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C ONTINUUM STATES OF LIGHT NEUTRON - RICH NUCLEI VIA TRANSFER & KNOCKOUT … ‟ Formless Continuum” – Jack Haas Example : N=7 structure - 9 He, 10 Li … …

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Presentation on theme: "C ONTINUUM STATES OF LIGHT NEUTRON - RICH NUCLEI VIA TRANSFER & KNOCKOUT … ‟ Formless Continuum” – Jack Haas Example : N=7 structure - 9 He, 10 Li … …"— Presentation transcript:

1 C ONTINUUM STATES OF LIGHT NEUTRON - RICH NUCLEI VIA TRANSFER & KNOCKOUT … ‟ Formless Continuum” – Jack Haas Example : N=7 structure - 9 He, 10 Li … … via single-neutron transfer on 8 He [ 9 Li] versus … nucleon knockout & fragmentation of fast secondary beams GOAL: Compare and contrast … Open issues and questions [ 5 H & 13 Be via proton removal ] NIGEL ORR * * T AL KALANEE, J GIBELIN, H AL FALOU + CHARISSA+DEMON + MUST C OLLABORATIONS

2 … toujours la même chose avec lui … mieux vaut peut-être rester ici avec mon ballon de rouge

3 T HE LIGHT NEUTRON - RICH NUCLEI … 10 Li … driplines and beyond experimentally accessible via knockout/breakup … driplines and beyond experimentally accessible via knockout/breakup neutron transfer 9 He... nuclear structure theory becoming mature (NCSM, ab initio, …)... nuclear structure theory becoming mature (NCSM, ab initio, …)

4 N=7 : S TRUCTURAL EVOLUTION WITH ISOSPIN * … T Otsuka et al. PRL 2001 T Otsuka et al. PRL 2001 … 9 He ?? PG Hansen et al. PG Hansen et al. 1/ /2 - level inversion … * Also input for 3-body models of 10 He, …

5 H ISTORICAL I NTERLUDE … … some cases accessible via heavy-ion multi-nucleon transfer & double-charge exchange from stable targets/beams … some cases accessible via heavy-ion multi-nucleon transfer & double-charge exchange from stable targets/beams → complex mechanisms, selectivity ( ℓ >>0), complex spectra, … → complex mechanisms, selectivity ( ℓ >>0), complex spectra, … HMI group, circa 1994

6 T WO ROADS TO THE CONTINUUM : NEUTRON TRANSFER & FAST BEAM KNOCKOUT / BREAKUP FAST BEAM KNOCKOUT / BREAKUP … INVERSE KINEMATICS … INVERSE KINEMATICS n (d,p) Si strip beam PID + E B tracking heavy beam-like residue (PID, E,  ) CD 2 or Be / C “knockout”

7 8 He(d,p) SINGLE - NEUTRON TRANSFER … 8 He(d,p) SINGLE - NEUTRON TRANSFER … 1s 1/2 1p 3/2 1p 1/2 2s 1/2 1d 5/2 N=6  Proton energy and angle  E x of recoil B  Proton angular distribution, d  / d   angular momentum transfered by neutron, ℓ n  angular momentum transfered by neutron, ℓ n  d  / d   (expt) = S d  / d   (reaction theory) 8 He(d,p) 9 He  J  = 1/2 +  1/2 -, 5/2 +, 3/2 - (iff 8 He gs “2p-2h”)* 8 He(d,p) 9 He  J  = 1/2 +  1/2 -, 5/2 +, 3/2 - (iff 8 He gs “2p-2h”)* ppp AA B d d + A  p + B n n d=p+n B=A+n neutrons 8 He gs J  = He gs J  = 0 + * 8 He(p,d) S(p3/2)  4… 8 He(p,t)  2p-2h … MUST [ PRC2006, PLB2007 ] * 8 He(p,d) S(p3/2)  4… 8 He(p,t)  2p-2h … MUST [ PRC2006, PLB2007 ]

8 9 He: SHELL MODEL (p-sd 0 –1ħ  ) … L Chen et al. PLB (2001)

9 d( 8 He,p) A 15 MEV / NUCLEON … d( 8 He,p) A 15 MEV / NUCLEON … T Al Kalanee, J Gibelin et al. [MUST2], PRC E r =180±85 (  =180±160) ; 1240±120 (  = / -130 ) ; 3420±780 (  =2900±400) keV

10 d( 8 He,p) A 15 MEV / NUCLEON … d( 8 He,p) A 15 MEV / NUCLEON … T Al Kalanee, J Gibelin et al., PRC DWBA & CCBA – N Keeley DWBA Optical Pot’ls: d+ 8 He global parameters Daehnick et al p+ 9 He systematics Koning+Delaroche p+ 9 He systematics Koning+Delaroche Form Factors: Woods-Saxon with “Weak Binding” approx CCBA : d breakup only - d+ 8 He CDCC

