Speaker
Description
Searching for evidence of Color Transparency (CT) is a vibrant experimental effort to observe hadrons in a small color-neutral transverse size configuration in the nucleus. CT is fundamentally predicted by quantum chromodynamics and is expected to be observable in exclusive scattering as a reduction of final state interactions (FSI) of the point-like hadron with the nuclear medium. The observation of the onset of CT lies at the intersections between the quark-gluon degrees of freedom and the nucleonic descriptions of nuclei. Experimentally, this would be observable as a rise in the measured transparency of the point-like hadron with increasing four-momentum transferred.
Searches for CT effects in mesons and baryons in electroproduction experiments at Jefferson Lab have yielded somewhat differing conclusions. Observations of CT in rho and pi+ electroproduction in the 6 GeV beam era at Jefferson Lab already established indications of an early onset of CT, and new experiments are extending these measurements to higher momenta in Halls B and C. However, the most recent experimental effort for the onset of CT in protons in Hall C ruled out observations up to a Q2=14 GeV2 in contrast with theory expectations. A future experiment will explore the onset of CT in protons in rescattering kinematics with an enhanced sensitivity to protons in point-like configurations. Furthermore, a photoproduction experiment in Hall D at Jefferson Lab explores CT phenomena through other reaction mechanisms. This talk will present the current experimental statuses of the recent experiments and opportunities in new future measurements.
This work was funded in part by the U.S. Department of Energy, including contract AC05-06OR23177 under which Jefferson Science Associates, LLC operates Thomas Jefferson National Accelerator Facility.
