Description
Conveners:
- Cรฉcile Caillol (CERN)
- Reina Camacho Toro (LPNHE)
- Joe Davighi (CERN)
- Benjamin Stefanek (IFIC Valencia)
Contact: eps-hep2025-conveners-T09-l@in2p3.fr
We present a model that extends the electroweak gauge symmetry of the Standard Model in a non-universal way to $SU(2)_{L}^{\prime}\times U(1)_X \times SU(2)_{L}^{q_3}\times SU(2)_R^{\ell^3}$. This symmetry is spontaneously broken to $SU(2)_L\times U(1)_Y$ near the TeV scale by a condensate of a new composite sector. Charging appropriately the fermionic degrees of freedom of the composite...
In the first part of the talk, we will introduce the main model building ideas, namely flavour non-universality and Higgs compositeness, that are central to our model, as well as the theoretical and experimental motivations for exploring these BSM avenues. In the second part of the talk, we present a flavour non-universal extension of the Standard Model combined with the idea of Higgs...
Results from the CMS experiment are presented for supersymmetry searches targeting so-called compressed spectra, with small mass splittings between the different supersymmetric partners. Such a spectrum presents unique experimental challenges. This talk describes the new techniques utilized by CMS to address such difficult scenarios and presents results based on these techniques.
A wide variety of searches for Supersymmetry have been performed by experiments at the Large Hadron Collider. In this talk, we focus on searches for Supersymmetric particles in events with missing energy signatures.
The direct production of electroweak SUSY particles, including sleptons, charginos, and neutralinos, is a particularly interesting area with connections to dark matter and the naturalness of the Higgs mass. The small production cross-sections and challenging experimental signatures, often involving compressed spectra, lead to difficult searches. This talk will highlight the most recent results...
Supersymmetry (SUSY) provides elegant solutions to several problems in the Standard Model, and searches for SUSY particles are an important component of the LHC physics program. Naturalness arguments favour supersymmetric partners of the gluons and third-generation quarks with masses light enough to be produced at the LHC. With increasing mass bounds on more classical MSSM scenarios other...
We discuss indirect probes of the MSSM at FCC-ee, with particular emphasis on the complementarity between single Higgs production and electroweak precision tests at the Tera-Z run. In addition to flavor-universal contributions to the STWY oblique parameters, we point out important flavor non-universal effects. An example of the latter is the heavy Higgs doublet, which gives tree-level shifts...
Many extensions of the standard model predict new particles with macroscopic lifetimes. Such particles produce different kinds of non-conventional signatures in the detector, for example, jets originating away from the primary proton-proton (pp) interaction vertex, known as displaced jets. Searches exploring the lifetime frontier using displaced jet signatures have become increasingly...
Various theories beyond the Standard Model predict new, long-lived particles with unique signatures involving jets, which are difficult to reconstruct and for which estimating the background rates is also a challenge. These include emerging jets, semi-visible, and soft unclustered energy patters. The talk will focus on the most recent results from ATLAS
The NA62 experiment at CERN, designed to measure the highly-suppressed decay $K^{+} \rightarrow \pi^{+}\nu\bar{\nu}$, has the capability to collect data in a beam-dump mode, where 400~GeV protons are dumped on an absorber. In this configuration, New Physics (NP) particles, including dark photons, dark scalars and axion-like particles, may be produced and reach a decay volume beginning 80~m...
Various theories beyond the Standard Model predict new, long-lived particles with unique signatures involving leptons or missing energy, which are difficult to reconstruct and for which estimating the background rates is also a challenge. These include displaced have neutral leptons, SUSY models involving displaced electron/muon pairs, heavy charged particles, and displaced vertices.. The talk...
In this talk, we revisit a class of lepton-flavor non-universal gauge extensions of the Standard Model that provide a compelling framework for generating neutrino masses and mixing angles via a high-scale seesaw mechanism, while ensuring exact proton stability to all orders in the effective field theory. This setup naturally accommodates minimal thermal leptogenesis, offering a robust...
The current Large Hadron Collider (LHC) data shows no clear indication of new physics yet and only incremental improvements are anticipated in the foreseeable future. LHC has been constraining TeV scale physics but new physics could be hiding below the electroweak scale. There are well-motivated dark matter models which predict a light mediator, coupled with Standard Model (SM) fermions and...
