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Continuum states of light neutron- rich nuclei via transfer & knockout…

Continuum states of light neutron- rich nuclei via transfer & knockout…. 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

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Continuum states of light neutron- rich nuclei via transfer & knockout…

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  1. Continuum states of light neutron-richnuclei via transfer & knockout… Example : N=7 structure - 9He, 10Li … … via single-neutron transfer on 8He [9Li] versus … nucleon knockout & fragmentation of fast secondary beams GOAL: Compare and contrast … Open issues and questions [5H & 13Be via proton removal ] nigelorr* * t al kalanee, j gibelin, h al falou+ CHARISSA+DEMON + MUST Collaborations ‟Formless Continuum” – Jack Haas

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

  3. The light neutron-richnuclei… 10Li 9He … driplines and beyondexperimentallyaccessible via knockout/breakup neutron transfer ... nuclear structure theorybecoming mature (NCSM, ab initio, …)

  4. N=7 : Structural evolutionwith isospin* … … 9He ?? PG Hansen et al. T Otsuka et al. PRL 2001 1/2+- 1/2-level inversion … *Also input for 3-body models of 10He, …

  5. Historical Interlude… … some cases accessible via heavy-ion multi-nucleontransfer & double-charge exchange from stable targets/beams → complexmechanisms, selectivity (ℓ>>0), complexspectra, … HMI group, circa 1994

  6. Tworoads to the continuum: neutron transfer& fastbeam knockout/breakup … inverse kinematics Si strip --------------------------------------------- (d,p) n tracking “knockout” beam PID + EB heavy beam-like residue (PID, E, q, f) CD2 or Be / C

  7. d +A p+B d=p+nB=A+n n d p p n A A B 8He(d,p) single-neutron transfer … 1d5/2 1p1/2 2s1/2 1p3/2 N=6 1s1/2 neutrons 8Hegs Jp= 0+ • Proton energy and angle  Exof recoil B • Proton angular distribution, ds/dW •  angularmomentumtransfered by neutron, ℓn • ds/dW(expt) = Sds/dW(reactiontheory) • 8He(d,p)9He Jp = 1/2+1/2-, 5/2+, 3/2-(iff8Hegs “2p-2h”)* * 8He(p,d) S(p3/2)  4… 8He(p,t)  2p-2h … MUST [PRC2006, PLB2007 ]

  8. 9He: shell model (p-sd 0 –1ħw) … L Chen et al. PLB (2001)

  9. d(8He,p)AHe@15mev/nucleon … Er=180±85 (G=180±160) ;1240±120 (G=130+170/-130) ;3420±780 (G=2900±400) keV T Al Kalanee, J Gibelin et al. [MUST2], PRC88 2013

  10. d(8He,p)AHe@15mev/nucleon … DWBA Optical Pot’ls: d+8He global parametersDaehnick et al p+9He systematics Koning+Delaroche Form Factors: Woods-Saxon with “Weak Binding” approx CCBA : d breakup only - d+8He CDCC T Al Kalanee, J Gibelin et al., PRC88 2013 DWBA & CCBA – N Keeley

  11. d(8He,p)AHe@15mev/nucleon … ‡ * [ Gsp(ℓ=0)  2700 keV] † ** [ Gsp(ℓ=1)  2400 keV] † [ Gsp(ℓ=2) 3000 keV] ‡as~-12 fm DWBA: * No reliable form factor for ℓ=0 using WBEA † Uncertainty dominated by form factor ** Barker (2004) R-Matrix < 0.1 T Al Kalanee, J Gibelin et al., PRC88 2013

  12. Vf Vf - Vn Vn Proj. target AZ A-1Z + n Knockout & Breakup … … nucleonremoval via “knockout” or breakupof projectile (b 0.3) withknown structure + in-flight decay  fragment – n FSI

  13. Approx. “SelectionRules” … (i) 1 & 2-proton knockout  Dℓn0 proj. valence neutron config.C(11Be,9Li+n)X ,C(11Be,8He+n)X s1/2 [ 11Be C2S (s1/2) 0.8 ]welladapted to probinglow-lying(s-wavestrength)(ii) fragmentation (-xp,-yn)  population via neutron-decay of N+1,2, … systemsfollowing proton removal C(14B,9Li+n)X , C(14B,8He+n)X , C(11Li,8He+n)X ,  s1/2 + p1/2 + …CAVEAT: decay of narrowresonances in N+1,2,… systems

  14. N=7 : Structural evolutionwith isospin … … 10Li * PG Hansen et al. ns1/2-np1/2level inversion … Brida e at al.,. NUPA (2006) * pp1/2ns1/2;np3/2  2-,1- ; 2+,1+

  15. Scattering/Virtual s-wave states … as = 0 fm no FSI ; as << 0 fm stronger FSI NB:final lineshape Ed(frag+n) depends on projectile and reaction + decay path

  16. 10Li: C(11Be,9Li+n) @ 35 MeV/nucleon[-1p] s-wave [as = -17±2 fm] + non-resonant continuum H Al Falouet al.

