Seminars in 2013:

Tuesday 10th December 2013

Mark Gieles (University of Surrey)

Nuclear fusion in stars as an analogy for the dynamics of stars in dense globular clusters

"Only the inertia of tradition keeps the contraction theory alive – or rather, not alive, but an

unburied corpse". This is what Sir Arthur Eddington wrote in the Observatory in 1920 in

reference to the common believe that the sun produces its energy by converting gravitational

energy into radiation by contracting. It is remarkable that it is less than a century ago that

Eddington had the brilliant insight that the structure of stars can be derived without actually

knowing the specifics of its energy source. It is now well known that nuclear fusion is the

source of energy that powers the sun, but Eddington derived the relations between density,

temperature and pressure by simply assuming a balance between pressure and gravity.

Globular clusters are collections of about a million stars, almost as old as the Universe and

they found in nearly all galaxies. Their evolution is governed by close interactions between

stars in the dense (10^6 stars per cubic light year) core. In this talk I will show how the dynamical

evolution of globular clusters, i.e. the combined results of all close encounters, can be described

by some very simply laws. The theory was originally developed by the French mathematician

Michel Henón and there are some fascinating analogies with nuclear fusion in stellar cores.

Henón's work was developed for idealised star clusters in which all the stars have the same

mass. I will show that the fundaments of the physics still holds in models of more realistic star

clusters with a (realistic) spectrum of stellar masses and stellar-mass black holes.

Tuesday 3rd December 2013
Raymond Mackintosh (Open University)
Dynamical Non-locality in Nuclear Interactions
The non-locality of the interaction between a nucleon and a nucleus, or between two nuclei,

has two sources: (1) exchange processes, and (2) dynamical coupling effects; the effect of 

coupling to collective, reaction or breakup channels. Non-locality of the first kind is well 

understood, is closely related to much of the energy dependence of the phenomenological 

local OMP, and leads to the well-known Perey effect. Dynamical non-locality, however, 

seems to be less well understood and is the subject of this talk. I will discuss the 

consequences of dynamical non-locality for the extraction of spectroscopic information using 

direct reactions.

Tuesday 26th November 2013
Makito Oi (Senshu University, Tokyo)
Physics and Mathematics of the pairing correlations
A balance between the nuclear shell structure for the single-particle levels and the pairing 

correlations among constituent particles determines the major part of the nuclear structure. 

It was found that the mean field approximation, in particular, the Hartree-Fock-Bogoliubov 

theory, works quite well in the description of these features in the single theoretical framework.

The recent interests to go beyond the mean field approximation brings us a motivation to 

understand the HFB theory in a deeper level from a mathematical point of view. The Pfaffian, 

Grassmann integrals, and the Fermion coherent states were newly introduced to nuclear 

structure physics in the 21 century, and we need to get accustomed to these concepts now,
as we did before for the Slater determinant, Gauss integral, and the Bosonic coherent states.
  

In this seminar, I would like to talk about the recent progresses in the mathematical
and physical studies of the pairing phenomenon based on the HFB theory.

Tuesday 19th November 2013

Brajesh Jain (MU-DAE Centre for Excellence in Basic Sciences, University of Mumbai)
Near Threshold Resonances and their Role in Nuclear Physics
In any many body system occurrence of a resonance near threshold normally has a profound 

effect on its dynamics.  The classic example of it is the crucial role played by the proximity of 

the 12C 7.65 MeV 0+ resonance to the 8Be-alpha threshold, and the closeness of a double 

alpha resonance to the 8Be ground state in helium burning in stars, and producing life-essential 

element.  There may be more such examples.

In present times similar situations arise when we go beyond the neutron-proton degrees of 

freedom to include mesons and baryon resonances in nuclear dynamics. The resonance 

N*(1535 MeV, ½- ) is found to lie very close to the eta meson (eta, 0-, 550 MeV)-nucleon 

threshold, and the strange resonance Lambda*(1405 MeV, ½- ) just below the K- (594 MeV, 

0-, S=-1)-nucleon threshold. These proximities result in a strong attractive interaction 

between eta-N and and K- -p systems in s-wave. Such  interactions generate a strong 

possibility for the existence of eta- and K- - nucleus bound states. Searches for the existence 

of such states have been pursued vigorously worldwide theoretically as well as experimentally. 

