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.