Joint Theory Seminar
Speaker: Markus Luty (UC Davis)
Title: UV and IR Asymptotics of 4D Quantum Field Theory
Host: Hsin-Chia Cheng
Room: 432
Abstract:
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High-Energy Seminars
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8:00am - 9:00am
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HE Seminar
Speaker: Bruce Schumm (UCSC)
Title: Searching for Supersymmetry with Final State Photons at ATLAS
Host: Chertok
Room: 416
Abstract:
Gauge-mediated Supersymmetry-breaking has a propensity to provide scenarios for which the next-to-lightest Supersymetric particle is a neutralino that decays promptly to an essentially massless gravitino. In many of these scenarios the NLSP neutralino has significant bino (SUSY partner of the U(1) gauge boson) content, which in turn possesses significant coupling to the photon. Thus, a major thrust in the possible discovery of gauge-mediated SUSY is the search for events with significant missing energy accompanied by one or more photons. I'll discuss the searches that are being done on ATLAS, their results to date, and some thoughts about where ATLAS might be headed in the future with regard to photon + missing energy final states.
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High-Energy Seminars
Time:
4:10am - 5:10am
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LHC Lunch
Speaker: Kit Colwell
Title: Dyons and Helicity Amplitudes
Host: Markus Luty
Room: 430
Abstract: Historically, the theory of monopoles and dyons has been plagued with nonlocality and broken Lorentz covariance, leading to difficulty in calculations of amplitudes involving magnetic currents. We present the Zwanziger 2-gauge formalism that addresses these problems, and use the spinor helicity method with twistors to greatly simplify results, such as in light-by-light scattering.
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High-Energy Seminars
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Joint Theory Seminar
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Room: 432
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High-Energy Seminars
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8:00am - 9:00am
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HE Seminar
Speaker: David Curtin (YITP Stony Brook)
Title: New Substructure Variables for Boosted RPV Gluinos
Host: Yuhsin Tsai
Room: 416
Abstract: We use modern jet-substructure techniques to propose LHC searches for multijet-resonance signals without leptons or missing energy. We focus on three-jet resonances produced by R-parity-violating decays of boosted gluinos, showing that shape analyses searching for a mass peak can probe such gluinos up to masses of 750 GeV (650 GeV) with 20/fb (5/fb) at the LHC at 8 TeV. This complements existing search strategies, which also include counting methods that are inherently more prone to systematic uncertainties. Since R-parity-violating gluinos lighter than all squarks hadronize before decaying, we introduce new color-flow variables, "radial pull" and "axis contraction", which are sensitive to the color structure of the R-hadron's decay. The former measures the inward pull of subjets in a fat jet, while the latter quantifies the inward drift of the N-subjettiness axes when changing the distance measure. We show that they can dramatically improve the discrimination of a boosted gluino signal versus QCD, ttbar, and combinatoric background for gluino masses comparable to the top mass. Cuts on axis contraction also noticeably improve the resonance shape for heavy gluinos with masses above 500 GeV. With minor adaptations, these variables could find application in substructure searches for particles in different color representations or with other decay topologies.
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High-Energy Seminars
Time:
4:10am - 5:10am
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LHC Lunch
Speaker:
Title: CMS Higgs to tau tau search
Host: Markus Luty
Room: 430
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High-Energy Seminars
Time:
5:30am - 6:30am
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Yes - 2 days 4 hour 0 minutes before start
Description:
Special Joint Theory Seminar
Speaker: Raman Sundrum
Title: Metaphor for Dark Energy
Host: John Terning
Room: 432
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High-Energy Seminars
Time:
5:30am - 6:30am
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Joint Theory Seminar
Speaker: GIovanni Villadoro (SLAC)
Title: Mini-Split
Host: Nemanja
Room: 432
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High-Energy Seminars
Time:
8:00am - 9:00am
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Description:
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High-Energy Seminars
Time:
4:10am - 5:10am
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Description:
LHC Lunch
Speaker: Yun Jiang
Title: Multiple/Degenerate Higgs scenarios within the NMSSM perspective
Host: Markus Luty
Room: 430
Abstract:
We have assessed the extent to which various semi-constrained NMSSM (scNMSSM) scenarios with, at least, a $\sim$125 GeV Higgs are able to describe the Higgs-like signal at the LHC and Tevatron. In light of the fact that broadened mass peaks are natural, we proposed a novel idea --- ``degenerate Higgs'' --- which predicts that not merely one but more than one Higgs has mass near 125 GeV. For the purpose of verifying our idea, we examined scNMSSM scenarios in which both the lightest Higgs h1 and the second lightest Higgs h2 have mass near 125 GeV. As what we expected, very substantially enhanced $\gamma\gamma$ and other signals are possible. Furthermore, we developed diagnostic tools that could discriminate whether or not there are two (or more) Higgs bosons versus just one contributing to the LHC signals at 125 GeV.
In addition, two interesting multiple Higgs scenarios will be presented. (i) For the 125 GeV+136 GeV LHC-Tevatron scenario, we showed that the best fit to the Tevatron results in the $b\bar{b}$ channel and the mild excesses in CMS data in the $\gamma\gamma$ channel at 136 GeV and in the $\tau\tau$ channel above 132~GeV can be explained by the heavier Higgs h2 in this mass range, together with the lightest h1 at 125 GeV discovered at the LHC. (ii) For the 98+125 LEP-LHC scenario, we saw that the lightest Higgs h1 is consistent with the small LEP excess at 98 GeV whereas the heavier Higgs h2 possesses the primary features of the LHC Higgs-like signals at 125 GeV, including an enhanced $\gamma\gamma$ rate. Both scenarios can be consistent with practically all available signal rates, including a reduced rate in the $b\bar{b}$ ($\tau\tau$) channel around 98 GeV (125 GeV) in the former (latter) scenario.
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High-Energy Seminars
Time:
5:30am - 6:30am
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Joint Theory Seminar
Speaker: Mithat Unsal
Title: Resurgence, transseries, and towards a continuum definition of QFT
Host: John Terning
Room: 432
Abstract:
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High-Energy Seminars
Time:
8:00am - 9:00am
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HE Seminar
Speaker: Doug Wright (LLNL)
Title: How to Unlock the Hidden Photon Collider in the LHC
Host: Mani Tripathi
Room: 416
Abstract: The physics reach of the LHC can be extended by detecting events in which the beam protons interact via the gamma-gamma or gluon-gluon process and remain intact. Since there is no "underlying event" background from the breakup of the protons, which occurs in typical proton interactions, this central exclusive production (CEP) mode can be used as an experimentally clean way to observe many new physics channels, such as a low-mass SUSY lepton, the Higgs boson, and anomalous production of W and Z boson pairs and to study hard-diffractive QCD physics. I will describe the upgrade effort of the CMS detector at the LHC to detect the off-momentum protons produced by these exclusive events and the expected physics performance.
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High-Energy Seminars
Time:
4:10am - 5:10am
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Description:
LHC Lunch
Speaker: Ralph Edezhath
Title: SUSY Avatars
Host: Markus Luty
Room: 430
Abstract: The MSSM provides a dark matter candidate and alleviates fine tuning, but it is difficult to see the impact of collider limits on the dark matter parameter space. We present some simple SM extensions adding only colored 'partners' and a DM candidate that couple to quarks. These could be treated as effective theories of new physics that preserves naturalness, and enable us to clearly see the connection between collider searches, direct detection limits and the relic density of dark matter.
Joint Theory Seminar: Markus Luty