Exclusive J/$\psi$ photoproduction off protons in ultra-peripheral p-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV

Abstract

We present the first measurement at the LHC of exclusive J/$\psi$ photoproduction off protons, in ultra-peripheral proton-lead collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV. Events are selected with a dimuon pair produced either in the rapidity interval, in the laboratory frame, $2.5<y<4$ (p-Pb) or $-3.6<y<-2.6$ (Pb--p), and no other particles observed in the ALICE acceptance. The measured cross sections $\sigma (\gamma +\mathrm{p}\to J/\psi +\mathrm{p})$ are 33.2 $\pm$ 2.2 (stat) $\pm$ 3.1 (syst) $\pm$ 0.7 (theo) nb in p-Pb and 284 $\pm$ 36 (stat) ${}_{-32}^{+27}$ (syst) $\pm$ 26 (theo) nb in Pb-p collisions. We measure this process up to about 700 GeV in the $\gamma \mathrm{p}$ centre-of-mass, which is a factor of two larger than the highest energy studied at HERA. The data are consistent with a power law dependence of the $J/\psi$ photoproduction cross section in $\gamma \mathrm{p}$ energies from about 20 to 700 GeV, or equivalently, from Bjorken-$x$ between $\sim 2\times 10^{-2}$ to $\sim 2\times 10^{-5}$, thus indicating no significant change in the gluon density behaviour of the proton between HERA and LHC energies.

17 pages, 3 captioned figures, 2 tables, authors from page 12, published version, figures at http://aliceinfo.cern.ch/ArtSubmission/node/1743

References in corpus (5)

• The Color Glass Condensate
• Observation of exclusive charmonium production and gamma+gamma to mu+mu- in p+pbar collisions at sqrt{s} = 1.96 TeV
• Standard candle central exclusive processes at the Tevatron and LHC
• Elastic and large t rapidity gap vector meson production in ultraperipheral proton-ion collisions
• Elastic and Proton-Dissociative Photoproduction of J/psi Mesons at HERA

Cited by in corpus (40)

• The ALICE experiment: a journey through QCD
• Revealing proton shape fluctuations with incoherent diffraction at high energy
• Imaging the nucleus with high-energy photons
• Energy dependence of dissociative $J/\psi$ photoproduction as a signature of gluon saturation at the LHC
• BFKL evolution and the growth with energy of exclusive J/Psi and Upsilon photo-production cross-sections
• Exclusive dimuon production in ultraperipheral Pb+Pb collisions at $\sqrt{s_{\mathrm{NN}}}=5.02$ TeV with ATLAS
• Observation of forward neutron multiplicity dependence of dimuon acoplanarity in ultraperipheral Pb-Pb collisions at $\sqrt{s_{\mathrm{NN}}}=$ 5.02 TeV
• Exclusive J/Psi and Psi(2s) photo-production as a probe of QCD low x evolution equations
• Investigating saturation effects in ultraperipheral collisions at the LHC with the color dipole model
• Probing small Bjorken-$x$ nuclear gluonic structure via coherent J/$\psi$ photoproduction in ultraperipheral PbPb collisions at $\sqrt{s_{\mathrm{NN}}}$ = 5.02 TeV
• Light vector meson photoproduction in hadron-hadron and nucleus-nucleus collisions at the energies available at the CERN Large Hadron Collider
• Coherent photoproduction of $J/\psi$ in nucleus-nucleus collisions in the color dipole approach
• Energy dependent nuclear suppression from gluon saturation in exclusive vector meson production
• Selected topics in diffraction with protons and nuclei: past, present, and future
• Sub-threshold $J/\psi$ and ${\rm Y}$ Production in $\gamma A$ Collisions
• Systematic analysis of the proton mass radius based on photoproduction of vector charmoniums
• Finite-size effects on small-$x$ evolution and saturation in proton and nuclear targets
• The ${\psi }^{(\ast )}p$ scattering length based on near-threshold charmoniums photoproduction
• Single-Transverse-Spin Asymmetries in Exclusive Photo-production of J/psi in Ultra-Peripheral Collisions in the Fixed-Target Mode at the LHC and in the Collider Mode at RHIC
• Charmonium production in ultra-peripheral heavy ion collisions with two-photon processes
• Exclusive and dissociative J/$\psi$ photoproduction, and exclusive dimuon production, in p$-$Pb collisions at $\sqrt{s_{\mathrm{NN}}}=8.16$ TeV
• Hard color-singlet exchange in dijet events in proton-proton collisions at $\sqrt{s}=$ 13 TeV
• Gluon Saturation Effects in Exclusive Heavy Vector Meson Photoproduction
• Exploring Baryon Resonances with Transition Generalized Parton Distributions: Status and Perspectives
• Global Bayesian Analysis of $\mathrm{J}/\psi$ Photoproduction on Proton and Lead Targets
• Analysis of the contribution of the quantum anomaly energy to the proton mass
• Entropy from entangled parton states and high-energy scattering behavior
• Measurement of exclusive $J/\psi$ and $\psi (2S)$ production at $\sqrt{s}=13$ TeV
• Exclusive quarkonium photoproduction: predictions with the Balitsky-Kovchegov equation including the full impact-parameter dependence
• Vector meson photoproduction in UPCs with FoCal
• Probing gluon fluctuations in nuclei with the first energy-dependent measurement of incoherent J/$\psi$ photoproduction in ultraperipheral PbPb collisions
• Exclusive diffractive J/psi and Psi(2S) production in dipole model using a holographic AdS/QCD light front wavefunction with longitudinal confinement
• Physics perspectives of a CMS near-beam proton spectrometer at the HL-LHC
• Measurement of the near-threshold J$/\psi$ photoproduction cross section with the CLAS12 experiment
• Physics with high-luminosity proton-nucleus collisions at the LHC
• Gluon imaging using azimuthal correlations in diffractive scattering at the Electron-Ion Collider
• Observation of coherent $\varphi$(1020) meson photoproduction in ultraperipheral PbPb collisions at $\sqrt{s_{\text{NN}}}$ = 5.36 TeV
• Energy dependence of the proton geometry in exclusive vector meson production
• Probing nuclear structure with the Balitsky-Kovchegov equation in full impact-parameter dependence
• Exclusive process $\gamma \gamma \to J/\psi +\gamma$ production in ultraperipheral proton and nuclear collisions at the HL-LHC and FCC