M.
Frédéric Dreyer
(LPTHE)
15/01/2015 09:25
As hadron collider physics continues to push the boundaries of precision, it becomes increasingly important to have methods for predicting properties of jets across a broad range of jet radius values R, and in particular for small R.
In this presentation we will start with a brief review of jet physics at hadron colliders, and introduce a method to resum all leading logarithmic terms,...
M.
Renaud Boussarie
(LPT Orsay)
15/01/2015 09:39
We present the calculation of the impact factor for the photon to quark, antiquark and gluon transition within Balitsky's high energy OPE. We also rederive the impact factor for photon to quark and antiquark transition within the same framework. These results provide the necessary building blocks for further phenomenological studies of inclusive diffractive DIS as well as for two and three...
Ou Zhang
(University of Arizona and IPN-Orsay)
15/01/2015 09:53
Soft radiation consists of coherent low energy gluons that interact with initial and final state jets at wide angles from the jet axis, and we show that this soft radiation in ee, ep and pp collisions is universal to order $\alpha_s^2$ in perturbation theory. We factor this soft radiation out of the multi-scale cross-section using Soft Collinear Effective Theory, which is an effective field...
24.
Quarkonia suppression in a quark-gluon plasma produced in heavy ion collisions at high energies.
M.
Roland Katz
(Subatech)
15/01/2015 10:21
The theory of elementary particles predicts the existence of a new state of matter: the Quark-Gluon Plasma (QGP). The latter may have existed at the first moments of the Universe following the Big Bang and can be, in theory, re-produced in heavy ion collisions at high energy colliders (e.g. the LHC). One of the QGP possible observables is the suppression of the quarkonia (heavy...
M.
Cédric Mezrag
(IRFU/SPhN)
15/01/2015 11:05
If at high energy QCD can be described using perturbation theory due to asymptotic freedom, when going at low energy the fundamental degrees of freedom of the theory, quarks are gluons, are bounded inside hadrons. The hadron structure in terms of partons has been studied since the 1960s. Today several objects have been both theoretically and experimentally studied, like for instance...
M.
Xiu-Lei REN
(IPN Orsay)
15/01/2015 11:19
We study the ground-state octet baryon masses and sigma terms using the covariant baryon chiral perturbation theory (ChPT) with the extended-on-mass-shell (EOMS) renormalization scheme up to next-to-next-to-next-to-leading order (N$^3$LO). In order to systematically study the lattice QCD data and to fix the low-energy constants (LECs), the finite-volume corrections (FVCs) and finite lattice...
Laurent Lellouch
(CPT Marseille)
15/01/2015 11:33
The difference between the masses of the neutron and the proton is only 0.14% of their average. Yet this difference has important implications for the existence and stability of ordinary matter. After explaining how electromagnetic and mass isospin breaking effects can be included in lattice QCD computations, I will show how this mass difference arises from a subtle cancellation of these two...
Antoine Gérardin
(Laboratoire de Physique Corpusculaire (LPC))
15/01/2015 11:47
Computing the quark propagator on the lattice gets more and more difficult as the light quark becomes small and approach its physical value. Therefore, most simulations are performed at unphysical light quark masses and the results are extrapolated to the physical mass using fit formulae inspired by chiral perturbation theory. In the case of heavy-light mesons, one can use the Heavy Meson...
Savvas Zafeiropoulos
(Goethe Universitaet Frankfurt)
15/01/2015 12:01
We summarize recent analytical results obtained for the discretization effects of the non-Hermitian Wilson Dirac operator. We include the effect of all three leading low energy constants in our analysis. In particular we discuss the results for the eigenvalue densities close to the continuum limit but we also consider the case of large lattice spacing which is closely related to the mean field...
Elena Petreska
(CPHT - Ecole Polytechnique)
15/01/2015 12:29
The field configuration in the first moments of high-energy heavy-ion collisions is represented by strong longitudinal chromo-electric and chromo-magnetic fields. The form of these fields is obtained by solving the classical Yang-Mills equations of motion for two color charge sheets passing through each other with appropriate boundary conditions on the light cone. We calculate perturbatively...
