Yale University

Yale University has been a member of the ATLAS Collaboration at the LHC since 2003.  This effort follows long standing research efforts at Fermilab in Illinois, BNL in NY, and Jefferson Lab in Virginia. Researchers at Yale played a major part in the construction effort, contributing to both the mechanical construction and electronic design and fabrication for part of the ATLAS Inner Detector.

There are currently three senior faculty and a large group of graduate students and postdoctoral researchers associated with this activity.

Physicists at Yale expect new and exciting discoveries at the energy frontier that the Large Hadron Collider provides.  Their physics interests are broad with emphasis on the expected new phenomena – never before observed in experiments and perhaps not even predicted by current models of particle interactions.  Some examples include searches for clues to long standing mysteries about Dark Matter, Dark Energy, the origin of mass, and how the universe came to be what it is today. Insights and answers may lie in forbidden decays of the heaviest (top) quark, extra dimensions, or supersymmetry, to name a few research areas the group members pursue presently.

Yale has also been active in preparing Zero Degree Calorimeters (ZDCs) for early LHC running.  These are small calorimeters for observing neutral particle production in the very forward direction from particle collisions (both proton and lead) at the new machine.  They will be useful for observing how many of these neutral particles are produced in the high energy proton collisions and in measuring neutron and photon properties that characterize Heavy Ion collisions.  Since these collisions closely resemble high energy cosmic rays striking particles in Earth’s upper atmosphere, it will also add to our knowledge of cosmic rays.

Yale University, Physics Department, Relativistic Heavy Ion (RHI) Group

 The goal of ALICE is to re-create conditions that existed 10 microseconds after the Big Bang, when all matter in the Universe existed in the form of a hot soup of quarks and gluons at an absolute temperature of 1012 K – one hundred thousand times hotter than the center of the sun.

Following a long tradition of participation and leadership in relativistic heavy ion experiments world-wide, most recently in the STAR experiment at the Relativistic Heavy Ion Collider in the US, the RHI Group at Yale joined the ALICE experiment in 2006. The RHI group at Yale is particularly interested in the production of large energy jets (clusters of particles and energy) that are a product of collisions at the LHC. Measurement of these jets in heavy ion collisions at the LHC is critical to determining properties of the hot matter created in these collisions and understanding the interaction of energetic quarks and gluons as they traverse this hot matter.

The RHI group at Yale is intimately involved in the construction of an electromagnetic calorimeter (a large detector that measures the distribution of energy emitted in the collisions) for the ALICE experiment. There are presently 2 university faculty, 4 postdoctoral research scientists, and 1 graduate student working on ALICE from the group with as many as 4-5 additional graduate students working in the group on ALICE at any given time once data-taking commences. Members of the group, both students and Ph.D.’s, are assembling and testing the detector from components built elsewhere world-wide and shipped to Yale. This is completed at Yale prior to shipment to CERN for installation in ALICE.

This detector is important for ALICE to be able to trigger on and measure large energy jets that will be crucial to determining properties of the hot matter created in these heavy ion collisions. The group expects to play an integral part in the analysis of these types of events and determining the properties of this new state of matter created at the LHC.