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Longitudinal double-spin asymmetry A(1)(p) and spin-dependent structure function g(1)(p) of the proton at small values of x and Q(2)

Author
Aghasyan M. INFN, Trieste
Finger Miroslav, prof. Ing. DrSc. Faculty of Mathematics and Physics, Charles University in Prague
Finger Michael, M.Sc. CSc. Faculty of Mathematics and Physics, Charles University in Prague, JINR Dubna
Slunečka Miloš, Ing. Faculty of Mathematics and Physics, Charles University in Prague, JINR Dubna
Smolík Jan, Mgr. Ph.D. Faculty of Nuclear Sciences and Physical Engineering CTU
Taševský  Marek, Mgr. Ph.D. Institute of Physics ASCR
et al.  COMPASS collaboration

Year
2018

Scientific journal
Physics Letters B, 781, 464-472

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Abstract
We present a precise measurement of the proton longitudinal double-spin asymmetry A(1)(p) and the proton spin-dependent structure function g(1)(P) at photon virtualities 0.006 (GeV/c)(2) < Q(2) < 1 (GeV/c)(2) in the Bjorken x range of 4 x 10(-5) < x < 4 x 10(-2). The results are based on data collected by the COMPASS Collaboration at CERN using muon beam energies of 160 GeV and 200 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)(p) and g(1)(P) are found to be positive. It is for the first time that spin effects are found at such low values of x. (C) 2018 The Author(s). Published by Elsevier B.V.

Cite article as:
M. Aghasyan, M. Finger, M. Finger, M. Slunečka, J. Smolík, M. Taševský , . et al., "Longitudinal double-spin asymmetry A(1)(p) and spin-dependent structure function g(1)(p) of the proton at small values of x and Q(2)", Physics Letters B, 781, 464-472 (2018)