April 30, 2007
Speaker:
Prof. Elena Aprile - Physics Department, Columbia University
Title:
“First Results from the XENON10 Dark Matter Experiment
at the Gran Sasso Laboratory"
Abstract:
We report the first results from a search for Weakly Interacting Massive
Particles (WIMPs) with the XENON10 experiment operating underground at the Gran
Sasso Laboratory. XENON10 is the first dual phase (liquid/gas) xenon time
projection chamber (XeTPC) module realized within the XENON program. The
3D-postion sensitive detector has an active mass of 15 kg of liquid xenon,
viewed by two arrays ofcompact photomultipliers, which measure simultaneously
the scintillation and the ionization, via proportional scintillation in the
gas. Background rejection on an event-by-event basis is achieved through this
measurement and 3D event localization. In-situ gamma and neutron calibrations
have been carried out to define event selection and energy threshold for
nuclear recoil candidates. A " blind " analysis of ~60 live-days of
Dark Matter Search science data has been performed. Results of this analysis
will be presented. Plans to improve the experiment sensitivity within 2007 as
well as plans to initiate the next phase of the XENON program with a 100kg
scale TPC will also be addressed.
April 11, 2007
Presented by: Prof. Mike Shaevitz
Physics Department, Columbia University
Title:
First Results From The MiniBooNE
Oscillation Experiment at Fermilab
Abstract:
This seminar reports the initial results from a search for muon neutrino to
electron neutrino oscillations by the MiniBooNE Collaboration. MiniBooNE was
motivated by the result from the LSND experiment which presented evidence for
oscillations at the delta_mass squared scale around 1 eV2.
The MiniBooNE experiment uses a high intensity neutrino beam produced by
protons from the Fermilab Booster accelerator; the average muon neutrino energy
for this beam is ~800 MeV.
A 1 kton pure mineral oil detector instrumented with ~1500 photomultiplier
tubes is placed 540 m away from the production target and used to identify and
measure muon or electron neutrino events. MiniBooNE performed a
"blind" analysis, where all analysis selections and fitting
procedures are determined before candidate electron neutrino events are
examined. Results of this analysis will be presented for the current neutrino
mode data set corresponding to 5.58E20 protons on target.
April 4, 2007
Speaker:
Laura Cadonati - MIT, LIGO
Scientific Collaboration
Title:
“Panning for gravitational gold:
status and prospects for the search of gravitational wave events in the LIGO
data stream”
Abstract:
The Laser Interferometer
Gravitational-wave Observatory (LIGO) has been collecting data at design
sensitivity with its three km-scale interferometers since November 2005. The
LIGO Scientific Collaboration is currently sifting through this data stream,
looking for "gold plated" gravitational wave signatures. In this talk
I will describe ongoing efforts in the search for transient events, with
duration from a few milliseconds to a few seconds in the LIGO sensitive band.
Plausible sources for such events are coalescences of compact binary systems
and supernova explosions; other still unmodeled sources could also be waiting
to be discovered in the gravitational wave sky. While matched filtering can be
used to extract a known waveform from the noise (for instance, the inspiral and
ringdown phase of a binary coalescence), more general approaches combine data
from multiple interferometers, either incoherently or coherently, and impose
tight coincidence requirements across detectors for a detection. I will outline
the challenges facing these analyses, report on their performance and
preliminary results and discuss future prospects.
March 21, 2007
Speaker:
Mike Syphers
- FNAL
Title:
Accelerating Charged Particles to High
Energy -- past, present and future
Abstract:
Modern
high-energy accelerators used for high energy physics research have relied upon
the generation of electromagnetic fields oscillating at radio frequencies (RF)
to provide kinetic energy to charged particles. In this talk we will review the
history of RF accelerators and discuss some of the issues facing the advancement
of accelerators of ever-increasing size and complexity. Existing energy-frontier
accelerators using standard RF technology demand innovative upgrades to continue
to meet the requirements of the user community. As the Large Hadron Collider
finally nears completion in Europe, and an International Linear Collider
community attempts to form, these facilities, too, are designing toward
upgradeability. A short glimpse of the LHC, the ILC concept, and possible future
acceleration techniques will be provided.
March 7, 2007
Speaker:
Patrick Huber - University of Wisconsin,
Madison
Title:
Upgraded experiments with super neutrino
beams
Abstract:
I compare the sensitivities of possible
upgrades of superbeam experiments, namely NOvA, T2KK and experiments with wide
band beams, to a nonzero \theta_{13}, to CP violation and to the neutrino mass
hierarchy. For the proposed luminosities, I find the best nominal CP violation
performance for T2KK and the best mass hierarchy performance for a wide band
beam experiment. However, for equal luminosities, the physics concept on which
NOvA is based has the best potential for discovering CP violation. I will also
discuss the optimal choice of the baseline and off-axis angle for a Fermilab
based superbeam experiment.
February 28, 2007
Speaker:
Chris Hays - University of
Oxford
Title:
First Run II Measurement of the W
Boson Mass with CDF
Abstract:
I present a
new measurement of the W boson mass fromthe CDF
Collaboration. With a total uncertainty of48 MeV/c^2,
this is the single most precise W massmeasurement to
date. This measurement tightens
theconstraintsontheproperties
ofunobserved particles,in
particular themass of
theStandard ModelHiggs
boson.
February 14, 2007
Speaker:
Prof.
Peter Shawhan, University of Maryland
Title:
Spacetime
Sirens
Abstract:
Our Galaxy is thought to be populated
by roughly a billion neutron stars, of which only a small fraction have been
seen as radio or X-ray pulsars. Rapidly spinning neutron stars may emit
gravitational waves, singing softly but distinctly enough to be heard by LIGO
and similar detectors. However, tuning in to their songs poses a number of data
analysis challenges, which I will describe. I will also discuss the prospects
for detecting such signals and connections with theoretical and observed neutron
star properties.
February 7, 2007
Speaker:
Igor
Gorelov, University of New Mexico
Title and
Abstract:
Please click to open Prof. Gorelov's
Title and Abstract (PDF format file)
January 24, 2007
Speaker:
Kate
Scholberg, Duke University
Title:
Prospects for
Measuring Neutrino-Nucleus Coherent Scattering at a Stopped-Pion Neutrino
Source
Abstract:
Coherent neutral current
neutrino-nucleus elastic scattering has never been
observed.Although the cross-section is very high, nuclear recoil
energies are very small.However, detection of the process may be
within the reach of the new generation of low-threshold
detectors.
A promising prospect for the first detection of this
process is an experiment at a high flux stopped-pion neutrino source such as the
SNS.Results of of some preliminary rate calculations will be
presented, and sensitivity of such a measurement to new physics
will be explored.
January 17, 2007
Speaker:
Heather
Ray, LANL
Title:
MiniBooNE and the
SNS
Abstract:
The MiniBooNE experiment at
Fermilab is designed to be a definitive test of the LSND evidence for neutrino
oscillations. If the LSND evidence is confirmed, then, together with the results
from solar, reactor, atmospheric, and accelerator neutrino oscillation
experiments, it would imply Physics Beyond the Standard Model, such as sterile
neutrinos, CPT/Lorentz violation, extra dimensions, or mass-varying
neutrinos.
After four years of operation, MiniBooNE has
collected over 750K neutrino events and will be reporting first neutrino
oscillation results soon. An outstanding follow-up experiment would be OscSNS,
which would involve the construction of a MiniBooNE-like detector at a distance
of 60 m from the SNS beam dump. OscSNS would be capable of proving,
for example, the existence of sterile neutrinos.
