We report on a study of sub-TeV $(10\mathrm{}\mathrm{GeV}<E_{\gamma }<1\mathrm{}\mathrm{TeV})$ gamma-ray-induced muon secondaries in coincidence with BATSE gamma ray bursts (GRBs). Each TeV gamma ray striking the atmosphere produces $\approx 0.2$ muons whose identity and angle can be measured by the Project GRAND array. Eight GRB candidates were studied; seven were selected based upon the optimum product of (detected BATSE fluence) $\times$ (GRAND’s acceptance). One candidate was added because it was reported as a possible detection by the Milagrito Collaboration. Seven candidates show a positive, though not statistically significant, muon excess. The only significant possible coincidence shows an excess of $466\pm 171$ muons during the BATSE T90 time interval for GRB 971110. The chance probability of such an excess in GRAND’s background at the time of this event is $3\times {10}^{-3}.$ The chance probability of observing such an excess in one of the eight bursts studied here is 0.025. If this event is real, the implied fluence of energetic $(>\mathrm{}10\mathrm{}\mathrm{GeV})$ gamma rays necessary to account for the observed muon excess would require that most of the GRB fluence arrived in the form of energetic gamma rays.

• Received 4 June 2002

DOI:https://doi.org/10.1103/PhysRevD.67.042001