Forward \(\pi^\circ\) production and associated transverse energy flow in deep-inelastic scattering at HERA

  • The H1 Collaboration
experimental physics

Abstract.

Deep-inelastic positron-proton interactions at low values of Bjorken-x down to \(x \approx 4\cdot 10^{-5}\) which give rise to high transverse momentum \(\pi^\circ\)-mesons are studied with the H1 experiment at HERA. The inclusive cross section for \(\pi^\circ\)-mesons produced at small angles with respect to the proton remnant (the forward region) is presented as a function of the transverse momentum and energy of the \(\pi^\circ\) and of the four-momentum transfer Q2 and Bjorken-x. Measurements are also presented of the transverse energy flow in events containing a forward \(\pi^\circ\)-meson. Hadronic final state calculations based on QCD models implementing different parton evolution schemes are confronted with the data.

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References

  1. 1.
    I. Abt et al. [H1 Collaboration], Z. Phys. C 63, 377 (1994)Google Scholar
  2. 2.
    S. Aid et al. [H1 Collaboration], Phys. Lett. B 356, 118 (1995) [hep-ex/9506012]CrossRefGoogle Scholar
  3. 3.
    C. Adloff et al. [H1 Collaboration], Nucl. Phys. B 538, 3 (1999) [hep-ex/9809028]CrossRefGoogle Scholar
  4. 4.
    J. Breitweg et al. [ZEUS Collaboration], Eur. Phys. J. C 6, 239 (1999) [hep-ex/9805016]; J. Breitweg et al. [ZEUS Collaboration], Phys. Lett. B 474 (2000) 223 [hep-ex/9910043]CrossRefGoogle Scholar
  5. 5.
    V.N. Gribov, L.N. Lipatov, Sov. J. Nucl. Phys. 15, 438 and 675 (1972); L.N. Lipatov, Sov. J. Nucl. Phys. 20, 94 (1975); G. Altarelli and G. Parisi, Nucl. Phys. B 126, 298 (1977); Y.L. Dokshitzer, Sov. Phys. JETP 46, 641 (1977)Google Scholar
  6. 6.
    E.A. Kuraev, L.N. Lipatov, V.S. Fadin, Sov. Phys. JETP 45, 199 (1977); I.I. Balitsky, L.N. Lipatov, Sov. J. Nucl. Phys. 28, 822 (1978)Google Scholar
  7. 7.
    M. Ciafaloni, Nucl. Phys. B 296, 49 (1988); S. Catani, F. Fiorani and G. Marchesini, Phys. Lett. B 234, 339 (1990); S. Catani, F. Fiorani and G. Marchesini, Nucl. Phys. B 336, 18 (1990); G. Marchesini, Nucl. Phys. B 445, 49 (1995); [hep-ph/9412327]. A. H. Mueller, Nucl. Phys. Proc. Suppl. 18C, 125 (1991); A. H. Mueller, J. Phys. G 17, 1443 (1991)CrossRefGoogle Scholar
  8. 8.
    C. Adloff et al. [H1 Collaboration], Phys. Lett. B 462, 440 (1999) [hep-ex/9907030]CrossRefGoogle Scholar
  9. 9.
    C. Adloff et al. [H1 Collaboration], Eur. Phys. J. C 12, 595 (2000) [hep-ex/9907027]CrossRefGoogle Scholar
  10. 10.
    S. Aid et al. [H1 Collaboration], Phys. Lett. B 356, 118 (1995) [hep-ex/9506012]CrossRefGoogle Scholar
  11. 11.
    M. Arneodo et al. [European Muon Collaboration], Phys. Lett. B 149, 415 (1984)CrossRefGoogle Scholar
  12. 12.
    J. Pumplin et al. , JHEP 0207, 12 (2002) [hep-ph/0201195]Google Scholar
  13. 13.
    G.A. Schuler, T. Sjöstrand, Phys. Lett. B 376, 193 (1996) [hep-ph/9601282]CrossRefGoogle Scholar
  14. 14.
    G. Ingelman, A. Edin, J. Rathsman, Comp. Phys. Comm. 101, 108 (1997) [hep-ph/9605286]CrossRefGoogle Scholar
  15. 15.
    G. Ingelman, A. Edin, J. Rathsman, Phys. Lett. B 366, 371 (1996) [hep-ph/9508386]CrossRefGoogle Scholar
  16. 16.
    H. Jung, Comp. Phys. Comm. 86, 147 (1995) (for an update see http://www-h1.desy.de/~jung/rapgap/rapgap.html)CrossRefGoogle Scholar
  17. 17.
    L. Lönnblad, Comp. Phys. Comm. 71, 15 (1992)CrossRefGoogle Scholar
  18. 18.
    B. Andersson, G. Gustafson, L. Lönnblad, Nucl. Phys. B 339, 393 (1990)CrossRefGoogle Scholar
  19. 19.
    N.H. Brook et al. in Monte Carlo Generators for HERA Physics, Hamburg, Germany (1999), A.T. Doyle, G. Grindhammer, G. Ingelman, H. Jung, (eds.), DESY-PROC-1999-02, p. 10 [hep-ex/9912053]; G. Grindhammer, D. Krucker, G. Nellen, ibid. p. 36Google Scholar
  20. 20.
    A. Kwiatkowski, H. Spiesberger, H.J. Mohring, Comp. Phys. Comm. 69, 155 (1992)CrossRefGoogle Scholar
  21. 21.