The new fully software-based trigger of the LHCb experiment operates at a 30 MHz data rate, opening a search window into previously unexplored regions of physics phase space. The BuSca (Buffer Scanner) project at LHCb acquires and analyzes data in real time, extending sensitivity to new lifetimes and mass ranges thanks to the recently deployed Downstream tracking algorithm. BuSca identifies...
The NuMI Off-Axis $\nu_e$ Appearance (NOvA) experiment is a long-baseline neutrino oscillation experiment primarily designed to study $\nu_e$, $\bar{\nu}_e$ appearance as well as $\nu_\mu$ and $\bar{\nu}_\mu$ disappearance in the energy range of $1 < E\nu < 4$ GeV. Interestingly, the NOvA far detector also records a non-negligible number of high-energy $\nu_e$ and $\bar{\nu}_e$ events in the...
The quest for new physics is a major aspect of the CMS experimental program. This includes a myriad of theoretical models involving resonances that can decay to massive bosons, photons, leptons or jets. This talk presents an overview of such analyses with an emphasis on new results and the novel techniques developed by the CMS collaboration to boost the search sensitivity. The searches are...
Though the Standard Model (SM) of particle physics has been a very successful theory in explaining a wide range of measurements, there are still many questions left unanswered such as incorporation of gravity into SM, neutrino masses, matter-antimatter asymmetry, supersymmetry, or existence of dark matter candidates. One of the possible solutions to address these challenges is the extension of...
The MEG II experiment at the Paul Scherrer Institute primarily aims to search for Physics beyond the Standard Model through the investigation of charged lepton flavor violation in the $\mu^+$ $\rightarrow$ $e^+ \gamma$ process.
However, it is also capable of searching for new particles.
We present a search for the X17, a hypothetical particle proposed to explain a resonant structure...
The PADME experiment at the Frascati National Laboratory of INFN has performed a
search for the hypothetical X17 particle, by observing the product of the collisions
of the positron beam from the DAฮฆNE LINAC on a diamond fixed target.
The beam energy has been varied in the range
265โ300 MeV, corresponding to values of โs between 16.4 and 17.5 MeV,
completely covering the the CoM...
The MEG II experiment, located at the Paul Scherrer Institute in Switzerland, operates with the highest continuous muon beam intensity currently achievable, reaching up to $10^8โ\,\,\mu^+/s$. The MEG II experiment has been dedicated for several years to the search for the charged lepton flavour violating (cLFV) decay $ \mu^+\to e^+\gamma $, setting the worldโs most stringent upper limits on...
The Electric Dipole Moment of the electron (eEDM) is typically investigated in experiments using paramagnetic molecules. However, the physical observable in these searches consists of a linear combination of CP-violating interactions, rather than the eEDM alone, which is commonly referred to as the equivalent EDM of the system. Assuming the presence of new CP-odd physics from heavy degrees of...
We present a discussion of model-independent contributions to the EDM of the electron.
We focus on those contributions that can emerge from an extended heavy scalar sector, and in particular we explore the decoupling limit of the aligned 2HDM.
In this model, Barr-Zee diagrams with a fermion loop produce logarithmically-enchanced contributions that are proportional to potentially large...
Future Electron-Positron Linear Collider Designs (ILC, CLIC, HALHF) offer high-energy, polarized beams and high-precision measurements. In the talk we discuss the impact of polarized beams for the detection of the Higgs couplings, CP-violation effects and Dark Matter candidates with respect to the model distinction in different Beyond the Standard Models (MSSM, 2HDMS, inflation models). The...
The electron-positron stage of the Future Circular Collider (FCC-ee) is a precision frontier factory for Higgs, electroweak, flavour, top quark, and QCD physics. It is designed to operate in a 91-km circular tunnel built at CERN, and will serve as the first step towards O(100 TeV) proton-proton collisions. In addition to an essential Higgs program, the FCC-ee offers unique and powerful...
Although the LHC experiments have searched for and excluded many proposed new particles up to masses in the TeV range, there are many scenarios that are difficult to address at a hadron collider. The linear collider facility, thanks to its staged running plan with different energy upgrade options, offers exciting new search possibilities. Reviewed in this talk are recent results, contributed...
