Modular Invariance Approach to the Lepton and Quark Flavour Problems: from Bottom-up to Top-down

Europe/Berlin
2413/2-430 - MITP Seminar Room (MITP - Mainz Institute for Theoretical Physics, Johannes Gutenberg University Mainz)

2413/2-430 - MITP Seminar Room

MITP - Mainz Institute for Theoretical Physics, Johannes Gutenberg University Mainz

Staudingerweg 9 / 2nd floor, 55128 Mainz
40
Description

Understanding the origins of flavour in both quark and lepton sectors is one of the most challenging fundamental problems in contemporary particle physics. The Workshop will be devoted to the approach to the flavour puzzle based on modular invariance, proposed in 2017 and since then extensively studied both in a bottom-up and a top-down perspective. Modular invariance has been investigated in the context of field and superstring theories, being a key feature of several theoretical constructions such as theories with toroidal compactification of extra dimensions, superstring theories on tori or orbifolds, supergravity theories. In this context the modular group acts on the matter generation space and is broken by the vacuum expectation value of a single complex scalar field, offering an economic setup to understand the origin of flavour, including CP violation, in particle physics. Yukawa couplings are described by modular forms, extensively studied by mathematicians since the 19th century, and more recently, in particular, for their major implications on number theory. Modular invariance can be investigated both in a bottom-up and in a top-down approach, thus representing a unique opportunity for phenomenologists and string theorists to confront their ideas. Open questions that will be discussed during the Workshop include:

  • Connection between bottom-up and top-down constructions.
  • The problem of moduli stabilisation and supersymmetry breaking.
  • Extensions of the modular group, such as symplectic or metaplectic groups.
  • CP violation in the quark and lepton sectors.
  • Reduction of parameters needed to describe the quark sector.
  • Relation between the flavour puzzle and critical phenomena.

We encourage participation from both the more mathematical and string theory related as well as phenomenology communities, to ensure a thorough discussion connecting bottom-up and top-down approaches to this formidable and extremely challenging endeavour.

The list of participants includes:

  • Gui-Jun Ding (USTC, Hefei)
  • Stephen King (University of Southampton)
  • Xiang-Gan Liu (UC, Irvine)
  • Myriam Mondragón (UNAM, Mexico)
  • Hajime Otsuka (Kyushu University)
  • João Penedo (INFN Roma Tre)
  • Saul Ramos-Sanchez (UNAM, Mexico)
  • Michael Ratz (UC, Irvine)
  • Nicole Righi (King's College London)
  • Morimitsu Tanimoto (Niigata University)
Contact @ MITP : Barbara Behrend
    • 1
      Registration
    • 2
      Flavour model building I
      Speaker: Stephen King
    • 11:00
      Coffee break
    • 3
      Flavour model building II
      Speaker: Myriam Mondragon
    • 12:30
      Lunch break
    • 4
      Flavour models with multiple modular symmetries
      Speaker: Ye-Ling Zhou
    • 5
      Quark-lepton mass relations in modular invariant models (blackboard talk)
      Speaker: Omar Medina
    • 15:30
      Coffee break
    • 6
      Modular forms at level 2 for flavour (blackboard talk)
      Speaker: Matteo Parriciatu
    • 7
      Modular invariant holomorphic observables (blackboard talk)
      Speaker: Xueqi Li
    • 8
      Bottom-up modular invariance approach to flavour I
      Speaker: Gui-Jun Ding
    • 10:30
      Coffee break
    • 9
      Quark mass hierarchy and CP violation in modular symmetry
      Speaker: Morimitsu Tanimoto
    • 10
      Discussion session on the bottom-up approach I
    • 12:00
      Lunch break
    • 11
      What can modular flavour symmetries do for you? (joint with the local theory seminar)

      In recent years, modular invariance has been applied to the SM flavour puzzle, yielding compelling results. In this string-inspired paradigm, one does not require a multitude of scalar fields (flavons) with aligned VEVs and complicated potentials. Taking a bottom-up approach, one may instead rely on a single complex field -- the modulus. Yukawa couplings and mass matrices are obtained from functions of its VEV, which can be the only source of flavour symmetry breaking and of CP violation. Such predictive modular setups may, among other things, shed light on the patterns of fermion mixing, the origin of fermion mass hierarchies and the strong CP problem.

      Speaker: João Penedo
    • 12
      Discussion session on the bottom-up approach II
    • 15:30
      Coffee break
    • 13
      Free discussion
    • 14
      Top-down modular invariance approach to flavour I
      Speaker: Saul Ramos-Sanchez
    • 10:30
      Coffee break
    • 15
      Top-down modular invariance approach to flavour II
      Speaker: Hajime Otsuka
    • 12:00
      Lunch break
    • 16
      F-theory models: some ways of being discrete
      Speaker: George Leontaris
    • 17
      Discussion session on the top-down approach
    • 15:30
      Coffee break
    • 18
      Free discussion
    • 19
      Beyond SL(2,Z) in the top-down approach
      Speaker: Kaito Nasu
    • 10:30
      Coffee break
    • 20
      Beyond SL(2,Z) in the bottom-up approach
      Speaker: Xiang-Gan Liu
    • 12:00
      Lunch break
    • 21
      Metaplectic flavor symmetries from magnetized tori (blackboard talk)
      Speaker: Victoria Knapp-Perez
    • 22
      Discussion session on beyond SL(2,Z)
    • 15:30
      Coffee break
    • 23
      Free discussion
    • 24
      Moduli stabilisation I
      Speaker: Nicole Righi
    • 10:30
      Coffee break
    • 25
      Moduli stabilisation II
      Speaker: Michael Ratz
    • 12:00
      Lunch break
    • 26
      Radiative stabilization and pseudo NG bosons from finite modular symmetry (blackboard talk)
      Speaker: Junichiro Kawamura
    • 27
      Modulus stabilisation and hilltop inflation with modular symmetry (blackboard talk)
      Speaker: Xin Wang
    • 28
      Discussion session on the moduli stabilisation
    • 15:30
      Coffee break
    • 29
      Free discussion