The results of these efforts have been positive, and the Indian researchers have contributed 

substantially to this search. The talk gives an overall present status of the field.   

Tuesday 12th November 2013

Gavin Lotay (University of Surrey)

Advances in Explosive Nuclear Astrophysics
Breathtaking results from the Planck satellite mission and Hubble space telescope have

highlighted the key role modern Astronomy is playing in our understanding of Big Bang

Cosmology. However, not so widely publicized is the similar wealth of observational data

now available on explosive stellar phenomena, such as X-ray bursts, novae and Supernovae.

These astronomical events are responsible for the synthesis of almost all the chemical

elements we find in our Galaxy, as well as energy generation throughout the Cosmos.

Regrettably, understanding the latest collection of astounding, new observational data

is currently severely hindered by large uncertainties in the underlying nuclear physics

processes that drive such stellar scenarios.

In this talk, a variety of experimental methods used for the investigation of explosive

astrophysical reactions will be considered. Direct studies play a key role in this field, but

equally important, are indirect methods that use both stable and radioactive ion beams.

Such investigations often require innovative new techniques, coupled with the latest

developments in detector technology, and highlight the close relationship between nuclear

structure and astrophysics.

Tuesday 22nd October 2013

Nobuya Nishimura (Keele University)

Recent progress of the r-process nucleosynthesis in astrophysics and nuclear physics

Astronomical origin of the heavy elements produced by the r-process is still shrouded in

mystery in spite of a half century of studies. Though the proto-neutron star wind scenario

was considered to be the most likely success, recent state-of-the-art hydrodynamic simulations

shows that it is seriously difficult to achieve the appropriate physical condition. The supernova

explosion, therefore, is not considered as standard astronomical candidate for the r-process.

We have studies external astrophysical phenomena, which are jet-like explosions of core-collapse

supernova by the strong magnetic field and compact object (neutron stars and black holes)

mergers, in the context of the r-process nucleosynthesis. In the presentation, I will talk about

nucleosynthesis results of our nucleosynthetic using recent sophisticated hydrodynamical

simulation models. Based on these astrophysical approach, I also discuss nuclear physics

uncertainties on the r-process.

Tuesday 15th October 2013

Andrew Simons (AWE)

Yttrium neutron cross section measurements at ASP

ASP is AWE's deuterium accelerator capable of accelerating deuterons up to 300 keV

with a milliamp beam current. The beam is impinged onto a tritiated titanium matrix

creating a source of up to 1012 neutrons per second. The facility has been used to

irradiate samples of yttrium to measure the Y89(n,n')Y89m and Y89(n,a)Rb86m reaction

cross sections. Aluminium and copper reference foils were used to confirm the neutron

flux as well as fission counters. Geant4 and MCNP simulations were used to predict the

neutron spectrum seen by the target and the TALYS code was used to generate cross

section curves for these reactions. Simulations using TAC1D (TALYS-Activity

Calculator in 1D) were used with the experimental data to scale the predicted cross

section curves. Future work replacing the Tritiated target with a deuterated one will

yield a second point on the cross section curves and allow more parameters to be

used within the TALYS code.

Friday 6th September 2013
Zhong Liu (Heavy Ion Research Facility, Lanzhou, China)

The Heavy Ion Research Facility in Lanzhou (HIRFL)

The Institute of Modern Physics (IMP), home for the Heavy Ion Research Facility in

Lanzhou (HIRFL), the largest research complex for heavy ion physics in China, is a

prominent nuclear physics research center. A brief introduction will be given on the

accelerators, experimental setups and research programs in nuclear and atomic

physics, applications of heavy ions in cancer therapy and mutation breeding,

developments of detectors. Some highlights in mass measurements on the storage

ring CSRm, g-spectroscopy, nuclear astrophysics and heavy elements will be

presented. The Future High Intensity Heavy-ion Accelerator Facility (HIAF) is being

proposed, features of this new project will be outlined.

