relativistic study of medium polarization effects on superfluidity in neutron matter
DESCRIPTION
Relativistic study of medium polarization effects on superfluidity in neutron matter. nuclear. Masayuki Matsuzaki. (Fukuoka University of Education). Medium polarization effect on superfluidity. Neutron matter. reduce pairing gap significantly. reduction is weak. Symmetric matter. - PowerPoint PPT PresentationTRANSCRIPT
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
1
Relativistic study of medium polarization effects on superfluidity in neutron matter
nuclear
Masayuki Matsuzaki(Fukuoka University of Education)
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
2
Medium polarization effect on superfluidity
Neutron matter
reduce pairing gap significantly
reduction is weak
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
3
Symmetric matter
enhance pairing gap
Finite nuclei
enhance pairing gap
… preliminary
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
4
Relativistic approach (σ-ω model)
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
5
Thermodynamics at T=0
instability !
Liquid-gas
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
6
Quantum mechanics
calculate meson propagator (q =0)0
7
Nucleon propagator
xxxxxx
xxx
k0
: pha decomposition--- M.Nakano et al.,PRC56, 3287 (1997)
: FD decompositon --- standard
hpmed GG
DFmed GG
paF GofpartaGG phD GofpartothertheGG ( , )
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
8
(Longitudinal) dielectric function
FD pha
instability ! instability !
9
Pairing interaction at 1-loop level
ill-defined at instability !
10
(Cross section of dielectric function)
infra-red cutoffis necessary
free from instability
0.65 is chosen
11(corrected using a form factor at tree (OBE) level)
(instability)
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
12
Form factor
at every vertex to modulate high mom. interaction
present
so as to reproduce the result of Bonn-B potential
M.M. and T.Tanigawa, NPA683, 406 (2001)
13σ,longitudinal-ω:attraction, σ-ωmix: repulsion
FD
pha
repulsion
attraction
OBERPA VV
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
14
Neutron matter
instability
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
15
Summary
Liquid-gas instability occurs at medium density
Medium polarization enhances gap at low and medium density
At high density, FD enhances gap whereas pha reduces gap
Characteristic cancellation among σ,ω, and σ-ωmix
Result for neutron matter is similar
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
16
Acknowledgement
Prof. P. Ring ( Munich) for suggesting the problem
Prof. H.Kouno ( Saga) for useful discussions
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
17
FD
pha
attraction
M. Matsuzaki, RIKEN "Mean-field theories and beyond", Mar. 21, 2006
18
M.M. and P.Ring, nucl-th/9712060
(Preliminary cal.)
OBE
pha FD