Publication
First measurement of the Sivers asymmetry for gluons using SIDIS data
| dc.contributor.author | COMPASS collaboration (228 authors) | |
| dc.contributor.author | Bordalo, P. | |
| dc.contributor.author | Franco, C. | |
| dc.contributor.author | Nunes, A.S. | |
| dc.contributor.author | Quaresma, M. | |
| dc.contributor.author | Quintans, C. | |
| dc.contributor.author | Ramos, S. | |
| dc.contributor.author | Silva, L. | |
| dc.contributor.author | Stolarski, M. | |
| dc.date.accessioned | 2019-02-04T12:09:47Z | |
| dc.date.available | 2019-02-04T12:09:47Z | |
| dc.date.issued | 2017-09-10 | |
| dc.date.updated | 2019-02-04T12:09:47Z | |
| dc.description.abstract | The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. For quarks, it was studied in previous measurements of the azimuthal asymmetry of hadrons produced in semi-inclusive deep inelastic scattering of leptons off transversely polarised nucleon targets, and it was found to be non-zero. In this letter the evaluation of the Sivers asymmetry for gluons is presented. The contribution of the photon–gluon fusion subprocess is enhanced by requiring two high transverse-momentum hadrons. The analysis method is based on a Monte Carlo simulation that includes three hard processes: photon–gluon fusion, QCD Compton scattering and the leading-order virtual-photon absorption process. The Sivers asymmetries of the three processes are simultaneously extracted using the LEPTO event generator and a neural network approach. The method is applied to samples of events containing at least two hadrons with large transverse momentum from the COMPASS data taken with a 160 GeV/ c muon beam scattered off transversely polarised deuterons and protons. With a significance of about two standard deviations, a negative value is obtained for the gluon Sivers asymmetry. The result of a similar analysis for a Collins-like asymmetry for gluons is consistent with zero. | |
| dc.description.version | Peer Reviewed | |
| dc.identifier | Phys.Lett. B772 (2017) 854-864; DOI 10.1016/j.physletb.2017.07.018 | |
| dc.identifier.uri | http://dx.doi.org/10.1016/j.physletb.2017.07.018 | |
| dc.identifier.uri | http://hdl.handle.net/10400.26/27270 | |
| dc.language.iso | eng | |
| dc.title | First measurement of the Sivers asymmetry for gluons using SIDIS data | |
| dc.type | journal article | |
| dspace.entity.type | Publication | |
| rcaap.rights | openAccess | pt |
| rcaap.type | article |