Bulletin of the American Physical Society
Spring 2017 Joint Meeting of the Texas Section of AAPT, Texas Section of APS, and Zone 13 of the Society of Physics Students
Volume 62, Number 3
Thursday–Saturday, March 9–11, 2017; San Antonio, Texas
Session B2: High Energy Physics, General Physics |
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Sponsoring Units: APS Chair: Daniel Marble, Tarleton State University Room: Oppenheimer OC 110 |
Friday, March 10, 2017 10:00AM - 10:12AM |
B2.00001: Search for beyond the Standard Model Higgs boson decaying to a pair of new light bosons in boosted dimuon final states Sven Dildick Light bosons that couple weakly to Standard Model (SM) particles are predicted in several extensions of the SM. These extensions include supersymmetric (SUSY) models with hidden valleys (dark SUSY) or with extended Higgs sector (such as NMSSM). In these scenarios the new light bosons are produced in non-SM Higgs decays or in the cascade of SUSY particles. In dark SUSY the light bosons may also have a non-zero lifetime. If the dark bosons couple to muons this may result in displaced muons in the event signature. While exotic SM Higgs decays can hide in indirect searches, e.g. because the branching ratio is too small, direct searches for light bosons can provide a powerful alternative to understanding the nature of the SM Higgs boson. We present preliminary results at 13 TeV of a direct search for non-SM Higgs boson decays to a pair of new light bosons with boosted dimuons in the final state using the CMS detector. [Preview Abstract] |
Friday, March 10, 2017 10:12AM - 10:24AM |
B2.00002: Resonant Di-Higgs Production in the $b \bar{b} W^{+} W^{-}$ channel with W leptonic decays: Probing the Electroweak Phase Transition at the LHC Tao Huang With the discovery of the Higgs boson at the LHC, exploring the thermal history associated with electroweak symmetry-breaking (EWSB) has taken on heightened interest. The process of EWSB in the early Universe, the electroweak phase transition, provides conditions able to explain the observed cosmic matter-antimatter asymmetry, if the transition were of first order and sufficiently strong. The prospects for resonant di-Higgs production searches at LHC, in the context of probing the electroweak phase transition, will be presented. We explore the sensitivity of the $b \bar{b} W^{+} W^{-}$ channel, with $W$ leptonic decays. The presence of neutrinos in the final state do not allow the reconstruction of the invariant mass of the heavy scalar, diminishing the sensitivity of this channel. We present a novel technique, called High Mass Estimator (HME), that allows to fully reconstruct the kinematic of the process, and therefore to reconstruct the heavy Higgs invariant mass. We prove that, with HME technique, this channel can be sensitive as much as $b\bar{b}b\bar{b}$, $b\bar{b}\gamma\gamma$, and $b\bar{b}\tau\tau$ channels, leading to a potential discovery of resonant di-Higgs production with the datasets accumulated in High Luminosity phase of LHC, foreseen in 2035 [Preview Abstract] |
Friday, March 10, 2017 10:24AM - 10:36AM |
B2.00003: Distinguishing Standard Model Extensions using Monotop Chirality Ian Taulli, Teruki Kamon, Ryan Mueller Many theories beyond the standard model of particle physics may produce top quarks with a specific chirality, either left-handed (LH) or right-handedness (RH). The handedness can be reflected in several kinematical distributions of the decay products of the top quark. We suggest a ratio of the bottom-quark energy to the top-quark energy, to examine the chirality. Monte Carlo simulations were performed to evaluate what would happen at the LHC if there exists a heavy color-triplet scalar mediator that decays into either a LH or RH top quark along with a dark matter particle. In the hadronic decay mode of the top quark, followed by hadronic decays of the simulation shows that the handedness of the model can be discerned to a high degree of accuracy by studying the shape of the distribution. If new models of particle physics preferentially produce a top quark of a specific chirality then they can be investigated at the LHC, providing a robust test of the standard model. [Preview Abstract] |
Friday, March 10, 2017 10:36AM - 10:48AM |
B2.00004: Dynamics of Particles in the Early Universe at High Temperature Samina Masood We study the electromagnetic properties of particles in the early universe and show that electromagnetic properties of the system become explicit functions of temperature for such systems. Parameters of the system such as dielectric constant, magnetic reluctivity, Debye length and the plasma frequency are expressed as a function of temperature in the early universe. Renormalization techniques of QED are used to determine the collective behavior of the medium. We compute propagation speed, refractive index, plasma frequency and Debye shielding length of a QED plasma at extremely high temperatures in the early universe. [Preview Abstract] |
