Transcript Slajd 1
Modification of scalar field inside dense nuclear matter
D I S
Hit quark has momentum j + = x p + Experimentaly
x = Q 2 /2M
n and is iterpreted as fraction of longitudinal nucleon momentum carried by parton(quark) for n
d
s
~
2 >
l
Q mn 2 -> oo (B W mn
W
jorken lim) mn ( W 1 , W 2
)
Bjorken Scaling e p
Q 2 , n
j r emnant
On light cone Bjorken x is defined as x = j + /p + where p + =p 0 + p z In Nuclear Matter due to final state NN interaction, nucleon mass M(x) depends on x , and consequently from energy e and density r .
F 2 (x)=
lim[( n/M) W 2 (q 2 , n)] Bjo
Rescaling inside nucleus
F 2 A (x)= F 2 [xM/M(x)] + F 2
p
(x)
for large x (no NN int.) the nucleon mass has limit
M B
M N
e -
e Fermi
Due to renomalization of the nucleon mass in medium we have enhancement of the pion cloud from
momentum sum rule
Relativistic Mean Field Problems
connected with Helmholz-van Hove theorem - e(p F )=M e In standard RMF electrons will be scattered on nucleons in average scalar and vector potential: Gives the nuclear distribution f(y) of longitudinal nucleon momenta p + =y A M A [a
p
+ b( M+U S ) - ( e -U V )]y=0 where U S =-g S /m S r S U V =-g V /m V r r
A
(
y A
)
=
4
r
d
4 ( 2
p
p
) 4
S N
(
p
0 , p )
1
p
3
E
(
p
)
y
-
(
p
0
m
p
3 )
U S = -400MeV r/ r 0 S N () - spectral fun. m - nucleon chemical pot.
U V = 300MeV r/r 0 r
A
(
y A
)
=
3
v A
2 4
-
(
y A v
3
A
-
1 ) 2 ,
v A
=
p F
/
E F
*
Strong vector-scalar cancelation
Relativistic MF
Nuclear Final State Interaction in the Deep
N
Inelastic Scatt.
r C - nucleon radius
•
if z(x) > r N M(x) = M N
z(x)
1/Mx = z distance how far can propagate the quark in the medium. (Final state quark interaction -
not known
) if z(x) < r C M(x) = M B
M B
M N
e -
e Fermi
Effective nucleon Mass M(x)=M( z(x) , r C ,r N ) renomalization of the nucleon mass in medium with the enhancement of the pion cloud
Kazimierz 2009
M(x) & in RMF the nuclear pions almost disappear
Because of Momentum Sum Rule in DIS Nuclear sea is slightly enhanced in nuclear medium - pions have bigger mass according to chiral restoration scenario
BUT also change sea quark contribution to nucleon SF
rather then additional (nuclear) pions appears The pions play role rather on large distances?
SF - Evolution in Density
R(x) = F 2 NM (x)/ F 2 N (x) “no” free parameters
Correction to Equation Of State for Nuclear Matter - ap. in Astrophysics
Soft EOS
(
density - 4
r ) Non Linear RMF Models
Pions take 5% of longitudinal momenta Good compressibility Chiral instability (phase transition) correction to effective NN
s
interaction for high density?
Fe eq. density r=0.12
fm -3
with G. Wilk Phys.Rev.
C71
(2005)
Stiff EOS
(
density
-
4
r) Walecka RMF Model
No enhancement of pion cloud Bad compressibilty K>300MeV
J Rozynek Int. Journal of Mod. Phys. In print
Results
“no” free paramerers
Fermi Smearing Constant effective nucleon mass x dependent effective nucleon mass with G. Wilk Phys.Rev.
C71
(2005)
Nuclear deep inelastic limit revisited
x dependent nucleon „rest” mass in NM F 2
N
(
x
)
=
f
(
x
)
F
2 2
N
(
x
)
( 1
-
f
(
x
))
F
2
N
f(x) - probability that struck quark originated from correlated nucleon
M x
=
M N
1
-
f
2 (
x
)
V N
> •
Momentum Sum Rule violation 1
A
F
2
A
(
x A
)
dx A F
2
N
(
x
)
dx
=
1
C[f
]
V N M
>
( 1
e
)
But in the medium we have correction to the Hugenholtz-van Hove theorem:
On the other hand we have nuclear energy the energy of quarks (plus gluons) as the integral over the structure function F 2 (x) and is given by E F. Therefore in this model we have to scale Bjorken x= q/2M
n
the ratio of old and new nucleon mass. 1
A
F
2
F
2
A N
( (
x A x
)
dx A
)
dx
=
1
C[f
V N M
>
( 1
e
)
Now the new nucleon nass will dependent on the nucleon energy in pressure but will remain constant below saturation point.
M m =M/ ( 1+(dE/d r)(r/E) ) and we have new equation for the relativistic (Walecka type) effective mass which now include the pressure correction
.
The density dependent energy carried by meson field Nuclear energy per nucleon for Walecka abd nonlinear models
Results Density correction started from ρ=.16fm
-3 Flow Constrain P.Danielewicz
Science(2002)
Density correction started from ρ=.19fm
-3 Dash curve include the reduction of the field in medium.
Maxwell construction
Spinodal phase transition
EOS in NJL
EMC effect
• pion mass in the medium in chiral symmetry restoration • Nucleon mass in the medium ?
Bernard,Meissner,Zahed PRC (1987)
Condensates and quark masses
The pressure at critcal temperature
CEP and Statistics
Physically
CONCLUSIONS Presented model correspond to the scenario where the part of nuclear momentum carried by meson field and coming from the strongly correlation region, reduce the nucleon mass by corrections proportional to the pressure. In the same time in the low density limit the spin-orbit splitting of single particle levels remains in agreement with experiments, like in the classical Walecka Relativistic Mean Field Approach, but the equation of state for nuclear matter is softer from the classical scalar vector Walecka model and now the compressibility K -1 =9(r 2 d 2 /dr 2 )E/A = 230MeV, closed to experimental estimate. Pressure dependent meson contributions when added to EOS and to the nuclear structure function improve the EOS and give well satisfied Momentum Sum Rule for the parton constituents. New EOS is enough soft to be is in agreement with estimates from compact stars [3] for higher densities. Finally we conclude that we found the corrections to Relativistic Mean Field Approach from parton structure measured in DIS, which improve the mean field description of nuclear matter from saturation density
r 0
to 3
r 0
.