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Title: Measurement of parity-violating spin asymmetries in W ± production at midrapidity in longitudinally polarized p + p collisions

Abstract

In this study, we present midrapidity measurements from the PHENIX experiment of large parity-violating single-spin asymmetries of high transverse momentum electrons and positrons from W±/Z decays, produced in longitudinally polarized p + p collisions at center of mass energies of √s = 500 and 510 GeV. These asymmetries allow direct access to the antiquark polarized parton distribution functions due to the parity-violating nature of the W-boson coupling to quarks and antiquarks. The results presented are based on data collected in 2011, 2012, and 2013 with an integrated luminosity of 240 pb–1, which exceeds previous PHENIX published results by a factor of more than 27. These high Q2 data probe the parton structure of the proton at W mass scale and provide an important addition to our understanding of the antiquark parton helicity distribution functions at an intermediate Bjorken x value of roughly MW/ √s = 0.16.

Authors:
 [1]
  1. Univ. of Colorado, Boulder, CO (United States).et al
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States); Brookhaven National Lab. (BNL), Upton, NY (United States). Relativistic Heavy Ion Collider (RHIC)
Sponsoring Org.:
USDOE Office of Science (SC), Nuclear Physics (NP)
Contributing Org.:
PHENIX Collaboration
OSTI Identifier:
1324118
Alternate Identifier(s):
OSTI ID: 1243007; OSTI ID: 1335476
Report Number(s):
BNL-112149-2016-JA
Journal ID: ISSN 2470-0010; KB0201022; ERKBP09
Grant/Contract Number:  
AC05-00OR22725; SC00112704
Resource Type:
Accepted Manuscript
Journal Name:
Physical Review D
Additional Journal Information:
Journal Volume: 93; Journal Issue: 5; Journal ID: ISSN 2470-0010
Publisher:
American Physical Society (APS)
Country of Publication:
United States
Language:
English
Subject:
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; 71 CLASSICAL AND QUANTUM MECHANICS, GENERAL PHYSICS; 73 NUCLEAR PHYSICS AND RADIATION PHYSICS; midrapidity; spin asymmetries; Relativistic Heavy Ion Collider

Citation Formats

Adare, A. Measurement of parity-violating spin asymmetries in W± production at midrapidity in longitudinally polarized p+p collisions. United States: N. p., 2016. Web. https://doi.org/10.1103/PhysRevD.93.051103.
Adare, A. Measurement of parity-violating spin asymmetries in W± production at midrapidity in longitudinally polarized p+p collisions. United States. https://doi.org/10.1103/PhysRevD.93.051103
Adare, A. Wed . "Measurement of parity-violating spin asymmetries in W± production at midrapidity in longitudinally polarized p+p collisions". United States. https://doi.org/10.1103/PhysRevD.93.051103. https://www.osti.gov/servlets/purl/1324118.
@article{osti_1324118,
title = {Measurement of parity-violating spin asymmetries in W± production at midrapidity in longitudinally polarized p+p collisions},
author = {Adare, A.},
abstractNote = {In this study, we present midrapidity measurements from the PHENIX experiment of large parity-violating single-spin asymmetries of high transverse momentum electrons and positrons from W±/Z decays, produced in longitudinally polarized p + p collisions at center of mass energies of √s = 500 and 510 GeV. These asymmetries allow direct access to the antiquark polarized parton distribution functions due to the parity-violating nature of the W-boson coupling to quarks and antiquarks. The results presented are based on data collected in 2011, 2012, and 2013 with an integrated luminosity of 240 pb–1, which exceeds previous PHENIX published results by a factor of more than 27. These high Q2 data probe the parton structure of the proton at W mass scale and provide an important addition to our understanding of the antiquark parton helicity distribution functions at an intermediate Bjorken x value of roughly MW/ √s = 0.16.},
doi = {10.1103/PhysRevD.93.051103},
journal = {Physical Review D},
number = 5,
volume = 93,
place = {United States},
year = {2016},
month = {3}
}

Journal Article:

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Cited by: 9 works
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Figures / Tables:

FIG. 1. FIG. 1.: (color online). (Upper panels) Spectra for (a) e+ and (b) e using the EMCal for momentum determination from p+p collisions at $\sqrt{s}$ = 510 GeV from 2013. From top to bottom, the curves are: solid [red] is the sum between background and signal; shaded band [orange] is themore » background estimation with the uncertainty from the GPR method; dashed [dark blue] is the W±/Z → e± signal obtained from simulation normalized to the data; and solid [light blue] is the contribution from Z → e+e. (Lower panels) Point-by-point comparison of the data and the fit result: (data$i$-fit)/σ$i$, where σ$i$ is statistical uncertainty of the $i$-th data point.« less

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