@article{bb3b60148d294cbbbb8c25939db80e1e,
title = "Transverse Single-Spin Asymmetry for Very Forward Neutral Pion Production in Polarized p+p Collisions at s =510 GeV",
abstract = "Transverse single-spin asymmetries of very forward neutral pions generated in polarized p+p collisions allow us to understand the production mechanism in terms of perturbative and nonperturbative strong interactions. During 2017, the RHICf Collaboration installed an electromagnetic calorimeter in the zero-degree region of the STAR detector at the Relativistic Heavy Ion Collider (RHIC) and measured neutral pions produced at pseudorapidity larger than 6 in polarized p+p collisions at s=510 GeV. The large nonzero asymmetries increasing both in longitudinal momentum fraction xF and transverse momentum pT have been observed at low transverse momentum pT<1 GeV/c for the first time, at this collision energy. The asymmetries show an approximate xF scaling in the pT region where nonperturbative processes are expected to dominate. A non-negligible contribution from soft processes may be necessary to explain the nonzero neutral pion asymmetries.",
author = "Kim, {M. H.} and O. Adriani and E. Berti and L. Bonechi and R. D'Alessandro and Y. Goto and B. Hong and Y. Itow and K. Kasahara and Lee, {J. H.} and T. Ljubicic and Y. Makino and H. Menjo and I. Nakagawa and A. Ogawa and Park, {J. S.} and T. Sako and N. Sakurai and K. Sato and R. Seidl and K. Tanida and S. Torii and A. Tricomi and M. Ueno and Zhou, {Q. D.}",
note = "Funding Information: We thank the staff of the Collider-Accelerator Department at Brookhaven National Laboratory, the STAR Collaboration, and the PHENIX Collaboration for supporting the experiment. We especially acknowledge assistance from STAR members for the design and construction of the detector manipulator, installation and uninstallation, integration of the data acquisition system, operation, and management of all these collaborative activities. We are also grateful to Dr. Daniel Pitonyak for the calculation of the asymmetry. This program is partly supported by the U.S.-Japan Science and Technology Cooperation Program in High Energy Physics, JSPS KAKENHI (No. JP26247037 and No. JP18H01227), the joint research program of the Institute for Cosmic Ray Research (ICRR), University of Tokyo, and the National Research Foundation of Korea (No. 2016R1A2B2008505 and No. 2018R1A5A1025563), and “UNICT 2020-22 Linea 2” program, University of Catania. Publisher Copyright: {\textcopyright} 2020 authors. Published by the American Physical Society.",
year = "2020",
month = jun,
day = "26",
doi = "10.1103/PhysRevLett.124.252501",
language = "English",
volume = "124",
journal = "Physical review letters",
issn = "0031-9007",
publisher = "American Physical Society",
number = "25",
}