Bulletin of the American Physical Society
APS April Meeting 2018
Volume 63, Number 4
Saturday–Tuesday, April 14–17, 2018; Columbus, Ohio
Session R08: Higgs Physics |
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Sponsoring Units: DPF Chair: Dmiitri Denisov, Fermilab Room: A110 |
Monday, April 16, 2018 10:45AM - 10:57AM |
R08.00001: Search for physics beyond the standard model in events with Higgs bosons and missing transverse momentum in proton-proton collisions at 13 TeV Frank Jensen A search for physics beyond the standard model in events with one or more high-momentum Higgs bosons decaying to pairs of b quarks in association with missing transverse momentum is presented. The data, corresponding to an integrated luminosity of 35.9 fb$^{-1}$, were collected with the CMS detector at the LHC in proton-proton collisions at the center-of-mass energy $\sqrt{s}$ = 13 TeV. The analysis utilizes a new b quark tagging technique based on jet substructure to identify jets from H $\rightarrow b\bar{b}$. Events are categorized by the multiplicity of H-tagged jets, jet mass, and the missing transverse momentum. No significant deviation from standard model expectations is observed. In the context of supersymmetry (SUSY), limits on the cross sections of pair-produced gluinos are set, assuming that gluinos decay to quark pairs, H (or Z), and the lightest SUSY particle LSP through an intermediate next-to-lightest SUSY particle NLSP. With large mass splitting between the NLSP and LSP, and 100$\%$ NLSP branching fraction to H, the lower limit on the gluino mass is found to be 2010 GeV. [Preview Abstract] |
Monday, April 16, 2018 10:57AM - 11:09AM |
R08.00002: Evidence for the Higgs boson decay to a bottom quark-antiquark pair Sean-Jiun Wang Evidence for the standard model Higgs boson decay to a bottom quark-antiquark pair is presented. The search for the $H \rightarrow b\overline{b}$ decay was performed for the following processes where the Higgs boson is produced in association with an electroweak vector boson: $Z(\nu\nu)H$, $W(\mu\nu)H$, $W(e\nu)H$, $Z(\mu\mu)H$, $Z(ee)H$. The analyzed data was recorded by the CMS experiment at the LHC during Run 2 in 2016, and corresponds to an integrated luminosity of $35.9 \textrm{ fb}^{-1}$ at $\sqrt{s} = 13 \textrm{ TeV}$. An excess of events is observed in data with a significance of 3.3 standard deviations and a signal strength of $1.2 \pm 0.4$ relative to the SM Higgs boson production. The combnation of these results with the similar Run 1 analysis yields a significance of 3.8 standard deviations and a signal strength of $1.06 \pm 0.3$. [Preview Abstract] |
Monday, April 16, 2018 11:09AM - 11:21AM |
R08.00003: Search for resonant pair production of Higgs bosons in the four bottom quark final state in proton-proton collisions at $\sqrt{s}$ = 13 TeV Daniel Guerrero A model-independent search for a narrow-width resonance produced in proton-proton collisions at a center-of-mass energy of 13 TeV and decaying to a pair of Higgs bosons that in turn each decay to a bottom quark-antiquark pair, is presented. This analysis is performed using data recorded by the CMS experiment at the LHC in 2016, corresponding to an integrated luminosity of 35.9 inverse femtobarns. No significant excess with respect to the standard model expectation is observed. Upper limits at a 95$\%$ confidence level on the production cross section for such a resonance, in the mass range from 260 to 1200 GeV, are reported. [Preview Abstract] |
Monday, April 16, 2018 11:21AM - 11:33AM |
R08.00004: Radiative Decays of the Higgs Boson to a Pair of Fermions Xing Wang, Tao Han We revisit the radiative decays of the Higgs boson to a fermion pair $h\rightarrow f\bar{f}\gamma$ in the Standard Model (SM). We include the chirality-flipping diagrams at the order $\mathcal{O}(y_f^2 \alpha)$, the chirality-conserving contributions at the order $\mathcal{O}(y_t^2 \alpha^3)$ and $\mathcal{O}(\alpha^4)$. The chirality-conserving electroweak-loop processes are interesting from the observational point of view. First, the branching fraction of the radiative decay $h \to \mu^+\mu^- \gamma$ is about a half of that of $h \to \mu^+\mu^-$, and that of $h \to e^+ e^- \gamma$ is more than four orders of magnitude larger than that of $h \to e^+ e^-$, both of which reach about $10^{-4}$. The branching fraction of $h \to \tau^+\tau^- \gamma$ is of the order $10^{-3}$. All the leptonic radiative decays are potentially observable at the LHC Run 2 or the HL-LHC. The kinematic distributions could provide non-ambiguous discrimination for the underlying mechanisms of the Higgs radiative decay. We also study the process $h \to c\bar c \gamma$ and evaluate the observability at the LHC. We find it potentially comparable to the other related studies and better than the $h \to J/\psi\ \gamma$ channel in constraining the charm-Yukawa coupling. [Preview Abstract] |
