S. Franchoo, F. Azaiez, D. Beaumel, I. ŞtefanS. Grévy, O. SorlinZ. Dombrádi

Orsay, Ganil, Debrecen

Measuring the d5/2-d3/2 interaction: the tensor force underneath the island of inversion

d3/2 bound in F but unbound in N, O

d5/2> ↔ d3/2< attractionbefore island of inversion

d3/2< f7/2>

island of inversionWildenthal PRC22 (1980)

2260 Warburton PRC41 (1990)

1147

Sakurai et al, PLB 448(1999)180

d5/2

>

s1/2

.. d3/2

16

....20..20

.....

M. Belleguic et al, NPA 682 (2001)M. Stanoiu et al, PRC (accepted)

34Si20

. d 3/2

s1/2

f7/2

d5/2

d3/2

14

30Ne20

s1/2

s1/2

f7/2

..d5/2

d3/2

need spectroscopic factors to determine strength functions!

E(N=20)

#(d5/2) d5/2

d3/2

s1/2

f7/2

20

Otsuka et al, PRL 95 (2005) 232502, PRL 97 (2006) 162501

need spectroscopic factors to determine strength functions!

Tensor force VT = [s1x s2](2) Y(2)

S = 1

Otsuka et al, PRL 95 (2005) 232502, PRL 97 (2006) 162501

MCSM sdfp: N=20 vanishingfp intruders in sd shell

Y. Utsuno et al., PRC 70 (2004) 044307

USD sd: N=20 maintained T=0 2p2h deformed intruders

E. Caurier et al., NPA 693 (2001) 374

20

20

also in copper isotopes cf work done by Leuven: universal feature !?need "absolute" C2S to determine evolution of strength functions!

3760 7/2- 3624 7/2-

2050(2090) 3/2+

1.30.5

0 1/2+

3316 5/2+

3891

3067 5/2+

1940 5/2+

1698 5/2+

2028 5/2+

2426 3/2+

1273 3/2+985 3/2+

1703 5/2+

0 1/2+ 0 1/2+

25Ne from Reed et al, PRC 60 (1999) 024311; Catford et al, JPG 31 (2005) S1655; Terry et al, PLB 640 (2006) 86

27Mg1

5

29Si1525Ne15

2350

1.5

2.4

0.76

0.06

4.5

1.4

1.2 3479 1/2+0.58

2317 3/2+

3227 5/2+3224 3/2+

2500 3/2+

2615 1/2+

772(765) 3/2- 0

3/2+

0 3/2+

2789 5/2+3134 7/2-

55 1/2+

0 3/2+

29Mg1

7

31Si17

752 1/2+

1695 5/2+

27Ne17

29Mg from Baumann et al, PRC 36 (1987) 765

27Ne from Belleguic et al, PRC 72 (2005) 054316; Obertelli et al, PLB 633 (2006) 33; Terry et al, PLB 640 (2006) 86; Z. Dombradi et al, PRL 96, 182501 (2006)

1095

1638 5/2+

885(904) 1/2+

2.91

0.77

0.08

0.29

0.34

6.00

20%

60%; 0.32

30%; 1.07Sn=1400 keV

28Si 29Si 30Si 31Sistable stable

26Mg 27Mg 28Mg 29Mgstable 20.9 h 24Ne 26Ne3.38 m 197 ms

22O 24O2.25 s 61 ms

N=14 N=16d5/2

6 d5/26s1/2

2d3/20f7/2

0

Z=14 d5/26

Z=12 d5/24

Z=10 d5/22

Z=8 d5/20

(d,p)

d5/2 ↔ d3/2f7/2

(d,p)

28Si(d,p)29Si Betz et al, ZPA 309 (1982) 163

no SF extracted from spectra

Ed = 10 MeV

30Si(d,p)31Si at Harwell & Oxford Watson & Slater, JPG 9 (1983) 1417

d5/2 6.5%s1/2 61.5%d3/2 79.2%f7/2 75%

30Si(d,p)31Si at Harwell & Oxford Watson & Slater, JPG 9 (1983) 1417

s1/2 100%d3/2 88%f7/2 56%

26Mg(d,p)27Mg at Utrecht splitpole

Meurders & van der Steld, NPA 230 (1974) 317Ed = 12 MeV

30Mg(d,p)31Mg at 2.2 MeV/u 5 104 pps

H Scheit et al, NPA 746 (2004) 96c & EPJA 25 s01 (2005) 397Th Kröll et al, upcoming experiment