Future e$^+$e$^-$ colliders provide a unique opportunity for long-lived particle (LLP) searches. We present a full simulation study of LLP searches using the International Large Detector (ILD), a detector concept for a future Higgs factory, with a gaseous time projection chamber as its main tracking device. Signatures of displaced vertices and kinked tracks are explored. We study challenging...
The Large Hadron electron Collider (LHeC) is the proposal to deliver electron-proton/nucleus collisions at CERN using the LHC hadron or nuclear beams and a 50 GeV electron beam from an Energy Recovery Linac (ERL) in racetrack configuration. While the 2021 update of its CDR [1] contemplated concurrent operation of electron-hadron and hadron-hadron collisions at the HL-LHC followed by standalone...
The direct pair-production of the superpartner of the $\tau$-lepton, the $\widetilde{\tau}$,
is one
of the most interesting channels to search for SUSY in:
the $\widetilde{\tau}$ is
likely to be the lightest of the scalar leptons,
and is one of the most experimentally challennging ones.
The current model-independent $\widetilde{\tau}$ limits come from LEP,
while limits obtained at the...
A Tera-Z factory, such as FCC-ee or CEPC, will have indirect sensitivity to heavy new physics up to the tens of TeV scale through higher-order loop contributions to precision measurements at the Z-pole. These provide complementary sensitivity to potential deviations from the Standard Model typically thought to best be constrained at leading order at higher energies above the Z-pole, leading to...
We explore the prospects of exclusive $W^+W^-$ production via
photon-photon fusion at the LHeC, operating at a center-of-mass energy
of 1.2 TeV [1]. Utilizing the clean experimental environment and high
luminosity of the LHeC [2,3], this process could provide a powerful
probe of electroweak interactions and possible deviations from SM,
particularly through anomalous quartic gauge...
The Standard Model Effective Field Theory (SMEFT) is an essential tool for probing physics beyond the Standard Model. With New Physics signals remaining elusive, deriving constraints on SMEFT Wilson coefficients is increasingly important in order to pinpoint its low-energy effects. This talk presents comprehensive global fits of SMEFT under the Minimal Flavour Violation (MFV) hypothesis. We...
Motivated by the long-standing discrepancy in lepton flavor universality ratios $R_D$ and $R_{D^{\ast}}$ we assess the status of scalar leptoquark states $R_2$, $\widetilde R_2$ and $S_1$ which can in principle provide a desired enhancement of $\mathcal{B}(B\to D^{(\ast )}\tau \nu)$ in a minimal setup with two Yukawa couplings only. We consider unavoidable low-energy constraints, $Z$-pole...
We present results of searches for massive vector-like top and bottom quark partners using proton-proton collision data collected with the CMS detector at the CERN LHC at a center-of-mass energy of 13 TeV. Single and pair production of vector-like quarks are studied, with decays into a variety of final states, containing top and bottom quarks, electroweak gauge and Higgs bosons. We search...
Many new physics models such as compositeness, extra dimensions, extended Higgs sectors, supersymmetry, and dark sectors are expected to manifest themselves in the final states with photons and/or leptons. This talk presents searches in CMS for new phenomena in such final states, focusing on the recent results obtained using the full Run-II and Run-III data-set collected by the CMS Experiment...
Many theories beyond the Standard Model predict new phenomena giving rise to multijet final states. These jets could originate from the decay of a heavy resonance into SM quarks or gluons, or from more complicated decay chains involving additional resonances that decay e.g. into leptons. Also of interest are resonant and non-resonant hadronic final states with jets originating from a dark...
Many theories beyond the Standard Model predict new phenomena, such as Z', W' bosons, KK gravitons, vector-like leptons or heavy leptons, in final states with isolated, high-pT leptons (e/mu/tau) or photons. Searches for new physics with such signatures, produced either resonantly or non-resonantly, are performed using the ATLAS experiment at the LHC.. The most recent ATLAS results will be reported.
We study the discovery potential of LHC experiments for resonantly produced vectorlike quarks ($\chi$), when the s-channel resonance is an ultraheavy diquark scalar particle ($S_{uu}$) of mass in the $7-8.5$ TeV range. Given that the $S_{uu}$ resonance can be reconstructed when both $W^+$ bosons decay hadronically, we focus on the 6-jet final state arising from the $pp \rightarrow S_{uu}...
