Final COMPASS results on the deuteron spin-dependent structure function g1dand the Bjorken sum rule

C. Adolph, M. Aghasyan, R. Akhunzyanov, M. G. Alexeev, G. D. Alexeev, A. Amoroso, V. Andrieux, N. V. Anfimov, V. Anosov, K. Augsten, W. Augustyniak, A. Austregesilo, C. D.R. Azevedo, B. Badełek, F. Balestra, M. Ball, J. Barth, R. Beck, Y. Bedfer, J. BernhardK. Bicker, E. R. Bielert, R. Birsa, M. Bodlak, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Büchele, W. C. Chang, C. Chatterjee, M. Chiosso, I. Choi, S. U. Chung, A. Cicuttin, M. L. Crespo, Q. Curiel, S. Dalla Torre, S. S. Dasgupta, S. Dasgupta, O. Yu Denisov, L. Dhara, S. V. Donskov, N. Doshita, Ch Dreisbach, V. Duic, W. Dünnweber, M. Dziewiecki, A. Efremov, P. D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger, H. Fischer, C. Franco, N. du Fresne von Hohenesche, J. M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O. P. Gavrichtchouk, S. Gerassimov, J. Giarra, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmüller, A. Grasso, Matthias Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, G. Hamar, D. von Harrach, F. H. Heinsius, R. Heitz, F. Herrmann, N. Horikawa, N. d'Hose, C. Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu Ivanshin, T. Iwata, V. Jary, R. Joosten, P. Jörg, E. Kabuß, A. Kerbizi, B. Ketzer, G. V. Khaustov, Yu A. Khokhlov, Yu Kisselev, F. Klein, K. Klimaszewski, J. H. Koivuniemi, V. N. Kolosov, K. Kondo, K. Königsmann, I. Konorov, V. F. Konstantinov, A. M. Kotzinian, O. M. Kouznetsov, M. Krämer, P. Kremser, F. Krinner, Z. V. Kroumchtein, Y. Kulinich, F. Kunne, K. Kurek, R. P. Kurjata, A. A. Lednev, A. Lehmann, M. Levillain, S. Levorato, Y. S. Lian, J. Lichtenstadt, R. Longo, A. Maggiora, A. Magnon, Naomi C R Makins, N. Makke, G. K. Mallot, B. Marianski, A. Martin, J. Marzec, J. Matoušek, H. Matsuda, T. Matsuda, G. V. Meshcheryakov, M. Meyer, W. Meyer, Yu V. Mikhailov, M. Mikhasenko, E. Mitrofanov, N. Mitrofanov, Y. Miyachi, A. Nagaytsev, F. Nerling, D. Neyret, J. Nový, W. D. Nowak, G. Nukazuka, A. S. Nunes, A. G. Olshevsky, I. Orlov, M. Ostrick, D. Panzieri, B. Parsamyan, S. Paul, Jen-Chieh Peng, F. Pereira, M. Pešek, D. V. Peshekhonov, N. Pierre, S. Platchkov, J. Pochodzalla, V. A. Polyakov, J. Pretz, M. Quaresma, C. Quintans, S. Ramos, C. Regali, G. Reicherz, C. Riedl, M. Roskot, N. S. Rossiyskaya, D. I. Ryabchikov, A. Rybnikov, A. Rychter, R. Salac, V. D. Samoylenko, A. Sandacz, C. Santos, S. Sarkar, I. A. Savin, T. Sawada, G. Sbrizzai, P. Schiavon, K. Schmidt, H. Schmieden, K. Schönning, E. Seder, A. Selyunin, L. Silva, L. Sinha, S. Sirtl, M. Slunecka, J. Smolik, A. Srnka, D. Steffen, M. Stolarski, O. Subrt, M. Sulc, H. Suzuki, A. Szabelski, T. Szameitat, P. Sznajder, S. Takekawa, M. Tasevsky, S. Tessaro, F. Tessarotto, F. Thibaud, A. Thiel, F. Tosello, V. Tskhay, S. Uhl, A. Vauth, J. Veloso, M. Virius, J. Vondra, S. Wallner, T. Weisrock, M. Wilfert, R. Windmolders, J. ter Wolbeek, K. Zaremba, P. Zavada, M. Zavertyaev, E. Zemlyanichkina, N. Zhuravlev, M. Ziembicki, A. Zink

Research output: Contribution to journalArticle

Abstract

Final results are presented from the inclusive measurement of deep-inelastic polarised-muon scattering on longitudinally polarised deuterons using a6LiD target. The data were taken at 160 GeV beam energy and the results are shown for the kinematic range 1(GeV/c)2<;Q2<100(GeV/c)2in photon virtuality, 0.004<;x<;0.7 in the Bjorken scaling variable and W>4GeV/c2in the mass of the hadronic final state. The deuteron double-spin asymmetry A1dand the deuteron longitudinal-spin structure function g1dare presented in bins of x and Q2. Towards lowest accessible values of x, g1ddecreases and becomes consistent with zero within uncertainties. The presented finalg1dvalues together with the recently published final g1pvalues of COMPASS are used to again evaluate the Bjorken sum rule and perform the QCD fit to the g1world data at next-to-leading order of the strong coupling constant. In both cases, changes in central values of the resulting numbers are well within statistical uncertainties. The flavour-singlet axial charge a0, which is identified in the MS‾renormalisation scheme with the total contribution of quark helicities to the nucleon spin, is extracted at next-to-leading order accuracy from only the COMPASS deuteron data: a0(Q2=3(GeV/c)2)=0.32±0.02stat±0.04syst±0.05evol. Together with the recent results on the proton spin structure function g1p, the results on g1dconstitute the COMPASS legacy on the measurements of g1through inclusive spin-dependent deep inelastic scattering.

Original languageEnglish (US)
Pages (from-to)34-41
Number of pages8
JournalPhysics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics
Volume769
DOIs
StatePublished - Jun 10 2017

Keywords

  • COMPASS
  • Deep inelastic scattering
  • Parton helicity distributions
  • Spin
  • Structure function

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

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    Adolph, C., Aghasyan, M., Akhunzyanov, R., Alexeev, M. G., Alexeev, G. D., Amoroso, A., Andrieux, V., Anfimov, N. V., Anosov, V., Augsten, K., Augustyniak, W., Austregesilo, A., Azevedo, C. D. R., Badełek, B., Balestra, F., Ball, M., Barth, J., Beck, R., Bedfer, Y., ... Zink, A. (2017). Final COMPASS results on the deuteron spin-dependent structure function g1dand the Bjorken sum rule. Physics Letters, Section B: Nuclear, Elementary Particle and High-Energy Physics, 769, 34-41. https://doi.org/10.1016/j.physletb.2017.03.018