We investigate the transition from the nucleon-meson to the quark-gluon description of the strong interaction using the photon energy dependence of the d(γ,p)n differential cross section for photon energies above 0.5 GeV and center-of-mass proton angles between 30° and 150°. A possible signature for this transition is the onset of cross-section s-11 scaling with the total energy squared, s, at some proton transverse momentum PT. The results show that the scaling has been reached for proton transverse momentum above about 1.1 GeV/c. This may indicate that the quark-gluon regime is reached above this momentum.
Physical Review Letters
Rossi, P.; Biselli, Angela; and CLAS Collaboration, "Onset of asymptotic scaling in deuteron photodisintegration" (2005). Physics Faculty Publications. 5.
P. Rossi et al. [CLAS Collaboration], "Onset of asymptotic scaling in deuteron photodis- integration", Phys. Rev. Lett. 94, 012301 (2005) 10.1103/PhysRevLett.94.012301
Copyright American Physical Society 2005.
Final publisher version also available at http://prl.aps.org/abstract/PRL/v94/i1/e012301