We report on the first measurement of exclusive single-photonmuoproduction on the proton by COMPASS using 160 GeV/c polarised μ+ and μ− beams of the CERN SPS impinging on a liquid hydrogen target. We determine the dependence of the average ofthe measured μ+ and μ− cross sections for deeply virtual Compton scattering on the squared four-momentum transfert from the initial to the final proton. The slope B of the t-dependence is fitted with a single exponential function, which yields B=(4.3±0.6stat+0.1−0.3∣∣sys)(GeV/c)−2. This result can be converted into a transverse extension of partons in the proton, √〈r2⊥〉=(0.58±0.04stat+0.01−0.02∣∣sys±0.04model) fm. For this measurement, the average virtuality of the photon mediating the interaction is〈Q2〉=1.8(GeV/c)2 and the average value of the Bjorken variableis〈xBj〉=0.056

Transverse extension of partons in the proton probed in the sea-quark range by measuring the DVCS cross section

Bradamante F.;Bressan A.;Chatterjee C.;Cicuttin A.;Dalla Torre S.;Dasgupta S. S.;Kerbizi A.;Levorato S.;Makke N.;Martin A.;Matousek J.;Moretti A.;Sbrizzai G.;Schiavon P.;Silva L.;Szabelski A.;
2019-01-01

Abstract

We report on the first measurement of exclusive single-photonmuoproduction on the proton by COMPASS using 160 GeV/c polarised μ+ and μ− beams of the CERN SPS impinging on a liquid hydrogen target. We determine the dependence of the average ofthe measured μ+ and μ− cross sections for deeply virtual Compton scattering on the squared four-momentum transfert from the initial to the final proton. The slope B of the t-dependence is fitted with a single exponential function, which yields B=(4.3±0.6stat+0.1−0.3∣∣sys)(GeV/c)−2. This result can be converted into a transverse extension of partons in the proton, √〈r2⊥〉=(0.58±0.04stat+0.01−0.02∣∣sys±0.04model) fm. For this measurement, the average virtuality of the photon mediating the interaction is〈Q2〉=1.8(GeV/c)2 and the average value of the Bjorken variableis〈xBj〉=0.056
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11368/2948706
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