Conveners
Searches for New Physics
- Christina Jane Potter (University of Cambridge (GB))
- Robert Schoefbeck (Austrian Academy of Sciences (AT))
- David Marzocca (INFN Trieste)
Searches for New Physics
- David Marzocca (INFN Trieste)
- Christina Jane Potter (University of Cambridge (GB))
- Robert Schoefbeck (Austrian Academy of Sciences (AT))
Searches for New Physics
- Robert Schoefbeck (Austrian Academy of Sciences (AT))
- David Marzocca (INFN Trieste)
- Christina Jane Potter (University of Cambridge (GB))
Searches for New Physics
- David Marzocca (INFN Trieste)
- Robert Schoefbeck (Austrian Academy of Sciences (AT))
- Christina Jane Potter (University of Cambridge (GB))
We present searches for new physics in events with one or more jets accompanied by large missing transverse momenta produced in proton-proton collision data recorded by the CMS experiment during the LHC Run2 operations (2016-18). Compressed chargino-neutralinos appearing in gluino cascades are studied using short tracks. The results are interpreted in the context of several simplified models...
Despite the absence of experimental evidence, weak-scale supersymmetry remains one of the best motivated and studied Standard Model extensions. This talk summarizes recent ATLAS results on inclusive searches for supersymmetric squarks of the first two generations and gluinos. It covers both R-parity conserving models that predict dark matter candidates and R-parity violating models that...
We make use of recently released parton density functions (PDFs) with threshold-resummation improvement to consistently calculate theoretical predictions for neutralino-chargino and slepton pair production at next-to-leading order and next-to-leading logarithmic accuracy. The updated cross sections have been computed for experimentally relevant higgsino/gaugino and slepton search channels at...
We present searches for pair production of supersymmetric partner of tau-leptons, and of partners of electroweak gauge bosons in events with at least one tau-lepton and missing transverse momenta produced in proton-proton collision data recorded by the CMS experiment during the LHC Run2 operations. The results are interpreted in terms of simplified models of supersymmetry production and decay...
Many supersymmetry models feature gauginos and sleptons with masses less than a few hundred GeV. These can give rise to direct pair production rates at the LHC that can be observed in the data sample recorded by the ATLAS detector. The talk presents recent ATLAS results from searches for pair produced charginos and neutralinos or sleptons in final states with leptons (including hadronic taus)...
Fine-tuning arguments suggest the mass of the supersymmetric partner of the Higgs boson, the higgsino, is not too far from the weak scale. The search for higgsinos represents an experimental challenge due to the near mass-degeneracy resulting in soft decay products, and the low production cross section. This talk presents recent ATLAS results of analyses explicitly targeting the higgsino with...
We present searches for third generation of supersymmetric top and bottom quarks based on proton-proton collision data recorded by the CMS experiment during the LHC Run2 operations (2016-18). The searches are performed in zero, single lepton (including taus) and dilepton final states, and the results are interpreted in the context of several decay modes of stop quarks.
Naturalness arguments for weak-scale supersymmetry favour supersymmetric partners of the third generation quarks with masses light enough to be produced at the LHC. The ATLAS experiment has a variety of analyses devoted to stop direct production exploiting advanced analysis techniques. This talk presents recent results of searches for stops and sbottoms, including models with long decay chains...
Most SUSY searches at the LHC are optimised for the MSSM, where gauginos are Majorana particles. By introducing Dirac gauginos, we obtain an enriched phenomenology, from which considerable differences in the LHC signatures and limits are expected as compared to the MSSM. Concretely, in the minimal Dirac gaugino model (MDGSSM) we have six neutralino and three chargino states. Moreover,...
We present searches for new physics scenarios like R-parity violating supersymmetry or compressed mass spectra which predict low missing transverse momenta, many jets and top quarks. The searches are based on proton-proton collision data recorded by the CMS experiment during the LHC Run2 operations.
I will present recent results from the Global and Modular
Beyond-the-Standard-Model Inference Tool (GAMBIT)
collaboration. Global fits with GAMBIT have been carried out on many
models including supersymmetric models, scalar singlet dark matter,
fermionic and vector Higgs portal dark matter and axions. In this
talk I will focus on our most recent study interpreting collider
constraints on...
The requirement of electroweak naturalness in simple supersymmetric models motivates the existence of a cluster of four light higgsinos with mass 100-300 GeV, the lighter the better. While such light compressed spectra may be challenging to observe at LHC, future e+e- colliders with sqrt(s) > 2m(higgsino) would serve as both a SUSY discovery machine and a precision microscope.
