Nuclear Dependence of the Transverse-Single-Spin Asymmetry for Forward Neutron Production in Polarized $p+A$ Collisions at $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$

C. Aidala , Y. Akiba , M. Alfred , V. Andrieux , K. Aoki , N. Apadula , H. Asano , C. Ayuso , B. Azmoun , V. Babintsev , A. Bagoly , N.S. Bandara , K.N. Barish , S. Bathe , A. Bazilevsky , M. Beaumier , R. Belmont , A. Berdnikov , Y. Berdnikov , D.S. Blau , M. Boer , J.S. Bok , M.L. Brooks , J. Bryslawskyj , V. Bumazhnov , C. Butler , S. Campbell , V. Canoa Roman , R. Cervantes , C.Y. Chi , M. Chiu , I.J. Choi , J.B. Choi , Z. Citron , M. Connors , N. Cronin , M. Csanád , T. Csörgő , T.W. Danley , M.S. Daugherity , G. David , K. Deblasio , K. Dehmelt , A. Denisov , A. Deshpande , E.J. Desmond , A. Dion , D. Dixit , J.H. Do , A. Drees , K.A. Drees , M. Dumancic , J.M. Durham , A. Durum , T. Elder , A. Enokizono , H. En'Yo , S. Esumi , B. Fadem , W. Fan , N. Feege , D.E. Fields , M. Finger , S.L. Fokin , J.E. Frantz , A. Franz , A.D. Frawley , Y. Fukuda , C. Gal , P. Gallus , P. Garg , H. Ge , F. Giordano , Y. Goto , N. Grau , S.V. Greene , M. Grosse Perdekamp , T. Gunji , H. Guragain , T. Hachiya , J.S. Haggerty , K.I. Hahn , H. Hamagaki , H.F. Hamilton , S.Y. Han , J. Hanks , S. Hasegawa , T.O.S. Haseler , X. He , T.K. Hemmick , J.C. Hill , K. Hill , R.S. Hollis , K. Homma , B. Hong , T. Hoshino , N. Hotvedt , J. Huang , S. Huang , K. Imai , J. Imrek , M. Inaba , A. Iordanova , D. Isenhower , Y. Ito , D. Ivanishchev , B.V. Jacak , M. Jezghani , Z. Ji , X. Jiang , B.M. Johnson , V. Jorjadze , D. Jouan (1) , D.S. Jumper , J.H. Kang , D. Kapukchyan , S. Karthas , D. Kawall , A.V. Kazantsev , V. Khachatryan , A. Khanzadeev , C. Kim , D.J. Kim , E.-J. Kim , M.H. Kim , D. Kincses , E. Kistenev , J. Klatsky , P. Kline , T. Koblesky , D. Kotov , S. Kudo , K. Kurita , Y. Kwon , J.G. Lajoie , E.O. Lallow , A. Lebedev , S. Lee , M.J. Leitch , Y.H. Leung , N.A. Lewis , X. Li , S.H. Lim , L.D. Liu , M.X. Liu , V.-R. Loggins , S. Lokos , K. Lovasz , D. Lynch , T. Majoros , Y.I. Makdisi , M. Makek , M. Malaev , V.I. Manko , E. Mannel , H. Masuda , M. Mccumber , P.L. Mcgaughey , D. Mcglinchey , C. Mckinney , M. Mendoza , W.J. Metzger , A.C. Mignerey , D.E. Mihalik , A. Milov , D.K. Mishra , J.T. Mitchell , G. Mitsuka , S. Miyasaka , S. Mizuno , P. Montuenga , T. Moon , D.P. Morrison , S.I.M. Morrow , T. Murakami , J. Murata , K. Nagai , K. Nagashima , T. Nagashima , J.L. Nagle , M.I. Nagy , I. Nakagawa , H. Nakagomi , K. Nakano , C. Nattrass , T. Niida , R. Nouicer , T. Novák , N. Novitzky , R. Novotny , A.S. Nyanin , E. O'Brien , C.A. Ogilvie , Orjuela Koop , J.D. Osborn , A. Oskarsson , G.J. Ottino , K. Ozawa , V. Pantuev , V. Papavassiliou , J.S. Park , S. Park , S.F. Pate , M. Patel , W. Peng , D.V. Perepelitsa , G.D.N. Perera , D.Yu. Peressounko , C.E. Perezlara , J. Perry , R. Petti , M. Phipps , C. Pinkenburg , R.P. Pisani , A. Pun , M.L. Purschke , P.V. Radzevich , K.F. Read , D. Reynolds , V. Riabov , Y. Riabov , D. Richford , T. Rinn , S.D. Rolnick , M. Rosati , Z. Rowan , J. Runchey , A.S. Safonov , T. Sakaguchi , H. Sako , V. Samsonov , M. Sarsour , K. Sato , S. Sato , B. Schaefer , B.K. Schmoll , K. Sedgwick , R. Seidl , A. Sen , R. Seto , A. Sexton , D. Sharma , I. Shein , T.-A. Shibata , K. Shigaki , M. Shimomura , T. Shioya , P. Shukla , A. Sickles , C.L. Silva , D. Silvermyr , B.K. Singh , C.P. Singh , V. Singh , M.J. Skoby , M. Slunečka , K.L. Smith , M. Snowball , R.A. Soltz , W.E. Sondheim , S.P. Sorensen , I.V. Sourikova , P.W. Stankus , S.P. Stoll , T. Sugitate , A. Sukhanov , T. Sumita , J. Sun , S. Syed , J. Sziklai , A Takeda , K. Tanida , M.J. Tannenbaum , S. Tarafdar , G. Tarnai , R. Tieulent (2) , A. Timilsina , T. Todoroki , M. Tomášek , C.L. Towell , R.S. Towell , I. Tserruya , Y. Ueda , B. Ujvari , H.W. van Hecke , S. Vazquez-Carson , J. Velkovska , M. Virius , V. Vrba , N. Vukman , X.R. Wang , Z. Wang , Y.S. Watanabe , C.P. Wong , C.L. Woody , C. Xu , Q. Xu , L. Xue , S. Yalcin , Y.L. Yamaguchi , H. Yamamoto , A. Yanovich , P. Yin , J.H. Yoo , I. Yoon , H. Yu , I.E. Yushmanov , W.A. Zajc , A. Zelenski , S. Zharko , L. Zou