Dr
Takashi Toma
(LPT Orsay)
15/01/2015 13:15
Gamma-ray generated by annihilation or decay of dark matter can be its smoking gun signature. In particular, gamma-ray coming from internal bremsstrahlung of dark matter is promising since it can be a leading emission of sharp gamma-ray. However if thermal production of Majorana dark matter is considered, the derived cross section for internal bremsstrahlung becomes too small to be observed by...
Dr
Lance Labun
(University of Texas, Austin)
15/01/2015 13:15
Locating the QCD critical point is the goal of several major heavy ion collision experiments, and it may be possible to see signatures of critical behaviour in event-by-event fluctuations of conserved charges. We show characteristic peaks in the third $\chi_3$ and fourth $\chi_4$ fluctuation moments of baryon number as a function of chemical potential (or center of mass energy) and how they...
M.
Lucien Heurtier
(CPHT, Ecole Polytechnique)
15/01/2015 13:15
Dr
Bradley Kavanagh
(IPhT Saclay)
15/01/2015 13:15
In order to analyse data from direct detection experiments, it has previously been necessary to make assumptions about the dark matter (DM) speed distribution. However, it has been shown that for a future discovery, poor astrophysical assumptions may lead to a bias in the reconstructed DM mass and cross section. I will present a completely general parametrisation of the speed distribution...
Sabine Kraml
(LPSC Grenoble)
15/01/2015 13:15
SModelS is an automatised public tool for the interpretation of so-called Simplified Model Spectra (SMS) results from the LHC. I will discuss the working principle of SModelS and present some applications to supersymmetric models.
Dr
Christian Torrero
(Centre de Physique Théorique (Université d'Aix-Marseille))
15/01/2015 13:15
Besides connecting the pion-nucleon and the kaon-nucleon amplitudes to the hadron spectrum, nucleon sigma terms play an important role in the direct detection of Dark Matter. A lattice computation will be outlined, preliminary results for the up-down and strange sigma terms will be presented and strategies to improve on their precision will be illustrated.
M.
Nicolas Deutschmann
(IPNL)
15/01/2015 13:15
One of the most interesting sectors to look for new physics at the LHC is that of the top quark, both for theoretical and phenomenological reasons. A number of possible final states involving the top have been considered by the experimental collaborations and they have successfully constrained many Beyond the Standard Model scenarios. In this presentation, I will describe a study intended to...
Jean-Baptiste Flament
(IPNL)
15/01/2015 13:15
As the LHC experimental collaborations have released results about the influence of the existence of the Higgs boson outside of its mass shell, interpreting it as a constraint on its total width, we propose a more model-independent way to recast these observations. We advocate for the use of the parametrisation previously introduced in hep-ph:0901.0927 and hep-ph:1210.8120 to use conjointly...
M.
Olcyr De Lima Sumensari
15/01/2015 13:15
Dr
Jérôme CHARLES
(CPT Marseille (UMR 7332))
15/01/2015 14:00
Dr
Michele Frigerio
(Laboratoire Charles Coulomb, CNRS)
15/01/2015 14:25
Dr
Cedric Weiland
(IFT UAM/CSIC)
15/01/2015 14:50
In previous works (JHEP03(2012)100, JHEP09(2012)015), we have highlighted that the Higgs and Z-mediated penguin diagrams contributing to lepton flavour violating (LFV) observables like $\tau \rightarrow \mu \mu \mu$ are strongly enhanced in the supersymmetric inverse seesaw model. It has recently been pointed out (Phys.Rev.D90(2014)013008) that an error in the literature for the Z-penguins...
M.
Luiz Henrique Vale Silva
(LPT)
15/01/2015 15:04
Left-Right Models (LRM) attempt at giving an understanding of the violation of parity (or charge-conjugation) by the weak interactions in the SM through a similar description of left- and right-handed currents at high energies. The spontaneous symmetry breaking of $ SU(2)_L \times SU(2)_R \times U(1)_{(B-L)} $ is usually triggered by an enlarged Higgs sector, usually consisting of two triplet...