  17. 10Li: C(14B,9Li+n) @ 35 MeV/nucleon[-2p,-2n] s-wave [as = -10±2 fm] + p-wave [Er = 0.50, G0 0.50 MeV] + background [ Decay of 11Li* & 12Li … ? ] H Al Falouet al.

  18. 9He: C(11Be,8He+n) @ 35 MeV/nucleon[-2p] s-wave [as = -3 ~ 0 fm (3s)] + non-resonantcontinuum H Al Falouet al.

  19. 9He: C(14B,8He+n) @ 35 MeV/nucleon[-3p,-2n] s-wave [as= -3 ~ 0 fm] + p-wave [Er = 1.2, G0 1.0 MeV] + background [ Decay of 10He & 11He … ? ] H Al Falouet al.

  20. 9He: p(11Li,8He+n) @ 280 MeV/nucleon[-1p-1n] [ Decay of 10He … ? ] GSI-LAND : HT Johansson, Yu. Aksyutina et al. (2010)

  21. 9He: “compare &contrast” … C(11Be,8He+n) • Threshold ℓ=0 strength dominates … as -3 fm d(8He,p) • ℓ=0 very low yield … as~ -12 fm [?] • Can lower EB to improve matching(but … )

  22. d(9Li,p)@2.36mev/nucleon … CCBA CCBA – Antonio Moro TB Jeppesenet al. [ISOLDE], PLB642 2006

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

  24. 9He: ab initiotheory… P Navratil – ECT* Nov 2013

  25. (some) open issues … Transfert: • How best to model transfer to continuum states ? … what is the best means to treat (s-wave) form factor ?? • Realistic estimates of Gsp to derive C2S ? Standard WS ? … ?? • Knockout/Breakup: • Proper reaction theory to continuum states (very crude at present) • Need to treat consistently “background” (core recoil, valence-n • scattering, non-resonant continuum) in theory • Ideally (transfert & knockout): • “Ab initio” yi& yf combined with realistic reaction theory …

  26. Spectroscopy of 18B : theshold s-wave strength … … PRELIMINARY Lebond, Ogoshi, et al., LPC-TITECH-SAMURAI: NP1106 – SAMURAI04 @ RIBF

  27. Historical Interlude… … some cases accessible via heavy-ion multi-nucleontransfer & double-charge exchange from stable targets/beams → complexmechanisms, selectivity (ℓ>>0), complexspectra, …

  28. 9He : d(8He,p) @ 15 MeV/nucleon S Fortier et al., AIP Conf Proc 912 (2007)

  29. d(8He,p)AHe@ 15mev/nucleon … T Al Kalanee, J Gibelin et al. [MUST2], PRC88 2013

  30. 17O : d(16O,p) @ 15 mev/nucleon … T Al Kalanee, J Gibelin et al., PRC88 2013

  31. d(160/8He,p)17O/9He@ 15mev/nucleon : resolution… T Al Kalanee, PhD Thesis LPC-Caen (2010)

  32. 9He: Summary … T Al Kalanee, J Gibelin et al., PRC88 2013

  33. 9He: ab initiotheory… P Navratil – ECT* Nov 2013

  34. Invariant mass spectroscopy: light nuclei@~40 MeV/u … 12Be+n 9Li+n

  35. Resolution Efficiency Experimentalresponsefunction… FWHM ~ 0.3 Ed1/2 en  model distributions mustbe“filtered”through the simulation JL Lecouey LPCC 04-03

  36. Final unbound state Initial bound state Comparison to data (c2) Decay Energy Simulation Initial State Dependence of Unbound States … • sudden approximation • neutron configuration of projectile preserved(Dℓn= 0) G Bertsch et al., PRC (1998), L Chen et al. PLB (2001)

  37. Initial State Dependence of Virtual s-States … as = 0 fm no FSI ; as << 0 fmstronger FSI H Al Falou LPCC 07-03

  38. 13Be: Discussion …

  39. 13Be: Discussion … Single-Neutron Removal in the p-sdshell : AZ A-1Z ns1/2intruder (halo) p-shell sd-shell InclusiveExpt : E Sauvan, et al., PLB (2000)

  40. 13Be: Discussion …

  41. 13Be: Discussion … Randisi et al. p,C(14Be,12Be+n) vs C(14B,12Be+n)

  42. 13Be: unmixedshell model (WBT/P) … [HMI/Dubna] DJ Millener, unpublished

  43. 13Be: C(14B,12Be+n) vs mixed (0–3)ħwshell model … * * * WBP & HTF predictions: 1/2+normalised to 0.40 MeV level in EXPeriment G Randisi et al.

  44. 13Be: C(14B,12Be+n) … G Randisi et al.

  45. 13Be: C(14B,12Be+n) … … virtual vs resonant s-wave strength + d-wave resonance G Randisi et al.

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

  47. 13Be: C(14B,12Be+g) … … 12Be*:Ex (2+) =2.1 MeV ; Ex (1-) =2.7 MeV ; Ex (0+) =2.25 MeV G Randisi et al.

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