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NSMAT2016
Proton elastic scattering and nucleon density distributions
-Recent status of the ESPRI project-
B01 group
Juzo Zenihiro, RIKEN Nishina Center
Neutron skin and EOS
Radius
Density
Proton: rp(r)
Neutron: rn(r)
Neutron Skin
Finite nucleus
Density: r
Asymmetry: d
0
balance
Nuclear matter EOS
)()()0,(),( 42 ddrrdr O SEE
Symmetry energy
Drawn by T. Isobe
)(2
)()( 32sym
sat rr OK
L SS
Neutron Skin
thickness
2016/11/22 2
N-s
kin
(fm
)Neutron skin as a probe of S(r)
Determine the slope coefficient L
of S(r) neutron matter EOS
Taken from L.-W. Chen et al., PRC72, 064309.
sat
sat
3
ρ
ρρε
)(2
)()( 32sym
sat rr OK
L SS
Baryon density (fm-3)
Ene
rgy
(Me
V)
NM : d = 1
SM : d = 0
S(r) : the slope L)()()0,(),( 42 ddrrdr O SEE
Impact on neutron star structure
• Radius, cooling system, etc.
Strong correlation!
2016/11/22 3
Variou Skyrme interactions
How to determine rp(r) & rn(r) & Drnp
+Ze
N+Z
e- e-
p p
Electron scattering
Proton scattering
@ 300 MeV
g
meson
)()()(
)()(
rqFqF
rqF
pp
p
ch
A
ch
A
ch
r
r
)()()( rrqF npnp rr
)(),( rr np rr
; Nuclear charge
; Nuclear matter
MottddA
chdd qF
2
)(
42016/11/22
RIA + an effective NN interaction at around 300 MeV
pnnp rrr D
: well established in 1980s
: our work
2016/11/22
Precise extraction of rn(r) from proton elastic scattering at 300 MeV
Established for stable nuclei experiments at RCNP
Pb cased/d, Ay @ 300MeV rn(r) : model independent SOG
RIA
+
Medium
Effect
5J.Zenihiro et al., Phys. Rev. C 82, 044611
2016/11/22 6
N+Z
p p
Proton scattering
@ 200 MeV
Proton scattering
@ 300 MeV
meson
)(),( rr np rr pnnp rrr D
Mainly for unstable nuclei
N+Z
p p
meson )()()()( 200200 rrqFtqFt npnpnppp rr
)()()()( 300300 rrqFtqFt npnpnppp rr
New method to extract rp(r) & rn(r)
+ Coulomb (rch)
+ Coulomb (rch)
Why two energies? 200 & 300 MeV/u
2016/11/22 7
p-A @300 ESPRI rn(r) + rp(r)
e-A SCRIT rch(r) rn(r), rp(r)
Idea: energy dependences of pp & pn interaction
p-A @300 ESPRI arn(r) + brp(r)
p-A @200 ESPRI crn(r) + drp(r)
101
102
103
10 100 1000
pppnnp
Elab. [MeV]
Cro
ss s
ecti
on
[m
b]
200 300 400
Demonstration of the new method with Zr data
Simultaneous extraction from two-energy p-elastic data of 90,92,94Zr
2016/11/22 8
Fitting results of 90Zr @ 200 & 300 MeV
Simultaneous search of Neutron & Proton
From 300 & 200 MeV data
Extracted densities of 90Zr
Unstable nuclei -ESPRI project-
Elastic Scattering of Protons from RI beams
Application to nuclei with large isospin asymmetry
ESPRI project
【nuclear chart】
: doubly magic nuclei process from 208Pb
208Pb@RCNP
132Sn@RIBF: This Spring
2016/11/22 10
66,70Ni@GSI
9,10,11,16C@HIMAC, RIBF
Elastic Scattering of Protons from RI beamsExtension of proton elastic scattering method to unstable nuclei
48Ca@RCNP
ESPRI devices
2016/11/22 11
Drift Chamber
Plastic scintillator
Solid hydrogen
target
1 mmt
φ30 mm
Recoil Proton Spectrometer (RPS)
ESPRI devices
2016/11/22 12
θlab = 66° - 80°, Ep=20-120 MeV, ΔΩ〜10 msr/deg.