We study...
We present latest results from searches for leptoquarks with the CMS detector. A variety of final states is considered, probing leptoquark couplings to all three generations of quarks and leptons.
Many theories beyond the Standard Model predict new phenomena which decay to final states containing both leptons and jets. Searches for new physics models with these signatures are performed using the ATLAS experiment at the LHC. The results of the most recent searches on 13 TeV pp data will be presented.
High-precision HERA data corresponding to a luminosity of around 1 fb$^{-1}$ have been used in the framework of $eeqq$ contact interactions (CI) to set limits on possible high-energy contributions beyond the Standard Model to electron-quark scattering. Measurements of the inclusive deep inelastic cross sections in neutral and charged current $ep$ scattering were considered. The analysis of the...
We examine new aspects of leptoquark (LQ) phenomenology using effective field theory (EFT). We construct a complete set of leading effective operators involving SU(2) singlets scalar LQ and the SM fields up to dimension six. We show that, while the renormalizable LQ-lepton-quark interaction Lagrangian can address the persistent hints for new physics in B-decays and the anomalous magnetic...
Many theories beyond the Standard Model predict new phenomena which decay to well isolated, high-pt leptons. Searches for new physics models with these signatures are performed using the ATLAS experiment at the LHC. The results reported here use 13 TeV pp collision data; prospects for HL-LHC will also be shown.
Various physics models beyond the standard model predict new particles that decay to leptons, photons or jets. This talk presents the status of CMS searches for new resonances decaying to a pair of leptons, photons or jets, as well as other states such lepton + missing transverse momentum. Searches for boosted dijet resonances recoiling against some high pT initial state radiation, as well...
Several new physics models such as those involving extra dimensions, leptoquarks, heavy neutrinos, W bosons with right handed couplings, excited fermions, seesaw models, etc. are expected to manifest themselves in non-resonant signatures with multiple leptons, photons or jets. This talk presents CMS searches for new non-resonant phenomena in the final states that involving leptons, photons...
Large Hadron Collider (LHC) is delivering an unprecedented amount of data which enables ATLAS and CMS detectors to perform the most precise measurements of the Drell-Yan and mono-lepton high-pT tails. One the one hand, the LHC is a collider of five-quark flavors and several excellent methods of heavy flavor tagging in the final state have recently been developed, while on the other hand, a...
Many theories beyond the Standard Model predict new phenomena which decay to quarks. Light-quarks are of particular interest at the LHC since new phenomena produced in parton collisions are likely to produce final states with (at least) two partons. Omg the other hand, b- and top-quarks offer great potential to reduce the Standard Model background, although with significant challenges in...
We present results from searches for new particles with enhanced couplings to third generation quarks, based on proton-proton collision data at a centre-of-mass energy of 13 TeV recorded by CMS. The signatures include single and pair production of vector-like quarks and heavy resonances decaying to third generation quarks. A wide range of final states, from multi-leptonic to entirely hadronic...
Most recent CMS results on searches for heavy resonances decaying into gauge and Higgs bosons (VV, VH where V = W, Z) are presented. The results are based on the large dataset collected during Run 2 of the LHC at a centre-of-mass energy of 13 TeV. The analyses are optimised for high sensitivity over a large range in resonance mass. Jet substructure techniques are used to identify hadronic...
Many extensions to the Standard Model predicts new particles decaying into two bosons (W, Z, photon, or Higgs bosons) making these important signatures in the search for new physics. Searches for such diboson resonances have been performed in final states with different numbers of leptons, photons and jets and b-jets where new jet substructure techniques to disentangle the hadronic decay...
We discuss the most relevant features of a BSM model with extra gauge symmetry, the so called 331 model. The gauge group is $SU(3)_c\times SU(3)_L \times U(1)_X$ implying the presence of extra gauge bosons, both charged and neutral, as well as extra/exotic fermions and an enlarged scalar sector. We present the relevant phenomenology of doubly-charged gauge bosons, which are a distinctive...
In this work, we calculate limits on masses and couplings of neutral, mono and doubly-charged vector bosons predicted by a class of models based on the $SU(3)_{C} \times SU(3)_{L} \times U(1)_{X}$ symmetry group. These models offer an elegant explanation for the threefold replication of quark-lepton families. Different final states, including two, three and four leptons and leptons plus...
The LHCb detector at the LHC offers unique coverage of forward rapidities. The detector also offers a flexible trigger that enables low mass states to be recorded with high efficiency, and a precision vertex detector that enables excellent separation of primary interactions from secondary decays. This allows LHCb to make important (and world-best) contributions in these regions of phase space...
