Do we understand the single-spin asymmetry for π⁰ inclusive production in pp collisions?

2003/11/30 by C. Bourrely, Claude Bourrely, Jacques Soffer +1 · 4 citations
Physics and Astronomy · #High-Energy Particle Collisions Research #Particle Detector Development and Performance #Particle physics theoretical and experimental studies #hep-ph

paper · pdf · doi:10.1140/epjc/s2004-01956-4

published as Eur.Phys.J.C36:371-374,2004 · text modified, version to be published in Eur. Phys. J. C, 6 pages, 5 figures

arxiv created 2004/05/28 · openalex publication_date 2004/07/13 · arxiv updated 2009/12/01 · openalex created_date 2016/06/24 · openalex updated_date 2026/07/28

Abstract

The cross section data for π⁰ inclusive production in pp collisions is considered in a rather broad kinematic region in energy √(s), Feynman variable x_F and transverse momentum p_T. The analysis of these data is done in the perturbative QCD framework at the next-to-leading order. We find that they cannot be correctly described in the entire kinematic domain and this leads us to conclude that the single-spin asymmetry, A_N for this process, observed several years ago at FNAL by the experiment E704 and the recent result obtained at BNL-RHIC by STAR, are two different phenomena. This suggests that STAR data probes a genuine leading-twist QCD single-spin asymmetry for the first time and finds a large effect.

Citations

• Fragmentation functions for pions, kaons, and protons at next-to-leading order

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