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Muhammad Ibrahim Abdulhamid, Bassam Aboona, Jaroslav Adam, Joseph Adams, Geydar Agakishiev, Ishu Aggarwal, Madan Aggarwal, Zubayer Ahammed, Alisher Aitbaev, Igor Alekseev, Derek Anderson, Alexey Aparin, Sameer Aslam, Joseph Atchison, Georgy Averichev, Vipul Bairathi, William Baker, Jonathan Gonzalo Ball Cap, Kenneth Barish, Pratibha Bhagat, Anju Bhasin, Somadutta Bhatta, Igor G. Bordyuzhin, James Brandenburg, Andrei Brandin, Xiang-Zhou Cai, Helen Caines, Manuel Calderon de la Barca Sanchez, Daniel Cebra, Jakub Ceska, Irakli Chakaberia, Brian Chan, Zilong Chang, Arghya Chatterjee, Ding Chen, J. Chen, J.H. Chen, Zhenyu Chen, Jianping Cheng, Yunshan Cheng, Subikash Choudhury, Bill Christie, William Christie, Xiaoxuan Chu, Henry J. Crawford, Gabriel Dale-Gau, Ayanabha Das, Michael Daugherity, Tatiana Dedovich, Ingo Martin Deppner, Anatoly Derevschikov, Arushi Dhamija, Launa Di Carlo, Prabhupada Dixit, Xin Dong, James Drachenberg, Eddie Duckworth, James Dunlop, Jack Engelage, Geary Eppley, ShinIchi Esumi, Olga Evdokimov, Annika Ewigleben, Kjeld Oleg Eyser, Renee Fatemi, Salvatore Fazio, Chan-Jui Feng, Yicheng Feng, Evan Finch, Yuri V. Fisyak, Fernando Antonio Flor, Chuan Fu, Taoya Gao, Frank Geurts, Navagyan Ghimire, Adam Gibson, Krishan Gopal, Xingrui Gou, David Grosnick, Anik Gupta, Ahmed Hamed, Yiding Han, Matthew Harasty, John W. Harris, Hannah Harrison-Smith, Wanbing He, Xionghong He, Yang He, Chenlu Hu, Qiang Hu, Y. Hu, H. Huang, H.Z. Huang, Shengli Huang, Te-Chuan Huang, Xinjie Huang, Y. Huang, Y. Huang, Thomas J. Humanic, Donald Isenhower, Moe Isshiki, William Jacobs, Ashish Jalotra, Chitrasen Jena, Yuanjing Ji, Jiangyong Jia, Chenliang Jin, Xinyue Ju, Eleanor Judd, Sonia Kabana, Md Latiful Kabir, Dmitry Kalinkin, Kejun Kang, David Kapukchyan, Kolja Kauder, Declan Keane, Armen Kechechyan, Matthew Kelsey, Benjamin Kimelman, Alexander Kiselev, Anders Knospe, Ho San Ko, Leonid Kochenda, Artem Korobitsin, Petr Kravtsov, Lokesh Kumar, Shyam Kumar, Raghav Kunnawalkam Elayavalli, Roy Alphanso Lacey, Jeffery Landgraf, Alexei Lebedev, Richard Lednicky, Jeong-Hun Lee, Yue-Hang Leung, Nicole Lewis, Changfeng Li, Wei Li, Xiujun Li, Y. Li, Y. Li, Ziyang Li, Xilin Liang, Yue Liang, Ting Lin, Chengyang Liu, Feng Liu, Guoming Liu, H. Liu, H. Liu, Li-ke Liu, Tong Liu, Xiaoyu Liu, Yanfang Liu, Zuowen Liu, Tonko Ljubicic, William Joseph Llope, Ondrej Lomicky, Ronald S. Longacre, E.M. Loyd, Tan Lu, Nicholas Lukow, Xiaofeng Luo, V.B. Luong, Long Ma, Rongrong Ma, Yu-Gang Ma, Niseem Magdy Abdelwahab Abdelrahman, Dukhishyam Mallick, Spiros Margetis, Howard Matis, Joel Anthony Mazer, Grant McNamara, K. Mi, Nikolai Minaev, Bedanga Mohanty, Mriganka Mondal, Isaac A. Mooney, Dmitry Morozov, Aleksandr Mudrokh, Marton Nagy, Ankita Nain, J.D. Nam, M. Nasim, Dylan Neff, John M. Nelson, Daniel Nemes, Maowu Nie, Grigory Nigmatkulov, Takafumi Niida, Risa Nishitani, Larisa Nogach, Toshihiro Nonaka, Grazyna Odyniec, Akio Ogawa, Saehanseul Oh, Vitaly A. Okorokov, Kosuke Okubo, Brian Page, Robert Pak, Jinjin Pan, Ashish Pandav, Ashutosh Pandey, Yuri Panebratsev, Tanmay Pani, Petr Parfenov, Ananya Paul, Chris Perkins, B.R. Pokhrel, Matthew Posik, Tristan Protzman, Navneet Kumar Pruthi, Joern Putschke, Zhi Qin, Hao Qiu, Amilkar Quintero, Cameron