Seminars in 2018:

Monte-Carlo methods. Written in C++, its functionality and modelling capabilities are

continuously expanding and the framework has found applications in many areas of physics

research. The Geant4 physics processes cover diverse interactions over an extended

energy range, from optical photons and thermal neutrons to the high energy electromagnetic

and hadronic interactions. There are a number of processes and models applicable to nuclear

physics, some are purely theoretical and some are data driven parameterisations and although

databases such as the ENSDF is utilised there is still a lot the nuclear physics community can

do to help improve the framework. In this seminar an overview of the Geant4 toolkit will be

given, highlighting its functionality and capabilities with a focus on its applicability to nuclear

physics. Some recent advances and outstanding challenges will also be discussed and how

nuclear physicists can help with validation and improvement of the applicable physics models.

nuclear structure. In order to study this feature of the nucleus we have to develop advanced

techniques and equipment that the exploit the unique physics of the system we are studying.
The spectroscopic study of Internal Conversion Electrons (ICE) is one such technique. This

electron emission process is one of the primary means available for the study of electric

monopole transitions, which are themselves a key observable in the study of nuclear

shapes and shape coexistence.
In this talk I will introduce conversion electrons in the context of nuclear structure studies

and present the SPectrometer for Internal Conversion Electrons (SPICE), one of the latest

generation of electron spectrometers recently commissioned at TRIUMF in Canada. After

introducing the device and the commissioning 110Pd experiment I will go on to discuss

the light selenium shape puzzle and present the results of our 70,72Se study.

of an essentially complete description of the nuclear many-body system, nuclear reactions

have often relied on phenomenological models, namely fitting optical potentials on elastic

scattering data.
It will be presented a work aiming to build a common framework for structure and reaction,

developed at University of Surrey. This work, proceeds by solving the nuclear many-body

problem using the Dyson equation, returning a consistent self-energy which is microscopically

equivalent to the generalized optical potential in the Feshbach theory. The properties of this

around 220Rn  and 224Ra  [2],  while  the  occurrence  of  octupolar  correlations  in  the 

Ba  isotopic  chain has been recently established experimentally up to N=90, with the

measurement of large B(E3:3− → 0+) transition probabilities [3,4].
To further extend the systematics, the evolution of shapes in the most neutron-rich members

of the Z = 56 isotopic chain accessible at present, 148,150Ba, has been studied via β-decay

at the ISOLDE Decay Station [5].
In this contribution, the first measurement of the positive- and negative-parity low-spin ex-
cited states of 150Ba will be presented, together with an extension of the decay scheme of
148Cs. Employing  the  fast  timing  technique,  half-lives  for  the  2+1 level  in  both  nuclei 

have  been  determined.  The systematics of low-spin states, together with the experimental

determination of the  B(E2:  2+ → 0+)  transition  probabilities,  indicate  an  increasing 

collectivity  in 148,150Ba, towards prolate deformed shapes.  The experimental data will be

compared to Symmetry Conserving Configuration Mixing calculations [6], confirming an evolution

of increasingly quadrupole deformed shapes with a definite octupolar character in these nuclei.
The future installations for β-decay studies at SPES will be presented in the last part of the
talk.
1.  P. A. Butler and W. Nazarewicz, Rev.  Mod.  Phys.  68, 349 (1996).
2.  L. P. Gaffney et al., Nature (London) 497, 199 (2013).
3.  B. Butcher et al.,Phys.  Rev.  Lett.116, 112503 (2016).
4.  B. Butcher et al., Phys.  Rev.  Lett.118, 152504 (2017).
5.  R. Lic ̆a et al., J. Phys.  G: Nucl.  Phys.  44, 054002 (2017).
6.  R. N. Bernard, L. M. Robledo, and T. R. Rodriguez, Phys.  Rev.  C 93,

     061302(R) (2016)
 

Wednesday 31st October and Thursday 1st November 2018

Friday 15th June 2018

Tibor Kibedi (Australian National University)
Looking for monopoles through a pair of glasses
Electric monopole (E0) transitions between spin-zero states in atomic nuclei were first

suggested by Gamow when interpreting a mysterious electron line in the β-decay spectrum

of radon. Single-photon 0 →  0 transitions are strictly forbidden. E0 transitions can only

proceed via internal conversion, electron-positron pair conversion, or very rarely by double-

photon emission. E0 transitions between the first excited 0+  state and the 0+  ground state

are one of the dominant features of the low-energy nuclear structure of even-even nuclei. 

It is widely accepted that E0 transitions provide sensitive tests of various nuclear structure

models for understanding volume oscillations, isotope and isomer shifts, and, in particular,

nuclear shape coexistence.
In this talk we will report on the recent results at the ANU, using the Super-e pair

spectrometer to observe conversion electrons and electron-positron pairs to study E0

transitions in light even-even nuclei between N=Z=20 and N=Z=28 magic nuclei. We also

report on the recent results to determine the radiative width of the Hoyle state from pair

conversion and gamma-ray experiments.

Thursday 24th and Friday 25th May 2018

6th UK Theory meeting: Program is available here

to test fundamental interactions and the Standard Model.  Predictions of nuclear properties

that start from forces among nucleons and their interactions with external probes as described

by chiral effective field theory are arguably the doorway to a solid connection between

observations and the underlying fundamental theory of quantum chromo-dynamics.
Today, thanks to advances in many-body theory and high performance computing, we can

calculate nuclear properties for increasingly large systems and estimate theoretical uncertainties.

