neutrino reactions on two-nucleon system and core-collapse supernova
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Neutrino reactions on two-nucleon system and core-
collapse supernova
Shota Nasu(Osaka.U)
Collaborators:
T. Sato (Osaka.U),K. Sumiyoshi(Numazu Coll.Tech.),S. Nakamura (JLab),F. Myhrer (USC),K.Kubodera (USC)
Introduction: neutrino reactions in core-collapse supernovae
Electron captures Elastic scattering Pair creation and annihilation Nucleon Bremsstrahlung
S. Bruenn (1985)
Absorption, production and scattering reactions
K. Sumiyoshi and G. Röpke, (2008)
Existence of light elements (d,t,3He) A. Arcones et al. (2008)
: E. O’Connor et al., (2007), A. Arcones et al., (2008)
: S. X. Nakamura et al.(2009)
Neutrino absorption reaction in light elements ( for heating )
Neutrino absorption: heating mechanism (shock wave revival -> delayed explosion)
production: cooling mechanism (proto-neutron star to neutron star, source of neutrinos)
In this work: neutrino production reaction in two-nucleon system (for cooling)
Motivation: Neutrino production in two nucleon collision
Modified URCA processes :
Neutrino bremsstrahlung :
Friman and Maxwell (1979) One-pion-exchangeHanhalt et al.(2001) Low Energy Theorem
Objective : Analysis of neutrino production reactions on two-nucleon system for SN simulations
deuteron in final state : EFT: deuteron as dibaryon Ando, Kubodera (2006)
Those works can be used only low energy region.
Today’s talk : process
Crucial for cooling mechanism
Formalism
Weak Hamiltonian:
Nuclear currents:
Standard Nuclear Physics Approach (SNPA)
model of nuclear current used to analyze nu-d for SNO data
exchange currents + excited exchange currents
Neutrino emissivity
: Fermi-Dirac distribution function
S.W.Bruenn(1985)T.A.Thompson et al.(2000) etc.
: emitted neutrino energy
Charged current process
: n-n kinetic energy
non-degenerate limit
→ keep only dominant 1S0(nn) -> 3S1(d) Gamov-Teller transition
Energy dependence of
: Neutron density
Strong E-dependence of |M| large 1S0 scattering length
emissivity
for nucleon
for lepton
Examine the simple case
The facter enhances the high energy contribution
Even at low temperature..
T.A.Thompson et al. (2000) etc.
Full result of emissivity
IA+EXC nuclear currents,Including higher partial waves
OPE model, approx. E-independent |M|
Summary
Analysis of neutrino emissivity
near future plan
・ examine validity of using low energy approximation
・ complete table of whole reactions rates including electron capture
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