Flavor changing supersymmetry interactions in a supernova

• Published in: Astroparticle physics 2005-09, Vol.24 (1), p.160-182
• Main Authors: Amanik, Philip S., Fuller, George M., Grinstein, Benjamin
• Format: Article
• Language: English
• Subjects: Beta decay; Collapse; Flavor (particle physics); Heavy nuclei; Neutrinos; Scattering; Stellar collapse; Supernovas; Weak interactions
• ISSN: 0927-6505; 1873-2852
• DOI: 10.1016/j.astropartphys.2005.06.004

We consider for the first time flavor changing neutral currents (FCNC’s) in the infall stage of stellar collapse. We take as an example R-Parity violating interactions of the minimal standard supersymmetric model involving neutrinos and quarks. However, our considerations extend to other kinds of flavor changing neutrino reactions as well. We examine non-forward neutrino scattering processes on heavy nuclei and free nucleons in the supernova core. This investigation has led to four principal original discoveries/products: (1) first calculation of neutrino flavor changing cross sections for spin 1/2 (e.g., free nucleon) and spin 0 nuclear targets; (2) discovery of nuclear mass number squared ( A 2) coherent amplification of neutrino-quark FCNC’s; (3) analysis of FCNC-induced alteration of electron capture and weak/nuclear equilibrium in the collapsing core; and (4) generalization of the calculated cross sections (mentioned in 1) for the case of hot heavy nuclei to be used in collapse/supernova and neutrino transport simulations. The scattering processes that we consider allow electron neutrinos to change flavor during core collapse, thereby opening holes in the ν e sea, which allows electron capture to proceed and results in a lower core electron fraction Y e. A lower Y e implies a lower homologous core mass, a lower shock energy, and a greater nuclear photo-disintegration burden for the shock. In addition, unlike the standard supernova model, the core now could have net muon and/or tau lepton numbers. These effects could be significant even for supersymmetric couplings below current experimental bounds.