Probing non-standard neutrino interactions with supernova neutrinos at Hyper-K

Abstract

Non-standard neutrino self interactions (NSSI) could be stronger than Fermi interactions. We investigate the ability to constrain these four-neutrino interactions by their effect on the flux of neutrinos originating from a galactic supernova. In the dense medium of a core collapse supernova, these new self interactions can have a significant impact on neutrino oscillations, leading to changes at the flavor evolution and spectra level. We use simulations of the neutrino flux from a 13 solar mass, core collapse supernova at 10 kpc away, and numerically propagate these neutrinos through the stellar medium taking into account vacuum/MSW oscillations, SM ν − ν scattering as well as ν − ν interactions that arise from NSSI. We pass the resulting neutrino flux to a simulation of the future Hyper-Kamiokande detector to see what constraints on NSSI parameters are possible when the next galactic supernova becomes visible. We find that these constraints depend strongly on the neutrino mass hierarchy and if the NSSI is flavor-violating or preserving. Sensitivity to NSSI in the normal hierarchy (NH) at Hyper-K is limited by the experiment's ability to efficiently detect ν e , but deviations from no NSSI could be seen if the NSSI is particularly strong. In the inverted hierarchy (IH) scenario, Hyper-K can significantly improve constraints on flavor-violating NSSI down to O(10 −1 )G F .

The Once and Present Standard Model of Elementary Particle Physics

“…But another possibility is consistent with the data, which has the mass hierarchy inverted in a topologically disconnected region of the parameter space. Knowing which island of parameter space is the correct island, NH or IH, has profound implications for flavor model building [8] and for prospects to find BSM signals in the neutrino sector (see, e.g., [27,24,40]). Thus, it is justifiable to specify one of the islands for SM-2019, while the other is relegated to a BSM possibility.…”

Neutrino non-standard interactions meet precision measurements of Neff

“…[53,[82][83][84][85] for neutrino trident production and neutrino-electron scattering from DUNE, refs. [24,56,[86][87][88][89][90][91][92][93] for oscillation experiments, refs. [24,94] for loop bounds on dimension-6 electronneutrino contact operators, refs.…”

Angular instabilities of a homogeneous neutrino gas from (pseudo)scalar nonstandard self-interactions

“…Today, the beyond-Standard-Model (BSM) physics manifested in such hypothetical interactions can also be tested at a completely new frontier of supernova neutrinos undergoing collective, i.e., self-induced flavor oscillations (see, e.g., Refs. [16][17][18][19][20]). Indeed, under extreme conditions (neutrino and matter densities, superstrong magnetic fields, temperatures, etc.)…”

“…typical for a supernova explosion, the effect of neutrino-neutrino forward scattering results in a strongly nonlinear flavor evolution [21][22][23][24], and this evolution, unlike the linear, noncollective one, can be quite sensitive to a number of new parameters. Among such parameters are the neutrino magnetic moment [20,25], the nontrivial flavor structure of the V-A interaction [16,17,19], the non-V-A four-fermion couplings possibly originating from BSM mediators [18,20], as well as the neutrino mass hierarchy and the very nature-Dirac or Majorana-of the neutrino [18,20,23,25].…”