Measurement of Direct-Photon Cross Section and Double-Helicity Asymmetry at p=510 GeV in p ⃗+p ⃗Collisions ffiffi s


Abdulameer N. J., Acharya U., Adare A., Aidala C., Ajitanand N. N., Akiba Y., ...More

PHYSICAL REVIEW LETTERS, vol.130, no.25, 2023 (SCI-Expanded, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 130 Issue: 25
  • Publication Date: 2023
  • Doi Number: 10.1103/physrevlett.130.251901
  • Journal Name: PHYSICAL REVIEW LETTERS
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus, Academic Search Premier, Aerospace Database, Chemical Abstracts Core, Compendex, INSPEC, zbMATH, DIALNET, Nature Index
  • Yıldız Technical University Affiliated: No

Abstract

We present measurements of the cross section and double-helicity asymmetry ALL of direct-photon production in p ⃗ + p ⃗ collisions at ffis ffi p = 510 GeV. The measurements have been performed at midrapidity (I & eta;I < 0.25) with the PHENIX detector at the Relativistic Heavy Ion Collider. At relativistic energies, direct photons are dominantly produced from the initial quark-gluon hard scattering and do not interact via the ffiffistrong force at leading order. Therefore, at p s = 510 GeV, where leading-order-effects dominate, these measurements provide clean and direct access to the gluon helicity in the polarized proton in the gluon-momentum-fraction range 0.02 < x < 0.08, with direct sensitivity to the sign of the gluon contribution.