Date	Speaker
Friday, September 27	Xiaochao Zheng, Massachusettes Institute of Technology "Precision Measurement of Neutron Asymmetry A_1^n in the large x_Bj region" We have measured the neutron virtual photon asymmetry A1n over the kinematic range 0.33<=xBj<=0.61$ and 2.8<=Q^2<=4.8 (GeV/c)^2 [1].  To extract A1n, longitudinal and transverse spin asymmetries have been measured for inclusive 3He(e,e') scattering, using a 5.7 GeV longitudinally polarized electron beam at Jefferson Lab and a high-density polarized 3He target in Hall A.  Physics motivation and experimental technique will be described first. Preliminary results of A1n will be presented and compared with various models, including the predictions of SU(6), broken SU(6) constituent quark models, perturbative QCD based models, statistical model, local duality model and chiral-soliton model. [1] Jlab E99-117, J. P. Chen, Z. -E. Meziani, P. Souder et al.,      http://hallaweb.jlab.org/physics/experiments/he3/A1n/
Friday, October 18	N. Scielzo, UC Berkeley "Beta-Neutrino Angular Correlation in Magneto-Optically Trapped 21Na" When an unpolarized nucleus beta decays, the beta particle and neutrino are not both emitted isotropically but instead have an angular correlation given by 1+a*(v/c)*cos(agl) where v is the velocity of the beta particle, c is the speed of light, agl is the angle between beta and neutrino momenta, and a is the beta-neutrino angular correlation coefficient. Measurements of a in a limited number of systems have restricted possible scalar and tensor contributions to the weak interaction predicted in some extensions to the Standard Model. Laser trapped radioactive atoms, such as our group's 21Na magneto-optical trap, are an ideal source of activity for precise decay correlation experiments. We produce 21Na (t1/2 = 22.47 s) on-line at the 88" Cyclotron at the Lawrence Berkeley National Laboratory and maintain traps with up to 800,000 21Na atoms for study. The atoms in these traps are isotopically pure, confined to a volume of ~ 1 mm3, nearly at rest, and the decay products emerge without scattering. This allows the unperturbed detection of the low-energy recoil daughter nuclei, from which the momentum of the neutrino can be inferred. The beta particle and recoil 21Ne ions are detected in coincidence using a Chevron microchannel plate and plastic scintillator ?E-E beta detector telescope. The beta-neutrino angular correlation is determined by the time-of-flight spectrum of the recoil ions in the presence of a drift electric field. A collimator in front of the beta detector restricts the detector's field of view to a narrow cone containing the trapped atoms, greatly suppressing potential backgrounds. We have collected ~600,000 coincident events which provides a statistical precision of 0.7%. The majority of 21Na decays proceed through an allowed mixed transition to the ground state of the mirror nucleus 21Ne. By comparing the ft value of this decay branch to that of the superallowed 0+ to 0+ decays, the Standard Model prediction for the beta-neutrino correlation of the mixed transition is determined to be 0.558+/-0.003 (where the uncertainty arises from the uncertainty in the 21Na ft value). The total systematic uncertainty has been estimated at a level of ~1% and arises from a variety of sources, the largest being the uncertainty in the magnitude of the pure Gamow-Teller decay branch to the first excited state of 21Ne. At this level of precision, several corrections beyond the allowed approximation must also be included in the analysis, such as recoil order corrections and inner bremsstrahlung effects.
Friday, October 25	Juan Collar, University of Chicago "Direct searches for new astroparticles: Heavy and light artillery at EFI" Axions, neutrinos, WIMPs, heavily ionizing exotica (quark nuggets, monopoles, etc.)...the list is fantastic when it comes to invoking new particles that may fill up the matter deficit in our current understanding of the universe. A few selected "better mousetraps" for these, under development at the Enrico Fermi Institute, will be discussed. News from CAST, the solar axiom telescope at CERN, will be dispatched.
