Nuclear Theory at SurreyThe Cosener’s House, Abingdon,

Wednesday 23rd May 2007

Jeff Tostevin, Department of PhysicsFaculty of Engineering and Physical SciencesUniversity of Surrey, UK

People and connectedness

Theory Personnel - May 2007 Academic Staff Jeff Tostevin (Professor) *** Jim Al-Khalili (Professor)

*** *** Makito Oi (Advanced Fellow and Lecturer) ***

Paul Stevenson (Lecturer) Phil Walker (fraction, Professor)

Ron Johnson (Emeritus Professor) Research Staff *** Qiang Zhao (Advanced Fellow) ***

Natasha Timofeyuk (PDRA) A.N. Other (PDRA) *** Alex Brown (MSU, Visiting Fellow: 4 months) *** *** Ian Thompson (LLNL, Visiting Fellow: 2 months)

*** Research students

12 PGR students

Collaboration and trainingWe link strongly with both the UK and international experimental programmes in RIB (GSI, GANIL, TRIUMF, MSU, RIKEN) and hadron physics (MAMI, Beijing, JLab);

Joint grants/investigatorsRISING (GSI) – Tostevin, Stevensonp-decay (L’pool, Daresbury) – Al-Khalili, StevensonLaser Spectroscopy (B’ham, Manchester) -

StevensonANU (Break-up and/on Fusion) -Tostevin

Experimental proposals, e.g.RIKEN (RIBF) 80Zn 78Ni, 2p knockoutMSU (NSCL) 2N knockout, pickup, break-up

Training Schools (theoretical pull to attract Visiting Fellows)Mini-School on the Nuclear Shell Model – March 2007 - BrownMini-School on Direct Nuclear Reactions (planned) – Thompson based on successful JINA event at MSU

Science base and scope

Nuclear reactions/dynamics: (Tostevin, Al-Khalili, Johnson) Reactions for exotic nucleus spectroscopy: e.g. nuclear- and nucleon-induced knockout, transfer, breakup, proton decay… Reaction dynamics and novel few- and many-body methodologies. Reactions for astrophysics and fusion reactions.Emphasis is on prediction of and quantitative confrontation of new data and phenomena.

Nuclear structures/dynamics: (Stevenson, Oi, Walker) Few, many-body and collective dynamical models. Unconstrained deformed mean field (and beyond) calculations. Time-dependence, dynamics, the nuclear response, and the GR. 3D rotation – novel rotational modes, Bose condensates. Isomeric states

Hadron physics: (Zhao, Al-Khalili) Hadron resonances and spectroscopy, multi-quark models.

Activity – increasingly, the borders merge

Nuclear reactions/dynamics: PRL 98, 152701 (2007), 96, 032502 (2006), 96, 162501 (2006),PRL 93, 042501 (2004), 91, 232501 (2003), 91, 012501 (2003), PRL 90, 159201 (2003), Nature 435, 922 (2005)

Nuclear dynamics/structures: PLB 641, 34 (2006), 634, 30 (2006), PRL 92, 252501 (2004), PLB 606, 43 (2005), 576, 75 (2003), 545, 291 (2002)

Hadron physics: PRL 96, 132003 (2006), 91, 022004 (2003), PLB 645, 173 (2007)PLB 636, 197 (2006), 631, 22 (2005), 596, 317 (2004), PLB 590, 176 (2004), 586, 91 (2004), 553, 211 (2003)

Theoretical activity – Recent “Letters”

Nuclear Structure Theory

Effective interactions and nuclear responses

effective interaction

mean field+ beyond

nuclear matter+ neutron stars

Giant resonances+ fusion reactions

Ground state structure

Funded collaborations with the Surrey/UK experimental effort

Funded collaborations with the Surrey/UK experimental effort

proton emitting nuclei

isomeric states

+ correlations in TDHF

Microscopic and Quantal descriptions of structure of many-body systems

under rotation

• High-spin nuclear structure (Fermion)– Self-consistency in collective and single-particle degre

es of freedom– Variational approach with quantum-number projections

(and Generator Coordinate Method) VAP (variation after projection)

• Rotating Bose-Einstein condensate of ultra-cold atomic gases in a trap (Boson)– Quantum phase transition from collective modes to vo

rtices and/or the Lowest Landau Level.