Dr
Nicolas Garron
(University of Cambridge)
15/01/2015 15:18
Kaon physics provides us with highly-non trivial tests of the Standard Model and is a rich source of information for Beyond the Standard Model (BSM) phenomenology. CP violation is among the most intriguing phenomena in particle physics and is very well measured in kaon decays, but a complete and quantitative theoretical prediction is still missing. However, the RBC-UKQCD collaborations have...
Jean Orloff
(LPC Clermont, Univ. Blaise Pascal)
15/01/2015 16:35
Prof.
Aldo Deandrea
(IPNL)
15/01/2015 17:05
Prof.
Fawzi Boudjema
(LAPTH)
16/01/2015 09:00
Filippo Sala
(IPhT CEA-Saclay)
16/01/2015 09:25
The search for signs of more scalars is a primary task of current and future experiments.
In particular, in the next-to-minimal supersymmetric Standard Model, the extra Higgs bosons could well be the lightest new particles around. I will outline a possible overall strategy to look for the extra CP-even scalars, comparing the impact of measurements of the SM Higgs couplings with the direct...
Dr
Haiying CAI
(IPNL, Lyon)
16/01/2015 09:53
We focus on the possibility that the Higgs boson is a state which is either as a Pseudo Goldstone Boson of an effective Lagrangian description or as a composite state made of techini fermions. In this composite Higgs model, the symmetry breaking pattern is SU(4)/SP(4) and the light Higgs will further mix with a heavier techni-Higgs. We consider the constraints on the parameter space both from...
Dr
sylvain fichet
(ICTP/SAIFR)
16/01/2015 10:07
We discuss the discovery potential of light-by-light scattering at the LHC, induced by the SM and by new exotic charged particles. Our simulation relies on intact proton detection in the planned forward detectors of CMS and ATLAS. The full four-photon amplitudes generated by any electrically charged particles of spins 1/2 and 1, including the SM processes involving loops of leptons, quarks and...
Martin Gonzalez-Alonso
(IPN Lyon)
16/01/2015 10:21
EFTs are a useful tool to analyze and compare different New Physics searches. I'll discuss the interplay between low-energy beta decay experiments and LHC searches, the application to Higgs decay data and the limitations of the method when light new particles are present.
M.
Michel Tytgat
(ULB)
16/01/2015 11:05
I briefly discuss the current status of dark matter
phenomenology, with an emphasis on simple (or simplified) models
and their possible experimental signatures.
Marco Taoso
(IPhT Saclay/CEA)
16/01/2015 11:30
A GeV gamma-ray excess has possibly been individuated in Fermi-LAT data from the Galactic Center and interpreted in terms of Dark Matter annihilations, either in hadronic or leptonic channels. In order to test this tantalizing interpretation, we address two issues: (i) we improve the computation of secondary emission from DM, confirming it to be very relevant for determining the DM spectrum in...
Dr
Giorgio Arcadi
(LPT Orsay)
16/01/2015 11:44
We analyze some simple but general scenarios in which the interactions of a (fermionic) Dark Matter with Standard Model particles are mediated by a scalar/pseudoscalar or vector state. We discuss the impact of current Dark Matter searches, with particular focus on the interpretation of the recently reported gamma-ray excess. We will also illustrate the prospect of detection in next future experiments.
Dr
Cedric Delaunay
(LAPTH)
16/01/2015 12:12
Direct searches of neutralino dark matter in underground scattering experiments constitute a significant pressure on weak scale naturalness in the MSSM. The resulting neutralino fine-tuning is almost as severe as that arising from the heavy stops required by a125GeV Higgs boson. We analyse in an effective field theory framework the implication for neutralino fine-tuning of MSSM extensions...