Special Kellogg Seminar Thursday, October 31 11:00 a.m.	Pauchy W-Y.Hwang, NTU "What is the nature of the dark energy? - The No.2 Question for the New Century"
Friday, November 1	John Ng, TRIUMF "Low Energy phenomenology of spit fermions scenarios"
Friday, November 8	Sergei Dzhosyuk, Harvard U "Using Magnetic Trapping of Ultracold Neutrons for Neutron Lifetime Measurement" Ultracold neutrons can be confined in an Ioffe-type superconducting magnetic trap. The trap is loaded by inelastic scattering of monochromatic 0.89 nm cold neutron beam in superfluid He4. Decays of the trapped neutrons are detected by observing scintillations in the helium produced by energetic decay electrons. The advantages of this technique over previous experiments are continuous detection of neutron decays and the elimination of wall losses and betatron oscillations. Recent results of the experiment, currently under way at NIST Center for Neutron Research, will be reported.
Friday, November 15	Michael Romalis, Princeton University "Limits on CP violation from Electric Dipole Moments" Searches for a permanent electric dipole moment (EDM) can provide a background-free signal of CP violation beyond the Standard Model. I will discuss recent experiments setting new limits on EDMs of ^199Hg and Tl atoms. The ^199Hg experiment is primarily sensitive to a CP-violating nuclear force and chromo-EDMs of the quarks, while the Tl experiment is sensitive to an EDM of the electron. A combination of limits on ^199Hg, electron, and neutron EDMs puts very stringent constraints on possible CP violation in Supersymmetry and other extentions of the Standard Model. I will discuss progress in improving the limits on nuclear EDMs using ^199Hg and ^129Xe and will give a brief overview of other new techniques for EDM searches.
Friday, November 22 269 Lauritsen	M. Koshiba, University of Tokyo "The Birth of Neutrino Astronomy"
Friday, December 6	D. McKinsey, Princeton U Dark Matter/CLEAN experiment
Special Seminar Wednesday, January 8 12:15 p.m.	Bira van Kolck, University of Arizona "The role of the Roper in QCD" The relevance of chiral symmetry to the spectroscopy of non-strange baryons is considered. The existing data suggest a simple scenario in which the nucleon, the delta and the Roper are chiral partners in a reducible representation of the full QCD chiral symmetry group. The nucleon axial coupling finds a natural and compelling explanation in this context. I discuss the relation between this scenario and the spin-flavor-symmetry expectations in the large-$N_c$ limit.
Friday, January 10	Randy Lewis "Strange electromagnetic form factors of the nucleon" The electric and magnetic form factors of a single nucleon contain contributions from virtual strange quarks, and the calculation of these effects presents a significant challenge. A recent study, combining quenched lattice QCD with quenched chiral perturbation theory, will be presented. Suggestions for future improvements will be discussed.
Special Seminar Tuesday, January 14 1:30 p.m.	Keh-Fei Liu, University of Kentucky "Chiral Behavior of Hadrons and Vacuum in Quenched QCD" The chiral logs in pion, rho, and nucleon masses in the quenched QCD are extracted from lattice calculation with the overlap fermion and the pion mass as low as 180 MeV. We show that the leading order chiral perturbation is good up to only ~ 300 MeV. The Roper resonance is seen close to the experimental value for the first time. From the local topological charge correlator, we demonstrate that the topological vacuum cannot be dominated by 4 dimensional same sign structures. The structures in lower dimensions are examined to explore the chiral symmetry breaking mechanism.
Special Seminar Wednesday, January 15 12:15 p.m.	Dan Riska, University of Helinski "Boosts, Wigner rotations and baryon form factors" Relativistic quark models for baryon form factors demand a choice of kinematics, the conventional choices being instant and front form kinematics. Recent phenomenologically satisfactory results for the nucleon form factors have been obtained with compact wavefunction models and pointlike quarks, which suggest kinematical effects to be the dominant feature. It will be shownt that point form kinematics implies universal scaling behavior of the form factors, which are insensitive to the model details. It will also be shown that the relativistic kinematic effects are almost insignificantly small in conventional instant form kinematics.
