Light Gluino Search for Decays Containing pi+pi- or pi0 from a Neutral Hadron Beam at Fermilab

TL;DR

This study conducted null searches for specific decay modes of a hypothesized light gluino bound state, setting new limits on its decay channels and lifetime within certain mass ranges at Fermilab.

Contribution

It provides the first experimental constraints on the decay modes and lifetimes of the light gluino bound state, the $R^0$, in the mass range up to 3 GeV/c^2.

Findings

Excluded $R^0$ decays to $^+^-$ and $^0$ for certain mass ranges.

Set lifetime limits for $R^0$ from $3 imes 10^{-10}$s to $10^{-3}$s.

No evidence found for the hypothesized particles within the explored parameter space.

Abstract

We report on two null searches, one for the spontaneous appearance of $\pi^+\pi^-$ pairs, another for a single $\pi^0$, consistent with the decay of a long-lived neutral particle into hadrons and an unseen neutral particle. For the lowest level gluon-gluino bound state, known as the $R^0$, we exclude the decays $R^0\to \pi^+\pi^-\tilde{\gamma}$ and $R^0\to \pi^0\tilde{\gamma}$ for the masses of $R^0$ and $\tilde{\gamma}$ in the theoretically allowed range. In the most interesting $R^0$ mass range, $\leq 3 GeV/c^2$, we exclude $R^0$ lifetimes from $3\times 10^{-10}$ seconds to as high as $10^{-3}$ seconds, assuming perturbative QCD production for the $R^0$.