FLASY 2025 - 11th Workshop on Flavour Symmetries and Consequences in Accelerators and Cosmology

30 Jun 2025, 00:30 → 4 Jul 2025, 18:00 Europe/Rome

Aula Magna Architettura "Adalberto Libera" (Roma Tre)

FLASY 2025 is the 11th Workshop on Flavour Symmetries and Consequences in Accelerators and Cosmology.

[ Update: Registration closes soon! (deadline extended to 15 Jun). ]
[ Update: Fee payment is available (see Conference Fee tab). ]
[ Update: Please beware of SCAM emails. Registration and fee payment are only possible via the indico webpage and links provided therein. There is no Hotel Booking service. ]

This workshop will bring together researchers in the fields of flavour symmetries, neutrino physics, Higgs physics, CP violation, accelerator physics, and cosmology to present new results and foster discussions that can lead to new and fruitful collaborations. 

FLASY 2025 will take place from June 30 to July 4 in Rome, Italy.

Confirmed plenary speakers include:   

• S. Antusch (University of Basel)
• F. Brizioli (U. Perugia and INFN Perugia) [for the NA62 Collab.]
• G. Burdman (U. São Paulo)
• P. W. Cattaneo (INFN Pavia) [for the MEGII Collab.]
• M.-C. Chen (UC, Irvine)
• S. C. Chuliá (Max Planck Inst., Heidelberg)
• C. Cornella (CERN)
• G.-J. Ding (USTC, Hefei)
• F. Feruglio (INFN Padova)
• M. Ghosh (Boskovic Inst., Zagreb)
• C. Hagedorn (València U., IFIC)
• P. Harrison (Warwick U.)
• J. Harz (Mainz U.)
• S. Jäger (University of Sussex)
• S. K. Kang (Seoul Natl. U.)
• T. Kephart (U. Vanderbilt)
• S. King (U. Southampton)
• E. Lisi (INFN Bari)
• E. Ma (University of California Riverside)
• A. Marrone (INFN Bari and U. Bari)
• G. Martinelli (U. Roma and INFN Roma)
• M. Mondragon (UNAM, Mexico)
• M. Nardecchia (U. Roma)
• E. Nardi (INFN, LNF and NICPB, Tallinn)
• H. Päs (T. U. Dortmund)
• S. Pascoli (INFN Bologna and U. Bologna)
• E. Peinado (Mexico U.)
• S. T. Petcov (Tokyo U., IPMU and SISSA Trieste)
• M. Ratz (UC, Irvine)
• G. Ricciardi (Naples U.)
• M. Tanimoto (Niigata U.)
• A. Titov (U. Pisa and INFN Pisa)
• A. Trautner (CFTP, IST Lisbon)
• J. Turner (Durham U., IPPP)
• I.dM. Varzielas (CFTP, IST Lisbon)
• Z.-z. Xing (IHEP, CAS and Peking U., CHEP)

Local Organising Committee:   

• D. Meloni (Chair, Roma Tre U.)
• F. Mescia (INFN, LNF)
• S. Morisi (Naples U.)
• M. Parriciatu (Roma Tre U.)
• J. Penedo (Co-chair, INFN Roma Tre)

 

FLASY 2025 is supported by:

Poster_FLASY2025_final.pdf

Monday, 30 June

08:00 Registration

Morning session

1 Opening

2 Unitarity triangle angles explained: a predictive new quark mass matrix texture

We propose a novel quark mass matrix texture-pair with five free parameters, which fits the four quark mass ratios $m_s/m_b$, $m_d/m_b$, $m_c/m_t$, $m_u/m_t$, and the four
CKM quark mixing observables. The matrices each have one texture zero, but the main innovation here is a ``geometric'' ansatz exploiting a pair of small complex expansion parameters, based on the geometry of the Unitarity Triangle. The fit to the observables is in good agreement with current experimental values renormalised to $\sim\!\!10^4$ TeV, and offers decisive tests against future high-precision measurements of the unitarity triangle angles at the weak scale. We identify two novel symmetries of these mass matrices which explain the phenomenologically-successful relations $\alpha\equiv\phi_2\simeq \pi/2$ and $\beta\equiv\phi_1\simeq\pi/8$.

