Off forward non-SCHC contributions to exclusive vector quarkonium production from the "spin dependent BFKL Pomeron"

Abstract

A novel contribution to off-forward, exclusive vector quarkonium production, ${\gamma }^{(\ast )}+p\to V+p$, at high energy is derived which corresponds to a $t$-channel exchange of a BFKL hard Pomeron, with a helicity flip of the proton. This ``spin-dependent BFKL Pomeron" is required in a consistent expansion in powers of the momentum transfer $t\approx -{\Delta }_{\perp }^2$ beyond first order. The spin-dependent Pomeron violates $s$-channel helicity conservation (SCHC) at $\mathcal{O}({\Delta }_{\perp }^2)$, and beyond. Expanding to leading twist only, it corresponds to GPD $E_g(x,t)$ for vanishing skewness. We derive explicit expressions for the eikonal BFKL amplitudes, to all orders in dipole size times momentum transfer, for all helicity configurations of the particles in the initial and final states. We also provide numerical estimates of the helicity flip two gluon exchange amplitude at moderate $x$ from a light-cone quark model of the proton. The spin dependent BFKL Pomeron could, in principle, be discovered via double spin asymmetries in $e+p\to e+p+J/\psi$ with transversely polarized proton and longitudinally polarized electron in the initial state.

12 pages incl. references and appendices; 2 figures; to be published in Phys. Rev. D

References in corpus (40)

• Exclusive diffractive processes at HERA within the dipole picture
• Exclusive photoproduction of J/psi mesons at HERA
• Elastic J/Psi Production at HERA
• Charge Density of the Neutron
• Perturbative QCD Analysis of the Nucleon's Pauli Form Factor F_2(Q^2)
• Transverse momentum dependent parton distributions in a light-cone quark model
• Scanning the BFKL pomeron in elastic production of vector mesons at HERA
• Diffractive Vector Meson Production at HERA: from Soft to Hard QCD
• Diffractive Heavy Quarkonium Photo- and Electroproduction in QCD
• Exclusive photoproduction of a heavy vector meson in QCD
• Exclusive vector meson production at high energies and gluon saturation
• Relativistic Constituent Quark Model of Electroweak Properties of Baryons
• Wavefunction-Independent Relations between the Nucleon Axial-Coupling g_A and the Nucleon Magnetic Moments
• Three-Quark Light-Cone Amplitudes of The Proton And Quark-Orbital-Motion Dependent Observables
• Gluon Tomography from Deeply Virtual Compton Scattering at Small-x
• Transverse single spin asymmetries at small x and the anomalous magnetic moment
• Gravitational form factors and mechanical properties of proton in a light-front quark-diquark model
• Single Spin Asymmetry $A_N$ in Polarized Proton-Proton Elastic Scattering at $\sqrt{s}=200$ GeV
• A Fixed-Target Programme at the LHC: Physics Case and Projected Performances for Heavy-Ion, Hadron, Spin and Astroparticle Studies
• Quark Sivers Function at Small $x$: Spin-Dependent Odderon and the Sub-Eikonal Evolution
• The Quark Orbital Angular Momentum in a Light-Cone Representation
• Color charge correlations in the proton at NLO: beyond geometry based intuition
• Extracting many-body color charge correlators in the proton from exclusive DIS at large Bjorken x
• Multi-quark matrix elements in the proton and three gluon exchange for exclusive ${\eta }_c$ production in photon-proton diffractive scattering
• Exclusive production of quarkonia as a probe of the GPD E for gluons
• Diffractive vector mesons beyond the s-channel helicity conservation
• Probing the Sivers function with an unpolarized target: GTMD distributions and the Odderons
• Energy dependent nuclear suppression from gluon saturation in exclusive vector meson production
• Spin-dependent Pomeron and Odderon in elastic proton-proton scattering
• Study of quark distribution amplitudes of 1S and 2S heavy quarkonium states
• Sub-femtometer scale color charge correlations in the proton
• Hadronic structure on the light-front IV: Heavy and light Baryons
• Small-x Evolution of the Gluon Generalized Parton Distribution Eg of the Nucleon
• The Pauli form factor of the quark induced by instantons
• 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
• Gluon Saturation Effects in Exclusive Heavy Vector Meson Photoproduction
• Gluonic Structure of the Constituent Quark
• Spin-flip gluon GTMD $F_{1,2}$ at small-$x$
• The Pauli Form Factor of Quark and Nontrivial Topological Structure of the QCD
• Six-dimensional light-front Wigner distributions of the proton