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Events During the Week of
November 29th through December 5th, 2009
Monday, November 30th, 2009
High Energy Seminar
Fully Leptonic Charged B Decays at Babar.
- Time: 4:00 pm
- Place: 4274 Chamberlin
- Speaker: Dr. Luke Corwin, Indiana University
- Abstract: The Babar detector was a multi-purpose particle physics detector
at the PEP-II accelerator in SLAC National Laboratory. It is named after
its primary objects of study, the B mesons, and a cartoon elephant. The
accelerator was tuned to produce the Upsilon(4S) resonance, which almost
always decays into a pair of B mesons. In this talk, I will describe the
challenges and methods of searching for events in which a charged B decays
into a charged lepton and a neutrino. The primary focus will be the search
for charged B mesons decaying into a tau lepton and a neutrino in the recoil
of a semi-leptonically decaying B. I will review complementary searches at
Babar and the Belle experiment in Japan, and I will present the implications
of these results for physics beyond the Standard Model.
- Host: Matthew Herndon
Tuesday, December 1st, 2009
Chaos & Complex Systems Seminar
Title to be announced
- Time: 12:05 pm
- Place: 4274 Chamberlin (Refreshments will be served)
- Speaker: Linda Reivitz, UW School of Nursing
Astronomy Colloquium
"The Invisibles: Revealing dark matter and the lower limit on galaxy Formation"
- Time: 3:30 pm
- Place: 3425 Sterling Hall
- Speaker: Beth Willman, Haverford College
- Abstract: Tracking the growth of stellar mass in galaxies is a fundamental characterization of the galaxy population. Recent observations have shown that the total mass in L>L* red galaxies has increased by a factor of ~2 at z<1, although at different rates as a function of galaxy mass. Despite the advance made by these studies of the whole galaxy population, until recently it has not been clear if the growth of the red sequence depended on environment. Galaxy clusters are a useful probe of this as they sample the most extreme environments. However, progress toward answering this question has been hampered by a lack of deep multi-band imaging of a large sample of clusters that can be well linked to those in the local universe. To address this I will present the evolution of the red sequence as measured in 16 intermediate redshift clusters drawn from the ESO Distant Cluster Survey (EDisCS). Unlike massive x-ray selected clusters, these clusters have velocity dispersions that make them likely progenitors of clusters that populate the local Universe. I will show how the luminosity function (LF) of red-sequence galaxies in these clusters has evolved over 50% of cosmic time, highlighting the rapid buildup of the faint cluster galaxy population. I will also compare the evolution of the red sequence in clusters to the evolution of the field red sequence population and show that they evolve at different rates. Finally I will address how the total mass on the red sequence evolves in clusters and will use this to constrain the mechanisms of how red galaxies can be added to clusters. From this analysis it appears likely that some fraction of the light in recently added cluster red sequence galaxies is currently in the in the form of intracluster stars.
Astronomy Colloquium
"The invisibles: Revealing dark matter
- Time: 3:30 pm
- Place: 3425 Sterling Hall
- Speaker: Beth Willman, Haverford College
- Abstract: In the past five years, more than two dozen dwarf galaxies have been discovered around the Milky Way and M31. Many of these discoveries are more than 100 times less luminous than any galaxy previously known and a million times less luminous than the Milky Way itself. The advent of wide-field, digital surveys (in particular the Sloan Digital Sky Survey) facilitated these discoveries, and hint at a much larger population that will be revealed in future imaging datasets. Despite their tiny luminosities, these dwarfs are the most dark matter dominated and most metal-poor galaxies known. These objects are changing our understanding of galaxy formation at the lowest luminosities and are currently our most direct tracers of the properties of dark matter on small scales. I will discuss recent and on-going progress in this field, highlighting evidence that the low luminosities of the ultra-faint dwarf galaxies are a product of nature rather than nurture.
- Host: Laura Chomiuk
Wednesday, December 2nd, 2009
No events scheduled
Thursday, December 3rd, 2009
R. G. Herb Condensed Matter Seminar
Title to be announced
- Time: 10:00 am
- Place: 5310 Chamberlin
- Speaker: HongWen Jiang, UCLA
- Host: Susan Coppersmith
NPAC (Nuclear/Particle/Astro/Cosmo) Forum
Acoustic Detection of Ultra-high Energy Neutrinos
- Time: 4:00 pm
- Place: 4274 Chamberlin
- Speaker: Naoko Kurahashi, Stanford
- Abstract: Study of Acoustic Ultra-high energy Neutrino Detection (SAUND) phase
II uses 1000km^2 of ocean as a neutrino detector. SAUND
aims to detect comic ray neutrinos of GZK energies and beyond
(>10^18eV) acoustically by utilizing the ocean water as the target and
an existing US Navy underwater microphone array as sensors. A DAQ
system was developed and deployed in 2005. The experiment ran during
2006 and 2007, collecting over 1 TB of data with over 100 days of
cumulative livetime. A study of the ocean ambient noise was performed
using SAUND data, characterising the background for neutrino signals.
Data analysis to isolate signals is performed in parallel to Monte
Carlo studies of the detector to optimize cut efficiencies and set a
neutrino flux limit in the ultra-high energy region.
- Host: Teresa Montaruli
Friday, December 4th, 2009
Physics Department Colloquium
VERITAS Results on Gamma-Ray Astronomy and the Future Prospects for AGIS
- Time: 4:00 pm
- Place: 2241 Chamberlin Hall (coffee at 3:30 pm)
- Speaker: Rene Ong, UCLA
- Host: Montaruli
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