Joint High Energy Physics/Theory Seminars
HEP/theory seminar mailing list
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2010/2011
Organizers: Andriy Badin, Ashutosh Kotwal, Tom Mehen and Kate Scholberg
Held in Duke Physics Room 278 (old Room 246) (Unless otherwise noted)Regular time for Fall '11 semester: Wednesdays 10 am. Currently all dates not listed are open.
Regular time for Spring '12 semester: Mondays or Wednesdays 1 pm. Currently all dates not listed are open.
September 21: Matthew Wetstein, U. of Chicago
For decades, the high energy physics (HEP) community has relied on photomultiplier tubes (PMTs) to provide low cost, large-area coverage for a wide variety of detector systems. Advances in material science and low-cost electronics allow for the possible development of new, high-resolution photodetector technology at costs competitive with those of conventional PMTs. The Large Area Picosecond Photodetector (LAPPD) collaboration is developing low-cost, compact microchannel plate (MCP) photomultiplier tubes capable of instrumenting large areas, and with sub millimeter, sub nanosecond spatial and temporal resolutions. One possible application of these large area MCPs could be the development of high resolution water cherenkov (WC) neutrino detectors with performance characteristic closer to those of Liquid Argon Time Projection Chambers (LAr-TPCs). In this talk, I give a brief overview of the LAPPD project. I will present some of our achievements en route to a fully commercializable photodetector. I will also discuss possible directions for MCP-based neutrino detectors, as well as tentative plans for a small, experimental WC prototype.
October 19: Nathan Goldschmidt, University of Florida
We search for resonant production of ttbar pairs in 4.8/fb integrated luminosity of ppbar collision data at sqrt(s)=1.96 TeV in the lepton+jets decay channel, where one top quark decays leptonically and the other hadronically. A matrix element reconstruction technique is used; for each event a probability density function (pdf) of the ttbar candidate invariant mass is sampled. These pdfs are used to construct a likelihood function, whereby the cross section for resonant ttbar production is estimated, given a hypothetical resonance mass and width. The data indicate no evidence of resonant production of ttbar pairs. A benchmark model of leptophobic Z' to ttbar is excluded with m_Z' < 900 GeV/c^2 at 95% confidence level.
November 9: Ciaran Williams, Fermilab
I will discuss currently available theoretical Monte Carlo codes for LHC physics predictions, focusing on MCFM and its role in the wider theoretical toolbox. I will give an overview of the codes capabilities and present some recent phenomenological applications.
April 30: Kendall Mahn, University of British Columbia, 3 pm
Neutrino mixing is consistent with three generations of neutrinos and a unitary mixing matrix. However, there is tension between the LSND experiments result of antineutrino oscillation at short baseline and the lack of such observation with the analogous result of the MiniBooNE experiment with neutrinos, indicating a possible third m^2 around 1 eV^2 due to more than three neutrino generations or other exotic physics. A complementary way to access the same physics as nu_e appearance is nu_mu disappearance. The MiniBooNE-only nu_mu and nu_mu_bar disappearance search was limited by flux and cross section uncertainties, which are reduced with the addition of data from the SciBooNE experiment, also present in the Fermilab Booster Neutrino beamline. This talk will describe the current picture of short-baseline neutrino disappearance, the flux constraint provided by SciBooNE, and the status of the joint MiniBooNE-SciBooNE analysis.