon decay searches at the Super-Kamiokande experiment.
Proton decay is a defining prediction of Grand Unified Theories (GUTs). It provides a unique test of energies around $10^{(14-16)}$ GeV, which are unreachable by accelerators and which could also be connected with other physics such as neutrino masses. We will present results of recent nucleon decay searches at the Super-Kamiokande experiment. Analyses of typically dominant non-SUSY and SUSY decay modes $p \rightarrow (e^+,\mu^+)\pi^0$ and $p\rightarrow \nu K^+$, $n - \overline{n}$ oscillations as well as more exotic channels such as $p \rightarrow(e^+,\mu^+)\nu \nu$, $p \rightarrow(e^+,\mu^+)X$, $p\rightarrow(e^+,\mu^+,\tau^+)\nu\nu$ will be discussed. Some of these searches are novel. The analyses set world best limits which circumvent the allowed parameter space of theoretical models.
Speaker: Volodymyr Takhistov (University of California, Irvine)
• 92
Results from the second CDMSlite run and plans for SuperCDMS
Gravitational effects observed at different astronomical scales indicate that ~85% of the matter content of the Universe consists of dark matter (DM), whose particles properties remain unknown. Weakly-interacting massive particles (WIMPs) are a well-motivated class of DM candidates, that in some models have typical masses between 1 and 10 GeV. The purpose of the Super Cryogenic Dark Matter Search (SuperCDMS) experiment is to detect galactic WIMPs scattering off germanium nuclei from a 9.2 kg target arranged in fifteen single-crystal detectors. It has been operating at Soudan Underground Laboratory between March 2012 and December 2015. The latest result from the experiment exploits the potential of SuperCDMS to search for low-mass WIMPs using an operation mode called CDMSlite, that enables to set an energy threshold substantially lower than that for nominal operation conditions. This is the second result based on CDMSlite, and it improves the previous measurement by using a lower energy threshold and including some background rejection. This result is competitive with other direct DM searches, and probes new parameter space for WIMP masses between 2 and 5 GeV. The SuperCDMS Collaboration is currently designing a more sensitive experiment that will be operating at SNOLAB. The new experiment is planned to start taking data around 2020, and it is expected to offer a world-leading sensitivity to low-mass WIMPs.
Speaker: Mr Elias Lopez Asamar (Durham University)
• 93
Search for low mass WIMPs with CRESST
In recent years growing interest in low mass dark matter particles can be noted. Cryogenic experi­ments like CRESST are well suited to search for low mass WIMPs with masses in the GeV and sub GeV region. CRESST is based on the phonon/light technique and uses scintillating CaWO$_4$ crystals as target material. CRESST-II, which stopped data taking in July 2015, allowed an accurate measurement of recoil energies down to 300 eV using a 300 g CaWO$_4$ crystal. The upcoming phase CRESST-III is designed to measure energies well below 100 eV, mostly by using about 12 times smaller target crystals with optimized phonon sensors. Given the low energy threshold in com­bination with light target nuclei, low mass dark matter particles can be probed with high sensitivity. We will present the results obtained with CRESST-II, which extend the reach of direct dark matter experiments to the sub GeV region and demonstrate that the energy threshold is the key parameter in the search for low mass dark matter particles. In addition we give an outlook on the expected perfor­mance of the upcoming data taking of CRESST-III and the future potential for direct dark matter detection with further improved CaWO4 cryogenic detectors.
Speaker: Dr Franz Pröbst (Max-Planck-Institut für Physik)
• 9:55 AM
break
• 94
Status of Direct Dark Matter Search with XENON100 and XENON1T
Weakly interacting massive particles (WIMPs) are a very popular explanation for the nature of dark matter. The XENON100 experiment and its next generation the XENON1T experiment aim for detecting WIMP-nucleon interactions using a dual phase time projection chamber (TPC) with a total liquid xenon target of 161 kg and 3500 kg, respectively. This talk will present the most recent results of XENON100 where exclusion limits are set on several leptophillic dark matter models and on the event rate modulation of electronic recoils. Those results are in strong tension with models that explain the signal seen in the DAMA experiment by dark matter interacting exclusively with leptons. Furthermore, the commissioning status of the XENON1T experiment and its scientific potential will be presented. Major achievements in background reduction allow to reach a sensitivity improvement by two orders of magnitude with respect to XENON100.
Speaker: Ms Constanze Hasterok (Max-Planck-Institut fuer Kernphysik)
• 95
Sensitivity to light weakly-coupled new physics at the precision frontier
Precision measurements in particle physics are often used to infer information about New Physics at some ultraviolate scale. In my talk, I explore the alternative route: new weakly-coupled physics in the IR, inducing deviations for the precision experiments. I give a classification to the precision measurements (EDMs, lepton flavour violation, g-2, quark flavour etc) as to whether they provide the senstivity to new physics in the UV, IR or both.
