Nuclear structure through dynamics and correlations Martin Freer, University of Birmingham

Nuclei from first principles

Nuclei from first principles What is the nature of the proton? How does the proton get its spin? 99% of mass can be attributed to the strong interaction and not the Higgs mechanism

Nuclei from first principles Can we understand the nuclear force?

Chiral EFT on the lattice

12C (and the Hoyle-state) Fred Hoyle F. Hoyle, D. N. F. Dunbar, W. A. Wenzel, Phys. Rev. 92, 1095 (1953) . C. W. Cook, W. A. Fowler, T. Lauritsen, Phys. Rev. 107, 508 (1957) 0+

Carbon-12 l=1 3- 4- 5- 4+ 0+ 2+ 4+ 2+ K J 0+

Carbon-12 3- 4- 5- 4+ 0+ 2+ 4+ 2+ 0+

Evidence for a 2+ excitation of the Hoyle-state Zimmerman, et al. PRL

12C(gamma,3α) 2+ 12C(4He,4He’)12C Freer, et al. PRC

12C(α,α’)3α 4+ 4+ 2+ 12C(4He,4He’)12C

O. S. Kirsebom, et al Phys. Rev. C 81, 064313 (2010)

What about the 5- ? 12C(a,3a) a 3- 0+ 4+ 5- D. J. Marín-Lámbarri Phys. Rev. Lett. 113, 012502 (2014)

5- 4+ 4- 3- 2+ 0+

Hoyle state structure? α-condensate / α-gas 8Be + α configuration Antisymmetrized Molecular Dynamics Fermionic Molecular Dynamics “Bent arm” Ab initio lattice calculations Linear chain Alpha cluster model Skyrme model α-condensate / α-gas THSR wave function Calculated direct decay vs sequential BR = 0.06%

Experimental Set-up Decay particles striking separate DSSDs gives a lower background Events where 2 particles hit the same DSSD were also considered α α α α

Break-up channel identification ε ≈ 0.5 ε ≈ ?

The Dalitz Plot Sequential ε3 ε1 + ε2 + ε3 = 1 P1 + P2 + P3 = 0 ε1 ≈ 0.5 ε2 ≈ 0.5 ε3 ≈ 0.5 ε1 ε2

The Dalitz Plot Direct ε3 BEC ε1 + ε2 + ε3 = 1 P1 + P2 + P3 = 0 ε1 ε2

2.4 × 104 events

Fitted projected Dalitz plots 0% BR 0.05% BR 0.1% BR BR < 0.047% (95% C.L.)

Predictions: 16O

28Si 16O beam at 10, 17.5, 25 AMeV 12C target 28Si* decays and populates series of states in daughter nuclei FARCOS CHIMERA For more information talk to Jack Bishop.

Alpha multiplicity