Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data
Author
Adolph C.
| Institute of Physics, University of Erlangen Nuremberg
|
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
|
et al. 
| COMPASS collaboration
|
Smolík Jan, Mgr. Ph.D.
| Faculty of Nuclear Sciences and Physical Engineering CTU
|
Taševský  Marek, Mgr. Ph.D.
| Institute of Physics ASCR
|
Year
2017
Scientific journal
European Physical Journal C, 77 (4), 209
Web
Abstract
Using a novel analysis technique, the gluon polarisation in the nucleon is re-evaluated using the longitudinal double-spin asymmetry measured in the cross section of semi-inclusive single-hadron muoproduction with photon virtuality Q(2) > 1 ( GeV/c)(2). The data were obtained by the COMPASS experiment at CERN using a 160 GeV/c polarised muon beam impinging on a polarised (LiD)-Li-6 target. By analysing the full range in hadron transverse momentum p(T), the different pT-dependences of the underlying processes are separated using a neural-network approach. In the absence of pQCD calculations at next-to-leading order in the selected kinematic domain, the gluon polarisation Delta g/g is evaluated at leading order in pQCD at a hard scale of mu(2) = < Q(2) > = 3( GeV/c)(2). It is determined in three intervals of the nucleon momentum fraction carried by gluons, x(g), covering the range 0.04< x(g)< 0.28 and does not exhibit a significant dependence on xg. The average over the three intervals, < Delta g/g > = 0.113 +/- 0.038(stat) +/- 0.036( syst) at < x(g) > approximate to 0.10, suggests that the gluon polarisation is positive in the measured x(g) range.
Cite article as:
C. Adolph, M. Finger, M. Finger, M. Slunečka, . et al., J. Smolík, M. Taševský , "Leading-order determination of the gluon polarisation from semi-inclusive deep inelastic scattering data", European Physical Journal C, 77 (4), 209 (2017)