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arXiv · 1405.6348

Elliptic flow of electrons from heavy-flavor hadron decays in Au+Au collisions at $\sqrt{s_{\rm NN}} = $ 200, 62.4, and 39 GeV

STAR Collaboration·L. Adamczyk·J. K. Adkins·G. Agakishiev·M. M. Aggarwal·Z. Ahammed·N. N. Ajitanand·I. Alekseev·D. M. Anderson·R. Aoyama·A. Aparin·D. Arkhipkin·E. C. Aschenauer·M. U. Ashraf·A. Attri·G. S. Averichev·X. Bai·V. Bairathi·A. Behera·R. Bellwied·A. Bhasin·A. K. Bhati·P. Bhattarai·J. Bielcik·J. Bielcikova·L. C. Bland·I. G. Bordyuzhin·J. Bouchet·J. D. Brandenburg·A. V. Brandin·D. Brown·I. Bunzarov·J. Butterworth·H. Caines·M. Calderon de la Barca Sanchez·J. M. Campbell·D. Cebra·I. Chakaberia·P. Chaloupka·Z. Chang·N. Chankova-Bunzarova·A. Chatterjee·S. Chattopadhyay·X. Chen·J. H. Chen·J. Cheng·M. Cherney·W. Christie·G. Contin·H. J. Crawford·S. Das·L. C. De Silva·R. R. Debbe·T. G. Dedovich·J. Deng·A. A. Derevschikov·L. Didenko·C. Dilks·X. Dong·J. L. Drachenberg·J. E. Draper·L. E. Dunkelberger·J. C. Dunlop·L. G. Efimov·N. Elsey·J. Engelage·G. Eppley·R. Esha·S. Esumi·O. Evdokimov·J. Ewigleben·O. Eyser·R. Fatemi·S. Fazio·P. Federic·P. Federicova·J. Fedorisin·Z. Feng·P. Filip·E. Finch·Y. Fisyak·C. E. Flores·L. Fulek·C. A. Gagliardi·D. Garand·F. Geurts·A. Gibson·M. Girard·D. Grosnick·D. S. Gunarathne·Y. Guo·S. Gupta·A. Gupta·W. Guryn·A. I. Hamad·A. Hamed·A. Harlenderova·J. W. Harris·L. He·S. Heppelmann
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Abstract

We present measurements of elliptic flow ($v_2$) of electrons from the decays of heavy-flavor hadrons ($e_{HF}$) by the STAR experiment. For Au+Au collisions at $\sqrt{s_{\rm NN}} = $ 200 GeV we report $v_2$, for transverse momentum ($p_T$) between 0.2 and 7 GeV/c using three methods: the event plane method ($v_{2}${EP}), two-particle correlations ($v_2${2}), and four-particle correlations ($v_2${4}). For Au+Au collisions at $\sqrt{s_{\rm NN}}$ = 62.4 and 39 GeV we report $v_2${2} for $p_T< 2$ GeV/c. $v_2${2} and $v_2${4} are non-zero at low and intermediate $p_T$ at 200 GeV, and $v_2${2} is consistent with zero at low $p_T$ at other energies. The $v_2${2} at the two lower beam energies is systematically lower than at $\sqrt{s_{\rm NN}} = $ 200 GeV for $p_T < 1$ GeV/c. This difference may suggest that charm quarks interact less strongly with the surrounding nuclear matter at those two lower energies compared to $\sqrt{s_{\rm NN}} = 200$ GeV.

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STAR Collaboration, L. Adamczyk, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, N. N. Ajitanand, I. Alekseev, D. M. Anderson, R. Aoyama, A. Aparin, D. Arkhipkin, E. C. Aschenauer, M. U. Ashraf, A. Attri, G. S. Averichev, X. Bai, V. Bairathi, A. Behera, R. Bellwied, A. Bhasin, A. K. Bhati, P. Bhattarai, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. Bouchet, J. D. Brandenburg, A. V. Brandin, D. Brown, I. Bunzarov, J. Butterworth, H. Caines, M. Calderon de la Barca Sanchez, J. M. Campbell, D. Cebra, I. Chakaberia, P. Chaloupka, Z. Chang, N. Chankova-Bunzarova, A. Chatterjee, S. Chattopadhyay, X. Chen, J. H. Chen, J. Cheng, M. Cherney, W. Christie, G. Contin, H. J. Crawford, S. Das, L. C. De Silva, R. R. Debbe, T. G. Dedovich, J. Deng, A. A. Derevschikov, L. Didenko, C. Dilks, X. Dong, J. L. Drachenberg, J. E. Draper, L. E. Dunkelberger, J. C. Dunlop, L. G. Efimov, N. Elsey, J. Engelage, G. Eppley, R. Esha, S. Esumi, O. Evdokimov, J. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, P. Federic, P. Federicova, J. Fedorisin, Z. Feng, P. Filip, E. Finch, Y. Fisyak, C. E. Flores, L. Fulek, C. A. Gagliardi, D. Garand, F. Geurts, A. Gibson, M. Girard, D. Grosnick, D. S. Gunarathne, Y. Guo, S. Gupta, A. Gupta, W. Guryn, A. I. Hamad, A. Hamed, A. Harlenderova, J. W. Harris, L. He, S. Heppelmann. 2017-03-16. Elliptic flow of electrons from heavy-flavor hadron decays in Au+Au collisions at $\sqrt{s_{\rm NN}} = $ 200, 62.4, and 39 GeV. https://doi.org/10.1103/physrevc.95.034907

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