15548726
Postbounce Evolution of Core-Collapse Supernovae: Long-Term Effects of the Equation of State
We study the evolution of a supernova core from the beginning of the gravitational collapse of a 15 M☉ star up to 1 s after core bounce. We present results of spherically symmetric simulations of core-collapse supernovae by solving general relativistic ν-radiation hydrodynamics in the implicit time differencing. We aim to explore the evolution of shock waves in the long term and investigate the formation of proto-neutron stars together with supernova neutrino signatures. These studies are done to examine the influence of the equation of state (EOS) on the postbounce evolution of shock waves in the late phase and the resulting thermal evolution of proto-neutron stars. We compare two sets of EOSs, namely, those by Lattimer and Swesty (LS-EOS) and by Shen et al. (SH-EOS). We found that, for both EOSs, the core does not explode and the shock wave stalls similarly in the first 100 ms after bounce. A revival of the shock wave does not occur even after a long period in either case. However, the recession of the shock wave appears different beyond 200 ms after bounce, having different thermal evolution of the central core. A more compact proto-neutron star is found for LS-EOS than SH-EOS with a difference in the central density by a factor of ~2 and a difference of ~10 MeV in the peak temperature. The resulting spectra of supernova neutrinos are different to an extent that may be detectable by terrestrial neutrino detectors.
118114185
Neutrino signal of supernova shock wave propagation:MSW distortion of the spectra and neucleosynthesis
S. Kawagoe ∗ab, H. Suzuki c, K. Sumiyoshi bd, H. Yamadae and T. Kajino ab f aDepartment of Astronomical Science, School of Physical Sciences, The Graduate University for Advanced Studies(SOKENDAI) 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan bNational Astronomical Observatory of Japan 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan cDepartment of Physics, Faculty of Science and Technology, Tokyo University of Science 2641 Yamazaki, Noda, Chiba 278-8510, Japan dNumazu College of Technology 3600 Ooka, Numazu, Shizuoka 410-8501, Japan eDepartment of Physics, Faculty of Science and Engineering, Waseda University 3-4-1 Okubo, Shinjuku, Tokyo 169-8555, Japan f Department of Astronomy, Graduate School of Science, University of Tokyo 7-3-1 Hongo, Bunkyo, Tokyo 113-0033, Japan E-mail: shiou@th.nao.ac.jp
122310560
NEUTRINOS PROM PROTONEUTRON STARS WITH VARIOUS EQUATION OF STATES
122249200
Constraining neutrino oscillation parameters with future observations of supernova neutrinos by various types of detectors
We evaluate the potential for constraining neutrino oscillation parameters with future observations of supernova neutrinos. For some selected oscillation parameters, we calculate the expected energy spectra and angular distributions of neutrino events in various detectors (Super-Kamiokande, ICARUS, KamLAND and IceCube) for an assumed galactic core-collapse supernova. We investigate to what extent the oscillation parameters could be constrained using χ2 analysis when the expected events are really observed.
118908804
Multigroup simulation of protoneutron star cooling and neutrino spectra
122604041
NEUTRINOS FROM PROTONEUTRON STARS
We performed numerical simulations of the quasistatic evolution of protoneutron star with neutrino transfer using multigroup flux limited diffusion scheme. The second half of the supernova neutrinos are emitted in this stage. We found 1) the flux decays rapidly and its mean energy falls below j/e's mean energy at the late stage, 2) Pe's carry out energy of about 24% of the total energy emitted in this cooling phase, and 3) the time-integrated energy spectra of u^s and v^s can be roughly fitted by the Fermi-Dirac spectra with positive chemical potentials while those of the other neutrinos can be fitted by MaxwellBoltzmann spectra. These results suggest that the total energy of the neutrino burst from SN1987A was overestimated if one assumed that the Pe's spectrum is the Fermi-Dirac one with a vanishing chemical potential and that all species of neutrinos contribute equally.
