[SEMINARI]: Dr. Wolf: Kinematic effects in energy spectra of quarkonia production and decay

[Arcadi Santamaria]

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                              S E M I N A R I

             [Image]   Departament de Física Teòrica    [Image]
                          Universitat de València
                       Institut de Física Corpuscular
                       Universitat de València - CSIC

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      Kinematic effects in energy spectra of quarkonia production and decay

                                 Stefan Wolf

                      (Departamento de Fisica Teorica)

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                     Aula de Seminaris de Física Teòrica
                 Thursday 25 of January of 2001 at 12:30 PM
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                                    Resum

    In this talk we present the energy (momentum) distributions in J/Psi
  photoproduction and J/Psi production in B meson decay. In particular the
 upper endpoint region of these spectra is examined where the effect of soft
 gluon emission from the ccbar pair becomes important. Constructing a model
 which is consistent with the so-called shape function formalism we consider
  these fragmentation effects and show that they weaken the so-called Hera
 problem, i.e. the steep raise of the octet contributions towards high J/psi
   energies which is predicted by naive NRQCD. Furthermore we consider the
   influence of possible colour octet contributions to the upper endpoint
     region of the photon energy spectrum in radiative Upsilon decays.

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