1. Mass, quark-number, and sqrt sNN dependence of the second and fourth flow harmonics in ultra-relativistic nucleus-nucleus collisions
- Author
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Abelev, B.I., Adams, J., Aggarwal, M.M., Ahammed, Z., Amonett, J., Anderson, B.D., Anderson, M., Arkhipkin, D., Averichev, G.S., Bai, Y., Balewski, J., Barannikova, O., Barnby, L.S., Baudot, J., Bekele, S., Belaga, V.V., Bellingeri-Laurikainen, A., Bellwied, R., Benedosso, F., Bhardwaj, S., Bhasin, A., Bhati, A.K., Bichsel, H., Bielcik, J., Bielcikova, J., Bland, L.C., Blyth, S.-L., Bonner, B.E., Botje, M., Bouchet, J., Brandin, A.V., Bravar, A., Bystersky, M., Cadman, R.V., Cai, X.Z., Caines, H., Calderon de la Barca Sanchez, M., Castillo, J., Catu, O., Cebra, D., Chajecki, Z., Chaloupka, P., Chattopadhyay, S., Chen, H.F., Chen, J.H., Cheng, J., Cherney, M., Chikanian, A., Christie, W., Coffin, J.P., Cormier, T.M., Cosentino, M.R., Cramer, J.G., Crawford, H.J., Das, D., Das, S., Daugherity, M., de Moura, M.M., Dedovich, T.G., DePhillips, M., Derevschikov, A.A., Didenko, L., Dietel, T., Djawotho, P., Dogra, S.M., Dong, W.J., Dong, X., Draper, J.E., Du, F., Dunin, V.B., Dunlop, J.C., Dutta Mazumdar, M.R., Eckardt, V., Edwards, W.R., Efimov, L.G., Emelianov, V., Engelage, J., Eppley, G., Erazmus, B., Estienne, M., Fachini, P., Fatemi, R., Fedorisin, J., Filimonov, K., Filip, P., Finch, E., Fine, V., Fisyak, Y., Fu, J., Gagliardi, C.A., Gaillard, L., Ganti, M.S., Ghazikhanian, V., Ghosh, P., Gonzalez, J.S., Gorbunov, Y.G., Gos, H., Grebenyuk, O., Grosnick, D., and Guertin, S.M.
- Abstract
We present STAR measurements of the azimuthal anisotropy parameter v_2 for pions, kaons, protons, Lambda, bar Lambda, Xi+bar Xi, and \Omega + bar Omega, along with v_4 for pions, kaons, protons, and Lambda + bar Lambda at mid-rapidity for Au+Au collisions at sqrt sNN=62.4 and 200 GeV. The v_2(p_T) values for all hadron species at 62.4 GeV are similar to those observed in 130 and 200 GeV collisions. For observed kinematic ranges, v_2 values at 62.4, 130, and 200 GeV are as little as 10 percent-15 percent larger than those in Pb+Pb collisions at sqrt s NN =17.3 GeV. At intermediate transverse momentum (p_T from 1.5-5 GeV/c), the 62.4 GeV v_2(p_T) and v_4(p_T) values are consistent with the quark-number scaling first observed at 200 GeV. A four-particle cumulant analysis is used to assess the non-flow contributions to pions and protons and some indications are found for a smaller non-flow contribution to protons than pions. Baryon v_2 is larger than anti-baryon v_2 at 62.4 and 200 GeV perhaps indicating either that the initial spatial net-baryon distribution is anisotropic, that the mechanism leading to transport of baryon number from beam- to mid-rapidity enhances v_2, or that anti-baryon and baryon annihilation is larger in the in-plane direction.
- Published
- 2008