Monday 29th - Tuesday 30th July 2013
IAS Workshop: Neutron Stars: Nuclear Physics, Gravitational Waves and Astronomy

A basic cornerstone of modern physics is the quest to describe quantitatively the

properties of nuclear matter. Neutron stars are unique beacons in this journey, as their

interiors expose matter to extreme regimes of density, temperature and energy, not

accessible to terrestrial experiments. Moreover, the intense gravitational fields in these

astrophysical compact objects, particularly in binaries, could give rise to potentially

detectable signals in the next generation of gravitational wave detectors. The

astronomical observation of compact objects thus provides a unique insight into the

properties of nuclear matter in extreme regimes. Better and more reliable theoretical

tools and a more thorough modelling are required to interpret observations. Finally,

one needs to connect present and future observation to the underlying microphysics

associated to the strong interaction.

This international workshop aims at bringing together a number of historically disjoint

research communities: nuclear physicists, astrophysicists and general relativists. Taking

advantage of a multi-disciplinary environment, we plan to identify key issues in compact

star physics and to develop strategies to make the most of the new generation of

astronomical observatories, gravitational wave detectors and nuclear experiments.

A multi-channel algebraic scattering formalism for astronuclear physics.
The multi-channel algebraic scattering (MCAS) formalism [1] has been used with success

for a decade with nuclear scattering problems. In MCAS, nuclear interaction potentials

taken from, in principle, any model of nuclear structure are separated by the Hilbert-Schmidt
expansion of amplitudes, which leads to a convenient algebraic solution of the Lippmann-

Schwinger equations of the scattering processes. Where the interaction potentials are

developed with collective models describing the nuclear target, the use of orthogonalising

pseudo potentials ensures that MCAS models the compound system of target and projectile

without violating the Pauli principle [2]. Without this feature, such calculations will include
spurious compound states. In addition, a rigorous mechanism is employed to identify

cross-section resonances, no matter how narrow or broad they may be.

Where MCAS has been used primarily to describe light-mass systems at low scattering

energies, with one colliding body being a nucleon, expansion into higher mass and energy

regimes and the use of alpha-particle projectiles is under way. Recently, work has been
focused on systems of interest to the radioactive ion beam [3] and nuclear astrophysics

communities, so that this method may shed light on problems in stellar models and nuclei

far from the valley of stability. The details of the model and its past results will be reviewed [4],

followed by preliminary results, including those for mass-23 systems relevant to white dwarf

[3] P. Fraser, K. Amos, L. Canton, G. Pisent, S. Karataglidis, J.P. Svenne, D. van der Knijff,

to EPJA (2013).

Deep inelastic reactions and Isomers in neutron-rich nuclei across the perimeter of

the A=180-190 deformed region

The region of deformed nuclei near Z = 72 and N = 104 is prolific in multi-quasiparticle

high-K isomers, formed by combining high-omega orbitals near the proton and neutron

Fermi surfaces. More are predicted to occur in stable and neutron-rich isotopes but few

are accessible by conventional fusion-evaporation reactions. Multi-nucleon transfer or

"deep-inelastic" reactions with heavy energetic beams offer an alternative, although

non-selective, means of production [1], complementing the broader reach of fragmentation

reactions (see, for example Ref. [2]).

We have carried out a series of systematic studies extending, to date, from the well

deformed Tm isotopes, through to the neutron-rich W and Os region and the intervening

odd-proton isotopes where the nuclei become gamma-soft. The results are from

measurements with Gammasphere and pulsed Xe-136 beams provided by the ATLAS

facility at Argonne National Laboratory, incident on a range of enriched targets.

I will cover some of the technical aspects of discovery, assignment and characterization,

and the motivation for studying multi-particle states in this region. Selected level schemes

and isomers identified in the rhenium, osmium, iridium and gold isotopes (see.e.g.[ 3,4,5])

will be discussed in the context of the tri-axial structures predicted by configuration-constrained

potential energy-surface calculations, and also dynamical effects such as particle alignment.

An unresolved issue is that low-lying states associated with the 12+, i13/2 two-neutron-hole

configuration are persistently predicted but have yet to be observed. These could result in

long-lived beta-decaying isomers.

[1] R. Broda, J. Phys. G 32, R151 (2006).

[2] M. Pfutzner et al. Phys. Lett. B 444, 32 (1998).

