Particle Physics

Lattice Quantum ChromoDynamics

Nicolas Garron (RBC-UKQCD and CalLat collaborations)
Liverpool Hope University and University of Liverpool (honorary)

Particle Physics

The theory of the strong nuclear interaction is called Quantum ChromoDynamics (QCD). It's a relativistic quantum field theory built on symmetries (gauges and space-time). The basics degrees of freedom are the quarks and the gluons. The strong nuclear force binds the quarks together "inside" the hadrons, such as neutrons and protons, but also the hadrons together which can then form composite nuclei.

Particle physics experiments help us to understand what happens at high energy, when particles collide at very high momenta. By smashing particle together we can "see" the inside of matter.
(Image credit: CERN)

Lattice QCD

Understanding the theory in the hadronic regime, in which the quarks are confined inside the hadrons is very challenging. Arguably the most natural and promising way is through numerical simulations. Space-time is replaced by a 4D lattice and the theory is sampled using Monte-Carlo methods. This is known as Lattice QCD, a well-established framework (K.G. Wilson 1974). However these simulations are numerically extremely expensive: obtaining realistic results requires large-scale computations performed with state-of-the-art algorithms and numerical resources.

(Image credits Evan Berkowitz).


Recent publications

https://arxiv.org/abs/2202.04394 Exploring interpolating momentum schemes

https://arxiv.org/abs/2112.11140 Non-perturbative renormalisation with interpolating momentum schemes

https://arxiv.org/abs/1912.08321 Lattice QCD Determination of gA

https://arxiv.org/abs/1904.12055 Short Range Operator Contributions to 0\nu\beta\beta0νββ decay from LQCD

https://arxiv.org/abs/1812.11127 Symmetries and Interactions from Lattice QCD

https://arxiv.org/abs/1812.08791 SU(3)-breaking ratios for D and B mesons

https://arxiv.org/abs/1812.04981 Beyond the Standard Model Kaon Mixing with Physical Masses

https://arxiv.org/abs/1805.12130 A per-cent-level determination of the nucleon axial coupling from quantum chromodynamics

Complete List here iNSPIRE-HEP

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Press releases

Collaborations

University of Liverpool: M. Gorbahn, J.A. Gracey, P.E.L. Rakow.

RBC-UKQCD: Columbia University (New York), Brookhaven National Lab, Universities of Edinburgh, Southampton, etc.

CalLat California Lattice Collaboration: UC Berkeley, Berkeley lab (LBNL), Lawrence Livermore National Laboratory (LLNL), etc.

Current research projects

Flavour physics, BSM phenomenology
Heavy Quark Effective Theory
Non Perturbative Renormalisation
Sign problem

Garron's resume

Lecturer at LHU (SMCE), honorary research staff member at University of Liverpool and visitor to the Higgs Centre for Theoretical Physics (University of Edinburgh).

Previous appointments:

Leverhulme research fellow (Universities of Liverpool and Plymouth) 2016-2019.
Cambridge DAMTP, research and teaching in Part III maths, 2015-2016.
Trinity College Dublin, assistant professor (lecturer) at the School of Mathematics: 2012-2014
University of Edinburgh, Particle Physics Theory / Higgs Centre for Theoretical Physics, PDRA, 2009-2012
Universidad Autónoma de Madrid, PDRA, 2007-2009
Deutsches Elektronen-Synchrotron (DESY) - Zeuthen Germany (close to Berlin), PDRA, 2004-2007
Centre de Physique Theorique, Marseille, France, 2001-2004.

Teaching qualifications: Lecturer and Full Professor

Awards: Hope star "innovation award" (2021) and Ken Wilson Lattice award with RBC-UKQCD (2012)