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Exotic dancing on the bridge between driplines TAMU – JBN

Exotic dancing on the bridge between driplines TAMU – JBN. A few comments on JBN  LGS First conversation  Asilomar CA 1980(?) – a DNP meeting (LGM said ~ “ go sit at his table – you can learn from him ”) The conversation has been unbroken for over three decades. JBN expertise

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Exotic dancing on the bridge between driplines TAMU – JBN

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  1. Exotic dancing on the bridge between driplinesTAMU – JBN • A few comments on JBN  LGS • First conversation  Asilomar CA 1980(?) – a DNP meeting • (LGM said ~ “go sit at his table – you can learn from him”) • The conversation has been unbroken for over three decades. • JBN expertise • Fusion, fission, HI reaction dynamics, SHE, EOS and Laser experiments • His work characterized by: BREATH, DEPTH, BOLDNESS • – he did not do what others were doing. • Equally impressive (and rare these days) is his calm and modest nature. • He has held the torch high of one of the most successful sub fields of science: •  NUCLEAR CHEMISTY

  2. NUCLEAR CHEMISTRY Why do I say …Nuclear chemistry is one of THE most successful fields in all of science ? With so few practitioners it has given birth to many subfields! Radioactive decay and nuclear medicine  M. Curie and Irene Curie Fission Hahn and Strassman Photosynthesis and biological tracers  S. Ruben and M. Kamen Transuranics  Wahl, Kennedy and Seaborg, followed by many Nucleosynthesis ideas  C. Coryell (before B2FH !) Isotope chemistry and chemical reaction dynamics  H. Urey and J. Bigeleisen Neutrino Astro “physics” – looking inside the sun  Ray Davis Large-molecule Mass spec.  Ron Macfarlane Positron-Emission Tomography  M. Phelps, E. Hoffman, J. Fowler…. Dinosour extinction  F. Asaro (and Luis and Walter Alvarez) Atmospheric chemistry  S. Rowland Nuclear Chemistry offers a license to be to bold.. What has Joe done with his? HI reaction dynamics, EOS (Low Den  RHIC) & Laser experiments Doing experiments and analyses that others did not do/could not imagine  JBN Lets talk about a few things JBN left for us peons to do…

  3. Exotic Dancing on the Bridge between driplines. 1. Overview of physics and experimental logic2. The structure of 11Li from its analogs3. A = 88C  6Be + (2p) a +2p + (2p) : 2p-2p & Isospin symmetry breaking 8BIAS6LiIAS + 2p : First IAS  IAS 2p decay4. A = 1212C Hoyle and 3- a decay : Exclusively through 8Beg.s.12O : A new mass and width12NIAS  10BIAS +2p : Second IAS IAS 2p decay + IMME12N (2-) new width : reduced “RAP” rate5. Many new states, for example…9Li (E* = 14.1 MeV), 10B(E*= 20.4 MeV)  Parts of analog structures ?  13O(E* ~< 3 MeV) 3 states now known with E* < first in mirror 13B

  4. I. Physics overview 2p decay New mass 2p decay New type A = 8 Your place or mine ? 8C 8He Multiple proton decay at the drip-line Continuum nuclear structure Improve/complete isospin multiplets Hopefully peering in at nucleon-nucleon correlations (in the medium) by “pushing” Fermi surface to (or into) the continuum. N Correlations ?? Secrets told in mass and re ? ? ? ? P Correlations Secrets told in mass and decay correlations

  5. From enriched Carborane C2[10B10]H12 I. Experimental logic TAMU using K500 cyclotron and the MARS separator ECR source Primary reaction (p,n) Secondary reaction K-500 cyc Inelastic excitation (t1/2 = 19.3 s) 2*105/s E* (parent) = “POP” – D mass A 4-particle correlation experiment ! E* = ETKE – Qgg  Time, Energy, and Particle resolving “CAMERA” with 4k pixels 

  6. 2,3 - particle 4-particle (aapp) intermediates Determined the decay paths for known and two new levels in 10C using….4-particle and sub event (2- and 3-particle) energy correlations. 9.7 Also disproved a level claimed by others at 4.2 MeV. The other group later retracted their claim.

