Bulletin of the American Physical Society
APS April Meeting 2019
Volume 64, Number 3
Saturday–Tuesday, April 13–16, 2019; Denver, Colorado
Session Q17: Collider and BSM III |
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Sponsoring Units: DPF Chair: Matthew Bellis, Siena College Room: Sheraton Grand Ballroom II |
Monday, April 15, 2019 10:45AM - 10:57AM |
Q17.00001: Higgs Boson to Invisible searches with the ATLAS Detector in Run 2 Rui Zou The total decay width of the Higgs boson under SM assumptions hasn’t been constrained precisely and allows for a branching fraction as large as O(30%) where the Higgs decays into invisible particles, such as dark matter particles. This talk will include the searches for invisible decays of the Higgs produced in three production modes using data, corresponding to an integrated luminosity of 36.1 fb-1, of the proton-proton collisions at a center-of-mass energy of 13 TeV with the ATLAS detector. Particular emphasis will be placed on the Vector Boson Fusion (VBF) production mode, which drives the sensitivity thus far. I will talk about the analysis techniques, leading constraints on sensitivity and resulting limits on the invisible branching fraction. The results of combining the production modes using data from Run 1 and Run 2 and projections for HL-LHC will also be presented. The Higgs to invisible branching fraction will be interpreted in the context of Higgs portal dark matter models and compared to direct dark matter searches. |
Monday, April 15, 2019 10:57AM - 11:09AM |
Q17.00002: Searches for exotic decays of the Higgs Boson to a pair of light resonances with the ATLAS detector Christopher Robyn Hayes <div js-mathjax"=""> Exotics decays of the Higgs boson provide a unique window for the discovery of new physics, as the Higgs may couple to hidden-sector states that do not interact under the Standard Model gauge transformations. Models predicting exotic Higgs decays to pseudoscalars can explain the galactic center gamma-ray excess, if the additional pseudoscalar acts as the dark matter mediator. This talk presents recent ATLAS searches for decays of the 125 GeV Higgs boson to a pair of new light bosons, H -> aa, where the a-bosons decay to various final states. These searches use LHC collision data at sqrt(s) = 13 TeV collected by the ATLAS experiment in 2015 and 2016. Upper limits on the branching ratio σ(H)/σ(SM) x Br(H -> aa) are set in the a-boson mass range between 1–60 GeV. Finally, a comparison of other ATLAS search channels is presented to illustrate the strength of each analysis in probing new physics. |
Monday, April 15, 2019 11:09AM - 11:21AM |
Q17.00003: Rare Higgs Decays into Quarkonia Pairs Himal Acharya Rare decays of the Higgs boson to mesons are a promising laboratory to study couplings to lighter quarks and physics beyond the standard model. A search for decays of the Higgs and the Z boson to pairs of J/ψ and Y resonances with subsequent decays of the mesons into muon pairs is performed with the Compact Muon Solenoid detector at the Large Hadron Collider (LHC). A data sample of proton-proton collisions collected in 2017 at a center-of-mass energy of 13 TeV is used. I will present results of this search and implications for future searches of beyond standard model signatures at high luminosity. |
Monday, April 15, 2019 11:21AM - 11:33AM |
Q17.00004: Search For a Light Pseudoscalar Higgs Boson with Boosted Topologies at CMS Grace Haza A search is performed for a light pseudoscalar Higgs boson (a) motivated by the theoretical framework of two Higgs doublet plus singlet models (2HDM+S). This search uses 2016 LHC data collected at 13 TeV by the CMS experiment and analyzes the decay channel H->a a->mu mu tau tau, with H being either the 125 GeV state or a more massive Higgs boson. Final state taus have a boosted and collimated topology due to the large mass difference between the H and a. Thus, a novel algorithm for this special final state is designed to increase the identification efficiency. Expected limits are derived in the context of four types of 2HDM+S models for H(125), and are complementary to current CMS results with resolved final state particles. Model-independent expected limits for heavier H masses are also presented. This analysis will be updated with machine learning techniques for the Full Run 2 dataset. |
