| Special Kellogg Seminar Tuesday, April 15 |
Robert Cooper, University of Michigan The Radiative Decay Mode of the Free Neutron The beta-decay of the neutron has been extremely important in understanding the framework of the Standard Model of physics. The neutron is an important laboratory to verify predictions from this and other new, exotic theories. The well-established theory of quantum electrodynamics predicts that neutron beta-decay, consisting of an emitted proton, electron, and anti-neutrino, can be accompanied by high-energy photons. The first observation of this rare decay mode was made by measuring the proton, electron, and photon in coincidence. A high magnetic field from a superconducting magnet was used to guide the charged particles to a silicon surface-barrier detector. The photons, being unaffected by magnetic fields, require a large area detector capable of operating in the cryogenic, high magnetic field environment of the superconducting magnet. An inorganic, bismuth germanate scintillating crystal coupled to an avalanche photodiode served as a novel photon detector. Furthermore, an electrostatic mirror was used to change the available phase space for decays by reflecting the low energy protons towards the surface-barrier detector that were initially emitted in the wrong direction for detection. Extensive Monte Carlo simulation was used to predict the decay rate versus applied mirror voltage. A branching ratio of (3.130.34)x10-3 was measured, consistent with the theoretical prediction of 2.85x10-3 for photons of energy 15 keV to 340 keV. Also described is work to improve the overall uncertainty to the 1% level. In order to increase the number of events collected, the design and testing of a new 12-element detector is described. |
| Special Kellogg Seminar Tuesday, April 22 |
Yunchang Shi, Indiana University Cold and Ultra-cold neutron studies at IUCF The Low Energy Neutron Source at Indiana University is a University-based long-pulsed source that makes use of a coupled solid methane moderator operating at temperatures below 10K. I will present recent results in which the moderator performance is compared to the predictions from our recently developed model for methane dynamics in the low temperature (Phase II). I will also present the study of UCN production in solid oxygen involving magnon (spin wave) exchanges in comparison with UCN production in solid deuterium. |
| POSTPONED-NEW DATE TO BE DETERMINED | Dr. Harvey Gould, LBL A New Search for the Electron Electric Dipole Moment It has been six years since any experiment lowered the limit on the electron electric dipole moment (eEDM) and nearly two decades since a new experiment lowered the eEDM limit. I will suggest why progress has stalled, how future eEDM experiments should be done, and progress in developing a new eEDM experiment that uses a fountain of laser-cooled atoms. Electron and other EDMs, large enough to be discovered in new experiments, are predicted by Standard Model extensions (Supersymmetry, Multi-Higgs models etc.), to arise from couplings to new particles with non-standard sources of CP violation. An EDMr discovery would signify new physics even in the absence of new particle discoveries at the LHC. |
| Date | Speaker |
|---|---|
| Special Kellogg Seminar Thursday, September 20 2:00 p.m. |
Dr. Peter Geltenbort, Institut Laue-Langevin "Status of Neutron Lifetime Experiments" |
| Friday, September 21 | Dr. Peter Geltenbort, Institut Laue-Langevin "The Neutron Electric Dipole Moment Experiment at the ILL" |
| Friday, October 5 | Dr. Bruce Vogelarr, Virginia Tech Borexino |
| Special Kellogg Seminar Wednesday, October 17 12:00 noon |
James Karamath, ILL "The Neutron EDM Experiment at ILL" |
| Special Kellogg Seminar Wednesday, October 17 |
Dr. Bill Marciano, BNL Muon Overview |
| Friday, October 19 | Dr. Tom Banks, U.C. Berkeley Mucap |
| Friday, October 26 | Dr. Seth Hoedl, U. Washington Particle Physics with a Torsion Pendulum: A new Axion Search. In the nearly 25 years since it was first proposed, the axion remains the preferred solution to the strong CP problem and a promising dark matter candidate. Although the mass of the axion is now limited to be greater than 1 eV by the known flat geometry of the universe and less than 10000 eV by the neutrino flux from SN1987A, between these limits the existence of the axion is unconstrained. The Eot-Wash group at the University of Washington has embarked on a new experiment to look for a macroscopic parity and time violating force mediated by virtual axions with a mass in the neighborhood of 200 eV. By using the torsion pendulum technique, we hope to be able to improve on the present limits on such a force by more than 13 orders of magnitude. This presentation will detail our experimental methods and progress to date. In addition, a brief overview of the Eot-Wash group's continuing experiments will also be discussed. |
| Friday, November 30 | Dr. Sam Werner, Missouri Emeritus Neutron Interferometry |
| Special Kellogg Seminar Wednesday, December 5 |
Pedro Ocha, Caltech MINOS |
| Friday, December 7 | Dr. C. P. Liu, LANL The Interpretation of Atomic and Nuclear EDM Measurements Searches for permanent electric dipole moments (EDMs) of any physical systems provide powerful probes of T/CP violation, and hence have fundamental implication for cosmology. However, reliable interpretations of experiments require careful analyses across many divides in physics. In this talk, I will focus on the issues pertaining to atomic and nuclear physics, with stress on the so-called Schiff screening effect which affects measurements in neutral systems. |
