2005 2nd Joint Meeting of the Nuclear Physics Divisions of the APS and The Physical Society of Japan
Sunday–Thursday, September 18–22, 2005;
Maui, Hawaii
Session 2WB: Workshop 2B: Strongly Interacting Matter Probed at RHIC
2:00 PM–5:00 PM,
Sunday, September 18, 2005
Ritz-Carlton Hotel
Room: Salon 3
Sponsoring
Units:
DNP JPS
Chair: Tetsuo Hatsuda, University of Tokyo
Abstract ID: BAPS.2005.HAW.2WB.4
Abstract: 2WB.00004 : Measurements of J/$\Psi$ and photons at RHIC
3:30 PM–4:00 PM
Preview Abstract
Abstract
Author:
Kyoichiro Ozawa
(CNS, Univ. of Tokyo)
Recent results on measurements of J/$\Psi$ and photons are
reported.
In spite of fruitful results in the first four years of RHIC
operation, there are still remaining questions to be answered
to further characterize the state of matter formed at RHIC. In
particular, direct information of deconfinement of quarks and
gluons and of the dense matter produced has not been obtained,
and should be provided.
From this point of view, electro-magnetic probes are important.
They created in the medium, and emerge from the matter without
strong final state interaction. Thus, they carry direct
information about conditions and properties of the medium.
Especially, direct photons and lepton decays of J/$\Psi$ are
unique observables. They allow direct access to the initial
state of the collision and information of deconfinement.
The $J/\Psi$ yield is considered to be one of the most
promising probes of deconfined matter, since theoretical models
predict that the $J/\Psi$ yield could be suppressed due to the
color Debye screening effect in QGP. On the other hand, recent
theoretical efforts shows the possibility of the $J/\Psi$ yield
increasing due to the coalescence of uncorrelated $c$ and $\bar
{c}$ quarks. Also, a cold nuclear effects, such as nuclear
absorption, may affect the final $J/\Psi$ yield. Thus, the
detailed study of $J/\Psi$ yield in several kinds of collisions
is important. We present the latest results of $J/Psi$
invariant yield and $J/Psi$ pT distribution obtained by using
its lepton decay mode in p+p, d+Au, and Au+Au collisions at
RHIC.
In addition to information from $J/Psi$ measurements,
information from photon measurements is obtained at RHIC. the
PHENIX discovery of a large photon excess over the meson-decay
background in central Au+Au collisions at high pT confirms the
final-state nature of the high-pT hadron suppression previously
observed. We present a systematic study of direct photon
production in p+p, d+Au, and Au+Au collisions.
To cite this abstract, use the following reference: http://meetings.aps.org/link/BAPS.2005.HAW.2WB.4