Théorie

PRESENTATION

Created in 1995, the Theory Pole is currently composed of five permanent members, both CNRS researchers and professors at the UCA, one postdoctoral researcher and two Ph.D. students.

The scientific research topics of the team have evolved from hadronic physics (QCD and few body systems) and pluridisciplinary physics (percolation models applied to biomaterials), to being currently focused on particle physics : Field Theory, Standard Model and New Physics, as well as Astroparticle Physics. Our research aims at addressing several open questions :

• How are strongly interacting particles (quarks and gluons) confined in mesons and baryons ?

• What is the origin of electroweak symmetry breaking ?

• What is the nature of neutrinos ? Which is the mechanism responsible for their mass ?

• Why is the Universe dominated by matter ? What was the mechanism responsible for baryogenesis ?

• What is the nature of dark matter ?

Many of these are also being (directly or indirectly) addressed by the experimental collaborations in the Particles and Universe pole. The members of the group have important interactions with other LPCA groups, especially ATLAS, LHCb, COMET and CKMFitter.

The Theory pole members contribute to the local scientific animation, and belong to the organising committees of a large number of national and international meetings (Schools, Workshops, Conferences), being also engaged in several Outreach activities ; they further hold numerous scientific and academic responsibilities (in national and international committees and boards). They are also active members of several French research federations, including the IRN Terascale, IRN Neutrinos, GdR Intensity Frontier and GdR DUPhy.

RESEARCH

The activities of the Theory Pole are currently focused on Particle Physics. The members pursue formal research in Field Theory, develop theoretical tools potentially applicable to particle physics, and carry extensive phenomenological studies in direct connection with experiment, focusing on flavour physics (quarks and leptons), neutrino physics and Dark Matter.

Concretely, our research revolves around the following axes :

  • Field Theory : field theory on the light front and finite field theories (based for instance on the Taylor-Lagrange renormalisation scheme). Application to physical observables in 3+1 dimensions and perturbative computation of radiative corrections to the Higgs boson mass.
  • Standard Model of Strong and Electroweak interactions :
    • Lattice QCD Semi-leptonic decays of B-mesons into the first orbital excitations of D-mesons
    • Heavy flavour phenomenology (study of b-hadron decays using covariant formulation of quark models à la Bakamjian-Thomas ; lepton flavour universality violation in heavy beauty-baryon semileptonic decays)
    • Precision tests (in the framework of the CKMFitter Collaboration)
  • Beyond the Standard Model : New Physics
    • Indirect searches from flavour physics : lepton flavour violation (low-energy and collider prospects), lepton number violation, heavy flavour physics (semi-leptonic B-decays, lepton universality tests, ...), flavoured tensions & anomalies
    • Neutrino phenomenology : sterile fermion searches, lepton properties, models of neutrino mass generation
    • Direct searches at the LHC and prospects for future colliders (extended gauge and scalar sectors, exotic fermions, long-lived particles, ...)
  • Dark Matter and particle cosmology :
    • Origin of dark matter : Thermal and non-thermal dark matter generation mechanisms in different cosmological scenarios.
    • New physics candidates : Microscopic models, prospects for dark matter detection experiments
    • Feebly interacting dark matter and baryogenesis : theory & phenomenology of "freeze-in" mechanism of DM production in the early Universe ; relation to theory and phenomenology of long-lived particles (observation and reconstruction of properties at current and future experiments) ; potential connections between baryogenesis and mechanisms of cosmological DM production
  • Application to health sciences :
    • Modelisation of the transformation of biomaterial implants in bones within percolation theory
    • Highlighting the impact of social relationships on the propagation of respiratory viruses using percolation theory - development of "PERCOVID"

COMPOSITION

PERMANENT STAFF MEMBERS :

• Andreas Goudelis (CNRS researcher)
• Jean-François Mathiot (Emeritus CNRS research director)
• Vincent Morénas (Professor, UCA)
• Jean Orloff (Professor, UCA)
• Ana M. Teixeira (CNRS research director, head of Theory group)

POSTDOCS AND Ph.D. STUDENTS :

• Adrian Darricau (Ph.D. student UCA)
• Huchan Lee (CNRS postdoctoral researcher)
• Thomas Reggio (Ph.D. student UCA)
• Baibhab Pattnaik (long-term visitor from IFIC-Valencia)