11 d( 8 He,p) A 15 MEV / NUCLEON … d( 8 He,p) A 15 MEV / NUCLEON … T Al Kalanee, J Gibelin et al., PRC [  sp (=0)  2700 keV] [  sp ( ℓ =0)  2700 keV] [  sp (=1)  2400 keV] [  sp ( ℓ =1)  2400 keV] [  sp (=2)  3000 keV] [  sp ( ℓ =2)  3000 keV] DWBA: * No reliable form factor for ℓ =0 using WBEA † Uncertainty dominated by form factor ** Barker (2004) R-Matrix < 0.1 † Uncertainty dominated by form factor ** Barker (2004) R-Matrix < 0.1 * † † ‡ ‡ a s ~ - 12 fm **

12 K NOCKOUT & B REAKUP … … nucleon removal via “knockout” or breakup of projectile (   0.3) with known structure + in-flight decay  fragment – n FSI VfVf VnVn V f - V n target Proj. A Z  A-1 Z + n

13 A PPROX. “S ELECTION R ULES ” … (i) 1 & 2-proton knockout   ℓ n  0 proj. valence neutron config. C( 11 Be, 9 Li+n)X,C( 11 Be, 8 He+n)X  s 1/2 [ 11 Be C 2 S ( s 1/2 )  0.8 ]  well adapted to probing low-lying (s-wave strength) (ii) fragmentation (-xp,-yn)  population via neutron-decay of N+1,2, … systems following proton removal C( 14 B, 9 Li+n)X, C( 14 B, 8 He+n)X, C( 11 Li, 8 He+n)X,  s 1/2 + p 1/2 + …  CAVEAT: decay of narrow resonances in N+1,2,… systems C( 14 B, 9 Li+n)X, C( 14 B, 8 He+n)X, C( 11 Li, 8 He+n)X,  s 1/2 + p 1/2 + …  CAVEAT: decay of narrow resonances in N+1,2,… systems

14 N=7 : S TRUCTURAL EVOLUTION WITH ISOSPIN … Brida e at al.,. NUPA (2006) … 10 Li * PG Hansen et al. PG Hansen et al. s 1/2 - p 1/2 level inversion … s 1/2 - p 1/2 level inversion …   p 1/2   s 1/2 ; p 3/2  2 -,1 - ; 2 +,1 +

15 S CATTERING /V IRTUAL S - WAVE STATES … a s = 0 fm no FSI ; a s << 0 fm stronger FSI NB: final lineshape E d (frag+n) depends on projectile and reaction + decay path

16 10 Li: C( 11 Be, 9 35 M E V/ NUCLEON [-1p] s-wave [a s = -17±2 fm] + non-resonant continuum H Al Falou et al.

17 10 Li: C( 14 B, 9 35 M E V/ NUCLEON [-2p,-2n] s-wave [a s = -10±2 fm] + p-wave [E r = 0.50,    0.50 MeV] + background [ Decay of 11 Li* & 12 Li … ? ] H Al Falou et al.

18 9 He: C( 11 Be, 8 35 M E V/ NUCLEON [-2p] s-wave [a s = -3 ~ 0 fm (3  )] + non-resonant continuum H Al Falou et al.

19 9 He: C( 14 B, 8 35 M E V/ NUCLEON [-3p,-2n] s-wave [a s = -3 ~ 0 fm] + p-wave [E r = 1.2,    1.0 MeV] + background [ Decay of 10 He & 11 He … ? ] H Al Falou et al.

20 9 He: p( 11 Li, M E V/ NUCLEON [-1p-1n] GSI-LAND : HT Johansson, Yu. Aksyutina et al. (2010) [ Decay of 10 He … ? ]

21 9 He: “ COMPARE & CONTRAST ” … C( 11 Be, 8 He+n) Threshold ℓ =0 strength dominates … a s  -3 fm d( 8 He,p) ℓ =0 very low yield … a s ~ -12 fm [?] Can lower E B to improve matching (but … )

22 d( MEV / NUCLEON … d( MEV / NUCLEON … TB Jeppesen et al. [ISOLDE], PLB CCBA – Antonio Moro CCBA