[3] G. D. Dracoulis et al. Phys. Lett. B 709, 59 (2012).

[4] G. D. Dracoulis et al. Phys. Lett. B 720, 330 (2013)

[5] G. D. Dracoulis et al. Phys. Rev. C 87, 014326 (2013)

Tuesday 11th June 2013

Nuclear Matter, Neutron Matter and Nucleon Optical Potential in Brueckner-Hartree

-Fock Theory.
Brueckner-Hartree-Fock (BHF) theory has been used to calculate the saturation property 

of symmetric nuclear matter (SNM) using several realistic two-body inter-nucleon potentials. 

The results reconfirm the Coester band. Two types of 3-body forces have been included in 

our BHF calculations to reproduce the saturation property of SNM. Equation of state of pure 

neutron matter (PNM) and symmetry energy in BHF is shown to give reasonable results.
Effect of 3-body forces on the calculated microscopic optical potential are shown. Satisfactory 

application to proton scattering from Sn, Pb and Ni- isotopic chain are shown. Results for 

exotic nuclei C22 and He6 are also discussed. 

resonances and application for nuclear astrophysics.
The talk is devoted to recent advances in low-energy nuclear reaction theory, a subject 

that has been mostly neglected for many years, but with the development of new radioactive 

beam facilities, it became the forefront of contemporary nuclear physics. The overarching 

objective of the work is to advance the theory of deuteron stripping reactions leading to 

bound states and resonances, utilizing the state-of-the-art theoretical and computational 

technology. The results of this research will be made available to experimental groups 

worldwide in form of new codes for analysis of reactions induced by the radioactive 

isotopes on deuterium targets. A reliable connection between direct and resonance 

astrophysical (n,gamma) processes and (d, p) reactions, which are unique tool to 

investigate neutron captures, will be provided. I will talk about four recent advances 

[1-3] in low-energy nuclear reaction theory.
1. New theory of deuteron stripping based on the surface integral formalism, generalized 

R-matrix and CDCC/ adiabatic model was formulated in [1]. It allows us to parameterize 

deuteron stripping amplitudes in terms of the same observables as in the conventional 

R matrix. In particular, for stripping to resonance states partial resonance widths can be 

extracted from the deuteron stripping in the same way as in the traditional R-matrix method 

for resonance scattering.
2. The developed new theory provides a new tool in using deuteron stripping reactions as 

indirect methods in nuclear astrophysics: ANC and Trojan Horse methods [2]. I will speak 

about recent work on determination of the astrophysical factor for the neutron generator  

using the combination of the Trojan Horse and ANC methods. I will speak also about the 

application of the Trojan Horse method to analyze the astrophysical reaction  [3] These 

indirect methods use the developed deuteron stripping theory.
The work was supported by the US Department of Energy under Grants No. DE-FG02-

93ER40773, No. DE-FG52- 09NA29467, and No. DE-SC0004958  and NSF under
Grant No. PHY-0852653.	
 
[1] A. M. Mukhamedzhanov, Phys. Rev. C 84, 044616 (2011).
[2] M. La Cognata et. al, Phys. Rev. Lett. 109, 232701 (2012).
[3] M. La Cognata, A. M. Mukhamedzhanov et. al, Astrophys. J. Lett. 739, L54 (2011).

accounts for the energy cost of producing a neutron to proton asymmetry in the nuclear 

medium. The accurate characterization of this quantity not only impacts on nuclear 

physics but also on nuclear astrophysics: the larger the slope of the symmetry energy 

as the density increases around nuclear saturation, the larger is the size of the neutron 

distribution in nuclei and the larger is the radius of a neutron star. Experiments on nuclear 

collective excitations, commonly known as Giant Resonances, probe the underlying 

nuclear interaction in the medium. Giant resonances in which neutrons and protons 

oscillate out of phase have as a restoring force the nuclear symmetry energy. For this 

reason, experimental and theoretical efforts have been devoted to this study. I will briefly 

present the work done by the Milano group on the Giant Dipole and Quadrupole 

Resonances and how one can extract information on the nuclear symmetry energy 

from experimental data.

