publication . Article . Other literature type . Preprint . 2018

Longitudinal double-spin asymmetry $A_1^{\rm p}$ and spin-dependent structure function $g_1^{\rm p}$ of the proton at small values of $x$ and $Q^2$

I. Gnesi; S. Sirtl; P. Schiavon; G. Reicherz; F. J. Klein; T. Iwata; I.A. Savin; T. Matsuda; Miroslav Sulc; P. Jörg; ...
Open Access English
  • Published: 01 Jan 2018
  • Publisher: HAL CCSD
We present a precise measurement of the proton longitudinal double-spin asymmetry $A_1^{\rm p}$ and the proton spin-dependent structure function $g_1^{\rm p}$ at photon virtualities $0.006~({\rm GeV}/c)^2<Q^2 < 1~({\rm GeV}/c)^2$ in the Bjorken $x$ range of $4 \times 10^{-5} < x < 4 \times 10^{-2}$. The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of $160~{\rm GeV}$ and $200~{\rm GeV}$. The statistical precision is more than tenfold better than that of the previous measurement in this region. In the whole range of $x$, the measured values of $A_1^{\rm p}$ and $g_1^{\rm p}$ are found to be positive. It is for t...
free text keywords: photon, COMPASS, momentum transfer: low, sum rule: Bjorken, small-x, x-dependence, CERN Lab, statistical, spin: asymmetry, structure function: spin, spin: longitudinal, p: structure function, spin: effect, muon: beam, beam: energy, spin: dependence, nucleon: spin, p: spin, Low [formula omitted], muon p: deep inelastic scattering, muon: polarized beam, experimental results, [formula omitted], Low x, Low Q2, g1, A1, Spin structure function, Inelastic muon scattering, CERN SPS, [PHYS.HEXP]Physics [physics]/High Energy Physics - Experiment [hep-ex], Particle Physics - Experiment, hep-ex, Physics, QC1-999, мюонные атомы, рассеяние, [ PHYS.HEXP ] Physics [physics]/High Energy Physics - Experiment [hep-ex], Nuclear and High Energy Physics, High Energy Physics - Experiment, A1; g1; Inelastic muon scattering; Low Q2; Low x; Spin structure function; Nuclear and High Energy Physics, Nuclear physics, Spin-½, Asymmetry, media_common.quotation_subject, media_common, Muon, Large Hadron Collider, Polarization (waves), Quantum chromodynamics, Proton
Funded by
Study of Strongly Interacting Matter
  • Funder: European Commission (EC)
  • Project Code: 283286
  • Funding stream: FP7 | SP4 | INFRA
NSF| A Program of Medium Energy Nuclear Physics
  • Funder: National Science Foundation (NSF)
  • Project Code: 1506416
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