The experimental groups participating in the Summer 2008 REU program at Nevis are: ATLAS, Double Chooz, DZero, eBubble, Mini-BooNE, XENON, and RARAF.

ATLAS

contact person: John Parsons

The ATLAS experiment is being prepared for operation at the Large Hadron Collider (LHC) at CERN in Geneva, Switzerland. The LHC is a proton-proton collider which, when becoming operational in 2008, will be the world's highest energy collider and will be the premier experimental HEP facility for many years.

The foremost question of HEP is the source of so-called "electroweak symmetry breaking" (EWSB), related to the issue of the origin of mass. The SM postulates the existence of the Higgs boson to solve this issue. However, many other scenarios (eg. supersymmetry, technicolor, even the existence of extra spacetime dimensions) have been proposed. The LHC and ATLAS are designed to probe an energy scale which should make possible investigation of the source of EWSB. For example, ATLAS should be able to either discover the SM Higgs boson or to definitively rule out its existence. If no SM Higgs is found, we expect to find instead indications of the true source of EWSB.

ATLAS is in the installation phase (check out the webcams in the underground ATLAS cavern to see rel-time images of the ongoing detector installation.). On-going ATLAS activities at Nevis include studies of the physics potential of ATLAS, development of algorithms and software tools for physics analysis, and commissioning of our state-of-the-art electronics for readout of the ATLAS calorimeter. REU students could be involved in any of these activities, depending on their interests and backgrounds. REU students working with the ATLAS group would be based at Nevis Labs.

Double Chooz

contact person: Mike Shaevitz

We have recently joined the Double Chooz experiment located in France. Double Chooz will study the oscillations of neutrinos produced by nuclear power reactors.

The Double Chooz experiment goal is to search for a non-vanishing value of the q₁₃ neutrino mixing angle. This is the last step to accomplish prior moving towards a new era of precision measurements in the lepton sector. The most stringent constraint on the third mixing angle comes from the CHOOZ reactor neutrino experiment with sin²(2q₁₃)<0.2. Double Chooz will explore the range of sin²(2q₁₃) from 0.2 to 0.03-0.02, within three years of data taking. The improvement of the CHOOZ result requires an increase in the statistics, a reduction of the systematic error below one percent, and a careful control of the backgrounds. Therefore, Double Chooz will use two identical detectors, one at 300 m and another at 1.05 km distance from the Chooz nuclear cores.

In addition, we will use the near detector to investigate the potential of neutrinos for monitoring the civil nuclear power plants.

The plan is to start operation in 2008 with one detector and to have both detectors operating by the end of 2009. REU students working with the CHOOZ group would be based at Nevis Labs.

DZero

contact person: Gustaaf Brooijmans

The Tevatron proton-antiproton collider at Fermilab, near Chicago, is currently the energy frontier for particle colliders. A new experimental run (Run 2) using an upgraded accelerator and detectors is underway, making this a particularly exciting time to be involved in the DØ experiment. We will make important contributions to the study of many of the most interesting questions in physics today. Included in a long list of topics are studies of the recently discovered top quark, attempts to understand the source of the huge preponderance of matter over antimatter in the universe (by studies of CP violation in b-quarks), probes of the electro-weak and strong forces and searches for the unexpected. Additionally, we there is the challenge of operating and understanding a complicated detector with more than one million channels of information coming from a variety of technologies.

The Columbia DØ group is involved a wide range of activities on the experiment. Our physics activities include studies of top-quarks, b-quarks, and searches for physics beyond the Standard Model. We have built cutting-edge electronics for the calorimeter and the level-2 muon trigger, and recently installed electronics we designed for an upgrade to the L1 calorimeter trigger. REU students working with the DZero group would be based at Nevis Labs or at the Fermi National Accelerator Laboratory near Chicago, IL.

eBubble

contact person: Bill Willis

For many years neutrino physics and collider detectors have been a major part of the Nevis program. Recently we established a new program, to move forward on research on new detectors, so that we will be prepared for the next round of experimental needs in these areas. We are focusing on ideas for detectors which utilize the advantages of a cryogenic environment, and in particular on detectors using liquid helium as the detection medium.

More than thirty years ago it was learned that the stable state of an electron in liquid helium is a bubble of about 2 nm diameter, with nothing but the electron inside. Electron bubbles ('eBubbles') can also exist in liquid neon and liquid hydrogen. These eBubbles have properties that appear to be well-suited to detecting particle interactions where the relevant energies are small, where good position and energy resolution are required, and where a large detection volume is needed. We anticipate that this technology may open up new possibilities for next-generation neutrino detectors, and may also have applications in detecting 'dark matter' particles and in future collider detectors. REU students joining the program would be based at Nevis with frequent trips to Brookhaven National Laboratory on Long Island.