We consider a NP scenario with a new heavy neutral gauge boson Zโ and the associated gauge symmetry U(1)โ. The heavy Zโ gauge boson has flavour non-universal quark and lepton couplings fixed in a such a way that the gauge anomalies generated by the presence of an additional U(1)โ gauge symmetry cancel. This implies correlations between FCNC processes within the quark sector, within the lepton...
Incorporating self-energy corrections via Dyson resummation can quantify the deviations from the fixed-width approximation, to an extent such that one can assess their implications on the myriad of collider observables. In this talk, I shall highlight the BSM reach of momentum-dependent particle widths and propagators of gauge and Higgs bosons, and the top quark using the SMEFT framework....
We present searches from the CMS experiment, performed with data collected during LHC Run 2 at a centre-of-mass energy of 13 TeV, for additional Higgs bosons. A variety of states are searched for, at masses both above and below 125 GeV.
The discovery of the Higgs boson with the mass of about 125 GeV completed the particle content predicted by the Standard Model. Even though this model is well established and consistent with many measurements, it is not capable of explaining some observations by itself. Many extensions of the Standard Model addressing such shortcomings introduce beyond-the-Standard-Model couplings to the Higgs...
The BDF/SHiP experiment is a general purpose intensity-frontier experiment for the search of feebly interacting GeV-scale particles and to perform neutrino physics measurements at the HI-ECN3 (high-intensity) beam facility at the CERN SPS, operated in beam-dump mode, taking full advantage of the available 4$\times 10^{19}$ protons per year at 400 GeV. The Collaboration is now in the phase of...
The proposed LUXE experiment (LASER Und XFEL Experiment) at DESY, Hamburg,
using the electron beam from the European XFEL, aims to probe QED in the
non-perturbative regime created in collisions between high-intensity laser
pulses and high-energy electron or photon beams. This setup also provides a unique opportunity to probe physics beyond the standard model. In this talk we show that by...
We investigate a novel collider signature within the minimal Left-Right Symmetric Model, featuring a Higgs sector composed of a bi-doublet and two triplets. Our study focuses on a region of the parameter space where the $SU(2)_R$ charged gauge boson $W_R$ lies in the multi-TeV regime (3-100 TeV) and the additional Higgs states play a significant role. In this scenario, a heavy neutral Higgs...
Exotic Higgs decays are among the most promising areas to be explored at the High-Luminosity LHC, given the unprecedentedly large amount $(\sim 3 \times 10^8)$ of 125 GeV Higgs bosons that will be produced. In this context, we propose a new search channel for which the Higgs boson decays to a (leptonically decaying) $Z$ boson and a light BSM pseudoscalar $a$, which subsequently decays to a...
Within the framework of a general non-linear effective field theory describing the electroweak symmetry breaking, we perform a detailed analysis of the next-to-leading contributions to the electroweak oblique parameters S and T from hypothetical heavy resonance states strongly coupled to Standard Model fields. This work extends our previous results by including parity-odd operators in the...
We discuss a class of exotic muon decay signatures that extend beyond the well-studied lepton flavor-violating channels such as $\mu \to e\gamma$ and $\mu \to eee$. We focus on rare processes featuring final states with $2m+1$ electrons and $n$ photons, exploring their theoretical origin and experimental relevance. Our analysis begins in the framework of the Standard Model Effective Field...
Motivated by the recent evidence of an excess in the rare decay $B\to K E_{\rm miss}$ presented by the Belle II collaboration we discuss possible new physics (NP) scenarios in which light invisible states participate in flavour-changing $b\to s$ transitions. Based on a model-independent EFT framework to describe the new light states, we study the signatures given by the differential...
We analyze publicly available $K^+ \to \pi^+ \nu \bar{\nu}$ data collected by NA62 from 2016 to 2022 to constrain the vectorial axion-down-strange coupling or, equivalently, the Peccei-Quinn scale $f_a$ rescaled by this coupling, obtaining $|(F_{V})_{23}| > 1.1 \times 10^{12}$ GeV. We also discuss the potential of applying the same approach to $K^+ \to \pi^+ \pi^0 \nu \bar{\nu}$ data, from...