FORMER MEMBERS

• Mariam Atoui (Ph.D. student UBP, 2010-2013)
• Gabriela Bailas (Ph.D. student, IN2P3, 2015-2018)
• Valentina De Romeri (Postdoctoral fellow, EU ITN "Invisibles" Network, 2013-2015)
• Antoine Gérardin (Postdoctoral fellow IN2P3, 2014-2015)
• Chandan Hati (CNRS-IN2P3 postdoctoral fellow, 2017-2019)
• Jonathan Kriewald (UCA PhD student, 2019 - 2022)
• Farvah Nazila Mahmoudi (MdC-UBP, 2008-2014)
• Hubert Mély (Ph.D. student, 2008-2011)
• Bruno Mutet (Postdoctoral fellow, 2010-2011)
• Siavash Neshatpour (Ph.D. student, 2009-2013)
• Emanuelle Pinsard (UCA Ph.D. student, 2020 - 2023)
• Natalia Tsirova (Postdoctoral fellow, 2008-2010)
• Savvas Zafeiropoulos (Postdoctoral fellow IN2P3, 2013-2014)

ACADEMIC and SCIENTIFIC RESPONSIBILITIES

Andreas Goudelis :
• Responsible for the internal communication at LPC
• Co-organiser of the LPC weekly seminars
• Member of the Journées Jeunes Chercheurs organising committee (since 2022)
• Convener of the IRN – Terascale “Dark Universe” group
Jean-François Mathiot :
• Member of the 29th section of the CNU (Conseil National des Universités)
• President of Committee for Scientific Prospectives of the LPC (2018)
Vincent Morénas :
• President of the local French Physical Society section (SFP-Auvergne)
• PI of the "Lattice calculations in Hadronic Physics" IN2P3 project (2016-2020)
Jean Orloff :
• President of the UCA Physics Department
• Member (elected) of Council of the UCA Physics and Engineering School
• President of the Scientific Council of the LPC
• PI of the "Hunting for Heavy Neutral Leptons" IN2P3 project (2023-2027)
Ana Teixeira :
• Chargée de Mission IN2P3 "Theory and Phenomenology" (since 2022)
• Member of the LPC Council
• Member of the COMET collaboration
• Member of the group responsible for the "Flavour physics" chapter of the "Update of the European Strategy for Particle Physics (ESPP) 2019"
• PI of the "Flavour Probes" IN2P3 project (2020-2023) and "Lepton Flavours" IN2P3 project (2016-2019)
• PI of the FJPPL project "LFV : muon to electron, and the tau sector" (2021-2023)

RESEARCH NETWORKS and COLLABORATIONS

  • European Union HIDDeN ITN
    A. M. Teixeira, J. Orloff : members of the French node
  • iTHEPHY Erasmus+ iTHEPHY Strategic Partnership for Innovating Team-Teaching for Physics
    J. Orloff : French coordinator
  • CKMFitter Project
    J. Orloff : member of the collaboration
  • IRN Terascale
    A. M. Teixeira : co-director of the IRN Terascale
    J. Orloff : steering council of the GdR “Terascale”
  • IRN Neutrinos
    A. M. Teixeira : coordinator of the “Beyond the SM” group
  • GdR Intensity Frontier
    A. M. Teixeira : coordinator of the "Interplay of Quark and Lepton Flavours" group

ORGANISATION OF SCIENTIFIC EVENTS

The Theory Pole hosts, and/or is directly involved in the organisation of numerous national and international events : Workshops, Schools, Meetings...
• 20th International Conference on B-Physics at Frontier Machines (BEAUTY 2023), Clermont-Ferrand, France 3-7 July 2023 (A. Morenas, J. Orloff, A. M. Teixeira, LOC)
• “Fourth International Conference on Charged Lepton Flavour Violation", Heidelberg, Germany 20-22 June 2023 (A. M. Teixeira, IAC).
• "Célébration des 50 ans de l’IN2P3 au LPC", LPC 18 June 2021 (J. Orloff, organising committee).
• "Atelier Physique Theorique des 2 infinies’’, CNRS 2021 (A. M. Teixeira, organising committee).
• “Rencontres de Physique des Particules – RPP2019”, LPC, 23-25 January 2019 (J.-F. Mathiot, J. Orloff, V. Morénas, A. M. Teixeira, organising committee).
• "Rencontres de Moriond - Electroweak session”, La Thuile, Italy (J. Orloff, organising committee).
• “Cargèse International Summer Schools in High Energy Physics", Cargèse, France (J. Orloff, organising committee, 2007, 2010, 2012, 2014, 2018, 2022).