Dr
ANDREAS GOUDELIS
(HEPHY - Vienna)
16/01/2015 12:26
The absence of BSM signals at the Large Hadron Collider and the strong cosmological evidence for dark matter (DM) have motivated a fairly model-independent Effective Field Theory (EFT) approach to describe the interactions of DM particles with the Standard Model. This approach is known to be both powerful, thanks to its simplicity, as well as subtle, due to its potential limitations. I will...
Dr
Scott Robertson
(LPT Orsay)
16/01/2015 14:25
Hawking radiation, despite being known to theoretical physics for 40 years, remains an elusive phenomenon. It also suffers, in its original context of gravitational black holes, from practical and conceptual difficulties. In order to gain better theoretical understanding and, it is hoped, experimental verification of Hawking radiation, much study is being devoted to laboratory systems which...
Prof.
Pascal Chardonnet
(Université de Savoie/LAPTH)
16/01/2015 14:39
According to theoretical models, massive stars with masses within the 100- 250 solar mass range should explode as pair-instability supernovae (PISNe). Since the first stars of the Universe are believed to be very massive, these supernovae should play a signicant role in the early stages of its history. But these stars represent the last unobserved population, owing to detection limits of...
Dr
Paolo Panci
(Institut d'Astrophysique de Paris)
16/01/2015 14:53
M.
Mathieu Boudaud
(LAPTh)
16/01/2015 15:07
The positron fraction in cosmic rays has been recently measured with
improved accuracy up to 500 GeV by the space-borne experiment AMS-02, and
it was found to be a steadily increasing function of energy, above 10 GeV.
This behaviour is in tension with standard astrophysical mechanisms, in
which positrons are secondary particles, produced in the interactions of
primary cosmic rays during...
M.
Stefano Magni
(Université Montpellier 2)
16/01/2015 15:21
The knowledge of the high velocity tail of the WIMP velocity distribution function has a strong impact on the way direct detection (DD) may constrain or discover light WIMPs in the GeV mass range. Recently, there have been important observational efforts to estimate the so-called Galactic escape speed at the position of the Earth, like for instance the analysis published in early 2014 by the...
Dr
Guillaume Bossard
(CPhT)
16/01/2015 16:05
I will review several recent important developments in high energy physics, including:
-Perturbative and non-perturbative results in supersymmetric non-abelian gauge theories (AdS / CFT, Localisation, non-Langrangian theories).
-Superstring and supergravity amplitudes, 3-loop amplitude in string theory, color kinematic duality and double copy, BMS symmetry and infrared behaviour.
-Black...
Prof.
Vincent RIVASSEAU
16/01/2015 16:30
We shall review briefly some current approaches to quantum gravity, focusing in particular on the recent progress on tensor-based models which sum over all discretized space-time geometries and can be shown renormalizable and asymptotically free.
26.
Renormalization Group Optimized Perturbation: some illustrations at zero and finite temperature.
Jean-Loic Kneur
(LCC Montpellier)
16/01/2015 16:50
We discuss our recently developed variant of the so-called optimized perturbation (OPT), 'RGOPT', consistently resumming renormalization group dependence generically for zero or finite temperature theories. It is illustrated with a rather precise determination of 1) the QCD basic scale and coupling from the pion decay constant $F_\pi$: $\alpha_S(m_Z)[\overline{MS}] \simeq 0.1174 \pm 0.002$;...
Dr
David Greynat
(Universita di Napoli and INFN)
16/01/2015 17:05
We will show how it is possible to implement a chiral symmetry breaking mechanism in soft-wall model of holographic QCD. By perturbing a dilaton potential, we show also that it is possible to reproduce the exact Operator Product Expansion and the spectrum of the vector-vector and axial-axial correlators in the Large-N$_c$ limit.
Dr
Bin Wu
(IPhT, CEA/Saclay)
16/01/2015 17:20
Nonequilibrium quantum field theory in the classical statistical approximation (CSA) has a broad range of applications to understanding thermalization of systems with a large occupation number both in cosmology and in ultra-relativistic heavy-ion collisions. In my talk, I would like first to give a brief introduction to the CSA in the $g^2\phi^4$ theory. Then, I will present our discovery of...
