DESY has been a leading centre for the production and use of ultra-relativistic spin-polarised electron and positron beams in high energy particle physics and for the theory of ultra-relativistic spin motion in accelerators. An impression of the topics studied can be found in the links to our publications. The HERA facility at DESY was the first storage ring to utilise the Sokolov-Ternov effect and spin rotators to provide high energy longitudinally polarised electron and positron beams to an HEP experiment (HERMES). See Physics Letters B343 1995.

In addition to our work on radiative polarisation with electrons and positrons, we have a strong interest in the (non-radiative) spin dynamics of protons and deuterons from a few GeV up to many hundreds of GeV. With the very large magnetic fields needed at such high energies, the traditional (and somewhat naive) ways of systematizing proton spin motion are inadequate. Instead, much more careful mathematical analysis is needed and concepts such as the invariant spin field and the amplitude dependent spin tune ( Spin 2000 and EPIC workshop ) must be exploited. Deuterons present a different challenge: since the gyromagnetic anomaly is so small (-0.143 compared to 1.7928 for protons) the spin dynamics is relatively simple --- but this, on the other hand, leads to difficulties with the deterministic manipulation of the spins. The invariant spin field and the amplitude dependent spin tune have also been valuable for clarifying aspects of proton and deuteron spin motion at low energies

All branches of physics depend for progress on the use of mathematics. This is especially true of polarisation theory, whence we place a high value on precise mathematical formulations with the aim of bringing our understanding to the highest level.

Following the closure of HERA , I have pursued, or am currently pursuing, the following:

Spin dynamics in the ring-ring option of the LHeC project (deceased).

Proton and deuteron spin dynamics in the COSY ring at the Forschungszentrum Juelich.

The spin dynamics of the measurement of the proton and deuteron electric dipole moments in storage rings.

Spin dynamics in the electron ring of ENC@FAIR concept (deceased).

Studies of mathematical topics with colleagues at the University of New Mexico.

Spin dynamics for the electron ring of ELIC, the figure-of-8 shaped e-p collider being considered at the Thomas Jefferson National Accelerator Laboratory (deceased).

The GigaZ project considering future re-use of HERA (deceased).

Spin dynamics for the SuperB project at Frascati (deceased).

Spin dynamics for the electron-proton colider (EIC) at Brookhaven National Lab.

Spin dynamics for the FCC-ee project at CERN and for the CEPC of the Chinese Academy of Sciences.

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Current and earlier collaborators surrounding spin polarisation in storage rings:

Mari Berglund, Royal Institute of Technology, Stockholm, Sweden

Jim Ellison, University of New Mexico, Albuquerque, USA

Eliana Gianfelice-Wendt, Fermilab, USA (formerly DESY)

Klaus Heinemann, University of New Mexico, Albuquerque, USA (formerly DESY)

Georg Hoffstaetter, Cornell University, USA (formerly DESY)

Gerhard Ripken, DESY (deceased)

Mathias Vogt, DESY

Oleksii Beznosov, Los Alamos National Laboratory, USA.

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Professional affiliations and attributes past and present:

Visiting Professor of Physics in the Department of Physics, University of Liverpool, UK.

Visiting Scientist at the Cockcroft Institute for Accelerator Science and Technology, UK.

Visiting Professor in the Department of Mathematics and Statistics in the University of New Mexico, Albuquerque, USA.

Fellow of the Institute of Physics (UK).

Chartered Physicist (UK).

Designated by the American Physical Society as an Outstanding Referee.

Committees:

1994 - 2000: Member of the Machine Review Committee for the
                      Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, Long Island, USA.

2004:             Member of the DOE Science and Technology Review Committee for the
                      Relativistic Heavy Ion Collider (RHIC) at Brookhaven National Laboratory, Long Island, USA.

2005:             Member of the DOE Science and Technology Review Committee for the
                      Thomas Jefferson National Accelerator Laboratory,Virginia, USA.

2006--2012: Member of the Program Advisory Committee for the proton/deuteron storage ring, COSY,
                     at the Institute for Nuclear Physics at the Juelich Research Centre, Germany.

2021--         Member of the Machine Advisory Committee for the EIC project at Brookhaven National Laboratory, Long Island, USA.

Current PhD student(s):

Last Update: June 2022.