par Adloff, Catherine;Clerbaux, Barbara 
;Collard, Caroline ;Favart, Laurent ;Janssen, Xavier ;Marage, Pierre ; [et al.]
Référence European Physical Journal C. Particles and Fields, 18, 2, page (293-302)
Publication Publié, 2000
;Collard, Caroline ;Favart, Laurent ;Janssen, Xavier ;Marage, Pierre ; [et al.]Référence European Physical Journal C. Particles and Fields, 18, 2, page (293-302)
Publication Publié, 2000
Article révisé par les pairs
| Résumé : | The inclusive cross section for the photoproduction of neutral pions has been measured as a function of the transverse momentum, rapidity, and Feynman cursive Greek chi of the π0 mesons at an average photon-proton centre-of-mass energy of 208 GeV and for photon virtualities below Q2 = 0.01 GeV2. The π0 measurement extends the range covered by previous charged particle measurements at HERA by two units of rapidity in the photon direction down to a value of -5.5 in the γp centre-of-mass frame. The π0 transverse momentum distribution is well described over the whole measured range by a power law ansatz, while an exponential fit falls below the data at transverse momentum values above 1.5 GeV/c. Good agreement with the predictions of the Monte Carlo models PYTHIA and PHOJET is found. In the context of the PYTHIA model the data are inconsistent with large intrinsic transverse momentum values in the photon. |
