High momentum jet quenching in \sqrt{s_{NN}} = 62.4 GeV heavy ion – Niels Bohr Institute - University of Copenhagen

Niels Bohr Institute > Calendar > 2007 > High momentum jet quen...

High momentum jet quenching in \sqrt{s_{NN}} = 62.4 GeV heavy ion

PhD defence: Truls Martin Larsen, Niels Bohr Institute 

Production of high p_T particles (p_T > 2 GeV/c) from 200 GeV Au+Au
collisions is dominated by initial hard processes, which can be used to
probe the medium created in heavy-ion collisions. The nuclear
modification factor show suppression of the high p_T particles, but no
dependence on pseudorapidity. R_CP at the same energy does not either
depend on the pseudorapidity. In 62.4GeV collisions, high p_T particle
production can be studied in the fragmentation region, where predictions
from models such as Color Glass Condensate and Recombination should show
a strong signal.

Collisions at 62.4 GeV can be used to span the data from SPS to RHIC.
The BRAHMS experiment measured in June 2006, p+p collisions at center of
mass energy of 62.4 GeV. These provide an extended baseline for the
exploration of medium effects in heavy ion collisions. BRAHMS can
measure particles from midrapidity out to the fragmentation region, y~3,
at this center of mass energy, a unique feature of BRAHMS.

I will present nuclear modification factors from mid- to
forward rapidity for Au+Au and Cu+Cu collisions using p+p collisions,
also recorded with BRAHMS, as reference data. The results includes
nuclear modification factors of inclusive charged hadrons and identified
particles (pions, kaons and (anti-) protons), as well as a system size
comparison of the Au+Au and Cu+Cu collisions.