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Lessons from Invariant Mass spectroscopy about light nuclei Accidental “cluster” physics

Lessons from Invariant Mass spectroscopy about light nuclei Accidental “cluster” physics.

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Lessons from Invariant Mass spectroscopy about light nuclei Accidental “cluster” physics

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  1. Lessons from Invariant Mass spectroscopy about light nuclei Accidental “cluster” physics A. 11O, 12O (mirrors of 11Li,12Be),16O fissionB. Another analog of 11LiC. Sequential 2p-2p decay D. 2p decay between IASsE. Hoyle/3- decay F. Extreme longitudinal spin alignmentsG. Isospin symmetry breaking (not)I. The interesting cases of two NEW resonances near p-decay thresholds. R. J. Charity, L. G. Sobotka+ J. Manfredi, R. Shane, K. Brown, T. Webb, D. Hoff, C. Pruitt + collaborators at NSCL, TAMU + M. Ploszajczak J. Okolowicz for last topic.

  2. From enriched Carborane C2[10B10]H12 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 3.6 k pixels 

  3. 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.

  4. A. New nuclei B. New states T. Webb et al., close to submission (2018) New state New nucleus Mirror of 11Li ? Due to width • End of nuclear spectroscopy • Cannot inform on amount of 2nd s in WF This is the mirror of 12Be and we now Have: 0+1,2 and 2+1,2 or 0+1 and 2+1,2 and the branching ratio of To gd and 1st excited state of 10C. ~ 15 k pixels

  5. 16O fission (i.e. two 8Be)E* = 19.2, 20.9, 22.0 G < 400 keV (maybe <<)Does the absence of a lower lying peak mean it does not exist? Perhaps not.

  6. B) Another new state: 11B DIAS  Analog of 11Li 11B → 2p+9Li (decay branch) DIAS in 11B E*=33.6 MeV G=306(182) keV Unfinished Bridge 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

  7. 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. Low-lying states On the bridge 11O • Charge (Z) T = 5/2 wave functions in a bigger box 11Li If isospin were a good QN (& Coulomb only 2-body) with 3 masses  Predict masses of all other members of multiplet.  Mass of 11O depends on % 2nd s in WF. R.J. Charity et al.,Phys. Rev. C 86 041307(R)(2012).

  8. B. Known state, new 12N (2-) width. Relevant for rap New width of 2- in12N (~ ½ NNDC value ) leads to reduced 11C(p,g) rate. L. G. Sobotka et al.,Phys. Rev. C 87, 054329 (2013). Calcs by Akram.

  9. C,D: Decay paths – new decay modes 8B reconstruction from 6Li+p+p TOP 9C  8Cgdst (0+, T=2) +nBOT9C  8BIAS (0+, T=2) +p g 6LiIAS Ligs + gamma 1p and 1n 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 90, 027304 (2014).

  10. C. 2p-2p decay  A 5-particle correlation study. QUESTION: What is dynamical path for 8C decay?Is 6Be a “rest stop”?Correlations between p’s? From 12C(a,8He) [Tribble et al., PRC 13, 50 (1976)] D = 35.094 MeV G= 230 keV Sp = + 65 keV From 10B(3He,6He) D = 27.870 MeV G= 1.4 MeV Sp = -2.207 MeV OLD ~ 3 zs G= 1.23 MeV Sp = -1.966 MeV T = 2 ~ 7 zs G= 92 keV Sp = + 595 keV p p p p T = 1 a 8C  ??  a+p+p+p+p T = 0

  11. First Some Combinatorics IF 8C decays via 8C [6Be] + 2p[a+2p]+2p ….. there will be two protons from the first step and two from the second. There are 6 ways to choose two protons from a set of four protons, 6 = 4!/(2!2!). Construct E*(6Be) from ETKE of a+2p, from all 6 combinations ONE combination will be correct and FIVE will be wrong.  Increment a histogram once for EACH combination. i.e. six increments/event, If6Be intermediate  1 correct & 5 wrong. 5 – particle correlation “like your hand” p p p p a

  12. 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)

  13. G. Tests of isospin symmetry Known 12N Known 13N 12O10C + 2p Narrower 12N* 10B* + 2p New No evidence of isospin symmetry breaking above that expected (few - several keV… Bertsch)

  14. G.Tests of isospin symmetry K. Brown et al, unpublished (2016) A = 7 M. Jager, et al., Phys. Rev. C 86, 011304 (R) (2012). A = 7 & 12 … no (longer) evidence for isospin sym. breakingA = 8 … case still stands as suggestive.