| Friday, January 11 | Dr. Dan Dwyer, Caltech Recent Results from KamLAND |
| Special Kellogg Seminar Monday, January 14 2:30 p.m. |
Dr. Bira van Kolck, Univ. of Arizona Post-Modern Nuclear Structure Theory --- the first steps |
| Special Kellogg Seminar Tuesday, January 15 1:00 p.m. |
Dr. Mike Ramsey-Musolf, Univ. of Wisconsin Baryogenesis, EDMs, and the Higgs Boson |
| Friday, January 18 | Dr. K. F. Liu, Univ. of Kentucky Glue and Sea Quarks in the Nucleon |
| Friday, January 25 | Dr. Gerry Garvey, LANL Interesting Results from MiniBooNE and MiniBooNE-NUMI |
| February 15 | Dr. Roland Winston, UC Merced From Hyperons to Solar Energy Hyperon beta decay has provided a marvelous laboratory for investigating weak interactions; the experiments gave confidence to the Cabibbo and eventually CKM theory which provides a framework for CP violation. Concurrently, the challenge of carrying out the experiments provided me with the inspiration to develop nonimaging optics which provides the framework for many advances in solar energy. |
| February 22 | Dr. Dan Phillips, Ohio University Electromagnetic reactions on deuterium in chiral effective theory I will discuss the predictions that chiral perturbation theory (ChiPT) makes for elastic electron-deuteron and elastic photon-deuteron scattering. I will begin with a brief review of chiral perturbation theory as applied to the two-nucleon system. Turning then to electron-deuteron scattering, I will first outline the chiral expansion for the deuteron current operator, and then show that the charge piece of that operator is parameter-free up to corrections that are suppressed by five powers of the ChiPT expansion parameter, P. Using the resulting J_0 operator to predict the ratio of deuteron and nucleon form factors yields results that are in good agreement with the world data on the deuteron's charge form factor for Q^2<0.35 (GeV/c)^2. However, as with all modern NN potential models, ChiPT's potentials produce a deuteron wave function whose quadrupole moment lies below the experimental value. I will explain how this problem has a natural resolution within the effective theory, and provide a prediction that tests this resolution. If time permits, I will finish by describing the results that arise when one applies the same methodology to Compton scattering from deuterium. |
| February 29 | Dr. Rene Ong, UCLA VHE Particle Astrophysics with VERITAS The field of very high energy (VHE) astrophysics has undergone profound change in the last decade as a result of many exciting discoveries. Ground-based telescopes have detected many new sources of TeV radiation, but we do not as yet fully understand the mechanisms that power these sources. This talk will review the status of VHE gamma-ray astronomy and will present first results from VERITAS - a newly-comissioned array of atmospheric Cherenkov telescopes operating in southern Arizona. |
| March 7 | Dr. Mu-Chun Chen, UC Irvine Model Predictions for Neutrino Oscillations Many theoretical models have been proposed to explain the observed neutrino masses and mixing pattern. In this talk, I will discuss the predictions of various theoretical models for theta13 and the possibility of distinguishing these models utilizing lepton flavor violating rare charged lepton decays and muon-electron conversion. As a specific example, I will show how all mixing angles can arise purely from the group theoretical CG coefficients of a non-abelian finite group, the double tetrahedral group (d)T, in a SU(5) model. As a result of the SU(5) GUT, the model gives rise to to a prediction for theta13 that depends on the Cabibbo angle. It also gives a novel quark-lepton complementary sum rule that relates the solar mixing angle, the Cabibbo angle and the leptonic Dirac CP phase. |
| March 21 | Raul Hennings-Yeomans, Case Western A Search for WIMP Nuclear Recoils Underground: First Five-Tower Data from CDMS Dark matter is concentrated in the halos of galaxies, including the Milky Way. If WIMPs make up these halos they should be detected via scattering from atomic nuclei in a terrestrial detector of nuclear recoils. In order to achieve sensitivity to WIMP nuclear recoils the experiment needs excellent background rejection and to be inside neutron and gamma-ray shields such as hydrogenated material, lead and the earth crust (underground). Nuclear recoils from cosmogenic fast neutrons in underground laboratories are one of the most challenging backgrounds to WIMP detection and are estimated using Monte-Carlo simulations. The first WIMP-search results from the Cryogenic Dark Matter Search (CDMS-II) experiment running with its full complement of 30 cryogenic particle detectors half a mile underground will be presented. Furthermore, neutron background studies will be discussed including the design of an instrument capable of benchmarking the Monte-Carlo simulations by measuring, for the first time, the rate of high-energy neutrons at the Soudan Underground Laboratory. |
| Special Kellogg Seminar Tuesday, Mar 25 1:00 p.m. |
Michelle Dolinski, UC Berkeley Cuoricino update and progress toward CUORE The Cuoricino experiment has been running at the Gran Sasso National Laboratories since 2003. I will present the current limit on the half-life for the neutrinoless double beta decay of Te-130, corresponding to 15.53 kg-yr of Te-130. I will also report on the status of CUORE, a next generation experiment consisting of 19 Cuoricino-like towers. I will discuss my work on the measurement of gamma-production cross sections for neutron-induced interactions on the stable Te isotopes. This measurement will be used to estimate the rates for neutron-induced backgrounds in CUORE. |
Leona Kershaw, 31 March 2008