Color fluctuations in hadrons and proton coherent diffractive dissociation on helium.

Abstract

The differential cross section of inelastic coherent diffractive dissociation off nuclei p${+}^{4}$He \ensuremath{\rightarrow}X${+}^{4}$He is expressed in terms of the relative cumulants of the cross-section distribution ${\mathit{P}}_{\mathit{N}}$(\ensuremath{\sigma}). The theoretical result for the ratio r=(d${\mathrm{\ensuremath{\sigma}}}_{\mathrm{diff}}$/dt${)}_{\mathit{t}=0}^{\mathit{p}\mathrm{He}}$/(d${\mathrm{\ensuremath{\sigma}}}_{\mathrm{diff}}$/dt $_{\mathit{t}=0}^{\mathit{pp}}$=6.8--7.6 is close to the value r=7.1\ifmmode\pm\else\textpm\fi{}0.7 which we extracted from the FNAL data. These are the only A\ensuremath{\gtrsim}2 data of this kind. The comparison provides the first confirmation of the color/cross-section fluctuation approach to the description of the absolute value of the inelastic diffraction cross section off nuclei. It provides also a new constraint on the first four cumulants of the cross-section distribution.