Thursday May 9th - Friday May 10th 2013

Nuclear Cross Sections Analysis and R-matrix tools - Minischool

of the matter in the Universe is both dark and non-baryonic. With no suitable explanation 

available from the Standard Model, this Dark Matter becomes the best evidence for, 

and arguably the best opportunity to explore, physics beyond the Standard Model. 

With such importance, the need to confirm the existence of dark matter has become 

one of the most pressing concerns of modern science.  
Direct dark matter search experiments hope to provide such confirmation. To hope 

to achieve this, backgrounds from known processes must be sufficiently reduced to 

allow a signal to be seen, requiring deep underground operation to escape cosmic 

ray radiation and its consequences, shielding from known local sources of radiation, 

and construction from extremely radio-pure materials. In addition, novel design and 

analysis techniques are employed. The latest results and plans of the world's leading 

projects will be presented. These include so-called Generation-2 instruments, with 

ton-scale target masses, and a sensitivity sufficient for discovery under many current 

theoretical models.   The solution to an 80 year old mystery, of fundamental importance 
to both particle physics and astronomy, may soon be at hand. 

disappears [1]. Recent experiments, such as 24Ne(d,p)25Ne with the TIARA array 

[2] showed the breakdown of the N = 20 magic number in favour of the new N = 16 

magic number. Theoretical work by Otsuka, Utsuno and collaborators [3] has highlighted 

the importance of sodium isotope structure in quantifying the evolution of single particle 

energies approaching the N = 20 island of inversion.
The first of a series of neutron transfer experiments has been conducted using the 

SHARC and TIGRESS [4] arrays at the ISAC-2 facility at TRIUMF. The overall aim 

of these experiments is to study in detail the disappearance of the N = 20 shell gap in 

very neutron rich sodium isotopes, as evidenced by a rise in energy for the ν(d3/2) 

orbital and relative lowering of the ν(f7/2) and ν(p3/2) orbitals. The reaction with 25Na 

is expected to populate the same neutron states as in the SPIRAL experiment with 

24Ne [2], but coupled to the odd d5/2 proton.
SHARC, the Silicon Highly-segmented Array for Reactions and Coulex, is a multi- purpose 

array for charged particle detection which features high spatial resolution and a large solid 

angle coverage. It fits entirely within the TIGRESS array of segmented Germanium clover 

detectors.
Preliminary analysis of the first experiment with the new SHARC array will be presented. 

This experiment studies the 25Na(d,p)26Na reaction in inverse kinematics with a beam of 

up to 3x10^7 pps of 25Na at 6 MeV/u.

Nuclei and nuclear matter from chiral effective field theory interactions
I discuss two different systems of correlated nucleons: infinite matter with arbitrary 

isospin asymmetry and open-shell nuclei. The two are studied from an ab initio 

perspective, i.e. using as only input two- and three-body interactions from chiral 

effective field theory. Asymmetric nuclear matter is considered at small proton 

fractions in view of astrophysical applications and to provide benchmarks for more 

phenomenological calculations. In finite systems, the Gorkov-Green's function approach 

provides the first ab initio studies of full isotopic chains in the medium-mass region of 

the nuclear chart.

Spectroscopy of Exotic nuclei 
The study of nuclear structure with radioactive ion beams at ISOL facilities is often 

limited by the purity of the beam of interest. As we strive to study nuclei always more 

exotic, production cross sections diminish and decay losses increase while 

contaminants dominate the beam content.
At CERN ISOLDE, a large part of the research is devoted to the optimisation of the 

target-ion-source system in order to provide the most exotic beams in the best conditions. 

There are however limitations imposed by the production and ionisation mechanisms that 

cannot always be overcome. It then falls to the experimental teams to compensate for the 

beam purity and seek additional means of purification in order to achieve the required 

conditions for their experiment.
In this presentation, I shall introduce the CERN ISOLDE facility and present some of the 

recent developments in target-ion-source developments and in experimental infrastructures 

relevant for the study of heavy nuclei in the lead region. A particular emphasis will be given 

to atomic techniques, such as the Resonant Ionisation Laser Ion Source (RILIS), the Laser 

Ion Source Trap (LIST), Collinear Resonant Ionisation Spectroscopy (CRIS), and the 

Multi-Reflection Time-of-Flight Mass Spectrometer (MR-ToF-MS) at ISOLTRAP.

