The photoproduction reaction gamma p --> mu(+)mu(-) p has been studied in ep interactions using the ZEUS detector at HERA. The data sample corresponds to an integrated luminosity of 43.2 pb(-1). The Upsilon meson has been observed in photoproduction for the first time. The sum of the products of the elastic Upsilon(1S),Upsilon(2S),Upsilon(3S) photoproduction cross sections with their respective branching ratios is determined to be 13.3 +/- 6.0(stat.)(-2.3)(+2.7)(syst.) pb at a mean photon-proton centre of mass energy of 120 GeV. The cross section is above the prediction of a perturbative QCD model. (C) 1998 Elsevier Science B.V. All rights reserved.

The photoproduction reaction gamma p --> mu(+)mu(-) p has been studied in ep interactions using the ZEUS detector at HERA. The data sample corresponds to an integrated luminosity of 43.2 pb(-1). The Upsilon meson has been observed in photoproduction for the first time. The sum of the products of the elastic Upsilon(1S),Upsilon(2S),Upsilon(3S) photoproduction cross sections with their respective branching ratios is determined to be 13.3 +/- 6.0(stat.)(-2.3)(+2.7)(syst.) pb at a mean photon-proton centre of mass energy of 120 GeV. The cross section is above the prediction of a perturbative QCD model. (C) 1998 Elsevier Science B.V. All rights reserved.

Measurement of elastic Upsilon photoproduction at HERA

CAPUA, Marcella;MASTROBERARDINO, Anna;Schioppa M;TASSI, Enrico;
1998-01-01

Abstract

The photoproduction reaction gamma p --> mu(+)mu(-) p has been studied in ep interactions using the ZEUS detector at HERA. The data sample corresponds to an integrated luminosity of 43.2 pb(-1). The Upsilon meson has been observed in photoproduction for the first time. The sum of the products of the elastic Upsilon(1S),Upsilon(2S),Upsilon(3S) photoproduction cross sections with their respective branching ratios is determined to be 13.3 +/- 6.0(stat.)(-2.3)(+2.7)(syst.) pb at a mean photon-proton centre of mass energy of 120 GeV. The cross section is above the prediction of a perturbative QCD model. (C) 1998 Elsevier Science B.V. All rights reserved.
The photoproduction reaction gamma p --> mu(+)mu(-) p has been studied in ep interactions using the ZEUS detector at HERA. The data sample corresponds to an integrated luminosity of 43.2 pb(-1). The Upsilon meson has been observed in photoproduction for the first time. The sum of the products of the elastic Upsilon(1S),Upsilon(2S),Upsilon(3S) photoproduction cross sections with their respective branching ratios is determined to be 13.3 +/- 6.0(stat.)(-2.3)(+2.7)(syst.) pb at a mean photon-proton centre of mass energy of 120 GeV. The cross section is above the prediction of a perturbative QCD model. (C) 1998 Elsevier Science B.V. All rights reserved.
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/20.500.11770/126933
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