J/psi production in J/psi production in Au+Au and Cu+Cu Au+Au and Cu+Cu collisions at RHIC- collisions at RHIC- PHENIX PHENIX Susumu Oda (Doctor course Susumu Oda (Doctor course student) student) Hamagaki group, CNS, University Hamagaki group, CNS, University of Tokyo of Tokyo 2007/08/28 2007/08/28 CISS07, Student/post-doc session CISS07, Student/post-doc session 1/11 1/11
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J/psi production in Au+Au and Cu+Cu collisions at RHIC-PHENIX
J/psi production in Au+Au and Cu+Cu collisions at RHIC-PHENIX. Susumu Oda (Doctor course student) Hamagaki group, CNS, University of Tokyo 2007/08/28 CISS07, Student/post-doc session. 1/11. My interest is …. Create QGP (Quark Gluon Plasma) and study its property experimentally. - PowerPoint PPT Presentation
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J/psi production in J/psi production in Au+Au and Cu+Cu Au+Au and Cu+Cu collisions at RHIC-collisions at RHIC-PHENIXPHENIX
J/psi production in J/psi production in Au+Au and Cu+Cu Au+Au and Cu+Cu collisions at RHIC-collisions at RHIC-PHENIXPHENIXSusumu Oda (Doctor course Susumu Oda (Doctor course student)student)Hamagaki group, CNS, University Hamagaki group, CNS, University of Tokyoof Tokyo
Participates in the PHENIX experiment at BNL-RHIC (circumference=3.8km). Starts to participate in ALICE
experiment at CERN-LHC (27km). These facilities are very very large
to collide particles with very high energy.
4/114/11
高原TakaharaLHC
This is me
He is our boss
What are the signals of QGP?How can we know whether QGP is created or not? Really big problem.
No definitive conclusion.
But, one good candidate is J/psi. J/psi is a bound state of a charm quark and an
anti-charm quark.J/psi will be created by only initial collisions. J/psi would melt and disappear in hot QGP. Yield would be suppressed. If J/psi melt in QGP, we detect the less number of
J/psi’s than expected.
I study J/psi production in Cu+Cu collisions.
5/115/11
How do we measure J/psi?
J/psi has lepton-pair decay channels.
Branching ratio (J/psie+e-)=5.94%, (J/psi+-)=5.93%
Electron (Cherenkov light, electromagnetic interaction) and muon (less absorption cross section by material) are easily identified.
If there is no hot nuclear effect nor cold nuclear effect, a heavy ion collision can be understood as superposition of nucleon-nucleon collisions (p+p, p+n, n+n). p+p : No nuclear effectp(d)+A : cold nuclear effect
Hot region is limited and is soon cooled down. A+A : hot nuclear effect (QGP) + cold nuclear effect
Large hot region isn’t soon cooled down. We can know hot nuclear effect by
(A+A)/(p+p)-(d+A)/(p+p) (hot+cold)-cold = hot nuclear effect
9/119/11
ppcoll
AAAA YieldN
YieldR
p+p d+A A+A
RAA vs Npart (the number of participating nucleon)
J/psi seems to be melted and QGP seems to be created at RHIC.