Friday, January 17	Gerry Brown, SUNY Stony Brook "RHIC Resonances; The dropping meson masses at RHIC"
Special Seminar Wednesday, January 22 12:15 p.m.	Vijay Pandharipande, University of Illinois "Quenching of Weak Interactions in Nucleon Matter"
Friday, January 24	Gerry Garvey, Los Alamos National Laboratory "Status report on MiniBooNE"
Friday, February 7	Jonathan Feng, UC Irvine "Black Holes, Extra Dimensions, and UHE Cosmic Neutrinos" Extra spatial dimensions have long been thought to play a role in the unification of forces. Recently, it has emerged that a spectacular prediction of "large" extra dimensions is the creation of microscopic black holes in high energy particle collisions. I will give an overview of these developments and the search for microscopic black holes produced in colliders and by ultrahigh energy cosmic neutrinos.
Friday, February 14	Jorge Morfin, FNAL high-statistics neutrino-nucleus scattering
Friday, February 21	Brad Plaster, JLAB neutron electric form factor measurements at Jlab
Friday, February 28	Silvia Pascoli, UCLA "Neutrinoless double beta decay, neutrino mass spectrum and cp-violation As strong experimental evidence of the existence of neutrino masses and neutrino mixing has been obtained, the crucial question relative to the nature of neutrinos -whether they are Dirac or Majorana particles, arises. The most sensitive process which can test the Majorana nature of neutrinos is neutrinoless double beta-decay. The present limit on the effective Majorana mass parameter is ||< 0.35 eV but many experiments, already taking data or planned, will improve sensibly this limit in the next future. In the hypothesis of 3 neutrino mixing and massive Majorana neutrinos, we analyze the implications of the results of the solar neutrino experiments and of the KamLAND experiment for the predictions of the effective Majorana mass || for the different mass spectra. Further, we analyze in detail the information concerning the neutrino mass spectrum, the absolute value of neutrino masses and CP-violation in the lepton sector, which is possible to get from either a measurement of || or a strong upper bound on it. We find that for \cos (2 \theta_sol) sufficiently large, a measurement or an upper bound on || will give precious information on the neutrino mass spectrum and might be able to identify the correct one. A measured value of || \geq 0.2 eV, combined with data on neutrino masses from the tritium beta-decay experiment KATRIN and/or cosmological observations might allow to establish whether the CP-symmetry is violated in the lepton sector due to Majorana CP-violating phases.
Friday, March 7	Paolo Bedaque, LBL "Effective Field Theory and few-nucleon systems"
Friday, March 21	Heidi Schellman, Northwestern U "Precision measurements of the weak interactions with incoming and outgoing neutrinos" The NuTeV collaboration at Fermilab exposed 680 tons of steel to a neutrino beam for a year. Several hundred thousand neutral and charged current neutrino interactions were compared in order to test the standard electro-weak model. The experimental data revealed a slight deficit relative to expectations in the neutral current interaction rate with quarks. I will present the data and several theoretical interpretations, ranging from novel strong interaction effects in the iron nuclei to additional heavy bosons and explore the possibilities for seeing this effect in other processes.
Special Seminar Tuesday, March 25 11:00	Valery Nesvizhevsky, Institut Laue-Langevin, France "Quantum states of neutrons in the Earth's gravitational filed and other experiments with ultracold neutrons" The discrete quantum properties of matter are manifest in a variety of phenomena. Any particle that is trapped in a sufficiently deep and wide potential well is settled in quantum bound states. For example, the existence of quantum states of electrons in an electromagnetic field is responsible for the structure of atoms, and quantum states of nucleons in a strong nuclear field give rise to the structure of atomic nuclei. In an analogous way, the gravitational field should also lead to the formation of quantum states. But the gravitational force is extremely weak compared to the electromagnetic and nuclear force, so the observation of quantum states of matter in a gravitational filed is extremely challenging. Because of their charge neutrality and long lifetime, neutrons are promising candidates with which to observe such an effect. Here we report experimental evidence for gravitational quantum bound states of neutrons. The particles are allowed to fall towards a horizontal mirror which, together with the Earth's gravitational field, provides the necessary confining potential well. Under such conditions, the falling neutrons do not move continuously along the vertical direction, but rather jump from one height to another, as predicted by quantum theory. Another new application of ultracold neutrons is related to their interaction with nanoparticles. For a few dacades physicists were trying to solve the problem of too high loss rates of ultracold neutrons stored in traps. Slow but steady progress was achieved. During these studies we found in 1997 a surprising phenomenon: UCN - which are normally reflected from trap walls precisely elastically - were upscattered by about 10^(-7) eV with the probability of 10^(-7)-10^(-5) per bounce. Last experiments and theoretical analysis showed that UCN change there energy due to rare collisions with surface nanoparticles, which experience permanent thermal motion. This research opened a few other promissing fields: a new concept of production of super-high UCN densities due to thermalization of neutrons in gels of ultracold nanoparticles and the sensitive method of study of nano-structures/nano-particles dynamics.
