fyi Unfortunately I cannot mail the figure from here/ Dear Gunther and other Phobos friends, I heard there will be a special seminar by PHOBOS to discuss the results of 62 GeV run. Unfortunately, I could not find any information about the talk or any web cast. So let me give you some results of my calculation. I am still writing it up. In Fig. 7 of nucl-th/0307036 I have calculated the energy dependence of R_AA(ch) at pt=4 GeV, assuming the parton energy loss is linearly proportional to the measured dN/d\eta and the lifetime of the dense matter is independent of the energy and larger than the system size. For 62 GeV, R_AA is about 0.6 at pt=4 GeV for charged hadrons. Here attached you can find R_AA as a function of pt at 200, 62 and 17 GeV. The solid lines are for charged hadrons and dashed lines for pion^0. There are two features of the R_AA at 62 GeV: (1)The difference between charged hadron and pion^0 is again due to coalescence effect which extend to higher pt than at 200 GeV. (2)R_AA at 62 GeV, decreases with pt and approaches to the value at 200 GeV collisions at high pt>7 GeV. These two features are both caused by the steeper pt spectra at 62 GeV than at 200 GeV. At LHC energies, the R_AA increases with pt as Ivan has shown before, because the spectra there are much flatter. My warning at this time is that if you only have a limit range of pt<4 GeV, you will see much less suppression of charged hadrons, partly because of smaller energy loss and partly because of baryon/coalescence effect. This effect will only go away at higher pt. If one looks at back-to-back correlation and find the suppression is about the same as in 200 GeV. The upper red lines, I changed the lifetime of the dense matter to be 4 fm, less than the transverse size of the medium, to demonstrate the sensitive. This, of course, will give less suppression. The blues lines are for SPS energy, with lifetime 0-1 fm. The data there can only accommodate a dense matter with very short lifetime. I hope to see your paper on the archive soon. Xin-Nian Lawrence Berkeley National Laboratory Nuclear Science Division, MS 70R0319 Berkeley, CA 94720 Tel: (510)486-5239 Fax: (510)486-4794 Home: http://www-nsdt.lbl.gov/~xnwang _______________________________________________ Brahms-l mailing list Brahms-l@lists.bnl.gov http://lists.bnl.gov/mailman/listinfo/brahms-lReceived on Wed May 5 09:38:22 2004
This archive was generated by hypermail 2.1.8 : Wed May 05 2004 - 09:38:49 EDT