Cut through the calculated energy surface for 256Fm, versus quadrupole deformation

Influence of nuclear shapes on decay rates These effects are being investigated in collaboration with Professor F Xu (Beijing University) using a Woods-Saxon-Strutinsky method with a realistic treatment of pairing.

P.M. Walker and F.R. Xu, Phys. Lett. B 635 (2006) 286F.R. Xu et al., Phys. Rev. Lett. 92 (2004) 252501

deformation

J=7 isomer

ground state

Will high-spin isomers enable the observable stability limits to be further extended?

Nucleon and resonance decays

(Halos and astrophysics)

Three-body decay as two sequential decays

E

Q1n

Threshold

Initial Intermediate Final

U

Q2n

6He 5He 4He

2+

0+

3/2-

Proton decay and 3-body decay widths[accuracy of R-matrix methods (Barker), also relevant to knockout reactions to unbound states, e.g. 6He(2+) ]

Nuclear reactions for astrophysicsImprovements to theories of nucleon transfer and capture reactions - used to determine relevant reaction rates.

Mirror symmetry as tool to pin down cross sections for (N, ), (, ), (N, ) reactions in stars. (Timofeyuk, IoP Conf 2007)

Improvements to theories of nucleon transfer and capture reactions - used to determine relevant reaction rates.

Mirror symmetry as tool to pin down cross sections for (N, ), (, ), (N, ) reactions in stars. (Timofeyuk, IoP Conf 2007)Possible pre-asymptotic abnormalities in single-particle behaviour near the drip-line and their influence on (N, ) reaction rates.

Possible pre-asymptotic abnormalities in single-particle behaviour near the drip-line and their influence on (N, ) reaction rates.

1) 7Li+8Li (TRIUMF) will test transfer theory and constrain 7Be(p,)8B using mirror symmetry solar neutrino physics

2) Pre-asymptotic abnormalities in 9C and 16C uncertainties in 8B(p, )9C (explosive hydrogen burning) and 15C(n, )16C (neutrino-driven wind r-process of supernova explosions)

New reaction methodologies for the most rare, exotic

systems

Experimental/theory advances:Phys Rev Lett 91 012501 (2003)NATURE 425,570 (2003), NATURE 435,924 (2005), NATURE 435, 897 (2005)

Knockout spectroscopy : First study of 36Mg1) Insufficient yield for, e.g. secondary beam inelastic scattering

2) Parent for beta decay, 37Na, is particle unbound3) So, use 2p removal from n-rich (sd-shell) parent, 38Si

9Be121j2j

TI ,

fJc

Microscopic theory of 2N removal developed at Surrey Phys Rev C 74 064604 (2006)Phys Rev C 70 064602 (2004)

38Si

p n p n p n

+

The Island of Inversion extends to 36Mg?

Monte-Carlo shell model calculations: SDPF-M interaction of Otsuka et al.

Measured cross sections and those calculated assuming population of the 0hw components of the final states by the direct 2p knockout reaction mechanism

RISING: neutron rich systems near 208PbWork in progress is looking at multi-proton knockout from 208Pb – and the yields/isomeric ratios of low seniority, high spin isomeric states in heavy neutron-rich systems (Steer, Podolyak, Regan)

Data: T. Kurtukian Nieto, PhD Thesis, Universidade de Santiago de Compostela (2007)

number of removed protons impact parameter (fm)

Cro

ss s

ect

ion (

mb)

208Pb + Be1 GeV/nucleon

Science and connectedness

Collaboration, fundamental questions, trainingWe link strongly with both the UK and international experimental programmes in RIB (GSI, GANIL, TRIUMF, MSU, RIKEN) and hadron physics (MAMI, Beijing, JLab);

Joint grants/investigatorsRISING (GSI) – Tostevin, Stevensonp-decay (L’pool, Daresbury) – Al-Khalili, StevensonLaser Spectroscopy (B’ham, Manchester) -

StevensonANU (Break-up and/on Fusion) -Tostevin

Experimental proposals: prediction and interpretation

e.g.RIKEN (RIBF) 80Zn 78Ni, 2p knockoutMSU (NSCL) 2N knockout, pickup, break-up, etc

Training Schools: We have the ‘pull’ to attract first class theorists that enrich and stimulate our programme

Fundamental theory developments: Structure, reactions, few- and many-body nuclear (and hadronic) systems.