Polarization of $\Lambda$ ($\bar{\Lambda}$) hyperons along the beam direction in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV
Nuclear Experiment
2019-10-02 v1
Abstract
The () hyperon polarization along the beam direction has been measured for the first time in Au+Au collisions at = 200 GeV. The polarization dependence on the hyperons' emission angle relative to the second-order event plane exhibits a sine modulation, indicating a quadrupole pattern of the vorticity component along the beam direction. The polarization is found to increase in more peripheral collisions, and shows no strong transverse momentum () dependence at GeV/. The magnitude of the signal is about five times smaller than those predicted by hydrodynamic and multiphase transport models; the observed phase of the emission angle dependence is also opposite to these model predictions. In contrast, blast-wave model calculations reproduce the modulation phase measured in the data and capture the centrality and transverse momentum dependence of the signal once the model is required to reproduce the azimuthal dependence of the Gaussian source radii measured via the Hanbury-Brown and Twiss intensity interferometry technique.
Cite
@article{arxiv.1905.11917,
title = {Polarization of $\Lambda$ ($\bar{\Lambda}$) hyperons along the beam direction in Au+Au collisions at $\sqrt{s_{_{NN}}}$ = 200 GeV},
author = {STAR Collaboration and J. Adam and L. Adamczyk and J. R. Adams and J. K. Adkins and G. Agakishiev and M. M. Aggarwal and Z. Ahammed and I. Alekseev and D. M. Anderson and R. Aoyama and A. Aparin and D. Arkhipkin and E. C. Aschenauer and M. U. Ashraf and F. Atetalla and A. Attri and G. S. Averichev and V. Bairathi and K. Barish and A. J. Bassill and A. Behera and R. Bellwied and A. Bhasin and A. K. Bhati and J. Bielcik and J. Bielcikova and L. C. Bland and I. G. Bordyuzhin and J. D. Brandenburg and A. V. Brandin and J. Bryslawskyj and I. Bunzarov and J. Butterworth and H. Caines and M. Calderón de la Barca Sánchez and D. Cebra and I. Chakaberia and P. Chaloupka and B. K. Chan and F-H. Chang and Z. Chang and N. Chankova-Bunzarova and A. Chatterjee and S. Chattopadhyay and J. H. Chen and X. Chen and J. Cheng and M. Cherney and W. Christie and H. J. Crawford and M. Csanád and S. Das and T. G. Dedovich and I. M. Deppner and A. A. Derevschikov and L. Didenko and C. Dilks and X. Dong and J. L. Drachenberg and J. C. Dunlop and T. Edmonds and N. Elsey and J. Engelage and G. Eppley and R. Esha and S. Esumi and O. Evdokimov and J. Ewigleben and O. Eyser and R. Fatemi and S. Fazio and P. Federic and J. Fedorisin and Y. Feng and P. Filip and E. Finch and Y. Fisyak and L. Fulek and C. A. Gagliardi and T. Galatyuk and F. Geurts and A. Gibson and K. Gopal and D. Grosnick and A. Gupta and W. Guryn and A. I. Hamad and A. Hamed and J. W. Harris and L. He and S. Heppelmann and S. Heppelmann and N. Herrmann and L. Holub and Y. Hong and S. Horvat and B. Huang and H. Z. Huang and S. L. Huang and T. Huang and X. Huang and T. J. Humanic and P. Huo and G. Igo and W. W. Jacobs and C. Jena and A. Jentsch and Y. JI and J. Jia and K. Jiang and S. Jowzaee and X. Ju and E. G. Judd and S. Kabana and S. Kagamaster and D. Kalinkin and K. Kang and D. Kapukchyan and K. Kauder and H. W. Ke and D. Keane and A. Kechechyan and M. Kelsey and Y. V. Khyzhniak and D. P. Kikoła and C. Kim and T. A. Kinghorn and I. Kisel