  7. Isospin primer • Ifisospin is a good quantum number, in the absence of Coulomb forces •  the energies of a multiplet should be independent of Tz. • If charge dep. forces only two-body •  the masses should if fit with a quadratic IMME. • 3. This equation allows for M as n  p (as Mn>Mp) • and M as n p (due to Coulomb repulsion) • If you need more terms, isospin symmetry is violated. • 4. Specifically, the need for dTz3 and eTz4 terms  isospin symmetry breaking. • (This statement is not invertible!) • 5. IF you know 3 masses of a 2T+1 multiplet, the (quadratic) IMME provides a prediction of the masses of ALL members of the multiplet.

  8. 2. Consider the Multiplet that includes 11Li: A = 11 Sextet T=5/2, J=3/2- 11B → 2p+9Li (decay branch) Unfinished Bridge DIAS in 11B E*=33.6 MeV G=306(182) keV Isospin-allowed 2p decay possible IAS known (RIKEN 1997) p+n decay Known particle-stable T=5/2, J=3/2-, sextet two-nucleon halo 11O 11Li T=3/2, J=1/2+,quartet one-nucleon halo 11N 11Be T=1/2, J=3/2-, doublet (used as reference) 12Be(p,2n)11B at E/A = 50 MeV @NSCL with HiRA array. 11C 11B

  9. Masses show the effect of the extended halo. Consistent with 11Li halo wavefunctions calculated by Hagino + Sagawa PRC 72 (2005) 044321 Can extrapolate to masses of proton-rich members of the sextet. p n Calc. Exp. DVC(11B-11Be) = 1.375 1.389(20) MeV DVC(11Be-11Li) = 1.797 1.69(8) R.J. Charity, et al.,Phys. Rev. C 86 041307(R)(2012).

  10. 3. 8C decay Peak / bkg 1 / 5 T = 2 a-p-p from a-p-p-p-p T = 1 a-p-p from 7Be beam T = 0 6Be is the (7 zs) intermediate, i.e. 8B  [6Be] + 2p + [a +2p] +2p We studied the 3-body correlation for 6Be decay AND the 3-body correlations for 8C decay. In ~ 1/3 of the events only ONE of the six combinations lies in the 6Be peak. For these events we can assign protons to first and second steps.  enhancement at small rel. mom. a-p-p-p-p from 9C beam Excitation energy (MeV)

  11. 8B reconstruction from 6Li+p+p TOP 9C  8Cgdst (0+, T=2) +nBOT9C  8BIAS (0+, T=2) +p g 6LiIAS Ligs + gamma 1p or n decays are forbidden by either energy or isospin R. J. Charity, et al.,Phys. Rev. C 82, 041304(R) (2010). K. Brown, et al., Phys. Rev. C in preparation (2013).

  12. Confirmation of Isospin symmetry breaking in A = 8 The fit (RESIDUALS) Needs d(Tz)3 term (as do A = 9 & 32) Does not need an e4 term. ? Reason ? Perhaps isospin mixing in T = 2 like T = 0 + 1 in 12C  Classic case of isospin mixing T R. J. Charity, et al., Phys. Rev. C. 84, 051308 (R) (2011).

  13. We have actually found two cases of this new class of 2p emitters: IAS  IAS A = 8: NSCL 8Cgs & 8BIAS IMME ? A = 16: NSCL 16Negs but NOT 16FIAS A = 12: TAMU 12Ogs & 12NIAS IMME

  14. 12Beg.s 12CIAS 12Og.s. 12BIAS. 12NIAS TZ = 2 TZ = 1 TZ = 0 TZ = -1 TZ = -2 T=2 T=1 T=0 5. The A=12 Isobar Energy Diagram b) Energy unknown c)Width controversy d) Second pair of isospin clones of 2p decays: 12Og.s. And 12NIAS • a) Decays of • 3- or • ….. • 0+ Hoyle • Both studied in • high statistics and excellent E resolution.

  15. i) Gate on Hoyle and Construct a rms energy Erms = [ <E2> - <E>2 ]1/2 Compare to simulations How do Hoyle and 3- states a decay? Equal Energy ii) Gate on 3- and generate 8Be* spectrum (choose smallest E*) Hoyle8Beg.s. R-matrix Gated data Equal Energy (UPPER LIMIT) = 0.45% 17 times lower than Raduta et al. value 12C (3-) 8Beg.s. + a ~100.% The “Ghost Peak” line shape is expected from R-matrix calc. 12C (Hoyle)  8Be g.s. + a > 99.5 % J. Manfredi, et al., Phys. Rev. C 85, 037603 (2012).