Speaker: Dr maxim pospelov (university of victoria)
• 96
Recent results on dark matter searches from the LUX collaboration and status of the LZ experiment.
The direct detection of dark matter – accounting for 85% of the mass content of the Universe – is one of the most important scientific missions of the 21st century and any discovery will provide an incontrovertible signature of physics beyond Standard Model. Weakly interacting massive particles (WIMPs) that arise naturally in several models are compelling candidates. The LUX experiment is a liquid xenon time projection chamber (TPC), operating in the Davis Cavern of the Sanford Underground Research Facility (South Dakota, USA) at 1.5 km underground. We present the re-analysis of the 2013 data sample. Exploiting several advances in the analysis tools, simulation and calibration, we set the most stringent constraint on spin-independent WIMP-nucleon interaction, improving the sensitivity to low-mass WIMPs compared to our previous results, and excluding cross section down to 0.6 zb at 90% CL for 33 GeV WIMP mass. New constraints on spin-dependent WIMP-neutron and -proton cross sections based on the same data sample will be also presented. The LUX-ZEPLIN experiment, to be located at the SURF facility after LUX data taking completion, is a next-generation instrument, featuring a 7-tonne active xenon TPC, surrounded by two outer detectors which can be used as veto systems for further background rejection. This makes LZ unique compared to its direct competitors. We present the status of the project and the physics reach.
Speaker: Dr Paolo Beltrame (University of Edinburgh)
• 97
Probing dark matter at the LHC through weakly interacting mediators
Searches for direct interactions of dark matter with standard-model particles at colliders are challenging and often constrained by direct detection experiments. However, many scenarios predict mediator particles with electroweak interactions, which could well be in reach of collider experiments. Focusing on Higgs-portal models with fermion dark matter, I will present the search strategies and prospects to find such mediators at the LHC. Connections with direct detection experiments and the observed dark-matter relic abundance will also be discussed.
Speaker: Dr Susanne Westhoff (Heidelberg University)
• DM & Cosmology: (afternoon)
• 98
Cosmological relaxation of the electroweak scale
Recently, a new mechanism to generate a naturally small electroweak scale has been proposed, the so-called "relaxion" . It exploits the coupling of the Higgs to an axion-like field and a long era in the early universe where the axion unchains a dynamical screening of the Higgs mass. We present a new realization of this idea with the new feature that it leaves no signs of new physics up to a rather large scale, 10^9 GeV, except for two very light and weakly coupled axion-like states. One of these scalars can be a viable Dark Matter candidate. Such a cosmological Higgs-axion interplay could be tested with a number of experimental strategies.
Speaker: Prof. Jose Ramon Espinosa (ICREA/IFAE)
• 99
Neutrinos from Cosmology
Since the breakthrough discovery that neutrinos are massive (2015 Nobel Prize in Physics and 2016 Breakthrough Prize in Fundamental Physics), pinpointing their total mass has become one of the greatest challenges in science today, at the cross-road between particle physics, astrophysics, and cosmology. After an introduction on the impact of massive neutrinos in structure formation, with a particular focus on the Lyman-α forest, I will present a novel method based on a combination of analytic techniques and state-of-the-art hydrodynamical simulations, which allows one to obtain competitive constraints on the number of effective neutrino species and the sum of neutrino masses from cosmology - in synergy with available data from the SDSS and additional CMB probes. Our results provide strong evidence for the cosmic neutrino background, and rule out the possibility of a sterile neutrino thermalized with active neutrinos at a significance of over 5σ – one of the strongest bounds to date. Finally, I will discuss the complementarity with particle physics experiments, along with possible interdisciplinary efforts.
Speaker: Prof. Graziano Rossi (Sejong University)
• 100
Results from the first science run of advanced GW detectors
On September 14, 2015 at 09:50:45 UTC the two LIGO detectors simultaneously observed a transient gravitational-wave signal. The signal matches the waveform predicted by general relativity for the inspiral and merger of a pair of black holes and the ringdown of the resulting single black hole. It was observed with a matched-filter signal-to-noise ratio of 24 and a false alarm rate estimated to be less than 1 event per 203000 years, equivalent to a significance greater than 5.1 sigma. The source lies at a luminosity distance of 410 Mpc corresponding to a redshift z=0.09. In the source frame, the initial black hole masses are 36 Msol and 29 Msol, and the final black hole mass is 62 Msol, with 3.0 Msol c^2 radiated in gravitational waves. These observations demonstrate the existence of binary stellar-mass black hole systems. This is the first direct detection of gravitational waves and the first observation of a binary black hole merger.