q=1-2.2 fm-1, ΔEx = 400-500 keV
Recoil drift chamber 436x436 mm2 (x-y-x’-y’-x’-y)
Plastic scintillator 440x440 mm2 x 2 mmt
NaI(Tl) calorimeter 431.8x45.72 mm2 x 50.8 mmt
Recoil Proton Spectrometer (RPS)
Light unstable nuclei : 9,10,11,12,16C
2016/11/22 13
Rec
oil
pro
ton e
ner
gy (
MeV
)
11C10C9C
12C
Preliminary
16CPreliminary
(T. Baba)
# of analyzed beams
9C 0.5x109
10C 3x109
11C 5x109
12C 6x109
16C 7x109
Preliminary
Preliminary
w/ Z=6 gated
w/ Z=6 gated
Kinematical correlation : Tp vs qp
ESPRI
CAT
April – May 2016: RIBF113(CAT)@F8 & RIBF79(ESPRI)@F12was performed in a parasitic way.
ESPRI experiment of 132Sn @ RIBF
2016/11/22 14
RI beam production Experimental
Accelerators
238U@345MeV/u~20pnA
RIBF79R1 (ESPRI) / RIBF113 (CAT)Experiment in the parasitic mode
F7 F8 F12
CAT (ISGMR)100 MeV/u 132Sn(d,d’)
ESPRI (Skin thickness)200 MeV/u 132Sn(p,p)
EXP (Beam time) CAT setup @F8 ESPRI setup @F12
RIBF113(CAT) in April 132Sn@ 100 MeV/u
(d, d’) GMR (d, d) elastic
RIBF79R1 (ESPRI) in May 132Sn@ 200 MeV/u
(p, p’) GMR (p, p) elastic
2016/11/22 15
Proton elastic scattering of 132Sn successfully measured at RIBF
132Sn (p, p) at 200 MeV/u was measured in May 2016: NP1512-RIBF79R1
[deg]
Pro
ton
en
ergy
by
NaI
[ch
]P
roto
n t
of
[ch
]
908580757065
Online plot
Clear elastic event
Recoil proton angle
1mmt solid hydrogen target
ESPRI detector setup
2016/11/22 16
Elastic Scattering of Protons with RI beams (ESPRI) project
RCNP
I.Tanihata
H.Jin Ong
J. Tanaka
GSI
S272 collaborators
NIRS-HIMAC
E.Takada
M.Kanazawa
RIKEN
T. Uesaka
H.Takeda
K.Ozeki
K.Yoneda
Tohoku Univ.
T.Kobayashi
Kyoto Univ.
T.Kawabata
T.Murakami
M.Tsumura
T.Furuno
Miyazaki Univ.
Y.Maeda
CNS, Univ. of Tokyo
S. Ota
Collaborators
J. Zenihiro (RIKEN)
S.Terashima (Beihang Univ.)
Y.Matsuda (Tohoku Univ. CYRIC)
H.Otsu (RIKEN)
H.Sakaguchi (RCNP)
2016/11/22 17
Summary
• Constraints on the symmetry energy parameters by neutron skin thicknesses• Proton elastic scattering method : rn(r)• 204,206,208Pb
• Recent progress
• Stable nuclei • double magic nuclei : 40,42,44,48Ca• Simultaneous extraction of rp(r) & rn(r) from 200 & 300 MeV data :
90,92,94Zr
• Unstable nuclei• ESPRI project : 9,10,11,16C, 20O, 66,70Ni• Double magic nucleus : 132Sn RIBF79R1 132Sn(p,p) @ 200MeV/u
• Future : • ESPRI experiment of 132Sn @ 300 MeV/u • Next target of ESPRI : 50,52Ca (magic ?)
2016/11/22 18