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arXiv · 1203.2644

Deviation from quark-number scaling of the anisotropy parameter v_2 of pions, kaons, and protons in Au+Au collisions at sqrt(s_NN) = 200 GeV

A. Adare·S. Afanasiev·C. Aidala·N. N. Ajitanand·Y. Akiba·H. Al-Bataineh·J. Alexander·K. Aoki·Y. Aramaki·E. T. Atomssa·R. Averbeck·T. C. Awes·B. Azmoun·V. Babintsev·M. Bai·G. Baksay·L. Baksay·K. N. Barish·B. Bassalleck·A. T. Basye·S. Bathe·V. Baublis·C. Baumann·A. Bazilevsky·S. Belikov·R. Belmont·R. Bennett·A. Berdnikov·Y. Berdnikov·A. A. Bickley·J. S. Bok·K. Boyle·M. L. Brooks·H. Buesching·V. Bumazhnov·G. Bunce·S. Butsyk·C. M. Camacho·S. Campbell·C. -H. Chen·C. Y. Chi·M. Chiu·I. J. Choi·R. K. Choudhury·P. Christiansen·T. Chujo·P. Chung·O. Chvala·V. Cianciolo·Z. Citron·B. A. Cole·M. Connors·P. Constantin·M. Csanád·T. Csörgö·T. Dahms·S. Dairaku·I. Danchev·K. Das·A. Datta·G. David·A. Denisov·A. Deshpande·E. J. Desmond·O. Dietzsch·A. Dion·M. Donadelli·O. Drapier·A. Drees·K. A. Drees·J. M. Durham·A. Durum·D. Dutta·S. Edwards·Y. V. Efremenko·F. Ellinghaus·T. Engelmore·A. Enokizono·H. En'yo·S. Esumi·B. Fadem·D. E. Fields·M. Finger·M. Finger, Jr.·F. Fleuret·S. L. Fokin·Z. Fraenkel·J. E. Frantz·A. Franz·A. D. Frawley·K. Fujiwara·Y. Fukao·T. Fusayasu·I. Garishvili·A. Glenn·H. Gong·M. Gonin·Y. Goto·R. Granier de Cassagnac·N. Grau
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Abstract

Measurements of the anisotropy parameter v_2 of identified hadrons (pions, kaons, and protons) as a function of centrality, transverse momentum p_T, and transverse kinetic energy KE_T at midrapidity (|η|<0.35) in Au+Au collisions at sqrt(s_NN) = 200 GeV are presented. Pions and protons are identified up to p_T = 6 GeV/c, and kaons up to p_T = 4 GeV/c, by combining information from time-of-flight and aerogel Cherenkov detectors in the PHENIX Experiment. The scaling of v_2 with the number of valence quarks (n_q) has been studied in different centrality bins as a function of transverse momentum and transverse kinetic energy. A deviation from previously observed quark-number scaling is observed at large values of KE_T/n_q in noncentral Au+Au collisions (20--60%), but this scaling remains valid in central collisions (0--10%).

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A. Adare, S. Afanasiev, C. Aidala, N. N. Ajitanand, Y. Akiba, H. Al-Bataineh, J. Alexander, K. Aoki, Y. Aramaki, E. T. Atomssa, R. Averbeck, T. C. Awes, B. Azmoun, V. Babintsev, M. Bai, G. Baksay, L. Baksay, K. N. Barish, B. Bassalleck, A. T. Basye, S. Bathe, V. Baublis, C. Baumann, A. Bazilevsky, S. Belikov, R. Belmont, R. Bennett, A. Berdnikov, Y. Berdnikov, A. A. Bickley, J. S. Bok, K. Boyle, M. L. Brooks, H. Buesching, V. Bumazhnov, G. Bunce, S. Butsyk, C. M. Camacho, S. Campbell, C. -H. Chen, C. Y. Chi, M. Chiu, I. J. Choi, R. K. Choudhury, P. Christiansen, T. Chujo, P. Chung, O. Chvala, V. Cianciolo, Z. Citron, B. A. Cole, M. Connors, P. Constantin, M. Csanád, T. Csörgö, T. Dahms, S. Dairaku, I. Danchev, K. Das, A. Datta, G. David, A. Denisov, A. Deshpande, E. J. Desmond, O. Dietzsch, A. Dion, M. Donadelli, O. Drapier, A. Drees, K. A. Drees, J. M. Durham, A. Durum, D. Dutta, S. Edwards, Y. V. Efremenko, F. Ellinghaus, T. Engelmore, A. Enokizono, H. En'yo, S. Esumi, B. Fadem, D. E. Fields, M. Finger, M. Finger, Jr., F. Fleuret, S. L. Fokin, Z. Fraenkel, J. E. Frantz, A. Franz, A. D. Frawley, K. Fujiwara, Y. Fukao, T. Fusayasu, I. Garishvili, A. Glenn, H. Gong, M. Gonin, Y. Goto, R. Granier de Cassagnac, N. Grau. 2012-03-12. Deviation from quark-number scaling of the anisotropy parameter v_2 of pions, kaons, and protons in Au+Au collisions at sqrt(s_NN) = 200 GeV. https://doi.org/10.1103/physrevc.85.064914

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