Tuesday 19th March 2013 

Over the past 8 years we have been developing the surrogate reaction technique

for the study of short-lived isotopes in collaboration with other research groups

around the world. We have recently upgraded our data acquisition system to help

improve the fidelity and quantity of data we can record during an experiment. The

VME based electronics and software upgrade were completed and commissioned

in April 2012. The silicon array used for particle detection and germanium array

used for gamma ray detection (STARLiTe) were also relocated to the Texas A&M

Cyclotron Institute in 2012. I will review the current status of the newly established

STARLiTe Collaboration centered at Texas A&M and the current and future

capabilities of the Cyclotron Institute. The current status of the following reactions

Am240(n,f), Am241(n,f), Am242(n,f), Y88(n,2n), Y87(n,g), Zr88(n,g), Zr90(n,g),

Zr92(n,g) and Zr94(n,g) being studied using the surrogate technique conducted

in 2012 will also be discussed.

This work was performed under the auspices of the U.S. Department of Energy by

Lawrence Livermore National Laboratory under Contract DE‐AC52‐07NA27344

and the Office of Defense Nuclear Nonproliferation Research & Development.

Tuesday 12th March 2013
Phil Walker (University of Surrey)
Isomer measurements in storage rings
The ability to store highly charged ions for long periods of time opens up novel

Tuesday 5th March 2013

Hugo F Arellano (University of Chile, Santiago)

determining the properties of both finite nuclei and infinite nuclear matter. Furthermore

3BF arise naturally in effective theories of nuclear interaction.
During the last decade, new substantial advances towards the solution of the nuclear

many-body problem have allowed to perform ab-initio calculation up to medium mass

isotopes and, recently, to successfully study the role of 3B forces in these systems.
In this talk I will present the latest results from self-consistent Green function (SCGF)

method, where 3B interactions are consistently included, focusing, in particular, on the

properties of Oxygen isotopes mainly close to the neutron drip line.

Alison Laird (University of York)

Fingerprints of nucleosynthesis

Observations of isotopic abundances from astrophysical environments can provide

crucial information on the physical conditions during particular stages of stellar

evolution, from hydrostatic burning stages in AGB or massive stars to explosive

events such as novae and supernovae. To interpret these data, however, a good

understanding of the underlying nuclear reaction rates is necessary.

This talk will describe recent measurements, involving both stable and radioactive

nuclei, and outline how these data can improve our understanding of stellar

conditions as well as the chemical evolution of the galaxy.

Tuesday 5th February 2013

Danyang Pang (University of Beihang):

Towards a systematic nucleus-nucleus potential for peripheral collisions

Angular distributions of elastic scattering cross sections of 6Li and 7Li from targets with

A>=40 were analyzed with a single-folding model based on the Bruyeres Jeukenne-

Lejeune-Mahaux (JLMB) model nucleon-nucleus potentials. Energy dependence of the

potential parameters were found for incident energies between 5 to 40 MeV/nucleon.

These parameters were found to give reasonable account for both elastic scattering and

total reaction cross sections for projectiles with mass number up to around 40, including

both stable and unstable nuclei, for incident energies from vicinity of Coulomb barrier

Tuesday 29th January 2013

Alexandre Obertelli (CEA Saclay)

Direct reactions with exotic nuclei. Recent results and new technical developments.

Direct reactions such as nucleon transfer and fast nucleon removal are specific ways

to probe the nuclear shell structure. For the last 20 years, these reactions have largely

contributed to investigate the properties of exotic nuclei.

Specificities of direct reactions applied to exotic nuclei –including very weakly bound

systems– will be discussed in the seminar through recent experimental data obtained

at the NSCL and GANIL. The results obtained from the transfer measurement 14O(d,t)

and (d,3He) at 20 MeV/nucleon and their analysis within the CRC formalism and with

different types of overlap functions will be detailed.

On a second stage, original developments at CEA Saclay dedicated to hydrogen-induced

direct reactions in inverse kinematics, namely the thin windowless hydrogen target

CHyMENE and the vertex tracker MINOS, will be introduced.