3–7 Apr 2017
University of Birmingham
Europe/London timezone

Vector Meson Electroproduction: a paradigm for Exclusive Physics at an Electron-Ion Collider

4 Apr 2017, 14:00
30m
Small Lecture Theatre, Poynting Building

Small Lecture Theatre, Poynting Building

WG2) Low x and Diffraction WG2 Low x and Diffraction

Speaker

John Dainton (The Cockcroft Institute)

Description

Progress is reported with a phenomenological analysis in full view of chromodynamics of a plausible Bethe-Heitler-like approach to measurements of exclusive elastic and dissociative electroproduction cross sections for vector-meson (VM) “quarkonia” of different flavour, namely ?\rho(760), u ubar - d dbar, \phi(??1019) s sbar, J\psi?(3096) c cbar and \Upsilon(??9460) b bbar? . First results are presented in the form of acceptable fits to measurements made by the H1 and Zeus experiments at the HERA electron-proton collider of the cross sections. The Bethe-Heitler-like hypothesis includes the factorisable, flavor-dependent,
combination of quark-antiquark contributions which describe measurements of real and virtual photon structure (??F_2^{\gamma*}), together with the appropriate, and universal, Regge-asymptotic form for flavour-blind, elastic, quark-proton (?qp) scattering which is based analyticity and on measurements
of the proton structure function F_2?? at appropriate Bjørken–x. The measurements are well described with constituent masses of u, d, s, c and b quarks and flavour-blind qp? scattering for which the Regge-asymptotic expansion is truncated at one leading pole with intercept consistent with that which tradition demands is called a “pomeron” and which depends on the “length” of elastic ?scattering. The pomeron is thus seen both to be at work at a scale which is below that of the interacting proton, that is of confinement, and, provided that account is taken of the “length” of ?scattering, to be universal.

Author

John Dainton (The Cockcroft Institute)

Presentation materials