M 05 Particle Physics in Supernovae Flavor evolution

M 05 Particle Physics in Supernovae: Flavor evolution, lepton-number violation, and sterile neutrinos Presented by Georg Raffelt (MPP) • Thomas Janka (MPA) & Georg Raffelt (MPP), PIs • Irene Tamborra (Niels Bohr Institute), Mercator Fellow • Postdocs: Robert Bollig, Ricard Ardevol (MPA) Francesco Capozzi (MPP) • Ph. D Students: Robert Glas (MPA), Tobias Stirner (MPP) & Various External Collaborators

M 05 Papers directly connected to this project – 1 [1] Bollig, Janka, Lohs, Martínez-Pinedo, Horowitz & Melson Muon Creation in Supernova Matter Facilitates Neutrino-Driven Explosions PRL 119 (2017) 242702, ar. Xiv: 1706. 04630 [2] Glas, Janka, Melson, Stockinger & Just Effects of LESA in Three-Dimensional Supernova Simulations with Multi-Dimensional and Ray-by-Ray-Plus Neutrino Transport, ar. Xiv: 1809. 10146 [3] Walk, Tamborra, Janka & Summa Identifying Rotation in SASI-Dominated Core-Collapse Supernovae with a Neutrino Gyroscope PRD 98 (2018) 123001, ar. Xiv: 1807. 02366 [4] Walk, Tamborra, Janka & Summa Effects of SASI and LESA in the Neutrino Emission of Rotating Supernovae ar. Xiv: 1901. 06235 [5] Tamborra, Hüdepohl, Raffelt & Janka Flavor-Dependent Neutrino Angular Distribution in Core-Collapse Supernovae Ap. J 839 (2017) 132, ar. Xiv: 1702. 00060

M 05 Papers directly connected to this project – 2 [6] Wu, Tamborra, Just & Janka Imprints of Neutrino-Pair Flavor Conversions on Nucleosynthesis in Ejecta from Neutron-Star Merger Remnants, PRD 96 (2017) 123015, ar. Xiv: 1711. 00477 [7] Stirner, Sigl & Raffelt Liouville Term for Neutrinos: Flavor Structure and Wave Interpretation JCAP 1805 (2018) 016, ar. Xiv: 1803. 04693 [8] Capozzi, Dasgupta & Mirizzi Model-Independent Diagnostic of Self-Induced Spectral Equalization versus Ordinary Matter Effects in Supernova Neutrinos PRD (2018) 063013, ar. Xiv: 1807. 00840 [9] Capozzi, Dasgupta, Mirizzi, Sen & Sigl Collisional Triggering of Fast Flavor Conversions of Supernova Neutrinos ar. Xiv: 1808. 06618 [10] Airen, Capozzi, Chakraborty, Dasgupta, Raffelt & Stirner Normal-Mode Analysis for Collective Neutrino Oscillations JCAP 1812 (2018) 019, ar. Xiv: 1809. 09137

M 05 Flavor Issues Strange hadrons (hyperons) important for nuclear Eo. S? (M 07 Fabbietti group) Early universe, stellar collapse & NS mergers naturally involve all flavor neutrinos Everyday physics and astrophysics only first family of fermions Muons (mass 105. 7 Me. V) easily produced in SN core Should be included in simulations Flavor conversion among neutrinos not yet included in SN simulations

M 05 Why worry about detailed neutrino transport? • Explosion mechanism: Shock-wave revival by nu energy deposition • Nucleosynthesis in neutrino irradiated outflows in SNe and NS-mergers depends on flavor (beta reactions!) • Signal interpretation of DSNB and next nearby SN NS-NS binary merger • Collective flavor conversion: interesting theoretical problem by itself

M 05 Kinetic Equation for Neutrino Transport Flavor-dependent phase-space densities (occupation number matrices) Diagonal: Usual occupation numbers Off-diag: Flavor coherence information Transport equation Streaming Gravitational forces (redshift, deflection) Collisions β

M 05 Muonisation of Supernova Core Proto neutron star (PNS) profile 350 ms postbounce Electron chemical potential Temperature

Muons in Supernovae Average entropy/nucleon (2 D model) Standard With muons Muons • Facilitate neutrino-driven explosion • Affect compactness of hot NSs • Change neutrino emission • May affect ν oscillations / nucleosynthesis • Affect grav. instability of hot NS BH • Should be included in SN and NS-NS/BH merger simulations • Require six-species neutrino transport with coupling of different flavors

Breaking Spherical Symmetry (3 D Effects) Melson, Janka, Bollig, Hanke, Marek & Müller, ar. Xiv: 1504. 07631 Supernova at Hyper-Kamiokande, Tokyo, 11– 12 Feb 2017 Georg Raffelt, MPI Physik, München

M 05 Hydrodynamic Instabilities (3 D Simulations) Convection Images: Tobias Melson SASI Standing accretion shock instability

M 05 LESA – A New Instability Lepton Emission Self-Sustained Asymmetry Positive dipole direction and track on sky Tamborra, Hanke, Janka, Müller, Raffelt & Marek, ar. Xiv: 1402. 5418

Spectra in the Two Hemispheres M 05 Neutrino flux spectra (11. 2 MSUN model at 210 ms) in opposite LESA directions Direction of maximum lepton-number flux Direction of minimum lepton-number flux During accretion phase, flavor-dependent fluxes can vary strongly with observer direction!

