Location: Cyclotron Building (434), Seminar Room
Dr. Gang Wang, Kent State University, Kent, Ohio
Anisotropic Flow at RHIC Based on Transverse Deflection of Spectator Neutrons
Abstract:
Modern physics is challenged by the puzzle of quark confinement in a strongly interacting system. High-energy heavy-ion collisions can experimentally provide the high energy density required to generate Quark-Gluon Plasma (QGP), a deconfined state of quark matter. For this purpose, the Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory has been constructed and is currently taking data.
Anisotropic flow, an anisotropy of the azimuthal distribution of particles with respect to the reaction plane, sheds light on the early partonic system and is not distorted by the post-partonic stages of the collision. Non-flow effects (azimuthal correlations not related to the reaction plane orientation) are difficult to remove from the analysis and can lead us astray from the true interpretation of anisotropic flow.
To reduce the sensitivity of our analysis to non-flow effects, we aim to reconstruct the reaction plane from the sideward deflection of spectator neutrons detected by the Zero Degree Calorimeter (ZDC). It can be shown that the large rapidity gap between the spectator neutrons used to establish the reaction plane and the rapidity region of physics interest eliminates all of the known sources of non-flow correlations. We upgrade the ZDC to make it position-sensitive in the transverse plane, and utilize the spatial distribution of neutral fragments of the incident beams to determine the reaction plane.