Measurement of exclusive ρ(770)0 photoproduction in ultraperipheral pPb collisions at sNN−−−√=5.02TeV
Greene, S.
Gurrola, A.
Janjam, R.
Johns, W.
Maguire, C.
Melo, A.
Ni, H.
Padeken, K.
Ruiz Alvarez, J. D.
Sheldon, P.
Tuo, S.
Velkovska, J.
Verweij, M.
Xu, Q.
:
2019-08-21
Abstract
Exclusive ρ(770)0 photoproduction is measured for the first time in ultraperipheral pPb collisions at sNN−−−√=5.02TeV with the CMS detector. The cross section σ(γp→ρ(770)0p) is 11.0±1.4(stat)±1.0(syst) μb at ⟨Wγp⟩=92.6GeV for photon–proton centre-of-mass energies Wγp between 29 and 213GeV. The differential cross section dσ/d|t| is measured in the interval 0.025<|t|<1GeV2 as a function of Wγp, where t is the squared four-momentum transfer at the proton vertex. The results are compared with previous measurements and theoretical predictions. The measured cross section σ(γp→ρ(770)0p) has a power-law dependence on the photon–proton centre-of-mass, consistent with electron–proton collision measurements performed at HERA. The Wγp dependence of the exponential slope of the differential cross section dσ/d|t| is also measured.