Many extensions of the Standard Model include the possibility of light new particles, such as axions or dark matter candidates. These scenarios can be probed using the large data sets collected by the $B$-factories, complementing measurements performed at the LHC. The $BABAR$ collaboration has conducted an extensive program to search for axions in $B$ decays and for self-interacting or...
Several theories predict dark matter to be a part of a larger dark sector of particles and forces. These dark sector particles such as dark photons, dark scalars or dark quarks may interact very weakly with standard model particles resulting in several distinct signatures in the high energy pp collision events at the LHC. This talk presents recent results from CMS on dark sector searches using...
Many theories beyond the Standard Model (BSM) predict unique signatures which are difficult to reconstruct and for which estimating the background rates is also a challenge. Signatures of new particles with fractional or multiple value of the charge of the electron or high mass stable charged particles are examples of experimentally demanding signatures. The talk will focus on the most recent...
The status of the milliQan experiment is discussed. milliQan is a proposed search for milli-charged particles produced at the LHC with expected sensitivity to charges of between 0.1e and 0.001e for masses in 0.1 - 100 GeV range. The proposed detector is an array of 4 stacks of 60 cm long plastic scintillator arrays read out by PMTs. It will be installed in an existing tunnel 33 m from the CMS...
The high-intensity setup, trigger system flexibility, and detector performance – high-frequency tracking of beam particles, redundant PID, ultra-high-efficiency photon vetoes – make NA62 particularly suitable for searching for new-physics effects from different scenarios. We report the results of a search for π0 decays to one photon and an invisible massive dark photon. From a total of about...
In this work, we study the discovery prospect of a heavy neutrino in the intermediate to very high mass range at $\rm e^{+}e^{-}$ collider. We consider two different c.m.energies $\rm \sqrt{s}=1.4$ TeV and $3\,\rm TeV$, respectively, that are relevant for CLIC. Contrary to the LHC, the production cross-section of a heavy neutrino at $\rm e^{+}e^{-}$ collider is fairly large. We consider two...
The Inert Doublet Model (IDM) is one of the simplest extensions of the Standard Model (SM), providing a dark matter candidate. It is a two Higgs doublet model with a discrete Z2 symmetry, that prevents the scalars of the second doublet (inert scalars) from coupling to the SM fermions and makes the lightest of them stable. We study a large statistics of IDM scenarios, which are consistent with...
LHCb has made a series of searches sensitive to Higgs-like bosons and their decays. These analyses include searches for long-lived particles produced in the decays of such resonances, with these particles decaying to various final states probed in different analyses, and a search for Higgs-like bosons that produce lepton-flavour-violating decays, producing a tau mu final state. The unique...
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 to solely explain some observations. Many extensions addressing this fact introduce additional Higgs-like bosons which can be either neutral, singly-charged or even...
The HIBEAM/NNBAR experiment is a two stage experiment for the European Spallation
Source (ESS) to search for baryon number violation. The experiment would make high sensitivity searches for baryon number violating processes: n → nbar and n → n′(neutron to sterile neutron), corresponding to the selection rules in baryon number ΔB = 2, 1 , respectively. The experiment addresses topical open...
The precision measurement of the anomalous magnetic moment of the muon presently exhibits a 3.5σ discrepancy with the Standard Model (SM) prediction. In the next few years this measurement will reach an even higher precision at Fermilab and J-PARC. While the QED and electroweak contributions to the muon g-2 can be determined very precisely, the leading hadronic (HLO) correction is affected by...
The E989 Muon g-2 Experiment has completed its first physics run and collected a dataset roughly two times larger than the previous Brookhaven experiment. With a target precision of 140 ppb, divided equally between statistics and systematics, E989 will achieve the most precise measurement to date of the muon's anomalous magnetic moment and will thus be able to confirm or resolve the larger...
MoEDAL is an LHC experiment designed to search for anomalously ionizing messengers of new physics such as magnetic monopoles or massive (pseudo-)stable charged particles, which are predicted to exist in many models beyond the Standard Model. It started data taking at the LHC at a centre-of-mass energy of 13 TeV in 2015. Its physics program yields insights into such foundational questions as:...
CODEX-b is a novel proposal to extend LHCb’s physics reach in long-lived particle searches by placing a 10X10X10m3 tracking volume around 25m from IP8, inside the LHCb cavern. The potential sensitivity probes not only high center of mass energy portals such as the Higgs invisible width to dark photons, but also
low-scale vector, scalar or fermion mixing portals, such as heavy neutral leptons...
