Measuring the pd5/2-nd3/2 interaction: the tensor force underneath the island of inversion S. Franchoo, F. Azaiez, D. Beaumel, I. Ştefan S. Grévy, O. Sorlin Z. Dombrádi Orsay, Ganil, Debrecen

nd3/2 bound in F but unbound in N, O pd5/2> ↔ nd3/2< attraction before island of inversion island of inversion Wildenthal PRC22 (1980) 2260 Warburton PRC41 (1990) 1147 pd5/2> Sakurai et al, PLB 448(1999)180 nd3/2< nf7/2>

M. Belleguic et al, NPA 682 (2001) M. Stanoiu et al, PRC (accepted) . . . . . . . . f7/2 20 f7/2 20 d3/2 d 3/2 d3/2 . . . . . . s1/2 d3/2 . . 16 s1/2 s1/2 s1/2 14 d5/2 d5/2 p n p n 34Si20 30Ne20 need spectroscopic factors to determine strength functions!

Tensor force VT = [s1 x s2](2) Y(2) S = 1 nf7/2 DE(N=20)  20 nd3/2 ns1/2 #(pd5/2)  nd5/2 Tensor force VT = [s1 x s2](2) Y(2) S = 1 Otsuka et al, PRL 95 (2005) 232502, PRL 97 (2006) 162501 need spectroscopic factors to determine strength functions!

also in copper isotopes cf work done by Leuven: universal feature !? Otsuka et al, PRL 95 (2005) 232502, PRL 97 (2006) 162501 also in copper isotopes cf work done by Leuven: universal feature !? need "absolute" C2S to determine evolution of strength functions! 20 20 MCSM sdfp: N=20 vanishing fp intruders in sd shell Y. Utsuno et al., PRC 70 (2004) 044307 USD sd: N=20 maintained pn T=0  2p2h deformed intruders E. Caurier et al., NPA 693 (2001) 374

25Ne from Reed et al, PRC 60 (1999) 024311; Catford et al, JPG 31 (2005) S1655; Terry et al, PLB 640 (2006) 86 3891 4.5 3760 7/2- 3624 7/2- 0.58 1.2 3479 1/2+ 3316 5/2+ 3067 5/2+ 2426 3/2+ 2350 0.5 2050(2090) 3/2+ 1940 5/2+ 0.06 2028 5/2+ 1.3 0.76 1703 5/2+ 1698 5/2+ 1273 3/2+ 2.4 985 3/2+ 1.4 1.5 0 1/2+ 0 1/2+ 0 1/2+ 25Ne15 27Mg15 29Si15

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) 3227 5/2+ 6.00 3134 7/2- 3224 3/2+ 0.34 2789 5/2+ 2615 1/2+ 0.29 2317 3/2+ 2500 3/2+ 0.08 Sn=1400 keV 1638 5/2+ 1695 5/2+ 30%; 1.07 1095 885(904) 1/2+ 0.77 752 1/2+ 60%; 0.32 772(765) 3/2- 55 1/2+ 2.91 0 3/2+ 20% 0 3/2+ 0 3/2+ 27Ne17 29Mg17 31Si17

(d,p) (d,p) Z=14 pd5/26 Z=12 pd5/24 Z=10 pd5/22 Z=8 pd5/20 28Si 29Si 30Si 31Si stable stable 26Mg 27Mg 28Mg 29Mg stable 20.9 h 24Ne 26Ne 3.38 m 197 ms 22O 24O 2.25 s 61 ms N=14 N=16 nd5/26 nd5/26s1/22d3/20f7/20 pd5/2 ↔ nd3/2f7/2

28Si(d,p)29Si Betz et al, ZPA 309 (1982) 163 no SF extracted from spectra 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% Ed = 10 MeV

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

26Mg(d,p)27Mg at Utrecht splitpole Meurders & van der Steld, NPA 230 (1974) 317 Ed = 12 MeV s1/2 100% d3/2 88% f7/2 56%

30Mg(d,p)31Mg at 2.2 MeV/u 5 104 pps H Scheit et al, NPA 746 (2004) 96c & EPJA 25 s01 (2005) 397 Th 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 one-neutron knockout at Ganil data on 29,31Mg Drift chambers M. Chartier & N. Orr, priv. comm. Drift chambers Thin Plastic Carbon ~150 mg/cm2 Thin degrader 23O ~ 60 pps 25F ~ 200 pps 30Mg, 32Mg EXOGAM + NaI det SPEG  Brmax = 2.88 Tm Carbon production target ~500 mg/cm2 Ionization chamber & Plastic SISSI 36S primary beam 77.5 MeV/nucleon, ~1 kW

Dℓ = 2 Kinematics 28Mg(d,p) Dℓ = 0 Dwuck 4 + Ch89 R. Varner Phys Rep 201 (1991) 57 Wales & Johnson NPA 274 (1976) 168 for C2S, need ≳ 5 MeV/u

22O(d,p)23O low Sn ⇒ high s angular momentum matching | ki - kf | = R/ℓ no "picket-fence" below 5 MeV/u  indirect mechanisms, Ex & Ip but no C2S

Dwuck4 + Ch89 30Si(d,p)31Si at 5 MeV/u Wales & Johnson NPA 274 (1976) 168 R. Varner Ph Rep 201 (1991) 57 30Si(d,p)31Si at 5 MeV/u Watson & Slater, JPG 9 (1983) 1417

Speg Vamos

TRACE ancillary detector Orsay - Legnaro - Trento

24Ne(d,p)25Ne at 10 MeV/u Catford et al, JPG 31 (2005) S1655 8 p mm mrad, no beam tracking! ℓ = 0 gs 1.70 MeV ℓ = 2 2.05 MeV ℓ = 2 Padgett et al, PRC 72, 064330 (2005)

44,46Ar(d,p)45,47Ar at 10 MeV/u Must1 + Cats + Speg at Ganil 45Ar: 100% f7/2, 50% p1/2,3/2 47Ar: 100% p1/2,3/2, 60% f5/2 L Gaudefroy et al, PRL 97 (2006) ℓ = 1 gs SF = 0.59(6) 1180, 1790 keV 1.5 MeV SF = 0.84(14), 0.17(7) 2710, 3280, 3800 keV 3.5 MeV SF = 0.21(4), 0.42(4)

-8% p n -45% Tensor force nf7/2 - pd3/2 : reduction of N=28 by 330 keV Tensor interaction (T. Otsuka) pd3/2 – nf7/2f5/2 20 29 18 29 p(s1/2d3/2) removed Density dependence (J. Piekarewicz) ps1/2 – np1/2p3/2 Tensor force nf7/2 - pd3/2 : reduction of N=28 by 330 keV Density dependence ps1/2 : 45% reduced SO for np Gaudefroy et al, PRL 97, 092501 (2006)

Measuring the strength of the pd5/2-nd3/2 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 nd3/2, nf7/2 strengths in 29Mg through transfer "safe" transfer when momentum matching "absolute" C2S from 5 MeV/u on Ip and Ex already below 5 MeV/u no 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

J. Terry et al, PLB 640 (2006) 86 1n knockout from 26,28Ne at MSU Z. Dombradi et al, PRL 96 (2006) 182501 1n knockout from 28Ne at Riken Ex(np3/2) (!) low ie N=20 vanishing 28Ne(p,p') shows need to fix effective charges

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