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