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Fall 2007

Schedule Fall 2007

September 11, 2007
12:20 pm (Tuesday)

Note unusual time

Dr. Stephen Bueltmann
Old Dominion University

Elastic Proton-Proton Scattering

The Relativistic Heavy Ion Collider at BNL presents the opportunity to investigate elastic and diffractive scattering of polarized protons up to a center of mass energy of 500 GeV.
Results from two initial runs for spin asymmetries and plans for future measurements, scheduled to begin in the coming months, will be discussed.


September 11, 2007
3:00 pm (Tuesday)

Dr. Bradley Fillippone
Caltech

What's so Cool about Ultra-Cold Neutrons


September 13, 2007
12:20 pm (Thursday)

Note unusual date and time

Dr. Christine Aidala
University of Massachusetts, Amherst

A Novel Shakedown of the Proton Spin Breakdown: How the Field has Become Wider with a Polarized Proton Collider

A myriad of new techniques and technologies made it possible to inaugurate the Relativistic Heavy Ion Collider (RHIC) as the world's first polarized proton collider in December 2001. Since then the RHIC spin program has been ramping up, adding a new dimension to the field of nucleon structure, traditionally explored via electromagnetic probes. Using strongly interacting probes offers both new challenges and new opportunities. An overview of the RHIC spin program as well as recent results and future prospects will be presented.


September 18, 2007
POSTPONED

Dr. Alexei Trifonov
Magiq Corporation

Title to be Announced


September 18, 2007
3:00 pm (Tuesday)

Dr. Nathaniel Tagg
Tufts University

Neutrino Oscillations and the MINOS Experiment

The study of neutrino properties has gone through a set of revolutions over the last 40 years as we have discovered the mechanism behind several astrophysical problems. We have discovered why the sun is too dim in neutrinos and why atmospheric neutrinos seem to have the wrong mixture of flavors. This explanation, neutrino oscillation, is now widely accepted as the correct model. The next stage of scientific work is precision measurement of the parameters in the model, of which MINOS is one of the first experiments. The MINOS experiment uses an artificial neutrino beam fired 730 km from Chicago, IL to Ely, MN, and two detectors made of kilotons of steel and scintillator. I'll show recent results of this experiment, and give some indication of the future of neutrino research.


September 20, 2007
12:20 pm (Thursday)

Note unusual date and time

Dr. Hovanes Egiyan
University of New Hampshire

Search for Phi- -(1860) Pentaquark

Regular nuclei consist of protons and neutrons which are bound together by a strong, or color, force. It is widely accepted that the Quantum Chromodynamics is the theory describing the strong interaction. The fundamental degrees of freedom in this theory are quarks interacting through gauge boson fields called gluons. This theory allows for existence of colorless states made of quark-antiquark pair, such as mesons, or three-quarks-states, such as protons and neutrons, as well as a larger number of quarks. The states made of five constituent quarks are called entaquarks, but their existence has been a subject of heated debates. While some experimental collaborations published evidence for existence of such states, many other experiments could not confirm these results. I will give a brief theory overview and summarize the experimental evidence for existence of pentaquarks. I will describe the recently completed experiment at Jefferson Lab to search for Phi--(1860) pentaquark state with doubly negative electric charge and strangeness S=-2 - a set of quantum numbers inconsistent with a system of three quarks. The preliminary results of this experiment will be shown and discussed.


September 25, 2007
12:20 pm (Tuesday)

Note unusual time

Dr. Pawel Nadel-Turonski
George Washington University

Strange Decays of Excited Nucleons

An important goal of nuclear physics today is to understand the structure of the nucleon and the nature of the strong interactions at low energies, where perturbative methods (pQCD) cannot be applied. In this regime, the excitation spectrum of the nucleon is a key element. It can, for instance, tell us whether the quarks inside the nucleon form pairs the way nucleons do in a nucleus and electrons in a superconductor. Recent advances in both theory (coupled-channels calculations) and experiment (high-statistics polarization measurements)allow for a systematic approach to the search for new and 'missing'states, which have been predicted by constituent quark models but not observed experimentally. The latter, in particular, are essential for determining the existence of diquarks inside the nucleon. Current data suggest that decays into strange channels will provide the most conclusive test. At the same time, the self-analyzing nature of some strange baryons ($Lambda$ and $Sigma^+$ hyperons) is ideally suited for polarization measurements. To this end, the g13 experiment was recently completed at the Jefferson Lab. It used tagged, polarized photons impinging a deuterium target. The exceptional statistics (comparable to all previous CLAS photoproduction experiments combined), will make it possible to investigate the neutron channels, where there currently are no data, at the precision level of recently published and upcoming proton results. Through rescattering, it will also open a new window on the study of hyperon-nucleon interactions.