  16. 13O  -n  12O 10C + 2p 13O  -p 12N*10B*+2p T = 2  1 T = 2  1 A = 12 data onusing 13O @ TAMU Known + 12N New mass & width 12O, G < 72 keV Old 400-600 keV & Complete quintet New 2nd case IASIAS 2p 13N Known Narrower 12O10C + 2p Narrower 12N* 10B* + 2p Quadratic IMME  perfect New No evidence of isospin sym. breaking @ A = 12 M. Jager, et al., Phys. Rev. C 86, 011304 (R) (2012).

  17. Returning to the same A = 12 2p experiment, we found…. New 12N 2- width new states in 13O Results: a) New width of 2- in12N (~ ½ NNDC value ) leads to reduced 11C(p,g) rate, 26% at T9 = 0.2; Greater reduction at higher T, less reduction at lower T.  b) Now 3 excited states in 13O below first excited state in mirror 13B.  Thomas-Ehrman physics. L. G. Sobotka, et al.,Phys. Rev. C 87, 054329 (2013).

  18. Summary Wealth of new information on light nuclei Complete 3-body decay PS for 6Be. Found Analog of 11Li in 11B. IAS IAS 2p decays. Hoyle and 3- decay in12C Found isospin symmetry breaking in A = 8 but not in A = 12. Many new levels and properties, e.g. 12N and 13O, the former with NA significance. Future plans • Compare the Phase-Space population of PAIRS of 2p emitters, (same T, different Tz). [NSCL] • We think we can get the mass of TWO more members of the T = 5/2, A = 11 sextet [NSCL] • 16O  13O  -2n, -np  11Ogs and 11NIAS  5 members of A = 11 sextet containing 11Ligs. •  Answer several decades old question on “particle-assisted Hoyle-state decay” [OHIO] • Ask me PLEASE ASK ME • What is the structure of some of the new states we found [TAMU] • e.g. 9Li (14.1 MeV)  part of analog structure of 9Hegs?? • e.g. 10B (20.4 MeV)  part of analog structure ?? • P Elastic scattering from 14O [14N(p,n)] and 20O [22Ne(-,2p)] [TAMU] • Really important for the DOM • stot(n) on stable but rare isotopes [LANSCE] • Photorespiration and drought [WU]

  19. END

  20. A. The “Hoyle” picture:a sequence of improbable events 9996/10000 4/10000 Width (ev) 5.5 8.5 Lifetime (s) 120 x 10-18 77 x 10-18 Decay of Hoyle state formation of Hoyle state (tail of exponential Maxwell-Boltzmann distribution)

  21. B. The Old unresolved issue The decay of an ISOLATED 12C* is well studied and as represented. BUT in hot and dense stars there is another process that can deexcite 12C* - ineastic UPSCATTERING. 12C* + n or p or a (low energy)  12C + n or p or a (high energy) This can lead to either 12Cgs or 12C4.44 Either way C has been made. All mechanics is time reversal invariant. So all you need to know are the cross sections for 12Cgs + n  12C7.65 + n’ and 12C4.44 + n  12C7.65 + n’. The latter cannot be measured and the former is Hard. WHY The Hoyle state structure is VERY different than that of the ground state and so the WF overlaps are small  small s (n,n’)

  22. Previous (n,n’) measurements Elastic cross section large Cross section to 2+ large, 3- medium Cross section to Hoyle small

  23. What is the point of measuring n’? • ONLY to confirm that the HOYLE was formed. • But IF the HOYLE is formed 9996 times/10,000 it decays 12C*  8Be + a  (a + a) + a That is 3. Forget looking for n’  just look for 8Be-a “Y” track. Why has it not been done before? Because the range in condensed matter is microns. The total decay energy is only 287 keV.  AT-TPC to the rescue a 12C* a a

  24. BUT now AT-TPC’s exist Idea: shoot n’s just above threshold into AT-TPC running with isobutane (C4H10(g)) and look for 8Be-alpha signature. s(n,p) is well known, will lead to single-ended tracks and thus is an internal calibration Running just above the 3- leads to another check that s (n,n’) can be extracted.

