The exclusive photoproduction reaction gamma p -> gamma(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 GeV2, 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(-1.3)(+2.0)(stat.)(-0.6)(+0.5) (syst.) GeV-2. This constitutes the first measurement of the t dependence of the gamma p -> gamma(1S)p cross section. (C) 2012 Elsevier B.V. All rights reserved. RI Doyle, Anthony/C-5889-2009; Fazio, Salvatore /G-5156-2010; Lukina, Olga/D-8875-2012; Gladilin, Leonid/B-5226-2011; Barreiro, Fernando/D-9808-2012; Shcheglova, Lydia/E-2221-2012; Katkov, Igor/E-2627-2012
Measurement of the t dependence in exclusive photoproduction of Upsilon(1s) mesons at HERA
Abramowicz H;CAPUA, Marcella;Fazio S;Schioppa M;Tassi E;
2012-01-01
Abstract
The exclusive photoproduction reaction gamma p -> gamma(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 GeV2, 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(-1.3)(+2.0)(stat.)(-0.6)(+0.5) (syst.) GeV-2. This constitutes the first measurement of the t dependence of the gamma p -> gamma(1S)p cross section. (C) 2012 Elsevier B.V. All rights reserved. RI Doyle, Anthony/C-5889-2009; Fazio, Salvatore /G-5156-2010; Lukina, Olga/D-8875-2012; Gladilin, Leonid/B-5226-2011; Barreiro, Fernando/D-9808-2012; Shcheglova, Lydia/E-2221-2012; Katkov, Igor/E-2627-2012I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
