Oak Ridge National Laboratory

Physics Division

Physics Division Seminars

Physics Division Seminars bring us speakers on a variety of physics related subjects. Usually these are held in the Building 6008 large Conference Room, at 3:00 pm on the chosen day, but times and locations may vary. For more information, contact our seminar chairman,

Alfredo Galindo-Uribarri
Tel (Office): (865) 574-6124  (FAX): (865) 574-1268

Thu., September 27, 2007, at 3:00 p.m. (refreshments at 2:40 p.m.)

Femtoscopy in relativistic heavy-ion collisions by PHENIX

Akitomo Enokizono, Lawrence Livermore National Laboratory
Building 6008 Conference Room

In the initial five years of operations, experiments at the Relativistic Heavy Ion Collider at BNL have found that Au+Au central collisions at 200 GeV per nucleon create a strongly coupled Quark-Gluon-Plasma state that is almost opaque to jets created in the matter. Hydrodynamics models also describe the matter as an almost perfect liquid (i.e., the ratio of the shear viscosity to entropy density) state. Despite our increased understanding of this partonic matter, there remain open questions with respect to the space-time evolution, e.g., how fast the extremely hot and dense matter thermalizes and freezes out, and the nature of the phase transition that occurs. Interferometry of two identical particles (a.k.a. HBT) has been recognized as a powerful tool to study such properties of space-time evolution of the source created in relativistic heavy-ion collisions because of its capability to measure the particle emission source sizes (HBT radii) on the order of femto-meter.

I present recent PHENIX HBT measurements for charged pions in Au+Au and Cu+Cu collisions at 62-200 GeV and charged kaons in Au+Au collisions at 200 GeV. Systematic comparisons of 3-D HBT radii give us an understanding about how the dynamics of the hadron freeze-out changes as the collision energy and species change. I will also present the recent development of imaging technique for HBT analysis which gives us the unique opportunity to measure more detailed structure of the particle emission source. Recent imaging studies at PHENIX revealed that hadron emission sources created in relativistic heavy-ion collisions have a non-Gaussian structure that contains important physics.

host: Vince Cianciolo (574-4712)