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Hard Exclusive Pion Leptoproduction

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Abstract

In this talk it is reported on an analysis of hard exclusive leptoproduction of pions within the handbag approach. It is argued that recent measurements of this process performed by HERMES and CLAS clearly indicate the occurrence of strong contributions from transversely polarized photons. Within the handbag approach such \(\gamma ^{\,*}_T\rightarrow \pi \) transitions are described by the transversity GPDs accompanied by twist-3 pion wave functions. It is shown that the handbag approach leads to results on cross sections and single-spin asymmetries in fair agreement with experiment. Predictions for other pseudoscalar meson channels are also briefly discussed.

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References

  1. Radyushkin, A.V.: Asymmetric gluon distributions and hard diffractive electroproduction. Phys. Lett. B 385, 333 (1996). [arXiv:hep-ph/9605431]

    Article  ADS  Google Scholar 

  2. Collins, J.C., Frankfurt, L., Strikman, M.: Factorization for hard exclusive electroproduction of mesons in QCD. Phys. Rev. D 56, 2982 (1997). [arXiv:hep-ph/9611433]

    Article  ADS  Google Scholar 

  3. Airapetian, A., et al. [HERMES Collaboration]: Single-spin azimuthal asymmetry in exclusive electroproduction of pi+ mesons on transversely polarized protons. Phys. Lett. B 682, 345 (2010). [arXiv:0907.2596 [hep-ex]]

  4. Bedlinskiy, I. et al. [CLAS Collaboration]: Exclusive \({\pi }^0\) electroproduction at \(W>2\) GeV with CLAS. Phys. Rev. C 90(2), 025205 (2014) [Phys. Rev. C 90(3), 039901 (2014)]. [arXiv:1405.0988 [nucl-ex]]

  5. Goloskokov, S.V., Kroll, P.: Transversity in hard exclusive electroproduction of pseudoscalar mesons. Eur. Phys. J. A 47, 112 (2011). [arXiv:1106.4897 [hep-ph]]

    Article  ADS  Google Scholar 

  6. Hoodbhoy, P., Ji, X.D.: Helicity flip off forward parton distributions of the nucleon. Phys. Rev. D 58, 054006 (1998). [arXiv:hep-ph/9801369]

    Article  ADS  Google Scholar 

  7. Diehl, M.: Generalized parton distributions with helicity flip. Eur. Phys. J. C 19, 485 (2001). [arXiv:hep-ph/0101335]

    Article  ADS  Google Scholar 

  8. Goloskokov, S.V., Kroll, P.: An attempt to understand exclusive pi+ electroproduction. Eur. Phys. J. C 65, 137 (2010). [arXiv:0906.0460 [hep-ph]]

    Article  ADS  Google Scholar 

  9. Ahmad, S., Goldstein, G.R., Liuti, S.: Nucleon Tensor charge from exclusive pi**o electroproduction. Phys. Rev. D 79, 054014 (2009). [arXiv:0805.3568 [hep-ph]]

    Article  ADS  Google Scholar 

  10. Braun, V.M., Filyanov, I.E.: Conformal invariance and pion wave functions of nonleading twist. Z. Phys. C 48, 239 (1990) [Sov. J. Nucl. Phys. 52, 126 (1990)] [Yad. Fiz. 52, 199 (1990)]

  11. Goloskokov, S.V., Kroll, P.: The Role of the quark and gluon GPDs in hard vector-meson electroproduction. Eur. Phys. J. C 53, 367 (2008). [arXiv:0708.3569 [hep-ph]]

    Article  ADS  Google Scholar 

  12. Olive, K.A., et al. [Particle Data Group Collaboration]: Review of particle physics. Chin. Phys. C 38, 090001 (2014)

  13. Ball, P.: Theoretical update of pseudoscalar meson distribution amplitudes of higher twist: the nonsinglet case. JHEP 9901, 010 (1999). [arXiv:hep-ph/9812375]

    Article  ADS  Google Scholar 

  14. Ji, X.D., Ma, J.P., Yuan, F.: Classification and asymptotic scaling of hadrons’ light cone wave function amplitudes. Eur. Phys. J. C 33, 75 (2004). [arXiv:hep-ph/0304107]

    Article  ADS  Google Scholar 

  15. Li, H.N., Sterman, G.F.: The perturbative pion form-factor with Sudakov suppression. Nucl. Phys. B 381, 129 (1992)

    Article  ADS  Google Scholar 

  16. Mankiewicz, L., Piller, G., Radyushkin, A.: Hard exclusive electroproduction of pions. Eur. Phys. J. C 10, 307 (1999). [arXiv:hep-ph/9812467]

