Updating spin-dependent Regge intercepts

Abstract

We use new high statistics data from CLAS and COMPASS on the nucleon's spin structure function at low Bjorken x and low virtuality, Q 2 < 0.5 GeV 2 , together with earlier measurements from the SLAC E-143, HERMES and GDH experiments to estimate the effective intercept(s) for spin dependent Regge theory. We find αa 1 = 0.31 ± 0.04 for the intercept describing the high-energy behaviour of spin dependent photoabsorption together with a new estimate for the high-energy part of the Gerasimov-Drell-Hearn sum-rule, −15 ± 2µb from photon-proton centre-of-mass energy greater than 2.5 GeV. Our value of αa 1 suggests QCD physics beyond a simple straight-line a1 trajectory.

Single-pion contribution to the Gerasimov--Drell--Hearn sum rule and related integrals

“…In addition, as mentioned above, σ tot begins to increase at high energies (Fig. 1 (bottom)), and its energy dependence can be parameterized in Regge formalism as [17] σ tot = 67.7 s +0.0808 + 129 s −0.4545 µb ,…”

“…Bottom panel: Total photoabsorption cross section off the proton target at high energies. The cyan solid curve shows the Regge best fit result [17] (see Eq. ( 4)).…”

Expanding Nuclear Physics Horizons with the Gamma Factory

“…[ 380 ] However, the higher‐energy part of the integral is estimated using a model‐based parametrization of existing deep‐inelastic data at low Q 2 [ 381–384 ] and their extrapolation to the real photon point. [ 385,386 ] A direct measurement at the GF would serve as an explicit check of that model.…”

Search for Exotic Hadronic Matter: Tetraquarks, Pentaquarks, Dibaryons and Mesic Nuclei

“…The status of the search for the mesic nucleus was described in the recent reviews [63,64], therefore here, we only briefly report on main results emphasizing perspectives of the search based on the high statistics data collected recently by the WASA-at-COSY Collaboration on proton-deuteron and deuteron-deuteron fusions near the threshold for the production of the η meson.…”

“…It was predicted almost 30 years ago by Haider and Liu [65]. However, despite intensive theoretical [63] and experimental investigations of reactions induced by pions [66], protons [67], deuterons [68][69][70][71][72][73] and photons [74,75], its existence was not confirmed so far.…”