Monday, April 16, 2018 11:33AM - 11:45AM |
R08.00005: Combined measurements of the Higgs boson production and decay rates in H->ZZ*->4l and H->gamgam decay channels using pp collisions at √s = 13 TeV with the ATLAS Experiment Hongtao Yang After the Higgs boson was discovered at LHC in 2012, it is of great importance to study Higgs boson's production and decay rates in order to understand how it interacts with Standard Model particles. In this presentation, I will report the combined measurements of Higgs boson production and decays in H->ZZ*->4l and H->gamgam decay channels using LHC Run 2 proton-proton collision data collected at center-of-mass energy of 13 TeV by the ATLAS detector in 2015 and 2016. I will also discuss how the measurements constrain the Higgs boson’s couplings to Standard Model particles as well as the existence of new physics. [Preview Abstract] |
Monday, April 16, 2018 11:45AM - 11:57AM |
R08.00006: Search for the standard model Higgs boson decaying to two muons in pp collisions at center-of-mass energy at 13 TeV Xunwu Zuo, Andrew Carnes, Andrew Brinkerhoff, Pierluigi Bortignon, Dimitri Bourilkov, Sergei Gleyzer, Darin Acosta A search for the standard model Higgs boson decaying to two muons is presented. The analysis is conducted using data recorded by the CMS experiment at the LHC in the 2016 at a center-of-mass energy of 13 TeV, corresponding to an integrated luminosity of 35.9 fb$^{\mathrm{-1}}$. Limits are set on the cross section times branching fraction of the Higgs boson decaying to two muons for mass hypotheses between 120 and 130 GeV. For a Higgs boson with a mass of 125 GeV decaying to two muons, the 95{\%} confidence level observed (expected) upper limit on the production rate is found to be 2.64(2.08) times the standard model value. The combination with data recoded at center-of- mass energies of 7 and 8 TeV yields a 95{\%} confidence level observed (expected) upper limit of 2.64(1.89) times the standard model value. This corresponds to an upper limit on the Higgs boson branching fraction to muons of 5.7*10$^{\mathrm{-4}}$, assuming standard model production cross sections. [Preview Abstract] |
Monday, April 16, 2018 11:57AM - 12:09PM |
R08.00007: Multivariate techniques for detection of $ttH\rightarrow\gamma\gamma$ events in ATLAS at $\sqrt{s}=$ 13 TeV Jennet Dickinson Higgs production in association with top quarks ($ttH$) is predicted by the Standard Model at a rate of about 1\% of the total Higgs cross section. This process directly probes the Higgs-top coupling, a critical parameter for isolating Beyond the Standard Model contributions to Higgs physics. The ATLAS search for $ttH$ events in conjunction with the decay $H\rightarrow\gamma\gamma$ takes advantage of the high photon detection efficiency and energy resolution of the ATLAS electromagnetic calorimeter, as well as the relatively low rate of diphoton background processes. The application of multivariate techniques to separate $ttH\rightarrow\gamma\gamma$ from diphoton backgrounds improves the sensitivity to $ttH$ compared to a simple cut-based analysis. With 36.1 fb$^{-1}$ of data, the expected significance in the $ttH\rightarrow\gamma\gamma$ channel is $1.7\sigma$, while the observed significance is $0.9\sigma$. In combination with other Higgs decay channels, $ttH\rightarrow\gamma\gamma$ contributes to evidence for $ttH$ production at the $4.2\sigma$ level in 36.1 fb$^{-1}$ of data. [Preview Abstract] |
Monday, April 16, 2018 12:09PM - 12:21PM |
R08.00008: Measurement of fiducial and differential cross sections of the SM Higgs boson in the 4l decay channel using the ATLAS detector. Andrea Gabrielli The latest results on the measurement of the fiducial and differential cross sections of the Higgs boson in the 4l decay channel with the ATLAS detector are presented, using approximately 36 fb-1 of pp collision data collected at 13 TeV. [Preview Abstract] |
Monday, April 16, 2018 12:21PM - 12:33PM |
R08.00009: Off-shell Higgs signal strength measurement in the high-mass ZZ final states with the ATLAS detector Heling Zhu Measurements of the ZZ final states in the mass range above the 2mZ thresholds provide a unique opportunity to measure the off-shell coupling strength of the Higgs boson. By correlating the measurement of the off-shell signal strength with the signal strength measurement on peak, the total width of the Higgs boson can be constrained indirectly. The measurements of the off-shell Higgs couplings in Higgs decay channels ZZ $\to $ 4l and ZZ $\to $ 2l2$\nu $ will be presented. The results are based on the data collected with the ATLAS experiment in proton-proton collisions at 13 TeV during the 2015 and 2016 data taking period, corresponding to an integrated luminosity of 36.1 fb$-$1. [Preview Abstract] |
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