Energy flow and rapidity gaps between jets in photoproduction at HERA

The H1 Collaboration

doi:doi:10.1007/s10052-002-0988-9

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2023 Impact factor 4.2

Particles and Fields

Eur. Phys. J. C 24, 517-527 (2002)
DOI: 10.1007/s10052-002-0988-9

Energy flow and rapidity gaps between jets in photoproduction at HERA

The H1 Collaboration

(Received: 8 March 2002 / Published online: 5 July 2002)

Abstract
Dijet events in photon-proton collisions in which there is a large pseudorapidity separation $\Delta \eta > 2.5$ between the two highest E_T jets are studied with the H1 detector at HERA. The inclusive dijet cross sections are measured as functions of the longitudinal momentum fractions of the proton and photon which participate in the production of the jets, x_p^jets and $x_{\gamma}^{jets}$ respectively, $\Delta \eta$ , the pseudorapidity separation between the two highest E_T jets, and E_T^gap, the total summed transverse energy between the jets. Rapidity gap events are defined as events in which E_T^gap is less than E_T^cut, for E_T^cut varied between 0.5 and 2.0 GeV. The fraction of dijet events with a rapidity gap is measured differentially in $\Delta \eta$ , x_p^jets and $x_{\gamma}^{jets}$ . An excess of events with rapidity gaps at low values of E_T^cut is observed above the expectation from standard photoproduction processes. This excess can be explained by the exchange of a strongly interacting colour singlet object between the jets.