23 9 He : d( 8 25 MeV/nucleon MS Golovkov et al., PRC76 (2007) →

24 9 He: AB INITIO THEORY … P Navratil – ECT* Nov 2013

25 ( SOME ) OPEN ISSUES … T RANSFERT : How best to model transfer to continuum states ? How best to model transfer to continuum states ? … what is the best means to treat (s-wave) form factor ?? … what is the best means to treat (s-wave) form factor ?? Realistic estimates of  sp to derive C 2 S ? Standard WS ? … ?? Realistic estimates of  sp to derive C 2 S ? Standard WS ? … ?? K NOCKOUT /B REAKUP : Proper reaction theory to continuum states (very crude at present) Proper reaction theory to continuum states (very crude at present) Need to treat consistently “background” (core recoil, valence-n Need to treat consistently “background” (core recoil, valence-n scattering, non-resonant continuum) in theory scattering, non-resonant continuum) in theory I DEALLY ( TRANSFERT & KNOCKOUT ): “Ab initio”  i &  f combined with realistic reaction theory … “Ab initio”  i &  f combined with realistic reaction theory …

26 Lebond, Ogoshi, et al., LPC-TITECH-SAMURAI: NP1106 – RIBF S PECTROSCOPY OF 18 B : THESHOLD S - WAVE STRENGTH … … PRELIMINARY

27

28 H ISTORICAL I NTERLUDE … … some cases accessible via heavy-ion multi-nucleon transfer & double-charge exchange from stable targets/beams … some cases accessible via heavy-ion multi-nucleon transfer & double-charge exchange from stable targets/beams → complex mechanisms, selectivity ( ℓ >>0), complex spectra, … → complex mechanisms, selectivity ( ℓ >>0), complex spectra, …

29 9 He : d( 8 15 MeV/nucleon S Fortier et al., AIP Conf Proc 912 (2007)

30 d( 8 He,p) A 15 MEV / NUCLEON … d( 8 He,p) A 15 MEV / NUCLEON … T Al Kalanee, J Gibelin et al. [MUST2], PRC

31 17 O : d( MEV / NUCLEON … T Al Kalanee, J Gibelin et al., PRC

32 d( 16 0/ 8 He,p) 17 O/ 9 15 MEV / NUCLEON : RESOLUTION … d( 16 0/ 8 He,p) 17 O/ 9 15 MEV / NUCLEON : RESOLUTION … T Al Kalanee, PhD Thesis LPC-Caen (2010)

33 9 He: S UMMARY … T Al Kalanee, J Gibelin et al., PRC

34 9 He: AB INITIO THEORY … P Navratil – ECT* Nov 2013

35 I NVARIANT MASS SPECTROSCOPY : LIGHT ~40 MeV/u … 9 Li+n 12 Be+n

36 Resolution E XPERIMENTAL RESPONSE FUNCTION … Efficiency FWHM ~ 0.3 E d 1/2 nnnn JL Lecouey LPCC JL Lecouey LPCC  model distributions must be “ filtered ” through the simulation  model distributions must be “ filtered ” through the simulation

37 I NITIAL S TATE D EPENDENCE OF U NBOUND S TATES … G Bertsch et al., PRC (1998), L Chen et al. PLB (2001) sudden approximation sudden approximation  neutron configuration of projectile preserved (  ℓ n = 0 )  neutron configuration of projectile preserved (  ℓ n = 0 ) Initial bound state Final unbound state DecayEnergySimulation Comparison to data (  2 )

38 I NITIAL S TATE D EPENDENCE OF V IRTUAL S -S TATES … a s = 0 fm no FSI ; a s << 0 fm stronger FSI H Al Falou LPCC 07-03

39

40 13 Be: D ISCUSSION …

41 s 1/2 intruder (halo) s 1/2 intruder (halo) p-shellsd-shell Single-Neutron Removal in the p-sd shell : A Z  A-1 Z Inclusive Expt : E Sauvan, et al., PLB (2000) Inclusive Expt : E Sauvan, et al., PLB (2000) 13 Be: D ISCUSSION …

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43 p,C( 14 Be, 12 Be+n) vs C( 14 B, 12 Be+n) p,C( 14 Be, 12 Be+n) vs C( 14 B, 12 Be+n). Randisi et al.

44 13 Be: UNMIXED SHELL MODEL (WBT/P ) … DJ Millener, unpublished [HMI/Dubna]

45 13 Be: C( 14 B, 12 Be+n) VS MIXED (0–3)ħ  SHELL MODEL … G Randisi et al. * WBP & HTF predictions: 1/2 + normalised to 0.40 MeV level in EXPeriment **

46 13 Be: C( 14 B, 12 Be+n) … G Randisi et al.

47 13 Be: C( 14 B, 12 Be+n) … G Randisi et al. … virtual vs resonant s-wave strength + d-wave resonance

48 13 Be: C( 14 B, 12 Be+n) … G Randisi et al.

49 13 Be: C( 14 B, 12 Be+  ) … G Randisi et al. … 12 Be* : E x (2 + ) =2.1 MeV ; E x (1 - ) =2.7 MeV ; E x (0 + ) =2.25 MeV


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