IPN Orsay

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IPN Orsay
Université Paris Sud 11 CEA, DAM, DIF
Università degli Studi di Milano Dipartimento
di Fisica INFN, Sezione di Milano
Impact of electro-weak processes during
core-collapse phase of type II Supernovae
Anthea F. FANTINA Patrick BLOTTIAU
(IPNO Univ.Milano)
(Cea,Dam,Dif)
Dr. E. Khan, Dr. J. Margueron (IPN Orsay) Dr.
Ph. Mellor (CEA, DAM, DIF) Dr. J. Novak, Dr.
Micaela Oertel (Luth, Meudon)
Prof. P. Pizzochero Dr. P. Donati (Univ. Milano
INFN)
CoCoNut meeting 2009, Valencia 04th - 06th
November
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We investigate
electro-weak processes in core collapse
supernova

• Nuclear inputs
• electron capture rates
• nucleon effective masses and Esym(T) via m(T)
• EoS

• Hydrodynamics
• ? one-zone code ( Fantina A.F. et al.,
  Phys. Lett. B676, 140 (2009) )
• ? 1D Newtonian code ( Blottiau P., PhD
  thesis (1989) )
• ? 1D Relativistic code ( Romero J. et
  al., Astroph. J. 462, 839 (1996) )

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in particular m(T) and Esym(T)
influence of T-dependence of nuclear symmetry
energy during core-collapse phase

• Donati P. et al, Phys. Rev. Lett. 72, 2835
  (1994)
• study of m(T) 98Mo, 64Zn, 64Ni in the
  range 0 lt T lt 2 MeV (QRPA)
• decrease of m(T) in the range 0 lt T lt 2 MeV
• increase of Esym ( 8)
• effects on gravitational collapse not negligible

• Dean D.J. et al, Phys. Rev. C66, 31801 (2002)
• study of Esym(T) A 56-66 in the range
  0.33 lt T lt 1.23 MeV (SMMC)
• increase of Esym ( 6) consistent with Donati
  et al.
• not significant changes for the collapse
  trajectory

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Effective mass Symmetry energy Ylept,tr
Donati P. et al., Phys.Rev.Lett. 74 (1994)
Esymm(T)
analogy with Fermi gas model
reduction of mw with T ? increase of Esymm
Q-value of electron capture rates!
increase of
less neutronization ? larger values of Ylept at
trapping
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Ylept,tr Shock wave energy
Shock wave loses energy while crossing matter.
dissociation energy
Brown G. et al, Nucl. Phys. A375, 481 (1982)
larger values of Ylept at trapping ? less
deleptonization
? less energy dissipated
Stronger shock wave explosion
m(T) Esym Yl,tr Shock wave
energy
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Physical model 1D Newtonian

• 1D code Newtonian ( Blottiau P., PhD thesis
  (1989) Ph. Mellor )
• - sphere divided in 40 zone for core, total
  100 zone
• - Lagrangian treatment, implicit scheme
• Matter made up by
• - nuclei (A, Z), neutrons and free protons
  (classical e non relativistic)
• - electrons and neutrinos (degenerate and ultra
  relativistic)
• ? EoS BBAL ( Bethe H.A. et al., Nucl. Phys.
  A324, 487 (1979) )
• Fuller ( Fuller G.M.,
  Astrophys. J. 252, 741 (1982) )
• increasing of ? to simulate
  stiffness of EoS
• Hydro equation coupled to equation for electron
  fraction evolution
• and capture
• Neutrino transport multigroup, flux limited
  scheme,
• inclusion of different Np Nh
• ( Bruenn S., Astrophys. J. Suppl. 58, 771
  (1985) )
• Trapping comes out automatically

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Preliminary results of collapse simulation at
trapping density (1D Newtonian code)
Bruenn S.W., Astrophys. J. Suppl. 58, 771 (1985)
Langanke K. et al., Phys. Rev. C66, 45802 (2001)
Impact of e- capture
Impact of m(T)
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Preliminary results of collapse simulation at
bounce (1D Newtonian code)
Bruenn S.W., Astrophys. J. Suppl. 58, 771 (1985)
Impact of e- capture
Langanke K. et al., Phys. Rev. C66, 45802 (2001)
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Conclusions

• Influence of T-dependence of Esym on the
  evolution of collapse
• ? systematic reduction of neutronization of the
  core
• (increasing of final lepton fraction)
  less energy dissipated by shock wave
• - one zone model -
• ? position of shock wave formation bigger
  homologous core
• - 1D Newtonian code -

• Gain in shock wave dissociation energy if we
  consider m(T)
• dT Ediss 0.4 foe (estimation with one-zone
  code,
• within
  reasonable physical ranges of parameters)
• and K 1 1.5 foe (Bethe H.A.
  Pizzochero P., Astrophys. J. 350, L33 (1990))
• ? even if no dramatic effect on dynamics of
  the collapse is expected
• (see fluid instabilities, SASI, magnetic
  field, )
• effects are not negligible!

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Outlook

• Nuclear point of view Microscopic
  calculation of nuclear inputs
• - Electron capture rates on nuclei
• ? ?2
• - Calculation of m(T) Esym(T)
• ? systematic calculations on more nuclei
• ? level density parameter (experiments?!)
• ? dependence on ?, A, Z, T
• - EoS
• ? Lattimer Swesty, Nucl. Phys. A535, 331
  (1991), with

IPN Orsay (E.Khan) N. Paar et al., submitted to
Phys.Rev. C (2009)
Milan IPN Orsay (P.Donati J.Margueron)

• Astrophysical point of view Hydrodynamics
• - multizone / multi-D code ? test in 1D
• - Newtonian Relativistic
• - more accurate treatment of neutrinos
• and shock formation

CEA Bruyères (P.Blottiau Ph. Mellor) LUTH
Meudon (J. Novak M.Oertel)
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Thank you
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Physical model one-zone

• One-zone code
• ? collapse of sphere with uniform density ?
• Matter made up by
• - nuclei (A, Z), neutrons and free protons (C,
  NR)
• - electrons and neutrinos (Q, UR)
• ? EoS BBP (Bethe et al., Nucl. Phys. A175,
  225 (1971) )
• BBAL (Bethe et al., Nucl.
  Phys. A324, 487 (1979) )
• Thermal dissociation in ?? particle included
  (Saha eq.)
• Entropy translational (nuclei, protons and
  free neutrons),
• excited states of nuclei, electrons and
  neutrinos (post trapping)
• Electron capture on freebound protons as
  2-level transition at finite T
• ( backward reaction after trapping ),
  inclusion of ?2
• Trapping as a discontinuity ? Yn 0 if r lt
  rtr
• ( after neutrino trapping ? Ylept const! )

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Numerical results of collapse simulation (one-zone
code)
g2 1
Langanke K. et al., Phys. Rev. Lett. 90, 241102
(2003)
g2 0.1
Fuller G.M., Astroph. J. 252, 741 (1982)
Fantina A.F. et al, Phys. Lett. B676, 140 (2009)
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Numerical results of collapse simulation (one-zone
code)
Standard parameters
Fantina A.F. et al, Phys. Lett. B676, 140 (2009)