Friday, March 10, 2017 10:48AM - 11:00AM |
B2.00005: Planck Constraint on Relic Primordial Black Holes Steven Clark Recent detections by LIGO have shown evidence of black hole mergers in the galaxy. While current black hole formation is well understood, numerous works have investigated methods through which they could be created in the early universe. We investigate constraints on the abundance of these black holes known as primordial black holes (PBHs) in the mass range $10^{15}-10^{17}$ g using data from the Cosmic Microwave Background (CMB) and extragalactic gamma-ray background (EGB). PBHs in this mass range emit energy through Hawking radiation which leaves an imprint on the CMB through modification of the ionization history and the damping of CMB anisotropies. Using a model for redshift dependent energy injection efficiencies, we show that a combination of temperature and polarization data from Planck provides the strongest constraint on the abundance of PBHs for masses $\sim 10^{15}-10^{16}$ g, while the EGB dominates for masses $> 10^{16}$ g. Both the CMB and EGB now rule out PBHs as the dominant component of dark matter for masses $\sim 10^{15}-10^{17}$ g. Planned MeV gamma-ray observatories are ideal for further improving constraints on PBHs in this mass range. [Preview Abstract] |
Friday, March 10, 2017 11:00AM - 11:12AM |
B2.00006: Cosmological Signature In Light Mass Dark Matter Searches With Phonon Mediated Detectors Fedja Kadribasic We are presenting a method for using solid state detectors with directional sensitivity to Dark Matter interactions, which provides an excellent tool to discriminate for WIMPs originating from the galactic sources against the irreducible backgrounds including solar neutrinos. There is a large body of literature for high-mass WIMPs detectors with directional sensitivity, in particular those using low-pressure TPC detectors, but there is no available technique to cover WIMPs in the mass range $<$ 500 MeV. We argue that very low temperature phonon-mediated semiconductor detectors, such as those developed for the future low-mass WIMPs search in SuperCDMS and beyond, also allow for directional sensitivity if properly calibrated. We find a signal to noise ratio for WIMPs of Mass $< $1 GeV large enough to identify the direction of nuclear recoil from WIMP scattering. This provides, for the first time, a straightforward directional sensitivity for low-mass WIMP dark matter. [Preview Abstract] |
Friday, March 10, 2017 11:12AM - 11:24AM |
B2.00007: The influence of dark energy on the expansion rate of the universe and its effects on dark matter relic abundance Esteban Jimenez Moya The expansion rate of the universe had a strong influence on the origin of the dark matter abundance during the early stages of the universe’s evolution, mainly prior to big-bang nucleosynthesis. Any departure of the expansion rate of the universe from the standard cosmological model during that time can modify the dark matter abundance. In this talk, I will explore the role played by a scalar field on the modification of the expansion rate of the universe arising from scalar-tensor theories of gravity coupled both conformally and disformally to matter, and also, I will show how these variations to the expansion rate would modify the dark matter content of the Universe. [Preview Abstract] |
Friday, March 10, 2017 11:24AM - 11:36AM |
B2.00008: Translational and angular accelerations measured inside a novel, physical model of a human head Jacob Moldenhauer, Stephen Slaughter, Cora Keil, Sydney McCloskey, Andrew Chang, James Frisby Studies of collisions occurring during concussive level events, such as in athletic competitions and training sessions consistently report translational and angular accelerations in correlation with concussions. In fact, more severe concussions seem to occur from relatively higher angular accelerations rather than higher translational accelerations. Currently, most measurements are recorded from devices placed externally on the head or inside the helmet of an athlete. We present results obtained from placing inertial measurement units (IMUs) inside a physical model of a human head, brain and skin constructed from ballistic gel and other materials during concussive type collisions. We compare the translational and angular accelerations inside the head to those obtained outside the head in a consistent collision. While the translational accelerations are consistent within $1\sigma$, $a_{in}=34.8 \pm 2.1 \,g$ and $a_{out}=29.2 \pm 4.1 \,g$, for inside and outside, respectively, the angular accelerations inside the head $\alpha_{in}=7545 \pm 1004$ rad/s$^2$ consistently measure larger (more than $2\sigma$) from those obtained outside the head, $\alpha_{out}=3235 \pm 1000$ rad/s$^2$. This new data from inside a physical model of a head supports higher angular accelerations in mo [Preview Abstract] |
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