  15. Why do there appear to be so many “tuned” resonances? 12C*, 11Li, 15F, 17O, 26O

  16. H. Two new resonances close to cp decay thresholds One in 9Li* the other in 10Be* Well as Faraday said to Maxwell… “What is the go of it?” Too low in E to be IAS. Vlad G. suggested AAS i.e. T< .

  17. Now back to 2008Secondary beam of 12Be (t1/2 = 24 ms)Smash it up-Look in debris using particle-particle correlations KNOWN 6Li* And 7Li* both T=1/2 and T=3/2 7He analog Unknown NOT IAS (T = 5/2) of 9He Too low in E Must be some sort of T = 3/2.

  18. Shell Model Embedded in the Continuum(SMEC) ….. M. Ploszajczak J. Okolowicz The continuum-coupling correlation energy – a correction to the SM eigenstate – is a strong function of the energy distance from the threshold. SM + continuum coupling between localized states and 1-nucleon decay channels The mixing of two SM eigenstates due to H1(E) consists of: a) the Hermitian principal value integral describing virtual excitations (within the SM space) and b) the anti-Hermitian residuum representing the irreversible decay out of the localized space. CSM are linear combinations of SM eigenstates

  19. A few details • SM calc uses YSOX interaction – full psd + (0-3)hbarw excitations. The Wigner-Bartlett contact interaction V12 = V0(a+b)Ps12d(r1-r2) Vnn= Vpp= V0(a-b) and Vnp=V0(a+b)  The eigenvalues of H(E) are real below lowest threshold, complex above. H(E) = HQ0Q0 + WQ0Q0 WQ0Q0 = HQ0Q1 G+Q1(E) HQ1Q0 Aside from SM matrix elements have V0, a and b as parameters.

  20. DATA SMECComparison 9Li* 10Be*

  21. DataSMEC

  22. Metric for continuum coupling:The continuum-coupling correlation energy proton continuum pushes resonance to threshold Adding neutron Channels, Pulls down Even more AND The near resonance Resonances acquire Large p SF. A simple explanation: the more “large box” states in the mixing problem the lower the energy. Even open neutron channels helps to make resonance Look more like (p) scattering state. …… ????

  23. IAS vs AAS WF decomposition Isospin coupling of residue + nucleon IAS5/2 = (4/5) <9LiIAS + n > + (1/5) <8He + p > AAS3/2 = (1/5) <9LiIAS + n > + (4/5) <8He + p >

  24. Summary (only last subject) • Open-shell QM allows for mixing (through the continuum) not present in standard SM treatments. • The splinters of the anti-analog strength, generate a comb of states, one or more or which can be ushered to a decay threshold by continuum-enhanced mixing. • Caution: mixing of states near one threshold may be strongly influenced by a lower (common) threshold. In particular, if the lower threshold in for n’s, this will draw down the optimal “window” for mixing closer to the cp threshold.

  25. 17Ne decay confirmedvia ghost story An enlightening Ghost story ! Actually this ghost (dog) did not say boo (bark)

  26. F. Large longitudinal spin alignment omit R. J. Charity et al., Phys. Rev. C. 91, 024610 (2015). D.E.M. Hoff et al., Phys. Rev. Lett. 119, 232501(2017); Phys Rev. C in press (2018).

  27. The “ go of it” Step 1: An angular-momentum – excitation energy-mismatch That compels “tilting” above a certain beam energy. Step 2: The transition matrix (defining the m-state distribution) can ~ be written as the sum of an “internal” and “external” CG coeffs. Step 3: Details (averaging, interference, angle coverage).

  28. E. Hoyle and 3- decay 1. Gate on Hoyle and Construct a rms energy Erms = [ <E2> - <E>2 ]1/2 Compare to simulations Equal Energy 2. Gate on 3- and generate 8Be* spectrum Hoyle8Beg.s. Gated data Equal Energy < 0.45% (3s) Two newer works have reported 10 x lower limits (2s). 12C (3-) 8Beg.s. + a ~100.% The “Ghost Peak” line shape is expected from R-matrix calc. omit J. Manfredi et al., Phys. Rev. C 85, 037603 (2012).

  29. Spectroscopic factor of the major decay resonance. The proton s1/2 spectroscopic factor for the Jnp= ½+5 state is 0.14 . This is the second largest spectroscopic factor among all J= ½+; T = 3/2 states. These relatively large spectroscopic factors are the hallmark of the continuum-induced collectivization.

