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Title: Nuclear Dependence of the Transverse-Single-Spin Asymmetry for Forward Neutron Production in Polarized p + A Collisions at s N N = 200 GeV

Journal Article · · Physical Review Letters
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We report that 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 three larger in absolute value and of opposite sign. Lastly, the interplay of different neutron production mechanisms is discussed as a possible explanation of the observed A dependence.

Research Organization:
Brookhaven National Lab. (BNL), Upton, NY (United States)
Sponsoring Organization:
USDOE Office of Science (SC), Nuclear Physics (NP)
Contributing Organization:
PHENIX Collaboration
Grant/Contract Number:
SC0012704
OSTI ID:
1416077
Alternate ID(s):
OSTI ID: 1413950
Report Number(s):
BNL-114783-2017-JA; PRLTAO; 022001
Journal Information:
Physical Review Letters, Journal Name: Physical Review Letters Vol. 120 Journal Issue: 2; ISSN 0031-9007
Publisher:
American Physical SocietyCopyright Statement
Country of Publication:
United States
Language:
English
Citation Metrics:
Cited by: 6 works
Citation information provided by
Web of Science

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