1 IPNO - Institut de Physique Nucléaire d'Orsay
2 IPNL - Institut de Physique Nucléaire de Lyon

During 2015, the Relativistic Heavy Ion Collider (RHIC) provided collisions of transversely polarized protons with Au and Al nuclei for the first time, enabling the exploration of transverse-single-spin asymmetries with heavy nuclei. Large single-spin asymmetries in very forward neutron production have been previously observed in transversely polarized p+p collisions at RHIC, and the existing theoretical framework that was successful in describing the single-spin asymmetry in p+p collisions predicts only a moderate atomic-mass-number (A) dependence. In contrast, the asymmetries observed at RHIC in p+A collisions showed a surprisingly strong A dependence in inclusive forward neutron production. The observed asymmetry in p+Al collisions is much smaller, while the asymmetry in p+Au collisions is a factor of 3 larger in absolute value and of opposite sign. The interplay of different neutron production mechanisms is discussed as a possible explanation of the observed A dependence.

Mots clés: spin: asymmetry; Brookhaven RHIC Coll; experimental results; 200 GeV-cms/nucleon; p nucleus: interaction; p: polarized beam; gold; aluminum; n: production; nucleus: heavy

Domaines: Physique des Hautes Energies - Expérience [hep-ex]; Physique Nucléaire Expérimentale [nucl-ex]

C. Aidala, Y. Akiba, M. Alfred, V. Andrieux, K. Aoki, et al.. Nuclear Dependence of the Transverse-Single-Spin Asymmetry for Forward Neutron Production in Polarized $p+A$ Collisions at $\sqrt{{s}_{NN}}=200\text{ }\text{ }\mathrm{GeV}$. Physical Review Letters, 2018, 120 (2), pp.022001. ⟨10.1103/PhysRevLett.120.022001⟩. ⟨hal-01703767⟩