Abstract.
The shape of jets produced in quasi-real photon-proton collisions at centre-of-mass energies in the range 134–277 GeV has been measured using the hadronic energy flow. The measurement was done with the ZEUS detector at HERA. Jets are identified using a cone algorithm in the \(\eta - \phi\) plane with a cone radius of one unit. Measured jet shapes both in inclusive jet and dijet production with transverse energies \(E^{jet}_T>14\) GeV are presented. The jet shape broadens as the jet pseudorapidity (\(\eta^{jet}\)) increases and narrows as \(E^{jet}_T\) increases. In dijet photoproduction, the jet shapes have been measured separately for samples dominated by resolved and by direct processes. Leading-logarithm parton-shower Monte Carlo calculations of resolved and direct processes describe well the measured jet shapes except for the inclusive production of jets with high \(\eta^{jet}\) and low \(E^{jet}_T\). The observed broadening of the jet shape as \(\eta^{jet}\) increases is consistent with the predicted increase in the fraction of final state gluon jets.
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Received: 30 September 1997
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ZEUS Collaboration., Breitweg et al., J. Measurement of jet shapes in photoproduction at HERA. Eur. Phys. J. C 2, 61–75 (1998). https://doi.org/10.1007/PL00021562
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DOI: https://doi.org/10.1007/PL00021562