Pauli-Blocking effects -...
Transcript of Pauli-Blocking effects -...
Realization of Λ-Superfluidity in Neutron Stars by ΛΛ interaction taking account of
Pauli-Blocking effects
T. Takatsuka ( RIKEN ; Iwate Univ.)
S. Nishizaki (Fac. Sci & Eng. Iwate Univ.)
Y. Akaishi (RIKEN)
NSMAT2016 (Nov.22, Sendai, Japan
1. Background and the aim here
2. Approach to Λ-superfluid problem
3. Results and concluding summary
Dramatic softening of EOS Necessity of “Extra Repulsion”
As a review T.Takatsuka, Prog.Theor.Phys.Suppl.No.156 (2004) 84.
5 10
Universal
3body
force Y-mixing
EOS
TNI3
(NO Y)
1500
1000
500
P
TNI3u
(Y)
0 5 10 15
Mass
TNI3(NO Y)
TNI3u(Y)
TNI3(Y)
2
1.5
1
In the earlier works, U was introduced quite phenomenologically.,
but ,in 2008, U(SJM) from the Strihg-Junction Model for quark structure
of baryons was constructed by R.Tamagaki,
[1], which is spin- and flavor-Independent
and hence gives the universality to the
3-baryon force .
Actually it has been shown that
the SJM 3-body force generates
a EOS stiff enough to sustain
the 2-solar-mass NSs, even under
the Y-mixing [2].
2–solar- mass NSs with Y core
are possible !
(it was before the observations) ------------------------------------------------------- [1] R.Tamagaki, Prog.Theor.Phys.119 (2008) 963.
[2] T.Takatsuka ,S.Nishizaki and R.Tamagaki, AIP.Cof.Proc. 1011(2008) 209.
Thermal Evolution of NSs
Log Time (years)
Tsuruta et al
Ap. J. 691
(2009) 621
(𝑀 > 0.8𝑀𝑠𝑢𝑛)
NO Λ-super due to “NAGARA”
A-dependence ?
1. Background and the aim here 1)Y-mixing causes 2 serious problems ① Too softened EOS ! eg. 𝑀𝑚𝑎𝑥={1,88(NO Y)→ 1.1(with Y)}𝑀𝑠𝑢𝑛→ clearly contradicts 2𝑀𝑠𝑢𝑛 -NS obs. → suggests the necessity of some extra repulsion . “Universal 3-body force U(BBB) has been found to be a solution [1] ② Too-rapid cooling! Some NSs need more efficient ν-emission than standard Murca process (n+N →p+N+𝑒−+ν, and the inverse) → YDurca (Λ→p+𝑒_ and the inverse, and so on) called “Y-cooling” is a candidate because ∈𝑌𝐷𝑢𝑟𝑐𝑎 ~105−6 ∈𝑀𝑢𝑟𝑐𝑎 . But when directly applied , it leads to “too-rapid cooling” → then the existence of Λ-superfluidity is a possible solution. 2) Λ-super is OK or not ? [2] Realization of Λ-super is okay for old ΛΛ int, but is hard when less attractive ΛΛ
int. suggested by the “NAGARA events 𝐻𝑒ΛΛ6 “ [3]→ Inclusion of Pauli-blocking
effects in ΛΛーΞN coupling channel to enhance the ΛΛ int. might be a solution. --------------------- [1]S.Nishizaki , Y.Yamamoto and T.Takatsuka, PTP. 105(2001)607;108(2002)703. [2]T.Takatsuka,PTP. Suppl.No.156(2004)84. [3T.Takahashi et al., ]
The aim here is to investigate the possibility of Λ-superfluid by taking account of the attractive effect on ΛΛ int. from the Pauli – blocking in ΛΛーΞN , by using single-particle properties under the EOS compatible with 2-𝑀𝑠𝑢𝑛 NSs recently observed
2. Approach to superfluid problem (1) EOS with Y-mixing consistent to massive NSs
○Effective interaction approach 𝑉 = 𝑣 (BB) + 𝑈 (BBB) ○ 𝑣 (BB) is based on the G-matrix calculations (RSC for NN, Nijmegen D pot. For YN and YY) ○3-body force 𝑼 (BBB) = 𝑼 (SJM) + = 𝑼 (TNA) ; Universal 𝑼 (SJM) from String-Junction Model for quark structure of baryons, proposed by R.Tamagaki[3] and has been shown to generate 2𝑀𝑠𝑢𝑛 NSs.[4]. ○𝑈 (TNA) from the attractive part of a phenomenological TNI of FP[5] is introduced so as to reproduce the saturation property of symmetric nuclear matter. (2) Free space ΛΛ interaction VF3 from Akaishi et al [6]which takes account of the Pauli-blocking effects in medium, keeping the consistency with NAGARA data. (3) Solve the gap equation for ΛΛ pairing by using the Single-particle properties such as the effective mass 𝑚Λ* and Fermi momentum 𝑘𝐹Λ under the EOS (1)。 [3]R.Tamagaki, PTP. 119(2008) 865 {4}T.Takatsuka,S.Nishizaki and R.Tamagaki, AIP Conf.Proc. 1011 (2008) 209. [5]B. Friedmann and V. R. Pandharipande, Nucl. Phys. A361 (1981) 502. [6] K. S. Myint, S. Shinmura and Y. Akaishi, Eur. Phys. J. A16 (2003) 21
(a) 2B come in short distance
(b) Deformation (resistance)
(c) Fusion into 6-quark state
(by R. Tamagaki)
Repulsion from SJM-----flavor independent
Prog. Theor. Phys. 119
(2008) 965.
○ Energy barrier (~2GeV) corresponds to repulsive core
of BB interactions
BBB interactions Additionally 2GeV excitation Height of 3-body pot.
Λ 𝚺−
Fraction (%)
M-R relation
ΛΛ―ΞN coupling
Pauli-
blocking
Ξ N Ξ N
Λ Λ Λ Λ
In free space in medium
Λ Λ Λ Λ
is
1 2 3 r(fm)
50
0
100
-50
-100
(MeV)
13.4GeV core
4.4GeV
2.0GeV
With NAGARA
ND-Soft original
Pauli-Blocking
VF3 {3}K.S.Myint,S.Shinmura
And Y.Akaishi ,
Eur.Phys.J.A16(2003)21
ΛΛ Pot.
○ Here, we note the 3-elements (Fermi momentum
k , effective mass m* and pairing interaction) to
control the energy gap.
#) For 3P2 NN pairing, the situation is similar, although the gap
equation becomes complex due to the 3P2-3F2 tensor-coupling.
FB B
2.Results and concluding summary
Critical Temperature of Λ-Superfluid
ND-Soft original
Taking account
of Pauli Blocking
Effects (VF3)
(VF2)
SJM2+TNA EOS
4 5
Tin ~
6
(K)
2.03
( 𝜌𝑐 = 7.4 𝜌0 )
NAGARA
Concludig summary
Due to the Y-mixing in NS cores, we are faced to two
serious problems ; too-softened EOS and too-rapid
cooling . Both of which contradict observations.
These two problems have to be solved at the same time
.
In the case of pure hadronic framework . the universal
3-body force is a solution for the former problem.
For the problem of too-rapid Y-cooling, a central concern
is how to revive the Λ-superfluidity , consistently with
NAGARA event. .We find a possibility to have the Λ-
superfluid in NSs, by taking account of the Pauli-
Blocking effects in medium for ΛΛ-ΞN coupling.