6061342
CP breaking in lattice chiral gauge theories
The CP symmetry is not manifestly implemented for the local and doubler-free Ginsparg-Wilson operator in lattice chiral gauge theory. We precisely identify where the effects of this CP breaking appear. We show that they appear in: (I) Overall constant phase of the fermion generating functional. (II) Overall constant coefficient of the fermion generating functional. (III) Fermion propagator appearing in external fermion lines and the propagator connected to Yukawa vertices. The first effect appears from the transformation of the path integral measure and it is absorbed into a suitable definition of the constant phase factor for each topological sector; in this sense there appears no ``CP anomaly''. The second constant arises from the explicit breaking in the action and it is absorbed by the suitable weights with which topological sectors are summed. The last one in the propagator is inherent to this formulation and cannot be avoided by a mere modification of the projection operator, for example, in the framework of the Ginsparg-Wilson operator. This breaking emerges as an (almost) contact term in the propagator when the Higgs field, which is treated perturbatively, has no vacuum expectation value. In the presence of the vacuum expectation value, however, a completely new situation arises and the breaking becomes intrinsically non-local, though this breaking may still be removed in a suitable continuum limit. This non-local CP breaking is expected to persist for a non-perturbative treatment of the Higgs coupling.
10800406
Remark on the consistent gauge anomaly in supersymmetric theories
Abstract We present a direct field theoretical calculation of the consistent gauge anomaly in the superfield formalism, on the basis of a definition of the effective action through the covariant gauge current. The scheme is conceptually and technically simple and the gauge covariance in intermediate steps reduces calculational labors considerably. The resultant superfield anomaly, being proportional to the anomaly d abc =tr T a { T b , T c }, is minimal without supplementing any counterterms. Our anomaly coincides with the anomaly obtained by Marinkovic as the solution of the Wess–Zumino consistency condition.
530595
Four-dimensional lattice chiral gauge theories with anomalous fermion content
In continuum field theory, it has been discussed that chiral gauge theories with Weyl fermions in anomalous gauge representations (anomalous gauge theories) can consistently be quantized, provided that some of gauge bosons are permitted to acquire mass. Such theories in four dimensions are inevitablly non-renormalizable and must be regarded as a low-energy effective theory with a finite ultraviolet (UV) cutoff. In this paper, we present a lattice framework which enables one to study such theories in a non-perturbative level. By introducing bare mass terms of gauge bosons that impose ``smoothness'' on the link field, we explicitly construct a consistent fermion integration measure in a lattice formulation based on the Ginsparg-Wilson (GW) relation. This framework may be used to determine in a non-perturbative level an upper bound on the UV cutoff in low-energy effective theories with anomalous fermion content. By further introducing the St?ckelberg or Wess-Zumino (WZ) scalar field, this framework provides also a lattice definition of a non-linear sigma model with the Wess-Zumino-Witten (WZW) term.
119833545
NEUTRINOS FROM SUPERNOVA EXPLOSION AND THE MIKHEYEV-SMIRNOV-WOLFENSTEIN EFFECT
It is shown that by taking the effect of the Earth into account the possible observation of electron neutrinos from the supernova SN1987A at the Kamiokande II is compatible with the solution of the solar neutrino puzzle by the Mikheyev-Smirnov-Wolfenstein mechanism. Our scenario requires relatively large mixing angles sin2 2θ ≳ 0.3 and, most probably, ∆m2 of the order of 10−6 ~ 10−5(eV)2. The implications of possible observation in other neutrino detectors are briefly discussed.
119113019
Thermodynamics of SU (3) gauge theory from gradient flow on the lattice
A novel method to study the bulk thermodynamics in lattice gauge theory is proposed on the basis of the Yang-Mills gradient flow with a fictitious time $t$. The energy density $ϵ$ and the pressure $P$ of $SU(3)$ gauge theory at fixed temperature are calculated directly on ${32}^{3}\ifmmode\times\else\texttimes\fi{}(6,8,10)$ lattices from the thermal average of the well-defined energy-momentum tensor ${T}_{\ensuremath{\mu}\ensuremath{\nu}}^{R}(x)$ obtained by the gradient flow. It is demonstrated that the continuum limit can be taken in a controlled manner from the $t$ dependence of the flowed data.