Three-flavour neutrino oscillations in a magnetic field

We analyze the impact of resonant conversions mediated by non-vanishing magnetic moments between active neutrinos and a heavy sterile neutrino on the supernova neutrino flux. We present the level-crossing scheme for such a scenario and derive the neutrino fluxes after conversion, paying particular attention to the order in which the resonances occur. We then compute the expected event rates from the neutronization burst of a future supernova at DUNE and Hyper-Kamiokande to derive new constraints on the neutrino magnetic moment. With this, we find a sensitivity down to a few 10-15 μB for a sterile neutrino in the O(eV) mass range.

Section: Jcap05(2024)056mentioning

confidence: 93%

Resonant spin-flavor precession of sterile neutrinos

Wang

2024

“…Magnetic moment-induced flavour conversions of ultra-high energy astrophysical neutrinos have been studied previously in refs. [104][105][106][107] in the context of spin-flavour precession, but not for ν L → N R conversions.…”

Section: Jcap03(2024)043mentioning

confidence: 99%

Magnetic moments of astrophysical neutrinos

Kopp,

Opferkuch,

Wang

2024

We study the impact of neutrino magnetic moments on astrophysical neutrinos, in particular supernova neutrinos and ultra-high energy neutrinos from extragalactic sources. We show that magnetic moment-induced conversion of Dirac neutrinos from left-handed states into unobservable right-handed singlet states can substantially change the flux and flavour composition of these neutrinos at Earth. Notably, neutrinos from a supernova's neutronisation burst, whose flux can be predicted with 𝒪(10%) accuracy, offer a discovery reach to neutrino magnetic moments ∼ few × 10-13 μB , up to one order of magnitude below current limits. For high-energy neutrinos from distant sources, for which no robust flux prediction exists, we show how the flavour composition at Earth can be used as a handle to establish the presence of non-negligible magnetic moments, potentially down to few× 10-17 μB if the measurement can be performed on neutrinos from a single source. In both cases, the sensitivity strongly depends on the galactic (intergalactic) magnetic field profiles along the line of sight. Therefore, while a discovery is possible down to very small values of the magnetic moment, the absence of a discovery does not imply an equally strong limit. We also comment on the dependence of our results on the right-handed neutrino mass, paying special attention to the transition from coherent deflection by a classical magnetic field to incoherent scattering on individual scattering targets. Finally, we show that a measurement of Standard Model Dirac neutrino magnetic moments, of order 10-19 μB , could be possible under rather optimistic, but not completely outrageous, assumptions using flavour ratios of high-energy astrophysical neutrinos.

“…In the context of high-energy neutrinos, previous studies of νMM were chiefly focused on neutrino propagation through the intergalactic medium [22][23][24][25]. There, the idea is that despite the small magnetic field involved, neutrinos carrying large νMM can undergo efficient flavor conversion across large propagation distances.…”

Section: Introductionmentioning

confidence: 99%

Magnetar-powered neutrinos and magnetic moment signatures at IceCube

Brdar,

Cheng,

Kuan

et al. 2024

The IceCube collaboration pioneered the detection of 𝒪(PeV) neutrino events and the identification of astrophysical sources of high-energy neutrinos. In this study, we explore scenarios in which high-energy neutrinos are produced in the vicinity of astrophysical objects with strong magnetic field, such as magnetars. While propagating through such magnetic field, neutrinos experience spin precession induced by their magnetic moments, and this impacts their helicity and flavor composition at Earth. Considering both flavor composition of high-energy neutrinos and Glashow resonance events we find that detectable signatures may arise at neutrino telescopes, such as IceCube, for presently unconstrained neutrino magnetic moments in the range between 𝒪(10-15) μB and 𝒪(10-12) μB .