Measurement of the t dependence in exclusive photoproduction of Upsilon(1S) mesons at HERA

TL;DR

This paper reports the first measurement of the t dependence in exclusive photoproduction of Upsilon(1S) mesons at HERA, providing new insights into the interaction dynamics at high energies.

Contribution

It presents the first measurement of the t dependence of the gamma p -> Upsilon(1S) p cross section in a specific kinematic range.

Findings

Measured the exponential slope b = 4.3 +2.0 -1.3 (stat.) +0.5 -0.6 (syst.) GeV^-2.

First to analyze the t dependence in Upsilon(1S) photoproduction.

Provides data for understanding the proton structure at high energies.

Abstract

The exclusive photoproduction reaction gamma p -> Upsilon(1S) p has been studied with the ZEUS detector in ep collisions at HERA using an integrated luminosity of 468 pb^-1. The measurement covers the kinematic range 60<W<220 GeV and Q^2<1 GeV^2, where W is the photon-proton centre-of-mass energy and Q^2 is the photon virtuality. The exponential slope, b, of the t dependence of the cross section, where t is the squared four-momentum transfer at the proton vertex, has been measured, yielding b = 4.3 +2.0 -1.3 (stat.) +0.5 -0.6 (syst.) GeV^-2. This constitutes the first measurement of the t dependence of the gamma p -> Upsilon(1S) p cross section.