Since the early days of A(e,e’p)A-1 valance shell knock-out experiments, it has been clear that effects beyond simple independent particle models are needed to explain the magnitude of the observed cross sections. One of the key ingredients added to the theoretical models to explain the data was short-range nucleon-nucleon correlations which were described as removing
strength from the shells.
While this explanation that a two-body would be the leading order
correction to the one body independent particle model was quite pleasing and logical, it took many decades to experimentally observe short-range correlations.
In 2008, by making measurements in extreme kinematics (xB>1 and Q2>2 GeV2) scientists at Jefferson Lab measured the 12C(e,e’pN) reaction and showed that nearly all the high missing momentum (e,e’p) events had a partner neutron. This proton-neutron pair dominance could only be explained by an initial-state effect (i.e. the short-range nucleon-nucleon behavior). Since
then there has been a rather robust program of experiments done around the world to better understand these correlations. Most recently, exclusive (p,2p A-2)N measurements used spectator tagging techniques to probe, for the first time, the residual nuclear system after SRC breakup – directly probing the low-energy nuclear structure associated with SRC formation. As SRCs are at the heart of a series of models for the EMC effect, these studies are leading the way for studying the partonic origin of nuclear structure and correlations.
Recently studies have been undertaken to understand what aspects of short-range nucleonnucleon correlations could be studied with the upcoming Electron-Ion Collider (EIC). It is clear that with its high luminosity and large kinematics reach, the EIC could easily study the so-called tagged deep inelastic scattering effect and definitively show if it is indeed initial-state high
momentum pairs that cause the modification of nucleons in the nucleus that is seen in the EMC effect. Further tagging of nuclear recoils can extend these studies to probe the partonic structure of nucleons in different nuclear configurations. There are many other short-range correlation processes that are being investigated for study. These include diffractive break-up of the deuteron, polarized deuteron break-up in extreme kinematics, the polarized 3He reaction in extreme kinematics, the A(e,e’pn) reaction using the far forward detectors and more. This workshop will help further develop this program with emphasis on (A) connections to SRC studies undertaken by the nuclear structure community at FRIB, RIKEN, GSI, and JINR, and (B) yellow-report type developments of required kinematical coverages, rates, and detection resolutions.