A new factorization test in diffraction, valid below GeV2

S. Erhan; P. Schlein

doi:10.1140/epjc/s2004-01609-8

EPJ

A new $\gamma^{*} p/\bar pp$ factorization test in diffraction, valid below $Q^2 \sim 6$ GeV²

S. Erhan and P. Schlein

University of California, 90095, Los Angeles, California, USA

Abstract

One of the key experimental issues in high energy hadron physics is the extent to which data from the diffractive interaction mechanism may be described by a factorized formula which is the product of a universal term describing the probability of finding a ${\cal P}$ omeron in a proton (loosely referred to as the “ ${\cal P}$ omeron flux-factor”) and a term describing the ${\cal P}$ omeron’s interaction with the other incident proton. In the present paper, after demonstrating that existing data on diffractive $\gamma^* p$ and $\bar pp$ interactions show that the ${\cal P}$ omeron flux-factor is not universal, we present the results of a new test of factorization in these interactions which does not rely on universality of the flux-factor. The test is satisfied to within $\sim 20\%$ for 1 < Q ² < 6 GeV² and $\beta \leq 0.2$ in the $\gamma^* p$ interactions, suggesting that the reasons for non-universality of the flux-factor have a limited effect on the factorization itself. However, a clear breakdown of this test is observed at larger Q ² . Kharzeev and Levin suggest that this can be attributed to the onset of QCD evolution effects in the ${\cal P}$ omeron’s structure. The breakdown occurs in a Q ² region which agrees with their estimates of a small ${\cal P}$ omeron size.

12 Internat. Congress of the Balkan Physical Union
July 8-12, 2025
Bucharest, Romania

EPJ

A new factorization test in diffraction, valid below GeV2

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A new $\gamma^{*} p/\bar pp$ factorization test in diffraction, valid below $Q^2 \sim 6$ GeV²