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arXiv · 1606.03725

Exclusive $\omega$ meson muoproduction on transversely polarised protons

C. Adolph·J. Agarwala·M. Aghasyan·R. Akhunzyanov·M. G. Alexeev·G. D. Alexeev·A. Amoroso·V. Andrieux·N. V. Anfimov·V. Anosov·W. Augustyniak·A. Austregesilo·C. D. R. Azevedo·B. Badelek·F. Balestra·J. Barth·R. Beck·Y. Bedfer·J. Bernhard·K. Bicker·E. R. Bielert·R. Birsa·J. Bisplinghoff·M. Bodlak·M. Boer·P. Bordalo·F. Bradamante·C. Braun·A. Bressan·M. Buechele·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·V. Duic·W. Duennweber·M. Dziewiecki·A. Efremov·P. D. Eversheim·W. Eyrich·M. Faessler·A. Ferrero·M. Finger·M. Finger jr.·H. Fischer·C. Franco·N. du Fresne von Hohenesche·J. M. Friedrich·V. Frolov·E. Fuchey·F. Gautheron·O. P. Gavrichtchouk·S. Gerassimov·F. Giordano·I. Gnesi·M. Gorzellik·S. Grabmueller·A. Grasso·M. Grosse Perdekamp·B. Grube·T. Grussenmeyer·A. Guskov·F. Haas·D. Hahne·D. von Harrach·R. Hashimoto·F. H. Heinsius·R. Heitz·F. Herrmann·F. Hinterberger·N. Horikawa·N. dHose·C. -Y. Hsieh·S. Huber·S. Ishimoto·A. Ivanov·Yu. Ivanshin·T. Iwata·R. Jahn·V. Jary·R. Joosten·P. Joerg·E. Kabuss·B. Ketzer·G. V. Khaustov·Yu. A. Khokhlov·Yu. Kisselev·F. Klein·K. Klimaszewski
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Abstract

Exclusive production of $\omega$ mesons was studied at the COMPASS experiment by scattering $160~\mathrm{GeV}/\mathit{c}$ muons off transversely polarised protons. Five single-spin and three double-spin azimuthal asymmetries were measured in the range of photon virtuality $1~(\mathrm{GeV}/\mathit{c})^2 < Q^2 < 10~(\mathrm{GeV}/\mathit{c})^2$, Bjorken scaling variable $0.003 < x_{\mathit{Bj}} < 0.3$ and transverse momentum squared of the $\omega$ meson $0.05~(\mathrm{GeV}/\mathit{c})^2 < p_{T}^{2} < 0.5~(\mathrm{GeV}/\mathit{c})^2$. The measured asymmetries are sensitive to the nucleon helicity-flip Generalised Parton Distributions (GPD) $E$ that are related to the orbital angular momentum of quarks, the chiral-odd GPDs $H_{T}$ that are related to the transversity Parton Distribution Functions, and the sign of the $\pi\omega$ transition form factor. The results are compared to recent calculations of a GPD-based model.

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C. Adolph, J. Agarwala, M. Aghasyan, R. Akhunzyanov, M. G. Alexeev, G. D. Alexeev, A. Amoroso, V. Andrieux, N. V. Anfimov, V. Anosov, W. Augustyniak, A. Austregesilo, C. D. R. Azevedo, B. Badelek, F. Balestra, J. Barth, R. Beck, Y. Bedfer, J. Bernhard, K. Bicker, E. R. Bielert, R. Birsa, J. Bisplinghoff, M. Bodlak, M. Boer, P. Bordalo, F. Bradamante, C. Braun, A. Bressan, M. Buechele, 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, V. Duic, W. Duennweber, M. Dziewiecki, A. Efremov, P. D. Eversheim, W. Eyrich, M. Faessler, A. Ferrero, M. Finger, M. Finger jr., H. Fischer, C. Franco, N. du Fresne von Hohenesche, J. M. Friedrich, V. Frolov, E. Fuchey, F. Gautheron, O. P. Gavrichtchouk, S. Gerassimov, F. Giordano, I. Gnesi, M. Gorzellik, S. Grabmueller, A. Grasso, M. Grosse Perdekamp, B. Grube, T. Grussenmeyer, A. Guskov, F. Haas, D. Hahne, D. von Harrach, R. Hashimoto, F. H. Heinsius, R. Heitz, F. Herrmann, F. Hinterberger, N. Horikawa, N. dHose, C. -Y. Hsieh, S. Huber, S. Ishimoto, A. Ivanov, Yu. Ivanshin, T. Iwata, R. Jahn, V. Jary, R. Joosten, P. Joerg, E. Kabuss, B. Ketzer, G. V. Khaustov, Yu. A. Khokhlov, Yu. Kisselev, F. Klein, K. Klimaszewski. 2016-06-12. Exclusive $\omega$ meson muoproduction on transversely polarised protons. https://doi.org/10.1016/j.nuclphysb.2016.12.015

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