The COMPASS sandwich veto detector and a first look at kaonic final states from a $\pi^-$ ($190\,\textrm{GeV}) beam on a proton target

TL;DR

This paper introduces the COMPASS sandwich veto detector used in CERN's 2008-2009 hadron runs and presents initial results on kaonic final states from a high-energy pion beam on a proton target.

Contribution

The paper details the design and implementation of the sandwich veto detector and provides first measurements of kaonic final states in a high-energy pion-proton collision.

Findings

Veto detector effectively identified particles outside spectrometer acceptance.

First mass spectra of $ o \pi^- ext{K}_S^0 ext{K}_S^0 p$ final states obtained.

Demonstrated capability to study kaonic states in high-energy hadron collisions.

Abstract

We introduce the sandwich veto detector that was built for the 2008 and 2009 hadron runs of the COMPASS experiment at CERN. During these beamtimes it was serving as a veto detector for neutral and charged particles outside the spectrometer acceptance, mostly thought to originate from reactions which excited the target. We also present first mass spectra from $\pi^-(190\,\GeV) p \to \pi^- \Kshort \Kshort p$ that were measured in the 2008 hadron run.