Nuclear response functions are key observables to study the nuclear dynamics. As such they

have been subject of intensive studies. I will present recent highlights, that portrait the role of

electromagnetic responses in tackling contemporary issues, such as the proton-radius puzzle

and the neutron-skin thickness.

protons, neutrons, nuclei, and the other inhabitants of the particle zoo remains elusive.

The Thomas Jefferson National Accelerator Facility (JLab) in the US has completed the

12 GeV Upgrade of it's mile-long electron machine and is poised to shed new light on

quarks and the force that binds them. I will start with a broad outline of what we know

about atomic nuclei and, more importantly, what we don't know. The goal of the physics

program at JLab is to image the interior of nucleons and nuclei with greater precision than

ever before. These new capabilities will enable us to decompose nuclear structure into its

quark components, map the distribution of electric charge and current to high momenta,

and unravel the spin and angular momentum of the nucleon interior. I will show how this

is done from accelerating electrons to capturing the momenta of the debris from a

nuclear collision. The contributions of students and young scientists is crucial to the

mission of JLab and I will devote some time to their role now and after they go out

into the world.

Costas Andreopoulos (University of Liverpool and STFC/RAL)
Neutrino-Nucleus Interactions at the few-GeV Energy Scale: Relevance, Present Status

and Future Prospects

Neutrinos have played an important role in particle physics since their discovery half a century

ago. They have been used to elucidate the structure of the electroweak symmetry groups, to

illuminate the quark nature of hadrons, and to confirm our models of astrophysical phenomena.

With the discovery of neutrino oscillations, neutrinos take centre stage as the object of study.

Measurements of potential CP-violation effects in the neutrino sector, the determination of the

neutrino mass hierarchy and stringent tests of the 3-flavour paradigm will be some of the 

major directions in science during the next decade and beyond. However, limitations in our

understanding of neutrino-nucleus interactions degrade our physics reach. A substantial

improvement  is required for the successful physics exploitation of the current and future

generation of accelerator neutrino experiments whose systematic error requirement approaches

the 1% level.
I will give a brief overview of the current accelerator neutrino physics landscape, explain the

significance of improving our understanding of neutrino-nucleus interactions and highlight some

of the most pertinent puzzles. In particular, I will emphasise open problems at the boundary

a neutrino-nucleus interaction simulation used by nearly all current and near future neutrino

experiments, and highlight opportunities collaborative work between the particle and nuclear

physics communities.

Wednesday 14th March 2018

and industry, for the purpose of industrial nuclear data measurements. This seminar will

establish the need for academic involvement in nuclear data measurements within the UK

nuclear energy sector, highlight the challenges faced making such measurements and

their cross-over with basic nuclear structure, and discuss recent experimental work

can be regarded as a fundamental aspect of finite quantum many-body systems.  The

“many-body” aspect of nuclei provides systematic details of the dependence of nuclear

rotation on the number of nucleons involved. In particular, the coupling of an unpaired

nucleon (in an odd-mass nucleus) to a rotating “core” (the neighboring even-even nucleus)

reveals important details about how nuclei rotate. A basic introduction to nuclear rotation

will be presented, followed by some very recent insights into the physics of nuclear

Thursday 18th January 2018

Marco Rocchini (INFN-LNL)
Coulomb excitation of low-lying states in 66Zn with the GALILEO + SPIDER setup at LNL
The development of the low-energy Coulomb excitation technique at the INFN Legnaro National

Laboratories is particularly important in view of the realization of a new radioactive ion beam

facility, SPES. To this aim, a new heavy-ion detector (SPIDER) has been recently developed

to be used at LNL with both stable and radioactive beams. The first Coulomb excitation

experiment at LNL with the SPIDER detector coupled with the GALILEO gamma-ray

spectrometer (also recently installed at LNL) has been performed using a stable 66Zn beam.

The aim of the experiment was both to the test the performances of the new setup and to

study the structure of the low-lying states in 66Zn. Transition probabilities and spectroscopic

quadrupole moments for the first excited states of this nucleus have been measured, in a

model-independent way. Some of them were already known, thus offering the possibility

to test the apparatus. At the same time, already at low-excitation energy, 66Zn presents

states whose properties are not yet studied. Deformation of the ground state and of the

first excited 0+ state have been determined, combining the obtained matrix elements using

the quadruple sum rule. The measured quantities provide an important benchmark to test

state-of-art shell model and beyond mean field calculations, typically used to interpret the

structure of the stable zinc isotopes. This seminar will outline the results of the experiment,

describing the performances of the setup that is now ready for further experiments with

both the available stable beams at LNL and the future radioactive beams that will be

provided by SPES.

Tuesday 9th January 2018

almost 50 years ago it is best known to the UK physics community for its radioactive beam

facility, ISAC. This is, however, only one part of what goes on at TRIUMF.  In this talk I

will give an overview of TRIUMF as well as the many, varied areas of research currently

being pursued. This will include nuclear  medicine, particle physics, material science and

accelerator development as well some brief comments about how these developments are

being used outside of the laboratory.