Author/Authors :
ZEUS Collaboration، نويسنده , , Valeri S. Chekanov، نويسنده , , M. Derrick، نويسنده , , S. Magill، نويسنده , , B. Musgrave، نويسنده , , D. Nicholass، نويسنده , , J. Repond، نويسنده , , R. Yoshida، نويسنده , , M.C.K. Mattingly، نويسنده , , M. Jechow، نويسنده , , N. Pavel، نويسنده , , A.G. Yagües Molina، نويسنده , , Mary Ann S. Antonelli، نويسنده , , P. Antonioli، نويسنده , , G. Bari، نويسنده , , M. Basile، نويسنده , , L. Bellagamba، نويسنده , , A. GIUNTOLI and M. BINDI، نويسنده , , D. Boscherini، نويسنده , , C. B. Vicentini and A. Bruni، نويسنده , , et al.، نويسنده ,
Abstract :
Three- and four-jet final states have been measured in photoproduction at HERA using the ZEUS detector with an integrated luminosity of image. The results are presented for jets with transverse energy image and pseudorapidity image, in the kinematic region given by the virtuality of the photon image and the inelasticity image and in two mass regions defined as image and image, where image is the invariant mass of the n-jet system. The four-jet photoproduction cross section has been measured for the first time and represents the highest-order process studied at HERA. Both the three- and four-jet cross sections have been compared with leading-logarithmic parton-shower Monte Carlo models, with and without multi-parton interactions. The three-jet cross sections have been compared to an image perturbative QCD calculation.
