Searches for new physics in events with a photon and $b$-quark jet at CDF

We have searched for evidence of physics beyond the standard model in events that include an energetic photon and an energetic b-quark jet, produced in $85{\mathrm{pb}}^{-1}$ of $\overline{p}p$ collisions at 1.8 TeV at the Tevatron Collider at Fermilab. This signature, containing at least one gauge boson and a third-generation quark, could arise in the production and decay of a pair of new particles, such as those predicted by supersymmetry, leading to a production rate exceeding standard model predictions. We also search these events for anomalous production of missing transverse energy, additional jets and leptons $(e,$ $\mu$ and $\tau ),$ and additional b quarks. We find no evidence for any anomalous production of $\gamma b$ or $\gamma b+X$ events. We present limits on two supersymmetric models: a model where the photon is produced in the decay ${\tilde{\chi }}_2^0\to \gamma {\tilde{\chi }}_1^0,$ and a model where the photon is produced in the neutralino decay into the gravitino LSP, ${\tilde{\chi }}_1^0\to \gamma \tilde{G}.$ We also present our limits in a model-independent form and test methods of applying model-independent limits.