The BESIII experiment has collected 2.6 billion $\psi(3686)$ events, 10 billion $J/\psi$ events, 20 $fb^{-1}$ of D meson pairs at 3.773 GeV, and 7.33 $fb^{-1}$ of $D_sD_s^*$ events from 4.128 to 4.226 GeV. The huge data samples allow us to search for rare processes in charm hadron decays. In this talk, we report searches for FCNC decay $J/\psi \to D^0\mu^+\mu^-$ and $D_s^+ \to h(h')e^+e^-$....
The observed matter-antimatter asymmetry in the universe is a serious challenge to our understanding of nature. BNV/LNV decays have been searched for in many experiments to understand this large-scale observed fact. In this talk, we present the recent results from the BESIII experiment on the searches for baryon number violation via $\Lambda-\bar{\Lambda}$ oscillation in $J/\psi \to \Lambda...
The muon magnetic anomaly, ,a_mu= (g โ 2)/2, can be both measured and computed to a very high precision, making it a powerful probe to test the Standard Model of particle physics and search for new physics. At the beginning of the 2000s, the E821 experiment at Brookhaven (USA) measured with a precision of 0.54 parts per million (ppm), finding a discrepancy of about three standard deviations...
The COMET experiment at J-PARC facility in JAPAN is designed to search for charged lepton flavour violation (cLFV), one of the most promising way of looking for physics beyond the Standard Model. Specifically, it will search for the coherent, neutrinoless conversion of a muon to an electron in the field of an aluminum nucleus, a process that is forbidden in the Standard Model and highly...
In modern experiments on flavour physics it is possible to search for the decays of $B$โs, $D$โs, or $\tau$โs into final states with heavy neutrinos $N$ (a.k.a. heavy neutral leptons). I present a common study of theorists and experimentalists from Belle II on constraints on $B \rightarrow D^{*} \ell N$. Next I discuss the status of the theory predictions of the various $N$ decay rates. In...
Some effects induced by SMEFT operators at one-loop have been fully computed, in particular, the renormalization of divergences by physical operators in single insertions of dimension-six operators. Important non-logarithmically enhanced contributions remain to be calculated. We discuss dimensional regularization in the Breitenlohner-Maison 't Hooft-Veltman scheme. The goal here consists of...
Signatures of new physics at the LHC are varied and by nature often very different from those of Standard Model processes. Novel experimental techniques, including dedicated datastreams are exploited to boost the sensitivity of the CMS Experiment to search for such signatures. In this talk we highlight the most recent CMS results, obtained using the data collected at the LHC Run-II and Run-III...
In the absence of direct evidence for new physics in targeted searches, model-independent strategies are becoming increasingly important. In this talk, we present recent results of model-agnostic searches that are facilitated by advanced machine learning techniques, opening a new avenue for unbiased detection of potential new physics signals.
Phase-0 of the MoEDAL-MAPP Facility began with installing the MoEDAL detector at IP8 on the LHC ring in 2010. In 2021, as part of Phase-1, CERN approved MoEDALโs reinstallation for Run-3 with key upgrades: a tenfold lower detection threshold, a fivefold luminosity increase, and a center-of-mass energy boost from 13 TeV to 13.6 TeV. MoEDAL will continue searching for highly ionizing particles...
One of the great open questions in modern physics is the origin of the matter-antimatter asymmetry. This requires baryon-number violation, which has never been experimentally observed. Baryon-number violation may arise in the neutron sector as the direct conversion between neutrons and antineutrons, or with a sterile/mirror neutron.
This process will be probed with the proposed HIBEAM/NNBAR...
The search for weakly interacting massive particles (WIMPs) remains a central goal of the High Luminosity Large Hadron Collider (HL-LHC). In this work, we explore radiative neutralino decays within the framework of the Zโ-invariant Next-to-Minimal Supersymmetric Standard Model (NMSSM), focusing on scenarios where the lightest supersymmetric particle (LSP) is a singlino-dominated neutralino. In...
We present a new application of Graph Neural Networks (GNNs) for LHC searches that aims to improve event classification by representing entire datasets as graphs, with events as nodes and kinematically similar events connected by edges. The strategy builds from our development of graph convolutions and graph attention mechanisms, where we apply scalable solutions for training various GNN...
Despite the large amount of data generated by the Large Hadron Collider (LHC) so far, searches for new physics have not yet provided any clear evidence of beyond the Standard Model (BSM) physics. Most of these experimental searches focus on exclusive channels, looking for excesses in specific final states. However, new physics could manifest as a dispersed signal over many channels. It...
