Nuclear Structure Now (precision and discovery) C.J.(Kim) Lister

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 2 Our Nuclear Domain

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 3

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 4 A different view of our nuclear world

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 5 Ab-initio Greens Functional Monte Carlo Calculations Pieper and Wiringa (ANL) Described in NP A c (2005)

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 6 Neutron Stars

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 7 Testing Ab-Initio Calculations

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 8 RMS Radii of 6,8 He 6 He P.Mueller et. al (ANL)

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 9 RMS Radii of 6,8 He L.-B. Wang et al., PRL 93, (2004) P. Mueller et al., PRL 99, (2007). After some convergence issues were resolved, predictions of charge radii very good, ~ 1%…..matter radii not quite so good.

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 10 Transfer Reactions ANL-UWM Collaboration A. H. Wuosmaa et. al. PRL and PRC (R) 2005 Example: 6 He(d,p) 7 He Issues: How reliable are calculations of unbound states? Is there a low lying state below 1MeV? S n =0.533 l=1 p 3/2 No renormalization to QMC calculations Data Fit to g.s. and E x =2.25,  =3.0 MeV state

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 11 Transfer Reactions Compare: 6 He(d,p) 7 He and 8 Li(d, 3 He) 7 He Issues: Is spectroscopy of broad resonances possible? Yes!! Using selective in both population and decay channels 1/2 - 5/2 -

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 12 The Special Case of Beryllium Nuclei

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 13 Key Issues: Microscopically, how do the neutrons really form a potential to bind the nucleus? Is it the same for all states?

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 14 Investigating 8 Be Upshot: Test of electromagnetic decay from unbound resonance Experiment Ab-Initio Theory …..Here in Mumbai!!

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 15 The Bound States of 10 Be Be E2 E1 E2 M1/E E Be+n

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA Be Data Compilation GFMC Theory Q ≤ 0 Q ≥ 0 A=10 nuclei provide a sensitive test of GFMC S.C. Pieper, K. Varga and R.B. Wiringa, Phys. Rev. C 66, (2002). Very sensitive to the effects of 3-body correlations.

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 17 Ken Nollett (ANL) and Brent Graner (UC) visulization of 10 Be J=2 1 state (2008) The Ab-Initio projection of T=0 and T=1 density

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 18 The Traditional Shell Model ( ) Kurath, Cohen and Kurath, Millener and Kurath, Millener and Warburton R=11.3

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA Be : A popular nucleus (e 2 fm 4 ) Ratio Author Okabe MO Caurier NCSM Itagaki TMO Navratil NCSM Arai MCM Wiringa GFMC 7.89(30) 2.08(26) 3.8 EXPT 10.5(1.0) ?? ?? NCSM : No-core shell model, E. Caurier et al., Phys. Rev. C 66, (2002). MO : Molecular orbit model, N. Itagaki and S. Okabe, Phys. Rev. C 61, (2000). MCM : Microscopic cluster model, K. Arai, Phys. Rev. C 69, (2004). TMO : Triaxial Molecular Orbital, N. Itagaki et al., Phys. Rev. C 65, (2002). GFMC : Greens Functional Monte Carlo, R. Wiringa and S. Pierper et al., Private Communication. (e 2 fm 4 ) Calc.

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 20 E.K. Warburton et al., Phys. Rev. 129, 2180 (1963). E.K. Warburton et al., Phys. Rev. 148, 1072 (1966). G.C. Morrison et al., - unpublished (1965). T.R. Fisher et al., Phys. Rev. 176, 1130 (1968). Evaluated  = 180(18) fs All DSAM measurements Previously measured DSAM J=2 1 lifetime in 10 Be Systematic problems of:- Initial recoil velocity ill-defined Stopping powers poorly known Very slow recoils State feeding poorly known Detector angle poorly defined At the time these measurements WERE cutting edge and provided discriminating tests of the (new) intermediate-coupling shell model (Kurath et al 1958). But now we need better!

