Conveners
Lightning round / new ideas: New results from ATLAS and CMS, in detail
- Federico Leo Redi (EPFL - Ecole Polytechnique Federale Lausanne (CH))
- Matthew Daniel Citron (Univ. of California Santa Barbara (US))
Lightning round / new ideas
- Nishita Desai (Tata Institute of Fundamental Research)
- Juliette Alimena (CERN)
Lightning round / new ideas
- Carlos Vazquez Sierra (CERN)
- Katherine Pachal (Duke University (US))
Lightning round / new ideas
- Katherine Pachal (Duke University (US))
- José Francisco Zurita (IFIC - Univ. of Valencia and CSIC (ES))
Lightning round / new ideas
- Juliette Alimena (CERN)
- Sascha Mehlhase (Ludwig Maximilians Universitat (DE))
A search for long-lived particles, which have come to rest within the ATLAS detector, is presented. The subsequent decays of these long-lived particles can produce high-momentum jets, resulting in large out-of-time energy deposits in the ATLAS calorimeters. These decays are detected using data collected during periods in the LHC bunch structure when collisions are absent. The analysed dataset...
A search for long-lived particles (LLPs) produced in decays of standard model (SM) Higgs bosons in $137~\mathrm{fb}^{-1}$ of proton-proton collisions at $\sqrt{s}=13~\mathrm{TeV}$ recorded by the CMS experiment during $2016$$-$$2018$ is presented. The search employs a novel technique to reconstruct hadronic decays of LLPs in the endcap muon system. The search is sensitive to a broad range of...
This talk is based on the result of ATLAS-CONF-2021-015. The search for long-lived charginos based on a disappearing track signature with the full Run-2 ATLAS dataset is performed. Improvements from the previous analysis are increasing statistics and implementing calorimeter veto for the background reduction. We only use 4-layer tracklets in this analysis. We observed 3 events and 1 event with...
This talk presents a search for long-lived particles (LLPs) produced in association with a $\mathrm{Z}$ boson. The search is performed with data from $13\,\mathrm{TeV}$ proton-proton collisions recorded by the CMS experiment during 2016--2018, corresponding to an integrated luminosity of $117\,\mathrm{fb}^{-1}$. The LLPs are assumed to decay into a pair of standard model fermions inside the...
A novel search for exotic decays of the Higgs boson to pairs of long-lived neutral particles, each decaying to a bottom quark pair, is performed using 139 fb$^{-1}$ of $\sqrt{s} = 13$ TeV proton-proton collision data collected with the ATLAS detector at the LHC. Events consistent with the production of a Higgs boson in association with a $Z$ boson are analyzed, with the leptonic decay of the...
A search for displaced dimuon resonances is performed using proton-proton collisions at a center-of-mass energy of 13 TeV, collected by the CMS experiment at the LHC in 2017−2018, corresponding to an integrated luminosity of 101 fb−1 . The data sets used in this search were collected using a dedicated dimuon trigger stream with low transverse momentum thresholds, recorded at high rate by...
FASER is one of the promising experiments which search for long-lived particles beyond the Standard Model. In this talk, we focus on dark photon associating with an additional U(1) gauge symmetry, and also a scalar boson breaking this U(1) symmetry. The sensitivity to the dark photon originated from U(1) breaking scalar decays is studied. We show that a sizable number of dark photon signatures...
We consider light neutralinos of mass about 1 GeV, produced from $\tau$ lepton rare decays at Belle II, in the context of R-parity-violating (RPV) supersymmetry. With large and clean samples of $\tau$ leptons produced at the Belle II experiment, excellent sensitivity to such light neutralinos with the exotic signatures of displaced vertices is expected. We focus on two benchmark scenarios of...
Confining dark sectors at the GeV scale can lead to novel collider signatures including those termed emerging jets with large numbers of displaced vertices. The triggers at the LHC experiments were not designed with this type of new physics in mind, and triggering can be challenging, especially if the mediator is relatively light and/or has quantum numbers such that additional jets are not...
The phenomenon of neutrino flavor oscillations motivates searches for sterile neutrinos in a broad range of masses and mixing-parameter values. A sterile neutrino $N$ that mixes predominantly with the $\tau$ neutrino is particularly challenging experimentally. To address this challenge, we propose a new method to search for a $\nu_\tau$-mixing with $N$ lighter than the $\tau$ lepton. The...
Extending the Standard Model with right-handed neutrinos (RHNs) is well motivated by the observation of neutrino oscillations. In the type-I seesaw model, the RHNs interact with the SM particles via tiny mixings with the active neutrinos, which makes their discovery in the laboratory, and in particular at collider experiments in general challenging. In this work we instead consider an...
We propose a model-independent approach for the search of charged long-lived particles produced in ultraperipheral collisions at the LHC. The main idea is to improve event reconstruction at ATLAS and CMS with the help of their forward detectors. Detection of both scattered protons in forward detectors allows complete recovery of event kinematics. Though this requirement reduces the number of...
Models for long-lived dark Z bosons are considered where the dark sector interacts with the standard model either via hypercharge or Higgs portals. In this context, the production mechanism of the dark Z is determined based on two simultaneous mixings where the standard-model Z boson can mix kinetically with the dark Z and the standard-model Higgs can mix with a dark Higgs. An exotic decay...
Low-scale models of neutrino mass generation often feature sterile neutrinos with masses in the GeV-TeV range, which can be produced at colliders through their mixing with the Standard Model neutrinos. We consider an alternative scenario in which the sterile neutrino is produced in the decay of a heavier particle, such that its production cross section does not depend on the active-sterile...
We present a framework for the construction of portal effective theories(PETs) that couple effective field theories of the Standard Model (SM) to light hidden messenger fields. Using this framework we construct electroweak and strong scale PETs that couple the SM to messengers carrying spin zero, onehalf, or one. The electroweak scale PETs encompass all portal operators up to dimension five,...
A future far detector at Belle II - GAZELLE - could enhance the search potential for long-lived particles at electron-positron experiments. An initiative of theorists and experimentalists has explored this potential for three common LLP scenarios with different production mechanisms. In this talk, we compare the projections of finding these LLPs at Belle II or GAZELLE. Due to Belle II's...
Hidden sectors are well motivated theoretically, and there is increasingly focused experimental activity to probe them. In this talk, I will present the theoretical framework to probe such sectors in a model-independent manner. I will focus on sectors that communicate with the standard model through irrelevant portal operators. Such portals can be shown to arise naturally, on very general...
Monopole and Exotics Detector at the LHC (MoEDAL) is a mostly passive detector located in the LHCb cavern, just outside LHCb detector. MoEDAL was designed to search for magnetic monopoles, but it also sensitive to long-lived charged particles.
A certain class of neutrino mass models predicts long-lived particles whose electric charge
is four or three times larger than that of protons....