September 25, 2007
3:00 pm (Tuesday)

Dr. Tim Gay
University of Nebraska

One Atom Too Many: An Atomic Physicist's Attempt To Learn About Simple Homonuclear Diatomic Molecules

When a polarized electron collides with an atom, it can transfer its spin to the residual target. This angular momentum can subsequently be partitioned among the various atomic angular momenta nuclear and electronic spin and electronic orbital angular momentum. The way in which this happens can provide important details about the collision dynamics. Molecular targets complicate this picture, because they have another "reservoir" into which the angular momentum can go: nuclear rotation. Recent experiments involving collisions of spinning electrons and photons with molecules have produced some surprising new results (see, e.g., PRL 92, 093201), even thought the molecular targets are the simplest available -- homonuclear diatomics. New directions for experiments, for those with enough intestinal fortitude to consider further work with molecular targets, will be proposed.


September 27, 2007
12:20 pm (Thursday)

Note unusual date and time

Dr. Matt Bellis
Carnegie Mellon University

The Missing Baryons Problem

While QCD (Quantum ChromoDynamics) is an elegant description of the strong nuclear interaction and has provided very accurate predictions in the high energy regime, it is notoriously difficult to solve for lower energy reactions. Conversely, the constituent quark model (CQM) comes from an relatively naive starting point and yet has remarkable predictive powers for the baryon spectrum. But there is a mystery lurking in this success story: a particular group of baryons predicted by the CQM have never been experimentally observed. This talk will discuss the issue as well as work involving data from Jefferson Lab that aims to resolve this dilemma.


October 2, 2007
12:20 pm (Tuesday)

Note unusual time

Dr. Frank Ellinghaus
University of Colorado

The Structure of the Nucleon

The exploration of the proton and neutron structure is an ongoing quest for about half a century. Much has been learned by scattering energetic electrons off protons and neutrons, collectively known as nucleons. At moderate electron energies elastic scattering revealed the nucleons transverse size, encoded in the so-called form factors. At electron energies large enough to penetrate and destroy the nucleon its inner structure consisting of quarks and gluons, also known as partons, was found. The distribution of partons inside the nucleon in longitudinal momentum space is encoded in the so-called parton distribution functions (PDFs). Recently scattering experiments with electrons of large enough energies to penetrate the nucleon, yet leaving it intact, have been performed. This class of reactions is able to probe the transverse position of the partons inside the nucleon and their momentum in longitudinal direction at the same time, thus unifying the descriptions of the nucleon in terms of form factors and PDFs into one framework, the so-called generalized parton distributions. A particular aspect of this first step into getting a three-dimensional picture of the nucleon is that the orbital motion and therefore the orbital angular momentum of partons can be studied. The latter is essentially unknown and the missing piece in the question of how the quarks and gluons conspire to make up the overall spin of 1/2 of the nucleon.


October 2, 2007
3:00 pm (Tuesday)

Dr. Marcia Bartusiak
MIT

Einstein's Unfinished Symphony

New observatories are beginning operation worldwide that will provide a whole new sense with which to explore the heavens. Instead of collecting light waves, these novel instruments are allowing astronomers to place their hands upon the fabric of space-time and feel the very rhythms of the universe. These vibrations in space-time-gravity waves-are the last prediction of Einstein's general theory of relativity yet to be observed directly. They are his unfinished symphony. Gravity waves will provide the first direct evidence of black holes and allow us to eavesdrop on the remnant echo of the Big Bang itself. Bartusiak will tell the story of the 45-year-long quest to capture these waves, introducing us to the people, the technology, and the science of this enterprise from a science writer's perspective.


October 16, 2007
3:00 pm (Tuesday)

Dr. Ana Maria Rey
ITAMP, Harvard University

Quantum Magnetism in Optical Superlattices

By loading spinor atoms in optical lattices it is now possible to simulate quantum spin models in controlled environments and to study quantum magnetism in strongly correlated systems. In this talk I will describe a technique that allows one to prepare, detect and control superexchange interactions in ultra-cold spinor atoms loaded in optical superlattices. I will focus this discussion in the context of recent experiments that measured for the first time such super-exchange interactions. Even though most of the experimental findings are in good agreement with first principles calculations based on the Hubbard Hamiltonain, it is possible to identify corrections which we can explain by an extended Hubbard model. I shall also discuss the many-body dynamics arising from coherent coupling between singlet-triplet pairs in adjacent double-wells. In particular the generation of complex magnetic and maximally entangled states by non-equilibrium dynamics.


October 23, 2007
POSTPONED

Dr. James H McGuire
Tulane University

Title to be Announced


October 30, 2007
3:00 pm (Tuesday)

Dr. Curtis Meyer
Carnegie Mellon University

QCD Exotics - Past, Present and Future

We believe that Quantum Chromodynamics is the theory of the strong interaction---the force which confines the quarks and gluons inside of the protons and neutrons which we observe in the universe. While this theory is very difficult to solve for protons and neutrons, our best efforts to do so lead to some very intersting predictions for new types of particles that more manifestly involve the gluons of QCD. Pure-glue particles known as glueballs and a more novel particle known as a hybrid. I will review the experimental evidence for these particles and discuss the future programs that we hope will find the new particles--providing a test of our understanding of QCD and its ability to confine quarks and gluons inside nuclear matter.


