Nuclear and hadron physics with electromagnetic probes

Our group uses high energy photon and electron beams (0.1 to 12 GeV) to investigate the structure of matter. A new generation of high intensity beam facilities has revolutionized the field in recent years such as the Thomas Jefferson National Laboratory (JLAB) in the USA and the recently upgraded MAMI-C facility in Germany. These beam facilities create exciting and new opportunities to elucidate the properties of strongly interacting matter, from the scale of nuclei down to the scale of their nucleon and quark components.

Our research spans distance scales from heavy nuclei (~10fm) down to the sub Fermi scales necessary to explore the structure of the nucleon and the nature of quark confinement itself. We work in collaborations ranging from around 30 to around 300 physicists. Some of our main physics themes are listed below::

  • Hunt for hybrid mesons using CLAS12 at Jefferson Lab and the new Forward Tagger. Hybrid mesons are exotic beasts of QCD which are predicted by the theory but not yet established. Establishing their properties would provide crucial constraints on the nature of light quark confinement and the origin of mass.
  • Hunt for hexaquarks using CLAS12 at Jefferson Lab and  the Crystal Ball at MAMI. Hexaquarks are exotic highly compact objects made of six quarks. Elucidating their nature is a key piece in our understanding of strong interactions. Hexaquarks may also appear as stable particles deep inside neutron stars.
  • Establishing the equation of state for neutron rich matter with precision neutron skin measurements, also of relevance for neutron stars.
  • Obtaining the first measurement of a transition matter form factor and direct evidence for three-body forces in the 1p shell with an electromagnetic probe
  • Providing key data to constrain the excitation spectrum of the nucleon, a fundamental test of non-perturbative QCD

More details on our published research,. Recent conference talks and proceedings listed below. Hunt for exotic particles is performed within Exotic Hadron Spectroscopy Network.

Our group leads a number of equipment developments at international facilities including:

We have also contributed to the setup and operation of polarized proton and neutron targets at Jefferson Lab, carried out R&D relating to the focusing disk DIRC design at PANDA and developed a novel new Germanium detector array for charged particle detection (GE6).

X-ray image of a neutron star

We also have expertise in analysis and simulation.

Quark, Gluon field in the nucleon
  • Our group developed the GEANT4 simulation for the Crystal Ball which is now used worldwide.
  • We also lead new developments in partial wave analyses in meson spectroscopy, recently carrying out the feasibility study for carrying out meson spectroscopy and hybrid searches with CLAS12. In particular, our group is the main developer of the New Event Generator (EdGen) chosen for study current CLAS6 data and to search for the feasibility of hybrid mesons channels with CLAS12.
  • We are the main developers and investigators for the simulation and background radiation calculation software for the SoLID project, using the two simulation packages with independent code base (GEANT4 and FLUKA). This allows independent cross checks both in geometry and in physics modeling. At the same time the two codes each provide unique capabilities expanding the overall reach. FLUKA provides useful tools that simplify the study of radiation damage and estimates.
SoLID activation studies

We have a number of applied projects which utilise advances made in our programme. This includes medical imaging where we are testing new concepts to improve the achievable image quality in positron emission tomography (PET). We are also leading new developments to exploit laser plasma acceleration of particles at the new SCAPA facility to be built at Stratchclyde and other world facilities.

People in Nuclear and hadron physics with electromagnetic probes

Telephone numbers in the list below are shown as UK numbers. Callers from outside the UK should remove the leading zero and use the UK country code (+44).

NamePositionContact detailsLocationPhoto
Academic staff
Derek BranfordSenior Honorary Professorial Fellow
Photo of Derek Branford
Research staff
Gary SmithPDRA
Photo of Gary Smith
Nicholas ZachariouErnest Rutherford Fellow
Research postgraduates
Conor Brian HamillPostgraduate Student
Photo of Conor Brian Hamill
Ivana StankovicPostgraduate Student
Adam ThorntonPostgraduate Student
Photo of Adam Thornton