  25. Genesis of this idea Sam Austin corned me at MSU saying ….. “Lee your clever & you have done n experiments… can figure out a way to measure this…..” After some thought, I said “Sam, this is how to do it ….and they guy 2 doors down from you has the device to do it” all we need to do is take it to a n – lab. They guy two doors down, Wolfi Mittig, said – “lets do it.” Now WE need to do it. References

  26. Secondary beam of 12Be (t1/2 = 24 ms)Smash it upLook in debris using particle-particle correlations Known 6Li* And 7He analog in 7LiIAS (I = 3/2-, T=3/2) Unknown 9He analog in 9LiIAS (I = 1/2+, T = 5/2) ? Its ~600 keV lower than “expected”. Could be of mixed isospin: T = 5/2 + 3/2 With almost pure 8He x p (1s1/2 character) with s- Coulomb shift.  John Millener

  27. Isospin 2-state mixing for 9LiIAS pair of mixed levels* like8BeIAS pair of T = 0+1 levels? Shell-model states Physical States a) Fa(space,spin,T = 5/2, IAS) a) Fa(space,spin, T= 3/2 + 5/2) b) Fb(space,spin,T = 3/2) b) Fb(space,spin, T = 3/2 + 5/2) Same space, spin, ~ E  mix a b a b T = 3/2 + 5/2 T = 3/2 + 5/2 T = 5/2 T = 3/2 Ip = 1/2+ Ip = 1/2+ Ip = 1/2+ Ip = 1/2+ Observed ? IF the lower state were almost pure | 8Heg.s. x 1s1/2(p) > It would explain the LOW Coulomb energy ! * Suggested by John Millener

  28. New 8C mass and uncertainty+ since last fit new 8He mass and correct error in previous fit. • Ifisospin is a good quantum number, in the absence of Coulomb forces •  the energies of a multiplet should be independent of Tz. • If charge dep. forces only two-body •  the masses should if fit with a quadratic IMME. • 3. The need for dTz3 and eTz4 terms  isospin symmetry breaking. (This statement is not invertible!) New since last fit - ours - previous fit used wrong mass uncertainty*. *NOTE: Previous work suggested isospin symmetry breaking in A = 8, but they used an uncertainty of the 8LiIAS energy 10x too small. Confirmed with authors. J. Britz, A. Pape, and M.S. Antony, Atomic Data and nuclear Data Tables 69, 125 (1998).

  29. 2. Prototype 3-body decay: 6Be  a + 2pONLY case with statistics to fill full Jacobi map.We now have maps for both gs and 2+ decay The correlation data for both gs and 2+ agree with 3-body QM treatment with proper asymptotic (3-body Coul.) forms. I. A. Egorova, et al., Phys. Rev. Lett. 109, 202502 (2012).

  30. B. Dispersive Optical Model - DOM g9/2 g9/2 J. M. Mueller, et al., Phys. Rev. C 83, 064505(2011), a 31 pg paper !

  31. G. Engel, et al., NIMS A652, 462(2011). R. Shane, et al., NIMS A614, 468 (2010). D. Technology 1. ASIC for Si strip detectors 2. ASIC for PSD capable scintillators 3. DSP method for stot(n) Dense stops in one macro pulse One stop, fit of DSP data Liquid scint n-g separation 2.5 % rms deviation from literature Used at: NSCL, TAMU, ORNL, LSU/FSU, RIKEN, ND, 1000’s of channels in a suitcase Used at: Wash. U. & LANL 1000’s of channels in a suitcase Used at: LANSCE

  32. C. Misc topicsGEMINI Hasy vs Easy M1 (48Ca) It is not always clear if experimental work extracts the asymmetry Energy or Enthalpy Light nuclei do not need a(E*) Heavy nuclei do need a(E*) The latter needed to understand survival against fission. An angular momentum dependence of the yrast energy slightly weaker than predicted by Sierk are needed. Another paper describes coupling of GEMINI to INC.  RJC  2 PRC papers Below phase transition It does not matter Above phase transition they diverge. Divergence will be model dependent.  LGS  1 PRC paper IMP  11.98 m2 CM (0hw)  8.96 (e,e’)  5.3 ERPA  ~ 6.1  LGS  1 PRC paper

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