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 21 F. Sarazin et al., Phys. Rev. C 70, (R) (2004)….  -decay at ISAC / TRIUMF 11 Li β-delayed 1-n emission Line shape depends on  Energies and intensities of all neutron branches feeding the level  Lifetime of the level  Angular correlation between gamma ray and neutron Y. Hirayama et. al. Phys Lets B (2005)…..polarized  -decay at ISAC/TRIUMF (high stats)

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 22 The Doppler Shift Attenuation Method (DSAM)

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 23 The Doppler Shift Attenuation Method   v0v0 E  = E o {1 + (v 0 /c)Cos  }   v(t) Free Space Stopping E  = E o {1 + F(t)Cos  } log(  F(  ) 1 0 Actually, recoils are sufficiently swift (v/c ~6%) that 2 nd order relativistic is correction needed

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 24 What SRIM shows us J.F. Ziegler, J.P. Biersack and M.D. Ziegler SLOW Ions…. 1 MeV 10 Be in 100  g/cm 2 Li on 6mg/cm 2 Au FAST Ions…. 15 MeV 10 Be in 100  g/cm 2 Li on 6mg/cm 2 Au (99.99% electronic stopping)

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 25 DSAM * DSAM done properly:- 2-body kinematics High recoil velocity Well defined recoil direction Well defined gamma direction Control of state population 7 Li( 7 Li,  ) 10 Be at 10 MeV α 10 Be 10 Be (g.s) = 18.2 MeV 10 Be * (3.3) = 16.5 MeV 10 Be * (5.9) = 15.0 MeV E.A. McCutchan et. al. (ANL)

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 26 E tot in Ion Chamber ΔEΔE Recoil -  Gated Data 3 mg/cm 2 Cu backing A=10 q=3 selected with FMA Recoil-gamma time

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 27 Extracting the lifetime from mean   N 123 time  ’s weighted by # of decays at given time t  determines weight Ideally you want all decays in the stopping material But… Need some finite thickness of production material Need nuclei to recoil out of target 1 Counts Energy 3 2 Counts Energy 2

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 28 Results (1): First excited State with J  =2 + at 3367 keV 7 Li 66  g/cm 2 7 Li on 6.95mg/cm 2 Au 115  g/cm 2 7 Li on 2.69mg/cm 2 Au 288  g/cm 2 7 LiF 2 on 2.48mg/cm 2 Cu     fs  fs  fs

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 29 Traditional DSAM analysis……and GS alignment 100  g/cm 2 7 Li on 2.33 mg/cm 2 Au

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 30 Results so far for 3369keV J=2 state

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 31 The Bound States of 10 Be Be E2 E1 E2 M1/E E Be+n

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 32 Some Detective Work Required I1 1I1   I2 2I2    I2 2I2    Is it possible to untangle the two- line J  =1 -,2 + mess? The states are only 1.8keV apart and have similar, short lifetimes

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 33 What we have learned so far

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 34 First J = 2 + state in 10 Be NNDC transition strength was Our new transition strength Ab-initio transition strength Note: The predicted ab-initio summed E2 decay strength is:

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 35 Second J = 2 + state in 10 Be NNDC lifetime This work Theory seems to have much too much mixing of J  =2 + states. The original GFMC with V 18 and IL2 three body force predicted R=3.8 Sarazin et. al. Much smaller than GFMC which initially predicted 2.08(26) e 2 fm 4

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 36 Lessons Learned We set out to test a model that was thought to be good at the <10% level. Tests were for calc. stability & validating 3-body forces. We Found: Good agreement in absolute binding energy of the ground state. Modest agreement in the binding energies of the excited states (correct ordering, too close in energy) Good agreement in the total collectivity, without resorting to any effective charges. Modest agreement in the distribution of strength.

C.J. (Kim) Lister:- Frontiers In Gamma Spectroscopy 2009, Mumbai INDIA 37 Conclusions for 10 Be In Experiment We have made a precise measurement of the lifetime of the first excited state in 10 Be. Reliable <5% DSAM IS possible. We have determined the ratio R, which shows there is very little mixing between first and second J=2 states. In Theory We need to reconcile the differences: Does the experimental distribution of B(E2) strength allow us to constrain the models of 3-body forces? YES, but reveals more work is needed