Special Seminar Thursday, April 3 11:00 a.m.	Pradeep Sarin, MIT "Silicon pixel detectors for charged particle measurements in ultra-relativistic heavy ion collisions at RHIC"
Friday, April 4	Elizabeth Jenkins, UC San Diego Neutrino masses and leptogenesis
Friday, 18 April	Richard Lebed, AZ State "Baryons in 1/N_c: The Classic and the Nouveau" The 1/N_c expansion (N_c the number of QCD colors) this year celebrates its 30th anniversary; its modern quantitative application to baryons, using operator methods, celebrates its 10th.  The first part of this talk reviews some of the classic works, in order to inform the audience of these methods and their successes.  Recently a new phase opened, that of treating baryon resonances in 1/N_c as poles in meson-nucleon scattering amplitudes (which is indeed the way they are experimentally observed).  This new approach, originally based on intuition gleaned from chiral soliton models but later found to be much more general, generates simple relationships between resonance masses and widths.  But moreover, this approach is shown to be fully compatible with the operator methods, and also explains in a natural way such phenomena as the small N(1535) partial width to pi-N.
Special Seminar Thursday, April 24 11:00 a.m.	Mark Vagins, UC Irvine "The Future of Super-Kamiokande? GADZOOKS!" Water Cherenkov detectors have been used for many years as cost-effective ways to study neutrino interactions and conduct nucleon decay searches. Examples include IMB, Kamiokande, SNO, and Super-Kamiokande. While many important measurements have been made with these detectors (e.g. discovery of neutrino oscillations, discovery of neutrinos from stellar collapse, non-observation of nucleon decay, confirmation of the Standard Solar Model) a major drawback has been the inability of such detectors to detect neutrons. A new technique, presently under study, which has the ability to lift this limitation will be introduced and discussed. Both inexpensive and immediately applicable to Super-Kamiokande, this potential upgrade will open up some startling new physics possibilities for that venerable experiment.
Friday, April 25	Rocco Schiavilla, JLAB "Parity-Violating Effects in Few-Nucleon Systems"
Friday, May 9	Dean Lee, NCSU "Many-body pion and nucleon interactions on the lattice" We present new work on lattice simulations for low energy pion and nucleon many-body interactions at finite temperature and baryon density. We discuss nucleon-nucleon correlation functions, pairing and superfluidity, algorithms and the sign/phase problem, and the gas-liquid transition.
Friday, May 16	Robert Atkins, LANL "Atmospheric Cherenkov Telescopes at Milagro to Study Cosmic Ray Composition" The array of Wide Angle Cherenkov Telescopes (WACT) consists of 6 atmospheric Cherenkov Telescopes surrounding the Milagro observatory. WACT is located 40 miles west of Los Alamos and is at an atmospheric depth of 750 g/cm^2. The primary physics goal of WACT is to measure cosmic ray composition in the region from several tens of TeV up to energies approaching the knee. WACT determines composition by measuring the lateral distribution of Cherenkov light produced in extensive air showers. This technique has been shown to be sensitive to the depth of maximum shower development. WACT is the first experiment that can bridge the gap between direct measurements of cosmic rays and indirect measurements of cosmic rays through air showers.
Friday, May 23	Mike Snow, IUCF "The LENS neutron source at IUCF"