  30. 3/2 1/2 = Tz = -1/2 -3/2

  31. Technology: G. L. Engel et al., NIM A573, 418 (2007). HINP M. S. Wallace et al., NIM A 583, 302 (2007). HIRA G. L. Engel et al., NIM A 612, 161 (2009). PSD improvements ported to HINP G. L. Engel et al., NIM A 652, 462(2011). HINP + PSD A = 5  5H and 5Be Wuosmaa et al., Phys. Rev. C 95, 014310 (2017); R. J. Charity et al. in preparation (2018). 6Be: L.V. Grigorenko et al., Phys. Lett. B 677, 30 (2009); L.V. Grigorenko et al., Phys. Rev. C 80, 034602 (2009). I.A. Egorva et al., Phys. Rev. Lett. 109, 202502 (2012). 8C and 8BIAS :R. J. Charity et al.,Phys. Rev. C 82, 041304(R) (2010); R. J. Charity et al., Phys. Rev. C 84, 014320 (2011). + miscK. W. Brownet al., Phys. Rev. C 90, 027304 (2014). AAS J. Okolowicz, M. Ploszajczak, R. J. Charity and L. G. Sobotka, Phys. Rev. C 97,044303 (2018). 10C: R. J. Charity et al., Phys. Rev. C 75, 051304(R) (2007); K. Mercurioet al., Phys. Rev. C 78, 031602(R) (2008), R. J. Charity et al., Phys. Rev. C 80, 024306 (2009). T = 5/211Li,11Be,11B R.J. Charity et al.,Phys. Rev. C 86, 041307 (R)(2012). 12C (Hoyle) J. Manfrediet al., Phys. Rev. C 85, 037603 (2012). 12O + 12NIAS M. Jageret al., Phys. Rev. C 86, 011304 (R) (2012) 11O + 12O T. Webb et al., close to submission (2018) 12Be: R. J. Charity et al., Phys. Rev. C 76, 064313 (2007). 13O decay and 12N (2-) L. G. Sobotka et al.,Phys. Rev. C 87, 054329 (2013). 16Ne (3-body)K. W. Brownet al., Phys. Rev. Lett. 113, 232501 (2014), K. W. Brownet al., Phys. Rev. C 92, 034329 (2015). 17Na + (8B,9B,9C,16F)K. W. Brownet al., Phys. Rev. C 95, 044326 (2017). 17Ne (alignment +) R.J. Charity et al.,Phys. Rev. C in press(2018). Misc (inc. 9Li*,10Be*): R. J. Charity et al., Phys. Rev. C 78, 054307 (2008). Isospin symmetry breaking R. J. Charity et al., Phys. Rev. C. 84, 051308 (R) (2011). Alignment 6Li, 7Be: R. J. Charity et al., Phys. Rev. C. 91, 024610 (2015). 7Li D.E.M. Hoff et al., Phys. Rev. Lett. 119, 232501(2017); D.E.M Hoff et al. Phys Rev. C in press (2018). Technology and light-nuclei continuum spectroscopy papers

  32. extra

  33. Aside (?) on super-radiant resonances(Auerbach, Volya and Zelevinsky) Originally (Dicke) for Quantum optics …. A collective interaction of “internal states” mediated through their common continuum, i.e. virtual emission and absorption of quanta, can generate spontaneous coherent radiation. (Not the same as traditional spontaneous radiation.) AVZ appreciation …. Radiation field  common decay channels.

  34. Wave Function decomposition

  35. Case # 3, ½+ state in 17O, the state enabling the s-process. After CNO (thus have some 13C)  13C(a,n)16O [High-mass stars 22Ne(a,n)25Mg] This state is 3 keV below CP threshold, but note n channel is well open. 7.20 3/2+ 280 keV 7.16 5/2- 1.4 keV 6.97 (7/2-) 1 kev 6.86 (5/2+) 1 kev 6.36 ½+ 124 keV

  36. Case # 5 15F* (Case 5a 14O*) 14O(p,p’)14OE* = 4.757 MeV G = 36 keVassigned to ½- and is almost pure quasi-bound p’s in 2s1/2.Gamow SM using 12C + 3 p’s129 keV above 2p threshold 12C + 3p model 

  37. Just to make sure we are on same page Case # 5 15F*

  38. D. Lots of Toys made over the years to do … (what follows) • Ion chambers large and small • Phoswiches DWARF Ball and Wall MINI-Wall • Large Si arrays LASSA Annular - Si HIRA • ASICS (chips) For Si arrays For Scints (mball – simulations + Si arrays)

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