December 7, Wednesday, 11:00am, Building 50A-Auditorium
Gravitational Waves: a New Window on the Universe
Dr. Jay Marx (Caltech/LIGO Lab)
Abstract: The Laser Interferometer Gravitational-Wave Observatory (LIGO) is a facility dedicated to the detection of cosmic gravitational waves and pioneering of the new field of gravitational wave astronomy. This talk will describe the nature of gravitational waves, possible astrophysical sources of detectable gravitational waves such as merging pairs of black holes and neutron stars, supernovae and the big bang, how LIGO works, the current status of LIGO, and future plans for LIGO. Prospects for a coordinated international network of gravitational wave detectors that will function as a global gravitational wave telescope will also be described.
February 15, Tuesday, 11:00am, Building 50A-Auditorium
PandaX: A Dark Matter Experiment in Sichuan, China
Prof. Xiangdong Ji (Maryland/Shanghai)
Abstract: In the southwest of Sichuan China, a deep underground tunnel provides an unprecedented opportunity to build one of the deepest science and engineering labs in the world. Since the first visit by physicists in 2009, a 6x6x40m experimental hall (JinPing lab) has been built, ready to start the first batch of experiments. In this talk, I will describe an effort to build a dual-phase xenon dark matter detector (PandaX) in China and to place it at the Jinping lab for dark matter search.
Contact Prof. Xiangdong Ji, firstname.lastname@example.org, if you are interested in a copy of the talk.
March 16, Wednesday, 11:00am, Building 50A-Auditorium
High Energy QCD and Hard Interactions
Prof. Al H Mueller (Columbia University)
Abstract: The theory and phenomenology of high energy QCD will be reviewed with a focus on phenomena that relate to high parton densities. The relationship between high energy QCD processes and similar phenomena in other branches of physics, as well as with string theory via the AdS/CFT conjecture, will be explored.
March 23, Wednesday, 11:00am, Building 50A-Auditorium
Information Content of a New Observable
Prof. Witold Nazarewicz (U Tennessee and ORNL)
Abstract: Nuclei communicate with us through a great variety of observables. Some are easy to measure, some take a considerable effort and experimental ingenuity. In this study, we show how to assess the uniqueness and usefulness of an observable, i.e., its information content with respect to current theoretical models. We also quantify the meaning of a correlation between different observables and discuss how to estimate theoretical statistical uncertainties. The methodology used in this work should be of interest to any theoretical framework that contains parameters adjusted to measured data.
April 6, Wednesday, 11:00am, Building 50A-Auditorium
Understanding the universe, one rare isotope at a time
Dr. Jens Dilling (TRIUMF)
Abstract: Many of the remaining big questions in understanding the universe, such as how and where the chemical elements in the universe are created, the life and death of stars, or the nature of neutrinos are intimately related to our fundamental understanding of the atomic nucleus. Progress in nuclear theory as well as the advent of rare-isotope beam facilities are key ingredient to getting closer to answering these questions. One of the premier facility for rare isotopes is the ISAC complex at TRIUMF, Vancouver. We have developed recently very sensitive and fast methods using ion trap techniques at TITAN (TRIUMF’ s Ion Trap of Atomic and Nuclear science). Using this, we are able to probe into the world of so-called nuclear halos. Teetering on the edge of nuclear stability, the properties of halo nuclei have long been recognized as one of the most stringent tests of our understanding of the strong force. Nuclear halos are an exotic form of nuclear matter that continues to defy the considerable scientific efforts focused upon them in the last two decades. In this talk I will report on theses measurements and how they relate to answering the big questions.
May 4, Wednesday, 11:00am, Building 50A-Auditorium
Heavy Ion Physics with the ALICE experiment at the CERN LHC
Dr. Jurgen Schukraft (CERN)
Abstract: ALICE is the experiment at the CERN Large Hadron Collider dedicated to ultra relativistic heavy ion physics. The talk will give a brief summary of the design and construction of the experiment, which took place between 1990 and 2009, and then show some physics results from pp collisions at 900 GeV and 7 TeV centre-of-mass energy, taken during the start-up of LHC in 2009, as well as first results from the heavy ion run in November 2010 with Pb-Pb collisions at 2.76 TeV/nucleon.
September 14, Wednesday, 11:00am, Building 50A-Auditorium
High Energy Nuclear Collisions and QCD Phase Structure
Dr. Nu Xu (LBNL)
Abstract: One of the most exciting goals in the field of high-energy nuclear collisions is to understand the phase structure of matter with partonic degrees of freedom, especially the transition from the hadronic phase to the partonic phase: the quark-gluon plasma (QGP). It is believed that the QGP phase dominates the evolution briefly during the early time of the Universe. In this talk, after reviewing the basic concepts about the high-energy nuclear collisions, I will discuss recent progresses in the STAR experiment at RHIC. Our current view on the future physics program at RHIC will be discussed as well.
October 19, Wednesday, 11:00am, Building 50A-Auditorium
Atom Trap Trace Analysis
Dr. Zheng-Tian Lu (Argonne National Lab)
Abstract: Since the invention of radiocarbon dating in 1949, trace analyses of long-lived cosmogenic isotopes have contributed to a wide range of scientific and technological areas. We have developed an analytical method called Atom Trap Trace Analysis (ATTA), in which individual atoms of the desired isotope are selectively captured and detected with a laser-based atom trap. ATTA possesses superior selectivity, and is used to analyze environmental radio-isotopes: 81Kr, 85Kr, and 39Ar. These three isotopes have extremely low isotopic abundances in the range of 10^-16 to 10^-11, and cover a wide range of ages and applications. As the first real-world application of ATTA, we have determined the mean residence time of the old groundwater in the Nubian Aquifer located underneath the Sahara Desert. Moreover, this method of capturing and probing atoms of rare isotopes is also applied to experiments that study exotic nuclear structure and test fundamental symmetries.
(November 9’s Colloquium is re-scheduled to Feb. 29, 2012.)
November 16, Wednesday, 11:00am, Building 50A-Auditorium
MeV to TeV Physics with Parity-Violating Electron Scattering
Prof. Krishna Kumar (University of Massachusetts)
Abstract: The technique of parity-violating electron scattering, where the fractional difference in the scattering rate is measured for incident right- and left-handed longitudinally polarized high energy electrons on unpolarized targets, is now commonly used to isolate the weak neutral current amplitude at low momentum-transfer. The parity-violating asymmetries are small, but over the past three decades the technologies required to measure them accurately have steadily improved. It has thus become feasible to address a variety of fundamental questions in nuclear and particle physics: with judicious choices of kinematics and targets, various experiments have been designed to probe the role of virtual strange quarks in nucleon form factors, to measure the rms radius of the ground-state neutron distribution in a heavy, spinless nucleus, to measure nucleon structure functions in the valence region, and to test the gauge structure of the weak neutral current interaction itself, in a manner complementary collider experiments. The potential impact of new results and ongoing experiments will be reviewed and new projects for future accelerator facilities will be discussed.