Hunting for QCD instantons at the LHC in events with large rapidity gaps

Abstract

We outline a strategy of how to search for QCD instantons of invariant mass 20–60 GeV in diffractive events in low-luminosity runs at the LHC. We show that, by imposing appropriate selection criteria on the final states, one can select the kinematic regime where the instanton signal exceeds the background by a factor of at least 8. In spite of the relatively strong cuts that we impose on the total transverse energy and the number of charged tracks, ${\sum }_i{E}_{T,i}>15\mathrm{GeV}$ and $N_{\mathrm{ch}}>20$ measured within the $0<\eta <2$ interval and excluding events with high-$p_T$ particles, the expected cross section is sufficiently large to study the instanton production in events with large rapidity gaps at low luminosities, thus avoiding problems with pileup. The paper also includes an updated computation of instanton cross sections and other parameters relevant for ongoing studies.