5-10 GeV neutrinos from gamma-Ray burst fireballs

Area of Science:

• Astrophysics
• Particle Physics
• High-Energy Physics

Background:

• Gamma-ray bursts (GRBs) are powerful cosmic explosions.
• The composition of GRB fireballs, particularly the presence of neutrons, is not fully understood.
• Neutrino and photon emissions from GRBs offer insights into their physics.

Purpose of the Study:

• To investigate the production of neutrinos and photons from inelastic collisions within a neutron-rich GRB fireball.
• To estimate the potential detectability of these secondary particles in terrestrial detectors.
• To identify potential observational signatures of neutron decay products.

Main Methods:

• Theoretical modeling of particle interactions within a GRB fireball.
• Simulation of neutrino and photon production from proton-neutron inelastic collisions.
• Calculation of expected event rates for km^3 neutrino detectors.

Main Results:

• Inelastic collisions produce muon neutrinos (nu_μ) around 10 GeV and electron neutrinos (nu_e) around 5 GeV.
• These neutrinos could yield approximately 7 events/year in km^3 detectors if neutron abundance is similar to proton abundance.
• Neutral pion (π^0) decay produces ~10 GeV photons, and neutron decay produces ~100 MeV neutrinos, which are difficult to detect.
• Neutron decay products generate MeV photons from shock interactions, potentially distinguishable from proton-related MeV photons.

Conclusions:

• Neutrino and photon production from proton-neutron interactions in GRBs is theoretically significant.
• The predicted neutrino event rates suggest potential for future detection with large-volume neutrino observatories.
• Characteristic photon signals from neutron decay products may offer a unique observational channel for studying GRB composition.