    Article  ADS  Google Scholar 

  17. Blok, H.P., et al. [Jefferson Lab Collaboration]: Charged pion form factor between \(Q^2\)=0.60 and 2.45 GeV\(^2\). I. Measurements of the cross section for the \({^1}\)H(\(e,e^{\prime }\pi ^+\))\(n\) reaction. Phys. Rev. C 78, 045202 (2008). [arXiv:0809.3161 [nucl-ex]]

  18. Favart, L., Guidal, M., Horn, T., Kroll, P.: Deeply virtual meson production on the nucleon. Eur. Phys. J. A 52(6), 158 (2016). arXiv:1511.04535 [hep-ph]

  19. Goloskokov, S.V., Kroll, P.: The pion pole in hard exclusive vector-meson leptoproduction. Eur. Phys. J. A 50(9), 146 (2014). [arXiv:1407.1141 [hep-ph]]

    Article  ADS  Google Scholar 

  20. Musatov, I.V., Radyushkin, A.V.: Evolution and models for skewed parton distributions. Phys. Rev. D 61, 074027 (2000). [arXiv:hep-ph/9905376]

    Article  ADS  Google Scholar 

  21. Diehl, M., Kroll, P.: Nucleon form factors, generalized parton distributions and quark angular momentum. Eur. Phys. J. C 73(4), 2397 (2013). [arXiv:1302.4604 [hep-ph]]

    Article  ADS  Google Scholar 

  22. Anselmino, M., Boglione, M., D’Alesio, U., Kotzinian, A., Murgia, F., Prokudin, A., Melis, S.: Update on transversity and Collins functions from SIDIS and e+ e- data. Nucl. Phys. Proc. Suppl. 191, 98 (2009). [arXiv:0812.4366 [hep-ph]]

    Article  ADS  Google Scholar 

  23. Gockeler, M., et al. [QCDSF and UKQCD Collaborations]: Quark helicity flip generalized parton distributions from two-flavor lattice QCD. Phys. Lett. B 627, 113 (2005). [arXiv:hep-lat/0507001]

  24. Gockeler, M., et al. [QCDSF and UKQCD Collaborations]: Transverse spin structure of the nucleon from lattice QCD simulations. Phys. Rev. Lett. 98, 222001 (2007). [arXiv:hep-lat/0612032]

  25. Burkardt, M.: Hadron tomography. AIP Conf. Proc. 915, 313 (2007). [arXiv:hep-ph/0611256]

    Article  ADS  MATH  Google Scholar 

  26. Barone, V., Melis, S., Prokudin, A.: The Boer–Mulders effect in unpolarized SIDIS: an analysis of the COMPASS and HERMES data on the cos 2 phi asymmetry. Phys. Rev. D 81, 114026 (2010). [arXiv:0912.5194 [hep-ph]]

    Article  ADS  Google Scholar 

  27. Schweitzer, P., Weiss, C.: Chiral-odd GPDs in large-N_c QCD. 2015, 041 (2015). arXiv:1601.03016 [hep-ph]

  28. Kubarovsky, V. [for the CLAS Collaboration]: Deeply virtual pseudoscalar meson production at jefferson lab and transversity GPDs. Int. J. Mod. Phys. Conf. Ser. 40, 1660051 (2016). arXiv:1601.04367 [hep-ex]

  29. Kim, A., et al.: Target and Double spin asymmetries of deeply virtual \(\pi ^0\) production with a longitudinally polarized proton target and CLAS. arXiv:1511.03338 [nucl-ex] (unpublished)

  30. Eides, M.I., Frankfurt, L.L., Strikman, M.I.: Hard exclusive electroproduction of pseudoscalar mesons and QCD axial anomaly. Phys. Rev. D 59, 114025 (1999). [arXiv:hep-ph/9809277]

    Article  ADS  Google Scholar 

  31. Feldmann, T., Kroll, P., Stech, B.: Mixing and decay constants of pseudoscalar mesons. Phys. Rev. D 58, 114006 (1998). [arXiv:hep-ph/9802409]

    Article  ADS  Google Scholar 

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  1. Fachbereich Physik, Universität Wuppertal, 42097, Wuppertal, Germany

    Peter Kroll

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  1. Peter Kroll
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Correspondence to Peter Kroll.

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This article belongs to the special issue “Nucleon Resonances”.

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Kroll, P. Hard Exclusive Pion Leptoproduction. Few-Body Syst 57, 1041–1050 (2016). https://doi.org/10.1007/s00601-016-1146-5

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