Search strategy using LHC pileup interactions as a zero bias sample

Abstract

Due to a limited bandwidth and a large proton-proton interaction cross section relative to the rate of interesting physics processes, most events produced at the Large Hadron Collider (LHC) are discarded in real time. A sophisticated trigger system must quickly decide which events should be kept and is very efficient for a broad range of processes. However, there are many processes that cannot be accommodated by this trigger system. Furthermore, there may be models of physics beyond the standard model (BSM) constructed after data taking that could have been triggered, but no trigger was implemented at run time. Both of these cases can be covered by exploiting pileup interactions as an effective zero bias sample. At the end of high-luminosity LHC operations, this zero bias dataset will have accumulated about $1\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data from which a bottom line cross section limit of $\mathcal{O}(1)\text{ }\text{ }\mathrm{fb}$ can be set for BSM models already in the literature and those yet to come.