We study dimuon events in 2.11/fb of 7 TeV pp collisions, using CMS Open Data, and search for a narrow dimuon resonance with moderate mass (14-66 GeV) and substantial transverse momentum (pT). Applying dimuon pT cuts of 25 GeV and 60 GeV, we explore two overlapping samples: one with isolated muons, and one with prompt muons without an isolation requirement. Using the latter sample requires...
Many extensions of the standard model including supersymmetry predict new particles with long lifetimes, such that the position of their decay is measurably displaced from their production vertex, and particles giving rise to other non-conventional signatures. We present recent results of CMS searches for long-lived particles and other non-conventional signatures obtained using data recorded...
With the current experiments at the particle accelerators, no search strategy will be able to observe the decay of neutral long-lived particles with masses above ~GeV and lifetimes at the limit set by Big Bang Nucleosynthesis (BBN), c$\tau$ $\sim$ 10$^7$-10$^8$ m. The MATHUSLA detector concept (MAssive Timing Hodoscope for Ultra-Stable neutraL pArticles) will be presented. It can be...
Supersymmetric models present a wide variety of signatures that might be accessible at the LHC. In some cases supersymmetric particles may acquire finite lifetimes, and once produced in collisions, their direct trajectories or decay products can be observed as highly distinctive signatures with relatively small backgrounds. In recent years, the capability of the ATLAS experiment to search for...
We present results from searches for new physics with uncommon jet substructure. The results cover a variety of final states that have been uncovered so far. The models considered range from stealth SUSY where a hard photon is merged with gluons into a single jet, to light resonances produced with a high Lorentz boost, decaying to quark-antiquark and reconstructed in a single jet.
The SHiP Collaboration has proposed a general-purpose experimental facility operating in beam dump mode at the CERN SPS accelerator with the aim of searching for light, long-lived exotic particles of Hidden Sector models. The SHiP experiment incorporates a muon shield based on magnetic sweeping and two complementary apparatuses. The detector immediately downstream of the muon shield is...
Extensions to the SM featuring a low-scale seesaw can be used to to explain the observation of neutrino oscillations, baryogenesis and dark matter. I present the potential to search for right-handed neutrinos using current experiments. I compare the reach of the main detectors at the LHC when a displaced vertex signature in proton collisions is used. Additionally, I show the potential to...
The Large Hadron Collider (LHC) has been successfully delivering proton-proton collision data at the unprecedented center of mass energy of 13 TeV. An upgrade is planned to increase the instantaneous luminosity delivered by LHC in what is called HL-LHC, aiming to deliver a total of about 3000/fb of data to the ATLAS detector at a center of mass energy of 14 TeV. To cope with the expected...
This talk explores the physics reach of the proton-proton Future Circular Collider (FCC-hh) and of the High-Energy LHC (HE-LHC) for searches of new particles produced in the $s$-channel and decaying to two high-energy leptons, jets (non-tops), tops or W/Z bosons (as discussed in arXiv:1902.11217). We discuss the expected discovery potential and exclusion limits for benchmark models predicting...
Future e+e- colliders will offer possibilities to search for new particles in a manner very complementary to the searches planned for HL-LHC. ILC, in particular, will operate triggerlessly, with sensitivity to very small energy depositions, and with beam polarization to both control and measure crucial backgrounds. In this contribution we will discuss the potential of ILC to discover new...
Right-handed neutrinos are among the best-motivated extensions beyond the Standard Model.
When they are subject to a protective symmetry they can have large mixings with the active neutrinos and masses at the electroweak scale. The effects of these particles can be studied in many different ways at the Future electron-positron Collider. In particular, the modifications of the weak currents...
The Compact Linear Collider (CLIC) is a mature option for a future electron-positron collider operating at centre-of-mass energies of up to 3 TeV. CLIC will be built and operated in a staged approach with three centre-of-mass energy stages currently assumed to be 380 GeV, 1.5 TeV, and 3 TeV. A selection of results from recent studies will be presented showing that CLIC has excellent...
The Large Hadron-electron Collider (LHeC) is a proposed upgrade of the LHC at CERN. It consists of an ERL providing electrons to collide with the HL-LHC, HE-LHC and the FCC-hh proton beams achieving centre-of-mass energies 1.3-3.5 TeV, respectively, at very high luminosities $\sim 10^{34}$ cm$^{−2}$ s$^{-1}$. These large luminosities and energies provide most interesting possibilities for...