M 05 LESA – Latest Developments After skeptical comments, confirmed by other groups Not an artifact of neutrino transport approximation Glas, Janka, Melson, Stockinger & Just, Effects of LESA in three-dimensional supernova simulations with multi-D and ray-by-ray-plus neutrino transport, ar. Xiv: 1809. 10146 Suppressed by fast rotation of progenitor Walk, Tamborra, Janka & Summa, Effects of SASI and LESA in the neutrino emission of rotating supernovae, ar. Xiv: 1901. 06235 LESA is a consequence of asymmetric proto-neutron star (PNS) convection But not yet a simple explanation (in 25 words or less) 1010 g /cm 3 1012 1014 Janka, Melson, Summa ar. Xiv: 1602. 05576 Radius [km] Ye

Supernova Neutrino Flavor Conversion

M 05 Flavor Conversion in Core-Collapse Supernovae • Adiabatic flavor conversion n o i g re MSW Flavor eigenstates are propagation eigenstates • Slow self-induced flavor conversion? (Spectral splits …) • Fast self-induced flavor conversion? (Flavor equilibration? ) Neutrino sphere Shock wave

M 05 Self-Induced Flavor Conversion

Kinetic Equation for Neutrino Transport – 2 M 05 Flavor-dependent phase-space densities (occupation number matrices) Diagonal: Usual occupation numbers Off-diag: Flavor coherence information Transport equation Streaming Gravitational forces Flavor oscillations Collisions Flavor evolution governed by “Hamiltonian matrix” (here for 2 flavors) Vacuum oscillations MSW effect Nu-nu interactions, nus feed back on each other

M 05 Kinetic Equation for Neutrino Transport – 3 Flavor-dependent phase-space densities (occupation number matrices) Transport equation Matter effect Airen, Capozzi, Chakraborty, Dasgupta, Raffelt & Stirner, Normal-mode analysis for collective neutrino oscillations, JCAP 1812 (2018) 019, ar. Xiv: 1809. 09137

A Dispersion Relation Approach Classification of instabilities of “flavor waves” (Two-beam model) Stable Classification of instabilities of plasma waves (Two-beam model) Particle-like Tachyon-like Landau & Lifshitz, Vol. 10, Physical Kinetics Chapter VI, Instability Theory

M 05 Criteria for Fast Flavor Instability Fulfilled? Spherically symmetric SN model • Forward-dip of electron-lepton number (ELN) flux never negative • 3 D models (LESA) “crossings” in some regions Tamborra, Hüdepohl, Raffelt, Janka, ar. Xiv: 1702. 00060 Accretion disk of NS mergers Wu & Tamborra, ar. Xiv: 1701. 06580

M 05 Jets & Outflows from Compact Binary Mergers Price & Rosswog, Science (2006) Ejecta are neutron rich r-process possible Torus emission geometry: favorable conditions for fast flavor conversion Wu, Tamborra, Just & Janka, PRD 96 (2017) 123015

M 05 Nucleosynthesis in NS-NS Merger Symmetric (1. 35+1. 35 Msun) NS-NS merger Wu, Tamborra, Just & Janka, PRD 96 (2017) 123015 Favorable conditions for fast conversion at any point above the torus emission region Electron fraction of ejecta Nucleosynthesis output Shift to higher mass number

M 05 Many Open Questions Flavor evolution in dense neutrino flows still on the level of simplified toy models and parametric studies • Realistic normal-mode analysis without symmetry assumptions? • Realistic triggering of stable or unstable flavor waves? (must depend on nu mixing) • Do tachyonic modes really lead to flavor equilibration? (Going beyond linearised stability analysis) • Realistic impact on SN explosion and nucleosynthesis? More work for next SFB funding period

M 05 Who ordered that? * *Dictum (Isidor Rabi) on discovery of the muon (1936) https: //abstrusegoose. com/18 Flavor gives us something to think about, in heaven and on Earth!

Backup

M 05 Stellar Collapse and Supernova Stages Adapted from A. Burrows (1990)

M 05 Three Phases of Neutrino Emission Explosion triggered • Shock breakout • De-leptonization of outer core layers Cooling on neutrino diffusion time scale Spherically symmetric Garching model (25 M⊙) with Boltzmann neutrino transport

M 05 SASI Detection Perspectives Recent models with rotation optimistic direction (along SASI dipole) pessimistic direction with shot noise Tamborra, Hanke, Müller, Janka & Raffelt ar. Xiv: 1307. 7936 Walk, Tamborra, Janka & Summa Identifying rotation in SASI-dominated corecollapse supernovae with a neutrino gyroscope PRD 98 (2018) 123001, ar. Xiv: 1807. 02366