SEARCH FOR LOW-ENERGY NU(E,MU,TAU) AND (NU)OVER-BAR(E,MU,TAU) IN COINCIDENCE WITH BATSE GAMMA-RAY BURSTS

Since neutrinos and gamma-rays productions are often associated in man y astrophysical processes, the detection of neutrinos in correlation w ith gamma-ray bursts (GRBs) could be a very important step towards the discovery of the sources of these events. A search for low-energy neu trinos of all flavours in correlation with similar to 200 gamma-ray bu rsts detected by BATSE aboard the Compton Observatory has been perform ed by the LSD (Liquid-Scintillator Detector) neutrino telescope. This kind of telescope, differently from the water Cerenkov detectors, is a lso sensitive to v(mu,tau) and (v) over bar(mu,tau) fluxes, through th e charged- and neutral-current interactions of neutrinos with carbon n uclei. No v(e,mu,tau) or (v) over bar(e,mu,tau) candidate has been det ected by LSD during the time interval in which BATSE detected 90% of t he photon flux for any of the GRBs analysed. The corresponding upper L imits to the neutrino fluxes, summed over 197 GRBs, are: F((v) over ba r(e)) less than or equal to 1.5 . 10(11) cm(-2) 9 less than or equal t o E(v) less than or equal to 50 MeV, F((v) over bar(e)) less than or e qual to less than or equal to 2.5 . 10(10) cm(-2), 20 less than or equ al to E(v) less than or equal to 50 MeV, F(v(e)) less than or equal to 5.1 . 10(11) cm(-2), 25 less than or equal to E(v) less than or equal to 50 MeV, F(v,(mu,tau)) less than or equal to 7.5 . 10(12) cm(-2), 2 0 less than or equal to E(v) less than or equal to 100 MeV, F((v) over bar(mu,tau)) less than or equal to 7.9 . 10(12) cm(-2), 20 less than or equal to E(v) less than or equal to less than or equal to 100 MeV.