OUP accepted manuscript

Abstract

The neutrino annihilation process in accretion discs is one of the leading models used to explain the generation of relativistic jets of gamma-ray bursts (GRBs). The neutrino annihilation efficiency (NAE) has been widely studied in black hole–accretion disc (BH–disc) systems, and the published results are mutually corroborated. However, there is still uncertainty regarding the NAE of neutron star–accretion disc (NS–disc) systems because of the complicated microphysics processes and the effects of strong magnetic fields. In this paper, we investigate the latter NAE by assuming that the prompt jet of GRB 070110 is driven by neutrino pair annihilation in the NS–disc system. Our calculation shows |$\eta _{\rm \nu \bar{\nu }}$| > 1.2 × 10^–3under the estimated accretion rate |$\dot{M}\simeq 0.04\,\rm M_{\odot }\, s^{-1}$|⁠. Independent of the detailed accretion disc models, our result shows that the magnetic field can play an important role in the neutrino annihilation process on the hyper-accreting magnetized accretion disc. Compared with the theoretical value of |$\eta _{\nu \bar{\nu }}$| of the non-magnetized BH–disc system, the NAE should increase significantly in the case of the NS–disc system if the GRB is powered by a magnetar–disc system.