"String Theory and Cosmology"

"Radiative B-decays at Belle"

"Stringy Corrections to Spacetime Superpotentials"

Braneworlds and Einstein's Greatest Blunder

Einstein introduced the cosmological constant into his theory of gravity to explain how the universe could be static, a common belief at the time. When it was discovered that the universe is expanding and the cosmological constant seemed unnecessary, Einstein referred to the unwelcome addition to his theory as his greatest blunder. Cosmological observations together with modern theories of particle physics introduce new puzzles related to the cosmological constant. The possibility of extra spatial dimensions may help to resolve some of these puzzles.

"Using Reactor Neutrinos to Study Neutrino Oscillations"

The discovery of neutrino oscillations in 1998 has spawned a golden age of neutrino physics. As we embark on a program of precision measurements to study the neutrino mixing matrix, the question of what is the value of the last unknown mixing angle, θ₁₃, plays a central role. Following a review of the theory and the current experimental state, this talk will focus on the role that reactor neutrinos will play in determining the value of the mixing parameter sin²2θ₁₃. The need for precision, the challenges to achieving that precision, and the solutions to those challenges will be discussed.

"Colliding with Dark Matter"

The universe is filled with matter. Our telescopes shower us with images of stars, nebula, galaxies and clusters of galaxies to the limits of our vision. But when we study the motion of this luminous matter and compare it to our expectation based on our knowledge of gravity, the calculations and observed quantities fail to agree. The evidence points to non-luminous matter, or dark matter, extending over larger distance scales than that of the luminous matter.

Big bang cosmology gives strong evidence for this dark matter to be massive, weakly interacting particles. If particle dark matter is present in the Milky Way it is possible to detect it in the laboratory. Detection strategies employ varied degrees of technical sophistication but most experiments to date have featured limited detector mass. Significant progress in the field -- discovery, particle property determination and astronomy -- is expected to arise from expanding detector mass towards the ton scale and perhaps beyond. This talk will broadly consider the search for dark matter and provide a framework for understanding why the dark matter issue is of central importance to astronomy, cosmology, and high energy physics.

The Development of Neutrino Physics: Solar neutrinos past, present, and future

Neutrinos are weakly interacting particles that are produced copiously at the center of the Sun through the nuclear fusion processes taking place there. The detection of these solar neutrinos provides us with vital information on the source of the Sun's energy, and also on the properties of the neutrinos themselves.

During the past few decades, various experiments have been conducted to measure the solar neutrino flux, and they have led to several significant discoveries. In the early stages, it was found that the observed solar neutrino flux was significantly less than what was theoretically expected based on our understanding of the Sun. This was the so called 'solar neutrino problem'. More recent experiments, such as Super-Kamiokande, which I will describe in some detail, have been able to detect solar neutrinos with high statistics and precision. The combined results of these experiments proved that neutrino oscillation phenomena, which was proposed as a solution to the solar neutrino problem, were indeed occurring for the neutrinos from the Sun.

At present, several challenging solar neutrino experiments, such as the LENS experiment under development at Virginia Tech, are being actively proposed. More than 90% of the neutrinos generated by the nuclear fusion reactions inside the Sun are thought to be in the low energy region where they have so far eluded direct observation. Most of the efforts for future detector development is directed toward observing solar neutrinos in this lower energy region, so that we may better understand the mechanism of energy generation in the Sun.

Argonne National Laboratory is developing solutions to the nuclear waste problem and is actively working to close the nuclear fuel cycle. Analysis of nuclear materials is critical to method development for nuclear research. The Analytical Chemistry Laboratory at Argonne National Laboratory is a key partner in the development of the nuclear fuel recycling program in the Chemical Engineering Division. Chemical methods development and inorganic and radiological analysis are provided by Analytical Laboratory personnel.

Gamma spectrometry is a powerful technique for analysis of nuclear materials, as multiple radioactive isotopes can be measured simultaneously and sample preparation is non-destructive. Especially when used in conjunction with mass spectrometry or alpha spectrometry, gamma spectrometry is an important research tool for the analysis of nuclear fuel and other fissioned samples. The application of gamma spectrometry to aqueous fuel separations research and newly irradiated uranium fuels will be discussed in detail.

Large scale underground detectors in Europe, an initiative for future Astrophysics and Particle physics

Large scale underground detectors sensitive for low energy signals with very low background provide a unique tool for astro and particle physics. We discuss detectors in the range of 50 to 500kt active material for the detection of proton decay, low energy neutrinos, and possibly the long baseline detection of neutrinos produced at an accelerator. Three detection techniques are investigated. These are a water Cerencov detector, a liquid argon position sensitive drift chamber and a homogeneus scintillation detector. For the physics and technical developments a European cooperation is being formed. The status and goals of this initiative are presented

Cryogenic light detectors with Neganov Luke amplification

CRESST (Cryogenic Rare Event Search with Superconducting Thermometers) searches for nuclear recoils induced by particle dark matter. For an active suppression of the background due to electron recoils both phonons and scintillation light generated in a CaWO4 crystal are detected simultaneously. As only a small fraction (about 1%) of the energy of the incident particles is detected as light, very sensitive light detectors are required. The threshold of the light detectors can be improved by applying an electric field to a silicon crystal leading to an amplification of the thermal signal due to the Neganov-Luke effect. Measurements with an applied Neganov-Luke voltage will be presented.