Mini-BooNE

contact person: Janet Conrad

Neutrino physics is currently one of the most active areas of research in modern particle physics. One of the main reasons for such heightened activity is the continued mystery regarding some of the basic properties of this elusive particle. Do neutrinos have mass? If so, can it be measured in current experiments? What does our knowledge about neutrinos imply about the evolution of galaxies and the visible universe?

The BooNE neutrino experiment at Fermilab is designed to address these questions. The BooNE experiment uses a muon-neutrino beam to determine whether muon neutrinos oscillate to electron neutrinos. An experiment at Los Alamos (LSND) indicates that this oscillation may indeed occur, but the results are not conclusive. Neutrinos could oscillate only if they have mass. The low energy neutrino beam is aimed at the BooNE detector -- a 40-foot-diameter tank filled with mineral oil. The neutrinos interacting with the oil will either release a muon or an electron, depending on the incoming neutrino flavor. The observation of electron production in the detector would indicate neutrino oscillations. In addition to neutrino oscillations, BooNE is also sensitive to other phenomena, such as supernova explosions and the decay of exotic particles.

REU students joining the MiniBoone program will likely spend their time at the Fermi National Accelerator Laboratory near Chicago, IL.

The XENON Dark Matter Experiment

contact person: Elena Aprile

Less than 5% of the Universe is known to us. The rest 95% has yet to be fully understood. 73% of the Universe density is made of dark energy, an unknown form of energy that is causing an acceleration of the expansion rate of the Universe. 22% is made of dark matter, a type of matter which cannot be observed using standard astronomical instrumentation but which is known to exist due to its gravitational effect. Most of this dark matter is believed to be in the form of exotic particles called WIMPs (Weakly Interacting Massive Particles), relic particles of the Big Bang sill existing today thanks to their rare interactions with ordinary matter. Supersymmetric theories suggest that the WIMP could be the neutralino, the lightest particle predicted by the theory. Understanding the nature of this dark matter is one of the most important open questions in cosmology today.

The XENON experiment looks for WIMPs using liquid Xenon as the target material. Direct detection of these particles is based on the elastic scattering of WIMPs off nuclei of the target Xenon atoms. The detector is a two-phase (liquid/gas) time projection chamber (TPC) which measures simultaneously the charge and light signals produced by a particle interaction in the liquid. The distinct ratio of the two signals allows to discriminate events arising from scatters off the Xenon nuclei (produced by WIMPs or neutrons), from events produced by the gamma-ray background alrgely due to natural radioactivity in the detector components.

An international collaboration led by Columbia University is currently testing the 10 kg implementation of the XENON detector (XENON10), which features 10 kg active Xenon target. The XENON10 detector has been installed at the Gran Sasso Underground Laboratory in Italy in March 2006, and has been taking dark matter data since the end of August 2006. We expect to surpass the world best sensitivity for WIMP direct detection, given the good discrimination and also the very low (<10 keV recoil) energy threshold. The detector uses key technologies and systems that were tested and optimized above ground by operating smaller detectors at the Columbia Nevis Laboratory.

The 10 kg system will be followed by a 100 kg module, aiming for an increased sensitivity to dark matter detection. Ten modules will constitute the proposed 1 ton experiment which is expected to have sensitivity to WIMPs more than a factor of thousand below the current experimental limits worldwide.

The development of the XENON program includes collaborators at other institutions in the US, Italy, Portugal and Germany. REU students could participate into the data taking of the 10 kg module and/or the development of the next (100 kg) experiment. Depending on their research activity, students could be based at Nevis Labs or at Gran Sasso Underground Laboratory (in the top left picture, 2006 REU students and Professor Aprile at Gran Sasso are shown).

Radiological Research Accelerator Facility (RARAF)

contact person: David Brenner

The Radiological Research Accelerator Facility (RARAF) is dedicated to providing user-friendly radiation sources and bio-labs for research in biology, radiation biology, and radiation physics. Our sources include a unique single-cell/single-particle microbeam irradiator that allows irradiation of single cells or parts of cells with exactly one (or more) charged particle(s). This provides a unique opportunity for scientists to study both structure and function of individual cells and, particularly, their response to damage.

RARAF involves a unique interaction of physics, engineering, and biology, and there are opportunities for research projects in the fields of beam line development (e.g., development of electrostatic focusing lenses), particle detector development (e.g., development of a secondary electron ion microscope), and automated cellular and sub-cellular imaging, both in terms of hardware and software.

Whatever the project, it is important to be able to talk to, and listen to, the on-site and visiting biologists, to make sure that what is being built is really what is needed.

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