Open issues in neutrino astrophysics

Abstract

Neutrinos of astrophysical origin are messengers produced in stars, in explosive phenomena like core-collapse supernovae, in the accretion disks around black holes, or in the Earth's atmosphere. Their fluxes and spectra encode information on the environments that produce them. Such fluxes are modified in characteristic ways when neutrinos traverse a medium. Here our current understanding of neutrino flavour conversion in media is summarized. The importance of this domain for astrophysical observations is emphasized. Examples are given of the fundamental properties that astrophysical neutrinos have uncovered, or might reveal in the future.Comment: 13 pages, 9 figures, manuscript improved, to appear in the Special Issue "Precision experiments and fundamental physics at low energies

Neutrino astrophysics : recent advances and open issues

“…They are interesting both as probes of the sources that produce them and for the information they give us on neutrino themselves (see e.g. [7]). Historically astrophysical neutrinos have brought milestones in our knowledge of particle physics and astrophysics.…”

Weak neutral current axial form factor using $$ \left(\overline{\nu}\right)\nu $$-nucleon scattering and lattice QCD inputs

“…This value is consistent with but more precise than the first simultaneous extraction of spin-dependent parton distributions and fragmentation functions from a global QCD analysis in ref. [55] where the authors obtained G s A (0) = −0.03 (10). We can now use the lattice QCD estimate of G s A (0) to obtain…”

“…Precision measurements of various matrix elements associated with (anti)neutrino-nucleon (ν)ν − N scattering can directly impact a wide variety of physical processes. These include an understanding of solar neutrino [1][2][3] and atmospheric [4][5][6] neutrino oscillations, three non-vanishing mixing angles [7,8] resulting in a phase-violating CP asymmetry leading to matter-antimatter asymmetry in the universe in the three-neutrino framework, dynamics of neutron-rich core-collapse supernovae [9,10], axial-vector structure of the nucleon, strange quark (s-quark) contribution G s A (0) ≡ ∆s to the proton spin, and non-standard interactions leading to beyond-the-standard-model physics [11]. One such matrix element is the neutral current weak axial charge G Z A (0) and the corresponding momentum-dependent form factor G Z A (Q 2 ), arising through the exchange of a neutral Z 0 boson between the lepton and quarks.…”

Weak Neutral Current Axial Form Factor Using $(\barν)ν$-Nucleon Scattering and Lattice QCD Inputs

“…Precision measurements of various matrix elements associated with (anti)neutrino-nucleon (ν)ν − N scattering can directly impact a wide variety of physical processes. These include, but are not limited to, an understanding of solar neutrino [1][2][3] and atmospheric [4][5][6] neutrino oscillations, three non-vanishing mixing angles [7,8] resulting in a phase-violating CP asymmetry leading to matter-antimatter asymmetry in the universe in the three-neutrino framework, dynamics of neutron-rich core-collapse supernovae [9,10], axial-sector structure of the nucleon, strange quark (squark) contribution ∆s to the proton spin, and nonstandard interactions leading to beyond-the-standardmodel physics [11]. One such matrix element is the weak neutral current (WNC) axial form factor (FF) G Z A , arising through the exchange of a neutral Z 0 boson between the lepton and quarks.…”