Central Pseudorapidity Gaps in Events with a Leading Antiproton at the Fermilab Tevatron pbar-p Collider

TL;DR

This paper measures the frequency of large pseudorapidity gaps in antiproton-proton collisions at Fermilab, providing insights into diffraction phenomena and comparing results with theoretical models.

Contribution

It presents the first detailed measurement of large pseudorapidity gap fractions in specific kinematic regions at two collision energies, enhancing understanding of diffraction in hadron collisions.

Findings

Large pseudorapidity gap fraction is approximately 24.6% at 1800 GeV.

Gap fraction is approximately 18.4% at 630 GeV.

Results are compared with minimum bias collision data and theoretical models.

Abstract

We report a measurement of the fraction of events with a large pseudorapidity gap $\Delta\eta$ within the pseudorapidity region available to the proton dissociation products $X$ in $\bar p+p\to \bar p+X$. For a final state $\bar p$ of fractional momentum loss $\xi_{\bar p}$ and 4-momentum transfer squared $t_{\bar p}$ within $0.06<\xi_{\bar p}<0.09$ and $|t_{\bar p}|<1.0$ [0.2] GeV$^2$ at $\sqrt s=1800$ [630] GeV, the fraction of events with $\Delta \eta>3$is found to be $0.246\pm 0.001 {\rm (stat)}\pm 0.042 {\rm (syst)}$ [$0.184\pm 0.001 {\rm (stat)}\pm 0.043 {\rm (syst)}$]. Our results are compared with gap fractions measured in minimum bias $\bar pp$ collisions and with theoretical expectations.