    K. Charchula, G.A. Schuler, H. Spiesberger, Comp. Phys. Comm. 81, 381 (1994)CrossRefGoogle Scholar
  22. 22.
    H. Jung, Comp. Phys. Comm. 143, 100 (2002) [hep-ph/0109102].CrossRefMATHGoogle Scholar
  23. 23.
    H. Jung, G.P. Salam, Eur. Phys. J. C 19, 351 (2001) [hep-ph/0012143]Google Scholar
  24. 24.
    M. Hansson, H. Jung, “The status of CCFM: Unintegrated gluon densities”, to appear in Proc. of the XI Int. Workshop on Deep Inelastic Scattering (DIS 2003), St. Petersburg, Russia, April 2003 [hep-ph/0309009]Google Scholar
  25. 25.
    J. Andersen et al. [Small x Collaboration], “Small x phenomenology: Summary and Status 2002” [hep-ph/0312333]Google Scholar
  26. 26.
    B. Andersson, G. Gustafson, G. Ingelman, T. Sjöstrand, Phys. Rep. 97, 31 (1983)CrossRefGoogle Scholar
  27. 27.
    T. Sjöstrand, Comp. Phys. Comm. 82, 74 (1994); T. Sjöstrand et al. Comp. Phys. Comm. 135, 238 (2001) [hep-ph/0010017]CrossRefGoogle Scholar
  28. 28.
    J. Kwieciński, A.D. Martin, J.J. Outhwaite, Eur. Phys. J. C 9, 611 (1999) [hep-ph/9903439]CrossRefGoogle Scholar
  29. 29.
    B.A. Kniehl, G. Kramer, B. Pötter, Nucl. Phys. B 597, 337 (2001) [hep-ph/0011155]CrossRefGoogle Scholar
  30. 30.
    A.D. Martin, R.G. Roberts, W.J. Stirling, R.S. Thorne, Eur. Phys. J. C 4, 463 (1998) [hep-ph/9803445]CrossRefGoogle Scholar
  31. 31.
    J. Kwieciński, A.D. Martin, P.J. Sutton, Z. Phys. C 71, 585 (1996) [hep-ph/9602320]CrossRefGoogle Scholar
  32. 32.
    J. Kwieciński, A.D. Martin, A.M. Staśto, Phys. Rev. D 56, 3991 (1997) [hep-ph/9703445]CrossRefGoogle Scholar
  33. 33.
    P. Aurenche, R. Basu, M. Fontannaz, R.M. Godbole, Eur. Phys. J. C 34, 277 (2004) [hep-ph/0312359]; M. Fontannaz, private communicationCrossRefGoogle Scholar
  34. 34.
    A.D. Martin, R.G. Roberts, W.J. Stirling, R.S. Thorne, Eur. Phys. J C 14 133 (2000)Google Scholar
  35. 35.
    I. Abt et al. [H1 Collaboration], Nucl. Instrum. Meth. A 386, 310 (1997); I. Abt et al. [H1 Collaboration], Nucl. Instrum. Meth. A 386, 348 (1997)Google Scholar
  36. 36.
    B. Andrieu et al. [H1 Collaboration Calorimeter Group], Nucl. Instrum. Meth. A 336, 499 (1993)Google Scholar
  37. 37.
    B. Andrieu et al. [H1 Collaboration Calorimeter Group], Nucl. Instrum. Meth. A 350, 57 (1994)Google Scholar
  38. 38.
    T. Nicholls et al. [H1 Collaboration SPACAL Group ], Nucl. Instrum. Meth. A 374, 149 (1996)Google Scholar
  39. 39.
    R.D. Appuhn et al. [H1 Collaboration SPACAL Group], Nucl. Instrum. Meth. A 382, 395 (1996)Google Scholar
  40. 40.
    A.A. Glazov, “Measurement of the proton structure functions F 2(x,Q 2) and F L(x,Q 2) with the H1 detector at HERA”, Ph.D. Thesis, Berlin University (1998) DESY-THESIS-1998-005.Google Scholar
  41. 41.
    T. Wengler, “Measurement of \(\pi^\circ\)-meson cross sections at low Bjorken-x in deep-inelastic e p collisions at \(\sqrt{s}\) = 300 GeV,” Ph.D. Thesis, Heidelberg University (1999) DESY-THESIS-1999-011.Google Scholar
  42. 42.
    B. Andrieu et al. [H1 Calorimeter Group Collaboration], Nucl. Instrum. Meth. A 344, 492 (1994)Google Scholar
  43. 43.
    J. Kwieciński, S.C. Lang and A.D. Martin, Phys. Rev. D 55, 1273 (1997) [hep-ph/9608355]CrossRefGoogle Scholar
  44. 44.
    R. Engel, J. Ranft, Phys. Rev. D 54, 4244 (1996) [hep-ph/9509373]CrossRefGoogle Scholar
  45. 45.
    C. Adloff et al. [H1 Collaboration], Z. Phys. C 74, 221 (1997) [hep-ex/9702003]CrossRefGoogle Scholar
  46. 46.
    A. Aktas et al. [H1 Collaboration], Eur. Phys. J. C 33, 477 (2004) [hep-ex/0310019]Google Scholar
  47. 47.
    K. Konishi, A. Ukawa and G. Veneziano, Phys. Lett. B 78 (1978) 243.Google Scholar
  48. 48.
    H. Lai et al. , Eur. Phys. J. C 12, 375 (2000) [hep-ph/9903282]CrossRefGoogle Scholar

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© Springer-Verlag Berlin/Heidelberg 2004

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  • The H1 Collaboration

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