28Mg(d,p)29Mg at Rex-Isolde determine f7/2 strength at SC: 2 106 /µC x 5% = 2 105 /2µC (t1/2 = 20.9 h)

SPEG

Carbon~150 mg/cm2

36S primary beam77.5 MeV/nucleon, ~1 kW

Carbonproduction

target~500 mg/cm2

SISSIIonization chamber

& Plastic

Bmax = 2.88 Tm

EXOGAM+ NaI det

Thindegrader 23O ~ 60 pps

25F ~ 200 pps30Mg, 32Mg

Drift chambersThin Plastic

one-neutron knockout at Ganildata on 29,31Mg

M. Chartier & N. Orr, priv. comm.

Dwuck 4 + Ch89

R. Varner Phys Rep 201 (1991) 57 Wales & Johnson NPA 274 (1976) 168

Kinematics 28Mg(d,p)

for C2S, need ≳ 5 MeV/u

ℓ = 0

ℓ = 2

angular momentum matching | ki - kf | = R/ℓ

no "picket-fence" below 5 MeV/u indirect mechanisms, Ex & I but no C2S

low Sn ⇒ high

22O(d,p)23O

30Si(d,p)31Si at 5 MeV/u

Watson & Slater, JPG 9 (1983) 1417

Dwuck4 + Ch89

Wales & JohnsonNPA 274 (1976) 168R. VarnerPh Rep 201 (1991) 57

Speg

Vamos

TRACE ancillary detector

Orsay - Legnaro - Trento

24Ne(d,p)25Ne at 10 MeV/u Catford et al, JPG 31 (2005) S1655

ℓ = 0 gs

1.70 MeV ℓ = 2

2.05 MeV ℓ = 2

8 mm mrad, no beam tracking!

Padgett et al, PRC 72, 064330 (2005)

44,46Ar(d,p)45,47Ar at 10 MeV/uMust1 + Cats + Speg at Ganil

45Ar: 100% f7/2, 50% p1/2,3/247Ar: 100% p1/2,3/2, 60% f5/2

L Gaudefroy et al, PRL 97 (2006)

1180, 1790 keV

2710, 3280, 3800 keV

ℓ = 1 gsSF = 0.59(6)

1.5 MeVSF = 0.84(14), 0.17(7)

3.5 MeVSF = 0.21(4), 0.42(4)

-8%-45%

20 1829 29

d3/2

s1/2

Density dependence (J. Piekarewicz)s1/2 – p1/2p3/2

p1/2

p3/2

f5/2

f7/2

Tensor interaction (T. Otsuka)

d3/2 – f7/2f5/2

Gaudefroy et al, PRL 97, 092501 (2006)

(s1/2d3/2) removed

Tensor force f7/2 - d3/2 : reduction of N=28 by 330 keV Density dependence s1/2 : 45% reduced SO for p

Measuring the strength of the d5/2-d3/2 interaction: the tensor force underneath the island of inversion

would [s x s](2) tensor force provoke island of inversion?

42Si: second island of inversion, S. Grévy et al.36Ca: mirror island of inversion, A. Bürger et

al.

measure d3/2, f7/2 strengths in 29Mg through transfer

"safe" transfer when momentum matching "absolute" C2S from 5 MeV/u onI and Ex already below 5 MeV/uno beam tracking if emittance is good

enough?

26Mg(d,p)27Mg

Meurders & van der Steld, NPA 230 (1974) 317

30Si(d,p)31Si

Watson & Slater, JPG 9 (1983) 1417

Z. Dombradi et al, PRL 96 (2006) 182501 1n knockout from 28Ne at Riken

Ex(p3/2) (!) low ie N=20 vanishing

28Ne(p,p') shows need to fix effective charges

J. Terry et al, PLB 640 (2006) 86 1n knockout from 26,28Ne at MSU

26Ne(d,p)27Ne at 9.7 MeV/u Obertelli et al, PLB 633 (2006) 33

Ex C2S 0 0.2(2) 765 0.6(2) 885 0.3(1)

24,26Ne(d,p)25,27Ne at Rex-Isolde: Good beam quality for post-accelerated beam Same intensity Rex - Spiral

24Ne: 1 106 /µC x 5% = 1 105 /2µC Ganil: 2 105 /s

26Ne: 4 104 /µC x 5% = 4 103 /2µC Ganil: 3 103 /s

U Bergmann et al, NIMB 204 (2003) 22

36S fragmentation Belleguic et al, PRC 72 (2005) 054316