Exotic dancing on the bridge between driplines

TAMU – JBN

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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 expertiseFusion, 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

NUCLEAR CHEMISTRY

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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 CurieFission Hahn and StrassmanPhotosynthesis and biological tracers S. Ruben and M. KamenTransuranics Wahl, Kennedy and Seaborg, followed by manyNucleosynthesis ideas C. Coryell (before B2FH !)Isotope chemistry and chemical reaction dynamics H. Urey and J. BigeleisenNeutrino Astro “physics” – looking inside the sun Ray DavisLarge-molecule Mass spec. Ron MacfarlanePositron-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…

1. Overview of physics and experimental logic

2. The structure of 11Li from its analogs

3. A = 8 8C 6Be + (2p) +2p + (2p) : 2p-2p & Isospin symmetry breaking 8BIAS6LiIAS + 2p : First IAS IAS 2p decay

4. A = 12 12C Hoyle and 3- decay : Exclusively through 8Beg.s. 12O : A new mass and width 12NIAS 10BIAS +2p : Second IAS IAS 2p decay + IMME 12N (2-) new width : reduced “RAP” rate

5. 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

Exotic Dancing on the Bridge between driplines.

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I. Physics overview

1. Multiple proton decay at the drip-line Continuum nuclear structure

2. Improve/complete isospin multiplets

3. 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 e

P CorrelationsSecrets told in mass anddecay correlations

Your place or mine ?

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8He 8C

A = 8 2p d

ecay

New

type

2p d

ecay

New

mas

s

Momentum Achromat Recoil Separator (MARS)

Scale (meters)

0 5

15 MeV/amu

B10

H GasTargetP = 1.7 atmT = 77 K

2

Velocit

y Filter

10.7 MeV/amu > 99.5%

10C Emittance

Slits

DP SlitsFaraday Cup

Q5Q4

D3

V1

D2S1 Q3 D1 Q2

Q1T

SW2 QY QX

SW1

From enriched CarboraneC2[10B10]H12

I. Experimental logic TAMU using K500 cyclotron and the MARS separator

ECRsource

K-500 cyc

E* = ETKE – Qgg

(t1/2 = 19.3 s)

2*105/s

A 4-particle correlation experiment !

E* (parent) = “POP” – mass

(p,n)

Inelastic excitation

Primary reaction

Secondary reaction

Time, Energy, and Particle resolving “CAMERA” with 4k pixels

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Determined the decay paths for known and two new levels in 10C using….

4-particle and sub event (2- and 3-particle)

energy correlations.

2,3 - particle 4-particle (pp) intermediates

9.7

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Also disproved a level claimedby others at 4.2 MeV. The other group later retracted their claim.

Isospin primer

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1. If isospin is a good quantum number, in the absence of Coulomb forces the energies of a multiplet should be independent of Tz.

2. 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 eTz

4 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.

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Unfinished Bridge

2. Consider the Multiplet that includes 11Li: A = 11 Sextet T=5/2, J=3/2-

11B → 2p+9Li (decay branch)

11C 11BT=1/2, J=3/2-, doublet (used as reference)

T=3/2, J=1/2+,quartetone-nucleon halo

T=5/2, J=3/2-, sextettwo-nucleon halo

11N

11O

11Be

11Li

Known particle-stable

Isospin-allowed 2p decay possible

E*=33.6 MeV=306(182) keV

12Be(p,2n)11B at E/A = 50 MeV @NSCL with HiRA array.

DIAS in 11B

IAS known (RIKEN 1997) p+n decay

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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.

Calc. Exp.VC(11B-11Be) = 1.375 1.389(20) MeVVC(11Be-11Li) = 1.797 1.69(8)

R.J. Charity, et al., Phys. Rev. C 86 041307(R) (2012).

np

-p-p-p-pfrom 9C beam

-p-pfrom 7Be beam

-p-pfrom -p-p-p-p

Peak / bkg 1 / 5

3. 8C decay

6Be is the (7 zs) intermediate, i.e.8B [6Be] + 2p + [ +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.

T = 2

T = 1

T = 0

Excitation energy (MeV)

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TOP 9C 8Cgdst (0+, T=2) +nBOT 9C 8BIAS (0+, T=2) +p

1p or n decays are forbidden by eitherenergy or isospin

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8B reconstruction from 6Li+p+p

6LiIAS Ligs + gamma

R. J. Charity, et al., Phys. Rev. C 82, 041304(R) (2010).K. Brown, et al., Phys. Rev. C in preparation (2013).

Confirmation of Isospin symmetry breaking in A = 8

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

The fit (RESIDUALS)

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TClassic case of isospin mixing

R. J. Charity, et al., Phys. Rev. C. 84, 051308 (R) (2011).

We have actually found two cases of this new class of 2p emitters: IAS IAS

?

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A = 16: NSCL16Negs but NOT 16FIAS

A = 12: TAMU 12Ogs & 12NIAS IMME

A = 8: NSCL 8Cgs & 8BIAS IMME

5. The A=12 Isobar Energy Diagram

T=2

T=1

T=0

TZ = 2 TZ = 1 TZ = 0 TZ = -1 TZ = -2

12Og.s.12NIAS

12CIAS12BIAS.

12Beg.s

b) Energy

unknown

c) Width controversy

a) Decays of

3- or …..

0+ Hoyle

Both studied in

high statistics and excellent E resolution.

d) Second pair of isospin clones of 2p decays:

12Og.s. And 12NIAS

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12C (3-) 8Beg.s. +

The “Ghost Peak” line shape is expected from R-matrix calc.

i) Gate on Hoyle and Construct rms energyErms = [ <E2> - <E>2 ]1/2 Compare to simulations

Equal Energy

Hoyle8Beg.s.