Racz, Sooraj Radhakrishnan, Nandita Raha, Lanny Ray, Hans Georg Ritter, Charles Robertson, Oleg Rogachevskiy, Manuel Rosales Aguilar, Diptanil Roy, Lijuan Ruan, Aswini Sahoo, Nihar Ranjan Sahoo, Hiroyuki Sako, Sevil Salur, Edward Samigullin, Susumu Sato, William B. Schmidke, Norbert Schmitz, Janet Seger, Richard Seto, Peter Seyboth, Neha Shah, Ehtiram Shahaliev, Prashanth V. Shanmuganathan, Tianhao Shao, Mahima Sharma, Natasha Sharma, Rishabh Sharma, Sharang Rav Sharma, Ashik Ikbal Sheikh, D. Shen, D.Y. Shen, Kaifeng Shen, Shusu Shi, Yingying Shi, Qi-Ye Shou, Fan Si, Jagbir Singh, Subhash Singha, Priyanshi Sinha, Michael Skoby, Yannick Soehngen, Youqi Song, Brijesh Srivastava, Shirvel Stanislaus, David Stewart, Mikhail Strikhanov, Blair Stringfellow, Yuan Su, Chuan Sun, X. Sun, Y. Sun, Y. Sun, Bernd Surrow, Dmitry Svirida, Zachary Sweger, Andrew Tamis, Aihong Tang, Zebo Tang, Arkadiy Taranenko, Terry Tarnowsky, James H. Thomas, David Tlusty, Takahito Todoroki, Michael Tokarev, Catherine Tomkiel, Steven Trentalange, Robert Tribble, Prithwish Tribedy, Oleg D. Tsai, Chun Yuen Tsang, Zhoudunming Tu, Jace Tyler, Thomas Ullrich, David G. Underwood, Isaac Upsal, Gene Van Buren, Alexander Vasiliev, Veronica Verkest, Flemming Videbæk, Stanislav Vokal, Sergei Voloshin, Fuqiang Wang, Gang Wang, J.S. Wang, J. Wang, Xiaofeng Wang, Y. Wang, Y. Wang, Y. Wang, Zhen Wang, Jason Webb, Philipp Weidenkaff, Gary D. Westfall, Howard Wieman, Gavin Wilks, Scott Wissink, J. Wu, J. Wu, X. Wu, X. Wu, Yang Wu, Baoshan Xi, Zhigang Xiao, Guannan Xie, Wei Xie, Haojie Xu, N. Xu, Qinghua Xu, Y. Xu, Y. Xu, Z. Xu, Z. Xu, Gaoguo Yan, Zhengxi Yan, Chi Yang, Qian Yang, Shuai Yang, Y. Yang, Z. Ye, Z. Ye, L. Yi, Kin Yip, Y. Yu, Wangmei Zha, ChunJian Zhang, Dingwei Zhang, Jinlong Zhang, Shenghui Zhang, Wei Zhang, Xin Zhang, Y. Zhang, Y. Zhang, Y. Zhang, Y. Zhang, Z.J. Zhang, Z. Zhang, Z. Zhang, Fengyi Zhao, Jie Zhao, Minghui Zhao, Chensheng Zhou, Jian Zhou, Shuai Zhou, Yingjie Zhou, Xianglei Zhu, Maria Zurek, Maksym Zyzak

• The polarization of Λ and Λ¯ hyperons along the beam direction has been measured relative to the second and third harmonic event planes in isobar Ru+Ru and Zr+Zr collisions at √sNN = 200 GeV. This is the first experimental evidence of the hyperon polarization by the triangular flow originating from the initial density fluctuations. The amplitudes of the sine modulation for the second and third harmonic results are comparable in magnitude, increase from central to peripheral collisions, and show a mild pT dependence. The azimuthal angle dependence of the polarization follows the vorticity pattern expected due to elliptic and triangular anisotropic flow, and qualitatively disagree with most hydrodynamic model calculations based on thermal vorticity and shear induced contributions. The model results based on one of existing implementations of the shear contribution lead to a correct azimuthal angle dependence, but predict centrality and pT dependence that still disagree with experimental measurements. Thus, our results provide stringent constraints on the thermal vorticity and shear-induced contributions to hyperon polarization. Comparison to previous measurements at RHIC and the LHC for the second-order harmonic results shows little dependence on the collision system size and collision energy.