September 10, 2008
Speaker: Prof. Andrea Lommen, Franklin and Marshall College
Title: "Gravitational Wave Burst Detection Using Pulsars"
Abstract:
At the time of this talk, pulsar timing for gravitational wave
detection will be in the midst of becoming an internationally
coordinated effort. I will review the idea of using pulsars to detect a
very low-frequency stochastic background of gravitational waves, and
discuss current limits that pulsar timing places on the energy density
of gravitational waves and what those limits correspond to in terms of
cosmological models, most notably the merger rate of super-massive
black holes in the early universe. I have become interested in the
possibility of taking these ideas farther and using pulsar timing to
detect bursts of gravitational radiation from a number of different
possible sources, which I will describe.
September 24, 2008
Speaker: Prof. David Saltzberg, UCLA
Title: "The ANITA telescope: A one million square kilometer objective lens for high energy neutrinos"
Abstract:
The Antarctic Impulsive Transient Antenna (ANITA) is a long-duration
balloon payload built to detect >3 EeV cosmic neutrinos. Such
neutrinos may reveal the true nature of the most powerful astrophysical
accelerators, and would allow us to probe the weak interaction at 150
TeV, an order of magnitude higher C.M. energy than at terrestrial
machines.
A near-certain source of these neutrinos is provided by the GZK effect,
in which the highest energy cosmic rays produce pions by scattering on
the 3K cosmic microwave background. The ANITA instrument uses the
Askaryan effect to detect neutrinos interacting in the Antarctic ice,
which produce radio-cherenkov radiation. Data from our first full
flight on a NASA long-duration balloon at 120,000 feet will be shown.
I will also describe the improved instrument we built to fly this
upcoming December. Ideas for achieving the next order of magnitude in
senstivity will be discussed.
October 15, 2008
Speaker: Brendan Casey, FNAL
Title: "Quark flavor physics highlights of 2008"
Abstract:
I will give an overview of some interesting results that have recently
come out of the B-factory and Tevatron programs. I will briefly cover
spectroscopy where Belle, BaBar, and DØ have all claimed discovery of
new states in summer 2008. Next, I will discuss searches for new
sources of CP violation needed to explain the matter dominance of our
universe. Here, I will focus on anomalous direct CP violation seen in
charmless two-body B decay at B-factories and anomalous indirect CP
violation seen in Bs mixing at the Tevatron. Finally, I will discuss
searches for new charged current interactions that violate lepton
universality such as a charged Higgs where information is now available
from top, bottom, charm, and strange quark decay.
October 22, 2008
Speakers: Bence Kocsis, Princeton University and Ryan O'Leary, CFA - Harvard University
Title: "Gravitational waves from scattering of stellar-mass black holes in galactic nuclei"
Abstract:
We will discuss a new and interesting source of gravitational waves for ground-based observatories such as LIGO. In the nuclei of most galaxies, stellar mass black holes segregate from the stars and form a steep density cusp around the supermassive black hole in the center.
During two-body encounters between the BHs, occasionally enough gravitational waves are emitted to form a binary, which rapidly coalesces in less than one year. The BH-BH mergers are predominately eccentric during their merger in the LIGO band. This distinguishes them from other binary inspiral events, which circularize before becoming detectable, and allows us to use future ground-based detectors to actually probe the astrophysics inside of galacticnuclei. We also show that eccentric mergers extend the observable range of LIGO to larger masses than thought possible before, even up to 700 M_sun.
October 29, 2008
Speaker: David Khatidze, Columbia University
Title:"Measurement of the electron charge asymmetry in ppbar -> W+X -> enu + X events"
Abstract:
We present a measurement of the electron charge asymmetry in p¯p ? W + X ? e + X events at a center of mass energy of 1.96 TeV using 0.75 fb?1 of data collected with the D0 detector at the Fermilab Tevatron Collider. The asymmetry is measured as a function of the electron transverse momentum and pseudorapidity in the interval (?3.2, 3.2) and is compared with expectations from next-to-leading order calculations in perturbative quantum chromodynamics. These measurements will allow more accurate determinations of the proton parton distribution functions.
November 12, 2008
Speaker: Prof. Omar Benhar, INFN and Department of Physics "Sapienza" Universita' di Roma, Italy
Title: "Modeling nuclear effects in neutrino scattering"
Abstract:
I will outline the theoretical description of nuclei based on nonrelativistic many-body theory and realistic hamiltonians, and discuss its application to the study of electron- and neutrino-nucleus scattering observables.
November 19, 2008
Speaker: Lidija Zikovic, Columbia University
Title: "Closing in on the Higgs Boson"
Abstract:
The Standard Model describes the unification of electromagnetic and
weak interactions. It was thoroughly tested over past thirty years,
and represents one of the major successes of modern physics. This
theory predicted the existence and the masses of the weak bosons. The
last remaining piece of the puzzle is the Higgs boson whose existence
is crucial for our understanding of the origin of particle masses.
Direct searches at LEP put a lower limit on the Higgs boson mass, and
together with precision measurement constrained it to ~<200 GeV. The
D0 and CDF experiments at the Tevatron recently excluded a new
interval in the Higgs mass. In this time when we are entering LHC era,
we are coming closer to the discovery or exclusion of the SM Higgs
boson.\\ I will discuss current searches for the SM Higgs boson with
the D0 experiment at Tevatron, highlighting the most important
techniques. I will also draw a parallel with future searches at LHC,
showing what we can learn from Tevatron experience.
December 3, 2008
Speaker: Prof. Karol Lang, University of Texas
Title: "A search for neutrinoless double beta decay with NEMO-3 and SuperNEMO detectors"
Abstract:
The observation of neutrino oscillations has proved that neutrinos have mass.This discovery has renewed and strengthened the interest in neutrinoless double beta decay experiments which provide the only practical way to determine whether neutrinos are Majorana or Dirac particles.NEMO-3, located in the Modane Underground Laboratory in the Frejus Tunnel under the French-Italian Alps, is an ongoing experiment looking for neutrinoless double beta decays using a powerful technique for detecting a two-electron final state by employing an apparatus combining tracking, calorimetry, and the time-of-flight measurements. We will present results from NEMO-3 and will discuss the status of SuperNEMO, the next generation experiment that will exploit the same experimental technique to extend the sensitivity of the current search.