November 6, 2007
3:00 pm (Tuesday)

Dr. Eric Silver
Harvard-Smithsonian Center for Astrophysics

Broad Band, High Resolution X-Ray Spectroscopy Using Microcalorimeters: Spin-Offs from Astrophysics Research

High resolving power, a bandwidth that can span 0.1-120 keV and low internal background are the hallmarks of cryogenic X-ray microcalorimeters. Initially developed for future satellite-borne spectroscopy of cosmic X-ray and gamma ray sources such as black holes,supernova remnants and clusters of galaxies, we are now using microcalorimeters for a wide range of applications on Earth. These include laboratory astrophysics studies of highly charged ions in an electron beam ion trap, measurements of the Lamb Shift in hydrogenic gold and uranium, industrial applications where high resolution x-ray spectroscopy is important to materials and chemical analysis, and biological and medical science explorations of cell metabolism and structure. I will discuss the important features of our detector technology, review a variety of our experimental results and discuss future work using this new tool.


November 27, 2007
3:00 pm (Tuesday)

Dr. Robert J Beichner
North Carolina State

The Student-Centered Activities for Large Enrollment Undergraduate Programs (SCALE-UP) Project

How do you keep a classroom of 100 undergraduates actively learning? Can students practice communication and teamwork skills in a large class? How do you boost the performance of underrepresented groups? The Student-Centered Activities for Large Enrollment Undergraduate Programs (SCALE-UP) Project has addressed these concerns. Materials developed by the project are now in use by more than 1/3 of all science, math, and engineering majors nationwide. Physics and chemistry classes are currently in operation, with biology, engineering, and oceanography adaptations in progress. Educational research indicates that students should collaborate on interesting tasks and be deeply involved with the material they are studying. We promote active learning in a redesigned classroom for 100 students or more. (Of course, smaller classes can also benefit.) Classtime is spent primarily on "tangibles" and "ponderables"-hands-on activities, simulations, and interesting questions. There are also hypothesis-driven labs. Nine students sit in three teams at round tables. Instructors circulate and engage in Socratic dialogues. The setting looks like a banquet hall, with lively interactions nearly all the time.

Hundreds of hours of classroom video and audio recordings, transcripts of numerous interviews and focus groups, data from conceptual learning assessments (using widely-recognized instruments in a pretest/posttest protocol), and collected portfolios of student work are part of our rigorous assessment effort. We have data comparing 16,000+ students. Our findings can be summarized as the following:

Ability to solve problems is improved.
Conceptual understanding is increased.
Attitudes are improved.
Failure rates are drastically reduced, especially for women and minorities.
Performance in later courses is enhanced.

In this talk I will discuss the classroom environment, describe some of the activities, and review the findings of studies of learning in various SCALE-UP settings.


December 4, 2007
3:00 pm (Tuesday)


Old Dominion University

Senior Thesis Presentations

Brachytherapy in Real Time"
Melissa Barruzza

"Prototype Studies of a Drift Chamber for CLAS12
Billy Lactaoen

"Classical Dynamics of electrons in Atoms near Surfaces
Charles Yommer

"Characteristics of Supersonic Flowing Plasmas
Brandon Rodgers


December 11, 2007
3:00 pm (Tuesday)

Old Dominion University

Senior Thesis Presentations

"A Fitting Framework for Lattice QCD Hadron Spectroscopy"
Matt Bass

"Measuring the Period of Rotation of the Sun Using Sunspots
Sabrina Cummings

"Determination of the Solar Limb Darkening coefficient"
Jim McGhee


December 19, 2007
12:30 pm (Wednesday)

Dr. Chandra S Nepali
Kent State University

Uranium + Uranium Collisions at RHIC

The matter formed in central collisions of Au+Au at 200 GeV at the Relativistic HeavyIon Collider (RHIC) seems to behave like a perfect fluid. This conclusion is based in part on approximate agreement between nonviscous hydrodynamic calculations and the experimental data on elliptic flow. The nonviscous hydrodynamic calculations predict the saturation of the strength of the elliptic flow, v2, with increase in transverse particle density, (1/S)(dNch/dy), at fixed impact parameter. The transverse particle density reached in Au+Au is not sufficient to test the saturation prediction. Uranium + uranium (U+U) collisions have the potential to produce more extreme conditions of excited matter then is possible using spherical nuclei like gold or lead at the same incident energy. Uranium has quadrupole deformed shape. The collisions of special interest are the "tiptip" orientation in which the long axes of both deformed nuclei are aligned with beam axis, and the "bodybody" orientation in which the long axes are both perpendicular to the beam axis and parallel to each other. The "tiptip" and "bodybody" collision events allow to test the hydrodynamic prediction by increasing the transverse particle density at spatial eccentricity similar to central Au+Au, and spatial eccentricity at transverse particle density similar to central Au+Au, respectively. However, this potential of U+U collisions will be lost unless these desired collision events are selected. I will discuss U+U collisions at 200 GeV, and the separation of the desired collision configurations using different model simulations.