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Measuring neutron-unbound states with MoNA-LISA
Jenna Smith ISAC Theory Forum 15 December 2014
Neutron decay measurements of 11Li and 12Be
Background on 11Li
Gurov et al., Bull. Russ. Aca. Sci., 740, 433 (2010)
Kobayashi et al., NPA, 538, 343 (1992)Korsheninnikov et al., PRC, 53, R537 (1996)11Li(p,p)
11B(π-, π+)11Li14C(π-, pd)X
Projectile Fragmentation Cross sections (Projectile Fragmentation)
18O + Be -> N=1-16Method: 4 - EPAX 3.1a: K.Summerer,Phys.Rev.C86(2012)014601
L I S E ++ [Noname]11-12-2014 15:18:08
1 3 5 7 9 11 13Neutrons (N)
1
3
5
7
9
11
Prot
ons
(Z)
4e-143e-133e-123e-113e-102e-092e-082e-072e-062e-052e-041e-031e-021e-011e+001e+011e+02
2H1.1e+01 mb
3He6.6e+00 mb
4Li1.0e+00 mb
3H5.6e+00 mb
4He1.4e+01 mb
5Li8.1e+00 mb
6Li1.8e+01 mb
7Be9.5e+00 mb
8B1.2e+00 mb
9C8.9e-02 mb
10N6.0e-03 mb
6He1.9e+00 mb
7Li1.2e+01 mb
8Be2.3e+01 mb
9B1.0e+01 mb
10C1.1e+00 mb
11N6.9e-02 mb
8Li3.4e+00 mb
9Be1.8e+01 mb
10B2.9e+01 mb
11C1.0e+01 mb
12N8.1e-01 mb
13O4.5e-02 mb
14F4.5e-04 mb
8He2.2e-02 mb
9Li5.6e-01 mb
10Be6.1e+00 mb
11B2.8e+01 mb
12C3.3e+01 mb
13N8.3e+00 mb
14O5.0e-01 mb
15F5.0e-03 mb
11Be1.3e+00 mb
12B1.2e+01 mb
13C4.3e+01 mb
14N3.4e+01 mb
15O5.4e+00 mb
16F5.4e-02 mb
17Ne1.1e-04 mb
18Na4.4e-08 mb
11Li4.3e-03 mb
12Be1.5e-01 mb
13B3.0e+00 mb
14C2.3e+01 mb
15N6.0e+01 mb
16O2.9e+01 mb
17F2.9e-01 mb
18Ne5.7e-04 mb
19Na2.3e-07 mb
20Mg1.8e-11 mb
14B5.7e-01 mb
15C8.1e+00 mb
16N4.9e+01 mb
17O7.3e+01 mb
18F7.3e-01 mb
19Ne1.5e-03 mb
20Na5.8e-07 mb
21Mg4.6e-11 mb
14Be1.3e-03 mb
15B6.8e-02 mb
16C2.1e+00 mb
17N2.3e+01 mb
18O1.2e+02 mb
19F2.3e-01 mb
20Ne4.7e-04 mb
21Na1.9e-07 mb
22Mg1.5e-11 mb
17C2.1e-02 mb
18N2.3e-01 mb
19O7.3e-01 mb
20F9.6e-02 mb
21Ne1.9e-04 mb
22Na7.7e-08 mb
23Mg6.1e-12 mb
17B1.4e-06 mb
18C4.2e-05 mb
19N4.7e-04 mb
20O1.5e-03 mb
21F1.9e-04 mb
22Ne3.8e-05 mb
23Na1.5e-08 mb
24Mg1.2e-12 mb
19C1.7e-08 mb
20N1.9e-07 mb
21O5.8e-07 mb
22F7.7e-08 mb
23Ne1.5e-08 mb
24Na3.1e-09 mb
25Mg2.5e-13 mb
19B4.4e-14 mb
20C1.3e-12 mb
21N1.5e-11 mb
22O4.6e-11 mb
23F6.1e-12 mb
24Ne1.2e-12 mb
25Na2.5e-13 mb
26Mg4.9e-14 mb
LISE++ calculation
Cross-section (m
b)
102
10-14Neutrons (N)
Prot
ons
(Z)
Interpretation through simulation
Physical reality
Experimental limitations Data+ =
PhysicsExperimental limitationsData - =
Interpretation through simulation
Physical reality
Experimental limitations Data+ =
Physics Simulation Simulated data+ =
Simulation
• Beam profile • Reaction dynamics • Fragment tracking • Detector acceptances and
resolutions • Neutron interactions in
MoNA-LISA • Cross-talk
• Decay energy distribution
Spin and parity in 12Be
• Requires L=1 decay to 1/2+, 1/2-
"• Population: 1p knockout from 13B
ground state of 3/2-
"• Very little 2n decay
• Spin: 0, 1, 2 "
• Eliminates 0-
""
• Negative parity
Probable spin and parity:"1-, 2-
Garrido et al., PRC, 86, 024310 (2012)Smith et al., PRC, 90, 024309 (2014)
Two neutron correlations
• Sequential model • continuum shell
model formalism • input: central energies
and widths • output: neutron energy
distributions • neutrons: same orbital,
paired to J=0+ • Dineutron model
• input: central energy and width • output: total energy and dineutron energy • assumes two L=0 decays
• 3-body model • phase space decay • input: central energy and width • output: energies and angles of particles
Future directions
• Combining neutron detectors with gamma, beta detectors "
• Identification of unique particles (neutrons) "
• Better models that track the entire decay "
• Neutron-rich beams needed to reach the neutron drip line at higher Z
Acknowledgements
• Local MoNA group • Thomas Baumann, Greg Christian, Michael Jones, Zach Kohley,
Shea Mosby, Jesse Snyder, Artemis Spyrou, Krystin Stiefel, Michael Thoennessen
• MoNA Collaboration • Michigan State University • NSCL • Funding
• NSF, NNDC