9-14 September 2018
University of Ferrara
Europe/Rome timezone

Status of the experimental studies on DVMP and transversity GPDs

11 Sep 2018, 17:15
A5 (Polo degli Adelardi - Via Adelardi, 33)


Polo degli Adelardi - Via Adelardi, 33

Parallel Sessions 3D Structure of the Nucleon: GPDs and Form Factors 3D Structure of the Nucleon: GPDs and Form Factors


Dr Valery Kubarovsky (Jefferson Lab, USA)


A longstanding goal in nuclear and particle physics has been to describe the three dimensional structure of the nucleon in terms of the quarks and gluon fields. In this regard, exclusive electron scattering experiments, in which all final state particles are measured, are important contributors. Examples are electron elastic scattering, deeply virtual Compton scattering (DVCS), and deeply virtual meson electroproduction (DVMP). The latter includes pseudoscalar mesons with intrinsic spin and parity JP=0-, such as π-, π0, π+ and η, and vector mesons, which have the same spin and parity as the photon, JP=1-, such as ρ-, ρ0, ρ+, ω and φ. Exclusive electron scattering reactions at high momentum transfers directly related to Generalized Parton Distributions (GPDs) of quarks and gluons. Most reactions studied, such as DVCS or vector meson electroproduction, are primarily sensitive to the chiral-even GPDs. Very little is known about the chiral-odd GPDs, except that HT becomes the transversity function h1 in the forward limit. The chiral-odd GPDs are difficult to access since hard subprocesses with the quark spin-flip are suppressed. It turns out that pseudoscalar meson electroproduction, and especially π0 and η production, were identified as especially sensitive to the parton helicity-flip subprocesses. Dedicated experiments to study Deeply Virtual Meson Production have been carried out at Jefferson Lab. The cross sections and asymmetries of the exclusive pseudoscalar meson electroproduction processes in a very wide kinematic range of Q2, xB and t have been measured with CLAS. The comparison of these data with the theoretical models will be discussed in the report. The new CLAS12 experiments are a major component of the CLAS12 program to provide detailed tomographic images the quark and gluon distributions.

Primary author

Dr Valery Kubarovsky (Jefferson Lab, USA)

Presentation Materials