Monday, April 15, 2019 11:33AM - 11:45AM |
Q17.00005: Understanding recent collider excesses in light of light Higgs bosons Evan Johnson, Patrick J Fox, Jose No Although the discovered scalar with a mass of 125 GeV appears to have the properties of the Standard Model Higgs, it remains a possibility that it belongs to an enlarged scalar sector containing other Higgs bosons waiting to be discovered. Motivated by the recent CMS and ATLAS diphoton excesses near 95 GeV, we consider a Type-I two-Higgs-doublet model in regions of high fermiophobia allowing for an enhancement in the γγ rate for scalars lighter than the Standard Model Higgs. We fix one CP-even neutral scalar to be SM-like with a mass of 125 GeV and consider separately the other CP-even neutral scalar or the CP-odd neutral pseudoscalar as the source of the observed signal excess. In both instances, we explore the parameter space and identify regions surviving experimental and theoretical constraints. We also consider the strength of the electroweak phase transition within the model and find regions where the transition is strongly first order, allowing for electroweak baryogenesis to explain the observed baryon asymmetry. |
Monday, April 15, 2019 11:45AM - 11:57AM |
Q17.00006: Search for dark matter in the Mono-Higgs final state. Marc Tost A search for WIMP dark matter particles is performed by looking for events with a large transverse momentum imbalance and a recoiling Higgs Boson. Proton-proton collision data with center-of-mass energy of 13 TeV collected by the CMS experiment at the CERN LHC is used. One of the production mechanisms considered is the Two Higgs Doublet model, where a high mass resonance Z decays to an A0 and a standard model Higgs Boson. |
Monday, April 15, 2019 11:57AM - 12:09PM |
Q17.00007: Searching for flavor changing neutral Higgs interaction in associated single top production at Hadron Colliders. RISHABH JAIN, Chung Kao, Jack Brown, Tao Han We investigate the prospect of discovering flavor changing neutral currents in the top associated Higgs production ($\phi^0 = h^0,H^0,A^0$) at the LHC and future hadron colliders. With top decaying to a bottom quark and two light quarks, and Higgs decay to $ZZ, W^+ W^-$ and $\gamma \gamma$, with the following final states, $b j j \ell^+ \ell^- \ell^+ \ell^-$, $b j j \ell^+ \ell^- \nu_{\ell} \bar{\nu}_{\ell}$ and $b j j \gamma \gamma$. We adopt a general two Higgs doublet model, keeping the CP symmetry. We are using Boosted Decision Trees, for classification and to study discovery potential at current center of mass energies of 13 TeV and 14 TeV. We also present results for future HE-LHC and upcoming hadron colliders at $\sqrt{s} =$ 27 TeV and 100 TeV. |
Monday, April 15, 2019 12:09PM - 12:21PM |
Q17.00008: Measurement of Higgs bosons decaying to Tau lepton pairs and Constraints on Anomalous HVV couplings. Samuel L Higginbotham An investigation in measuring anomalous HVV couplings using matrix element techniques is conducted on 2016 and 2017 data taken with the Compact Muon Solenoid (CMS) experiment at the LHC corresponding to an integrated luminosity of 77.7 fb-1 . In addition, a standard model Higgs decay to tau leptons measurement is highlighted. Of interest is the performance of machine learning and matrix element methods (MELA) in the categorization and classification of optimal discrimination observables to probe HVV couplings in this decay channel. |
Monday, April 15, 2019 12:21PM - 12:33PM |
Q17.00009: Search for electroweak supersymmetry using vector boson fusion in pp collisions at sqrt(s) = 13 TeV with the ATLAS detector Andrew Aukerman, Benjamin Carlson, Tae Min Hong We present a search for electroweak supersymmetry in in pp collisions at sqrt(s) = 13 TeV with the ATLAS detector. The search focus on decays to final states with two low-momentum leptons and missing transverse energy. Particular emphasis is placed on the vector boson fusion selection. |
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