First measurement of the Sivers asymmetry for gluons from SIDIS data
Abstract
The Sivers function describes the correlation between the transverse spin of a nucleon and the transverse motion of its partons. It was extracted from measurements of the azimuthal asymmetry of hadrons produced in semi-inclusive deep inelastic scattering of leptons off transversely polarised nucleon targets, and it turned out to be non-zero for quarks. In this letter the evaluation of the Sivers asymmetry for gluons in the same process is presented. The analysis method is based on a Monte Carlo simulation that includes three hard processes: photon-gluon fusion, QCD Compton scattering and 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/ muon beam scattered off transversely polarised deuterons and protons. With a significance of more than 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.
Keywords
Cite
@article{arxiv.1701.02453,
title = {First measurement of the Sivers asymmetry for gluons from SIDIS data},
author = {C. Adolph and M. Aghasyan and R. Akhunzyanov and M. G. Alexeev and G. D. Alexeev and A. Amoroso and V. Andrieux and N. V. Anfimov and V. Anosov and A. Antoshkin and K. Augsten and W. Augustyniak and A. Austregesilo and C. D. R. Azevedo and B. Badelek and F. Balestra and M. Ball and J. Barth and R. Beck and Y. Bedfer and J. Bernhard and K. Bicker and E. R. Bielert and R. Birsa and M. Bodlak and P. Bordalo and F. Bradamante and C. Braun and A. Bressan and M. Buechele and W. -C. Chang and C. Chatterjee and M. Chiosso and I. Choi and S. -U. Chung and A. Cicuttin and M. L. Crespo and Q. Curiel and S. Dalla Torre and S. S. Dasgupta and S. Dasgupta and O. Yu. Denisov and L. Dhara and S. V. Donskov and N. Doshita and Ch. Dreisbach and V. Duic and W. Duennweber and M. Dziewiecki and A. Efremov and P. D. Eversheim and W. Eyrich and M. Faessler and A. Ferrero and M. Finger and M. Finger and H. Fischer and C. Franco and N. du Fresne von Hohenesche and J. M. Friedrich and V. Frolov and E. Fuchey and F. Gautheron and O. P. Gavrichtchouk and S. Gerassimov and J. Giarra and F. Giordano and I. Gnesi and M. Gorzellik and S. Grabmueller and A. Grasso and M. Grosse Perdekamp and B. Grube and T. Grussenmeyer and A. Guskov and F. Haas and D. Hahne and G. Hamar and D. von Harrach and F. H. Heinsius and R. Heitz and F. Herrmann and N. Horikawa and N. d'Hose and C. -Y. Hsieh and S. Huber and S. Ishimoto and A. Ivanov and Yu. Ivanshin and T. Iwata and V. Jary and R. Joosten and P. Joerg and E. Kabuss and A. Kerbizi and B. Ketzer and G. V. Khaustov and Yu. A. Khokhlov and Yu. Kisselev and F. Klein and K. Klimaszewski and J. H. Koivuniemi and V. N. Kolosov and K. Kondo and K. Koenigsmann and I. Konorov and V. F. Konstantinov and A. M. Kotzinian and O. M. Kouznetsov and M. Kraemer and P. Kremser and F. Krinner and Z. V. Kroumchtein and Y. Kulinich and F. Kunne and K. Kurek and R. P. Kurjata and A. A. Lednev and A. Lehmann and M. Levillain and S. Levorato and Y. -S. Lian and J. Lichtenstadt and R. Longo and A. Maggiora and A. Magnon and N. Makins and N. Makke and G. K. Mallot and B. Marianski and A. Martin and J. Marzec and J. Matousek and H. Matsuda and T. Matsuda and G. V. Meshcheryakov and M. Meyer and W. Meyer and Yu. V. Mikhailov and M. Mikhasenko and E. Mitrofanov and N. Mitrofanov and Y. Miyachi and A. Nagaytsev and F. Nerling and D. Neyret and J. Novy and W. -D. Nowak and G. Nukazuka and A. S. Nunes and A. G. Olshevsky and I. Orlov and M. Ostrick and D. Panzieri and B. Parsamyan and S. Paul and J. -C. Peng and F. Pereira and M. Pesek and D. V. Peshekhonov and N. Pierre and S. Platchkov and J. Pochodzalla and V. A. Polyakov and J. Pretz and M. Quaresma and C. Quintans and S. Ramos and C. Regali and G. Reicherz and C. Riedl and N. S. Rogacheva and M. Roskot and D. I. Ryabchikov and A. Rybnikov and A. Rychter and R. Salac and V. D. Samoylenko and A. Sandacz and C. Santos and S. Sarkar and I. A. Savin and T. Sawada and G. Sbrizzai and P. Schiavon and K. Schmidt and H. Schmieden and K. Schoenning and E. Seder and A. Selyunin and L. Silva and L. Sinha and S. Sirtl and M. Slunecka and J. Smolik and A. Srnka and D. Steffen and M. Stolarski and O. Subrt and M. Sulc and H. Suzuki and A. Szabelski and T. Szameitat and P. Sznajder and S. Takekawa and M. Tasevsky and S. Tessaro and F. Tessarotto and F. Thibaud and A. Thiel and F. Tosello and V. Tskhay and S. Uhl and J. Veloso and M. Virius and J. Vondra and S. Wallner and T. Weisrock and M. Wilfert and J. ter Wolbeek and K. Zaremba and P. Zavada and M. Zavertyaev and E. Zemlyanichkina and N. Zhuravlev and M. Ziembicki and A. Zink},
journal= {arXiv preprint arXiv:1701.02453},
year = {2017}
}
Comments
18 pages, 8 figures