Equal Energy (UPPER LIMIT) = 0.45% 17 times lower than Raduta et al. value

ii) Gate on 3- and generate 8Be* spectrum (choose smallest E*)

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Gat

ed d

ata

R-matrix

12C (Hoyle) 8Be g.s. +

J. Manfredi, et al., Phys. Rev. C 85, 037603 (2012).

How do Hoyle and 3- states decay?

A = 12 data onusing 13O @ TAMU

12O10C + 2p

12N* 10B* + 2p

New mass & width 12O, < 72 keV Old 400-600 keV

&

Complete quintet

No evidence of isospin sym. breaking @ A = 12

13O -n 12O 10C + 2p 13O -p 12N*10B*+2p T = 2 1 T = 2 1

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Known +

Known

New

Narrower

New

Narro

wer

2nd case IASIAS 2p

12N

13N

M. Jager, et al., Phys. Rev. C 86, 011304 (R) (2012).

Quadratic IMME perfect

Returning to the same A = 12 2p experiment, we found….

Results:

a) New width of 2- in12N (~ ½ NNDC value ) leads to reduced 11C(p,) 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.

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L. G. Sobotka, et al., Phys. Rev. C 87, 054329 (2013).

New 12N 2- width new states in 13O

SummaryWealth 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 in12CFound 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.

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Future plansCompare 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

tot(n) on stable but rare isotopes [LANSCE]

Photorespiration and drought [WU]

END

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A. The “Hoyle” picture: a sequence of improbable events

Decay of Hoyle state

formation of Hoyle state(tail of exponential Maxwell-Boltzmann distribution)

Width (ev) 5.5 8.5Lifetime (s) 120 x 10-18 77 x 10-18

9996/10000 4/10000

B. The Old unresolved issueThe 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 for12Cgs + n 12C7.65 + n’ and12C4.44 + 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

(n,n’)

Previous (n,n’) measurementsElastic cross section large

Cross section to 2+ large, 3- medium

Cross section to Hoyle small

What is the point of measuring n’?

1. ONLY to confirm that the HOYLE was formed.

2. But IF the HOYLE is formed 9996 times/10,000 it decays 12C* 8Be + (+) +

That is

3. Forget looking for n’ just look for 8Be- “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

12C*

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.

(n,p) is well known, will lead to single-ended tracks and thus is an internal calibrationRunning just above the 3- leads to another check that (n,n’) can be extracted.

Genesis of this ideaSam 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

Known

6Li*

And 7He analog in 7LiIAS

(I = 3/2-, T=3/2)

Unknown9He analog in 9LiIAS (I = 1/2+, T = 5/2) ?Its ~600 keV lower than “expected”.

Could be of mixed isospin: T = 5/2 + 3/2With almost pure 8He x p (1s1/2 character)

with s- Coulomb shift. John Millener

Secondary beam of 12Be (t1/2 = 24 ms)Smash it up

Look in debris using particle-particle correlations

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Isospin 2-state mixing for 9LiIAS pair of mixed levels* like

8BeIAS pair of T = 0+1 levels?

Shell-model states Physical States

a) aspace,spin,T = 5/2, IAS) ) space,spin, T= 3/2 + 5/2)

b) bspace,spin,T = 3/2) ) space,spin, T = 3/2 + 5/2)

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T = 5/2

T = 3/2

I = 1/2+

I = 1/2+

I = 1/2+

I = 1/2+

T = 3/2 + 5/2

T = 3/2 + 5/2

IF the lower state were almost pure| 8Heg.s. x 1s1/2(p) >

It would explain the LOW Coulomb energy !

Observed ?

a

b

Same space, spin, ~ E mix

* Suggested by John Millener

New 8C mass and uncertainty+ since last fit

new 8He mass and correct error in previous fit. 1. If isospin is a good quantum number, in the absence of Coulomb forces

the energies of a multiplet should be independent of Tz.2. If charge dep. forces only two-body

the masses should if fit with a quadratic IMME.

3. The need for dTz3 and eTz

4 terms isospin symmetry breaking. (This statement is not invertible!)

New since last fit - ours - previous fit used wrong mass uncertainty*.

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*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).

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2. Prototype 3-body decay: 6Be + 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).

B. Dispersive Optical Model - DOM

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g9/2

J. M. Mueller, et al., Phys. Rev. C 83, 064505 (2011), a 31 pg paper !

g9/2

D. Technology

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1. ASIC for Si strip detectors 2. ASIC for PSD capable scintillators 3. DSP method for tot(n)

Used at: NSCL, TAMU, ORNL, LSU/FSU, RIKEN, ND, 1000’s of channels in a suitcase Used at: LANSCE

Used at: Wash. U. & LANL1000’s of channels in a suitcase

Liquid scintn- separation

G. Engel, et al., NIMS A652, 462 (2011).R. Shane, et al., NIMS A614, 468 (2010).

Dense stops in one macro pulse

One stop, fit of DSP data

2.5 % rms deviation from literature

C. Misc topicsGEMINI Hasy vs Easy M1 (48Ca)

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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 transitionIt does not matter

Above phase transitionthey diverge. Divergence will be modeldependent.

LGS 1 PRC paper

It is not always clear if experimental work extractsthe asymmetry Energy or Enthalpy

IMP 11.98

CM (0hw) 8.96(e,e’) 5.3ERPA ~ 6.1

LGS 1 PRC paper