Onset of Color Transparency in Holographic Light-Front QCD

The color transparency (CT) of a hadron, propagating with reduced absorption in nucleus, is fundamental property QCD (quantum chromodynamics) reflecting its internal structure and effective size when it produced at high transverse momentum, Q. CT has been confirmed many experiments, such as semi-exclusive hard electroproduction, eA?e??X, for mesons Q2>3GeV2. However, recent JLab (Jefferson Laboratory) measurement proton electroproduced carbon eC?e?pX, where X stands the inclusive sum all final states, fails to observe Q2 up 14.2 GeV2. In this paper, onset determined by comparing Q2-dependence hadronic cross sections initial formation small color-singlet configuration using generalized parton distributions from holographic light-front QCD. A critical dependence on hadron’s twist, ?, number hadron constituents, found CT, no significant effects nuclear medium. This effect can explain absence present kinematic range experiment. predicted have “two-stage” differing spin-conserving (twist-3, ?=3) Dirac form factor higher spin-flip Pauli (twist-4) factor. contrast, neutron “one-stage” because dominance model also predicts strong low energies flavor quark current coupling hadron.