Mondays at 4:00 PM (Unless otherwise noted)
Coffee and Cookies at 3:45 in the lobby

Ronald Geballe Auditorium, PAA Rm. A-102 (Unless otherwise noted)

Winter Quarter Colloquium Chair:
Toby Burnett

January 9
Jeffrey Wilkes (University of Washington)
Title: The T2K neutrino experiment
Abstract: The T2K (Tokai to Kamioka) experiment sends a beam of neutrinos 295 km through the Earth across Japan, to measure neutrino oscillations, a phenomenon that illustrates basic quantum mechanics on a macroscopic scale, and lets us learn more about the weak interaction. Neutrinos come in three flavors, electron, muon, and tau, and only interact with matter through the weak force, so most pass through the Earth without interacting. In June, 2011, T2K announced the first experimental evidence for a rare oscillation process, where particles in a high intensity muon-flavored neutrino beam were detected as electron-flavored neutrinos after traveling from the J-PARC accelerator lab at Tokai to the massive Super-Kamiokande underground neutrino detector near Kamioka. T2K is also making the most accurate measurements to date of oscillations from muon neutrinos to tau neutrinos, the process that provided the first evidence of non-zero neutrino mass when reported in 1998 by Super-Kamiokande. The Tohoku Earthquake in March, 2011 interrupted T2K data taking, but damage at the Tokai accelerator lab has been repaired, and running will resume later this month. Current status and future plans for T2K will be described and discussed.

January 17 (Tuesday)
Christos Leonidopoulos (CERN)
Title: A comprehensive search strategy for New Physics at the LHC
Abstract: The end of the 2011 Run brings the LHC physics program to a major crossroads: A significant region of the SUSY phase space has already been excluded, and we may be able to rule out a SM Higgs by the end of 2012. An important question to ask ourselves centers on the next steps that need to be taken. In my view, the main priority for collider physics should be to ensure that our searches for New Phenomena are comprehensive and thorough, and that the analysis of the vast amount of collected data leaves “no stone unturned”. Perhaps more importantly, in the tuning process of our sophisticated Online Selection for the next Run, we should leave some room for the “unexpected” to be recorded and observed in the experiments. This is a process that determines the content of our datasets and, therefore, our discovery potential.

January 23                  
Matthew Kerr (Stanford)
Title: Pulsars: From Radio Waves to Gamma Rays
Abstract: Pulsars---rapidly pulsating radio sources---were discovered in 1967 and quickly determined to be the first known neutron stars. Forty-five years later, pulsar science is a many-faceted thing, encompassing studies of strongly magnetized plasmas, particle acceleration, general relativity, the neutron star equation of state, gravitational waves, massive star evolution, and the cosmic ray content of the Galaxy. Despite great progress in these fields, fundamental mysteries remain, including the structure of neutron star magnetospheres and the mechanism by which they generate their hallmark pulses. Because pulsars emit the bulk of their radiation at 1 GeV, the Fermi Large Area Telescope is ideal for their study. After an overview of pulsar science at radio wavelengths, I will discuss the advances made after three years of Fermi observations, including identification of the site of gamma-ray emission and the LAT-guided discovery of new millisecond pulsars that may be used in gravitational wave arrays. I will conclude with prospects for probing magnetospheric physics with geometric models and phase-resolved gamma-ray spectroscopy.

January 25 (Wednesday)                  
Zhenyu Ye (FNAL)
Title: Top-Quark Mass Measurements at D0
Abstract: The top quark is the heaviest fundamental particle discovered so far. The large mass of the top quark, corresponding to a Yukawa coupling to the Higgs boson equal to unity within the uncertainty, suggests a special role for the top quark in the breaking of electroweak symmetry. The interest in the top-quark mass also arises from the constraint imposed on the mass of the Higgs boson from the relationship among the values of the top-quark mass, Higgs-boson mass and the radiative corrections to the W-boson mass. I will present the latest top-quark mass measurements by the D0 experiment at the Fermilab Tevatron proton-antiproton collider. I will also discuss future prospects of top-quark mass measurements.

