Transverse single spin asymmetry for very forward π⁰ production in polarized proton-proton collisions at √s = 510 GeV

¹ Department of Physics, Korea University, Seoul, South Korea
² RIKEN Nishina Center for Accelerator-Based Science, Saitama, Japan
³ RIKEN BNL Research Center, Brookhaven National Laboratory, New York, USA
⁴ Department of Physics, Seoul National University, Seoul, South Korea
⁵ Japan Atomic Energy Agency, Ibaraki, Japan
⁶ Institute for Space-Earth Environmental Research, Nagoya University, Nagoya, Japan
⁷ Kobayashi-Maskawa Institute for the Origin of Particles and the Universe, Nagoya University, Nagoya, Japan
⁸ Institute for Cosmic Ray Research, University of Tokyo, Kashiwa, Chiba, Japan
⁹ RISE, Waseda University, Shinjuku, Tokyo, Japan
¹⁰ Graduate School of Science, Nagoya University, Nagoya, Japan
¹¹ Tokushima University, Tokushima, Japan
¹² INFN Section of Florence, Florence, Italy
¹³ INFN Section of Catania, Italy
¹⁴ University of Catania, Catania, Italy
¹⁵ University of Florence, Florence, Italy

^* e-mail: jipangie@korea.ac.kr

Published online: 10 May 2019

Abstract

Transverse single spin asymmetry, A_N, of very forward π⁰ production from polarized p + p collisions provides new information toward an understanding of its production mechanism. A_N of forward π⁰ in the pseudorapidity region of 3 < η < 4 has been described by the partonic structure of the proton in the perturbative QCD framework. However, recent data indicates a potential contribution from not only partonic but also diffractive interactions. In order to provide a new insight on the origin of the A_N, we measured the very forward π⁰ production in the pseudorapidity region of 6 < η from √s = 510 GeV polarized p + p collisions at RHIC in 2017. We report our measurement of the very forward π⁰ over the transverse momentum range of 0 < p_T < 1 GeV/c and the preliminary result.