Speaker: Dr Alessio Rocchi (INFN Roma Tor Vergata)
• 101
Binary black hole merger
Speaker: Mr Alessandro Nagar (IHES)
• 6:30 PM
break
• 102
Generic search for Dark Matter at LHC 13TeV
Speaker: Matteo Cremonesi (FNAL)
• 103
From Composite Higgs to the not so SIMPle miracle
Speaker: Francesco Sannino (CP3-Origins)
• Young Scientist Forum: #5
• 104
An Inclusive Search for Supersymmetry in the CMS Experiment:  Challenges and Methods for the All-Hadronic Jets + MET Final State
We present results from a generic search for strongly-produced supersymmetric particles in pp collisions in the multijet + missing transverse momentum final state. The data sample corresponds to 2.3 fb$^{-1}$ recorded by the CMS experiment at $\sqrt{s}=13$ TeV. This search is highly motivated by both theoretical and experimental considerations. In supersymmetry (SUSY) theories disfavoring fine-tuning of the Higgs mass, strongly-produced SUSY particles, including the gluino and top squark, are predicted to have masses on the order of a TeV. These particles also have some of the highest production cross sections in SUSY and give rise to final states with distinct, high jet multiplicity event signatures. To make the analysis sensitive to a wide range of such final states, events are classified by the number of jets, the scalar sum of the transverse momenta of the jets, the vector sum of the transverse momenta of the jets, and the number of b-tagged jets. The tails of the distributions of these variables make up a region of extreme kinematics for the significant standard model (SM) backgrounds. As these distributions are difficult to model in simulation, we model them using dedicated techniques and control regions in data for each background process. No significant excess is observed beyond the SM expectation. The results are interpreted as limits on simplified SUSY models. In these models, gluinos with masses as high as 1600 GeV are excluded at 95% CL for scenarios with low $\tilde{\chi}_{1}^{0}$ mass, exceeding the limits set in Run I by more than 200 GeV.
Speaker: Mr John Bradmiller-Feld (UC Santa Barbara)
• 105
A Search for Monoenergetic Neutrinos from Dark Matter Decay
In 2013, the IceCube experiment brought to light the existence of a flux of very high energy neutrinos. The origin of those neutrinos was shown to be extraterrestrial, as they do not fit atmospheric backgrounds at high energy. Still, where those neutrinos are exactly sourced from remains to this day an open question. In the context of dark matter searches, the discovery of a neutrino line would provide a smoking gun for the existence of the dark matter particle. We propose to review a search for this spectral feature using IceCube data. No significant hint was found in the analysed dataset. Yet, a very strong improvement of the limits was attained, which makes it worth discussing how these limits now compare to the ones obtained with gamma lines, the other possible smoking gun for dark matter.
Speaker: Ms Chaimae EL AISATI (Universite Libre de Bruxelles)
• 106
Non-linear H portal to Dark Matter
The Higgs portal to scalar Dark Matter is considered in the context of non-linearly realised electroweak symmetry breaking. We determine the dominant interactions of gauge bosons and the physical Higgs particle h to a scalar singlet dark matter candidate. Phenomenological consequences are also studied in detail, including the possibility of distinguishing this scenario from the standard Higgs portal in which the electroweak symmetry breaking is linearly realized. This new context deeply affects the dark matter relic abundance, as well as the expected signals in direct and indirect searches and collider phenomenology, where Dark Matter production rates are enhanced with respect to the standard portal.
Speaker: Mrs Rocío del Rey Bajo (UAM - IFT)
• 107
Probing Neutrino Mass Models at the LHC through pp--> l^+ l^- +E_{miss}
In this work, we investigate the possibility of probing a class of three-loop models for neutrino mass at the LHC with 8 and 14 TeV energies. The existence of lepton flavor violating interactions for singlet charged scalar, S±, that couples to the leptons could induce many processes such as pp -> ℓ± ℓ∓ E_{miss}. Using the processes with ℓ ℓ = ee, eμ, μμ, we found that an inclusive cut on the MT2 event variable is vital and leads to an effective suppression of the large SM background. Our results show possible detectability of the charged scalars effect, especially at the LHC@14.
Speakers: Mrs chahrazed guella (université des sciences et de la technologie mohamed boudiaf oran (algérie)) , Ms dounia cherigui (université des sciences et de la technologie mohamed boudiaf oran (algérie))
• Saturday, March 19
• Summaries
• 108
Experimental summary
Speaker: Andreas Hoecker (CERN)
• 109
Therory summary
Speaker: Mr Alex Pomarol (CERN & Universitat Autonoma de Barcelona)