January 30                  
Ben Monreal (UCSB)
Title: A weakly-interacting Universe: searching for the mass of the neutrino
Abstract: Our daily experiences with the Universe primarily involve electromagnetism and gravity. However, the weak interaction is often behind the scenes of astrophysics, working on many different systems in interesting ways. One weakly-interacting component of the Universe, the neutrino, has a small but still-unmeasured (despite 70 years of searching) mass; depending on this mass, neutrinos may or may not have a major impact on small-scale structure formation. I will describe two experiments, KATRIN and Project 8, that will try to measure the neutrino mass, calling on a broad and interdisciplinary mix of experimental techniques. The weakly-interacting side of the Universe may include the still-undetected dark matter; I will discuss one very recent advance in dark matter detector technology.

February 6                  
Sheldon Stone (Syracuse)
Title: In Pursuit of New Physics with LHCb
Abstract: The LHCb experiment is investigating the weak decays of charm and beauty with the objective of detecting physics beyond that explained by the Standard Model. I will discuss rare decays and CP violating decays, as well as searches for Majorana neutrinos.

February 9 (Thursday - PAA A-118)               
Alison Lister (University of Geneva)
Title: Searching for new physics using top quarks at the LHC
Abstract: The standard model of particle physics describes current collider physics data extremely well, but we know it has some limitations. Many theories beyond the standard model have been developed to solve at least some of these limitations and most introduce new particles at the TeV scale, a scale accessibly at the Large Hadron Collider. This talk focuses on describing one way to search for these new particles, by using the heaviest known fundamental particle, the top quark. Considerable emphasis will be placed on how top quarks are identified in the ATLAS detector, requiring a thorough understanding of almost all of the components of the detector. Recent results from the ATLAS experiment involving top quarks will be presented. Both measurements of its standard model properties and searches for new physics involving top quarks will be discussed.
Some remarks about the prospects for the 2012 data and future speculations will conclude this presentation.

February 13               
David Ceperley (University of Illinois at Urbana-Champaign)
Title: The phases of Hydrogen and Helium at High Pressure as revealed by simulations
Abstract: Hydrogen and helium account for much of the visible mass in the universe. Their properties are important for understanding the giant planets, Jupiter and Saturn, but experiments under the relevant conditions are challenging. Even though they are the simplest elements in the periodic table, calculating their properties is not simple since they are highly quantum systems. For example, it has long been an open question how hydrogen makes a transition from a molecular insulating state to an atomic metallic state. We have developed new simulation methods to treat such systems and using them, have studied molecular dissociation in liquid hydrogen and have observed clear evidence of an “extra” liquid-liquid phase transition for temperatures 600K < T < 1500 K. We have performed a “random structure search” to determine the ground-state crystal structures of atomic metallic hydrogen from 500 GPa to 5 TPa. We also examined hydrogen–helium mixtures at Mbar pressures and high temperatures (4000 to 10000 K) and determined the temperature, at a given pressure, when helium becomes insoluble in dense metallic hydrogen: this could explain some of the observed differences between Jupiter and Saturn.

February 16 (Thursday - PAA A-118)               
James Loach (Lawrence Berkeley National Lab)
Title: TBA
Abstract: TBA

February 22 (Wednesday - PAA A-110)               
Shih-Chieh Hsu (Lawrence Berkeley National Lab)
Title: TBA
Abstract: TBA

February 27              
Joe Formaggio (Massachusetts Institute of Technology)
Title: Weighing Neutrinos
Abstract: Neutrino oscillation experiments performed throughout the latter half of the twentieth century have yielded valuable information on the nature of neutrino masses and mixings. The evidence gathered represent the first significant challenge to the Standard Model of particle physics in many years of searching. As the next century begins, a new suite of precision experiments will come online to provide greater insight into the physics and significance of neutrino mass. This talk will review our current state of knowledge on neutrino masses, their connection to cosmology, and how new experiments will complement the knowledge of those two disciplines for years to come.

March 1 (Thursday - PAA A-118)              
Wojtek Fedorko (Michigan State University)
Title: TBA
Abstract: TBA

March 5              
Jason Detwiler (Lawrence Berkeley National Lab)
Title: TBA
Abstract: TBA