and A. Kisiel and M. Kocan and L. Kochenda and L. K. Kosarzewski and L. Kramarik and P. Kravtsov and K. Krueger and N. Kulathunga Mudiyanselage and L. Kumar and R. Kunnawalkam Elayavalli and J. H. Kwasizur and R. Lacey and J. M. Landgraf and J. Lauret and A. Lebedev and R. Lednicky and J. H. Lee and C. Li and W. Li and W. Li and X. Li and Y. Li and Y. Liang and R. Licenik and T. Lin and A. Lipiec and M. A. Lisa and F. Liu and H. Liu and P. Liu and P. Liu and T. Liu and X. Liu and Y. Liu and Z. Liu and T. Ljubicic and W. J. Llope and M. Lomnitz and R. S. Longacre and S. Luo and X. Luo and G. L. Ma and L. Ma and R. Ma and Y. G. Ma and N. Magdy and R. Majka and D. Mallick and S. Margetis and C. Markert and H. S. Matis and O. Matonoha and J. A. Mazer and K. Meehan and J. C. Mei and N. G. Minaev and S. Mioduszewski and D. Mishra and B. Mohanty and M. M. Mondal and I. Mooney and Z. Moravcova and D. A. Morozov and Md. Nasim and K. Nayak and J. M. Nelson and D. B. Nemes and M. Nie and G. Nigmatkulov and T. Niida and L. V. Nogach and T. Nonaka and G. Odyniec and A. Ogawa and K. Oh and S. Oh and V. A. Okorokov and B. S. Page and R. Pak and Y. Panebratsev and B. Pawlik and D. Pawlowska and H. Pei and C. Perkins and R. L. Pintér and J. Pluta and J. Porter and M. Posik and N. K. Pruthi and M. Przybycien and J. Putschke and A. Quintero and S. K. Radhakrishnan and S. Ramachandran and R. L. Ray and R. Reed and H. G. Ritter and J. B. Roberts and O. V. Rogachevskiy and J. L. Romero and L. Ruan and J. Rusnak and O. Rusnakova and N. R. Sahoo and P. K. Sahu and S. Salur and J. Sandweiss and J. Schambach and W. B. Schmidke and N. Schmitz and B. R. Schweid and F. Seck and J. Seger and M. Sergeeva and R. Seto and P. Seyboth and N. Shah and E. Shahaliev and P. V. Shanmuganathan and M. Shao and F. Shen and W. Q. Shen and S. S. Shi and Q. Y. Shou and E. P. Sichtermann and S. Siejka and R. Sikora and M. Simko and J. Singh and S. Singha and D. Smirnov and N. Smirnov and W. Solyst and P. Sorensen and H. M. Spinka and B. Srivastava and T. D. S. Stanislaus and M. Stefaniak and D. J. Stewart and M. Strikhanov and B. Stringfellow and A. A. P. Suaide and T. Sugiura and M. Sumbera and B. Summa and X. M. Sun and Y. Sun and Y. Sun and B. Surrow and D. N. Svirida and P. Szymanski and A. H. Tang and Z. Tang and A. Taranenko and T. Tarnowsky and J. H. Thomas and A. R. Timmins and D. Tlusty and T. Todoroki and M. Tokarev and C. A. Tomkiel and S. Trentalange and R. E. Tribble and P. Tribedy and S. K. Tripathy and O. D. Tsai and B. Tu and Z. Tu and T. Ullrich and D. G. Underwood and I. Upsal and G. Van Buren and J. Vanek and A. N. Vasiliev and I. Vassiliev and F. Videbæk and S. Vokal and S. A. Voloshin and F. Wang and G. Wang and P. Wang and Y. Wang and Y. Wang and J. C. Webb and L. Wen and G. D. Westfall and H. Wieman and S. W. Wissink and R. Witt and Y. Wu and Z. G. Xiao and G. Xie and W. Xie and H. Xu and N. Xu and Q. H. Xu and Y. F. Xu and Z. Xu and C. Yang and Q. Yang and S. Yang and Y. Yang and Z. Yang and Z. Ye and Z. Ye and L. Yi and K. Yip and I. -K. Yoo and H. Zbroszczyk and W. Zha and D. Zhang and L. Zhang and S. Zhang and S. Zhang and X. P. Zhang and Y. Zhang and Z. Zhang and J. Zhao and C. Zhong and C. Zhou and X. Zhu and Z. Zhu and M. Zurek and M. Zyzak},
journal= {arXiv preprint arXiv:1905.11917},
year = {2019}
}
Comments
8 pages, 4 figures, Submitted to Phys. Rev. Lett