Speaker: Paul Harrison (University of warwick)

3 The mu-tau reflection symmetry of Majorana neutrinos in a cross seesaw system

In the canonical seesaw framework flavor mixing and CP violation in weak charged current interactions of light and heavy Majorana neutrinos are correlated with each other and described respectively by the $3\times 3$ matrices $U$ and $R$. We show that the very possibility of $\big|U^{}_{\mu i}\big| = \big|U^{}_{\tau i}\big|$ (for $i = 1, 2, 3$), which is strongly indicated by current neutrino oscillation data as a good approximation, automatically leads to a novel relation $\big|R^{}_{\mu i}\big| = \big|R^{}_{\tau i}\big|$ (for $i = 1, 2, 3$). We show that behind these two sets of equalities and the experimental evidence for leptonic CP violation lies a minimal flavor symmetry: the overall neutrino mass term keeps invariant when the left-handed neutrino fields transform as $\nu^{}_{e \rm L} \to (\nu^{}_{e \rm L})^c$, $\nu^{}_{\mu \rm L} \to (\nu^{}_{\tau \rm L})^c$, $\nu^{}_{\tau \rm L} \to (\nu^{}_{\mu \rm L})^c$ and the right-handed neutrino fields undergo an arbitrary unitary CP transformation. Such a generalized $\mu$-$\tau$ reflection symmetry, together with the fact that all the active-sterile flavor mixing angles in $R$ are expected to be considerably smaller than the active flavor mixing angles in $U$, provides an intriguing illustration of the emergence of a cross seesaw system for both neutrino masses and flavor mixing effects of Majorana neutrinos.

Speaker: Zhi-zhong Xing (Institute of High Energy Physics, Chinese Academy of Sciences)

11:00 Coffee break

Morning session

4 Global neutrino analysis 2025: Knowns and Unknowns

Speaker: Eligio Lisi (Istituto Nazionale di Fisica Nucleare)

5 Past, Present and Future in Flavor Physics, the Unitary Triangle Fit, Anomalies and all that

Speaker: Guido Martinelli (Istituto Nazionale di Fisica Nucleare)

12:30 Free time for lunch

Afternoon session

6 Modular invariance and the strong CP problem

I discuss a set of conditions under which the strong CP problem is solved by spontaneous CP violation. Such conditions find their natural realization in anomaly-free modular invariant supersymmetric theories, suggesting a common solution to the strong CP problem and the flavor puzzle. In its minimal realization, this solution requires a single chiral multiplet, beyond those of the MSSM. If one of its spin-zero components is light, it provides a viable Dark Matter candidate.

Speaker: Ferruccio Feruglio (Istituto Nazionale di Fisica Nucleare)

7 TBA

Speaker: Eduardo Peinado

8 TBA

Speaker: Julia Harz (Technical University of Munich (TUM))

16:00 Coffee break

Afternoon session

9 Updated result from µ+→e+ γ search in MEGII and future projects

We report the result of the search for the decay µ+ → e+ γ undertaken at the Paul Scherrer
Institut in Switzerland with the MEG II experiment using the data collected in the 2021–2022
physics runs. The MEG II detector consists of a spectrometer built around a solenoidal
magnet delivering a gradient field, consisting of a large cylindrical drift chamber and a
highly segmented timing counter for positron detection, and a large liquid xenon detector
for gamma-ray detection.
The sensitivity of this search improves significantly that obtained with the full MEG dataset,
obtained in a data taking period of about one fourth that of MEG,
thanks to the superior performances of the new detector.
Additional improvements are expected with the data collected during the years 2023–2024.
The data-taking will continue in the coming years.
We report also on the ongoing activity for designing a future experiment for µ+ → e+ detection
with an expected improvement in sensitivity of an additional order of magnitude compared to the
full MEG II data set, based on gamma-ray converter and innovative technology for tracking.

Speaker: Paolo Walter Cattaneo (Istituto Nazionale di Fisica Nucleare)

10 Observation of the 𝐾⁺ → 𝜋⁺𝜈𝜈 decay and measurement of its branching ratio at NA62

Speaker: Francesco Brizioli (INFN Perugia (IT))

17:30 Welcome cocktail

Tuesday, 1 July

08:30 Registration

Morning session

11 TBA

Speaker: Serguey Petcov (Istituto Nazionale di Fisica Nucleare)

12 TBA

Speaker: Antonio Marrone (Istituto Nazionale di Fisica Nucleare)

13 TBA

Speaker: Michael Ratz (UC Irvine)

14 TBA

Speaker: Gui-Jun Ding (University of Science and Technology of China)

11:00 Coffee break

Morning session

15 TBA

Speaker: Mu-Chun Chen (University of California at Irvine)

16 CP violations of quarks and leptons in the setup with T^2/Z_3 orbifold compactification

CP invariance is a very attractive solution to the strong CP problem in QCD. This solution requires the vanishing phase of (det M_d det M_u) of the mass matrices for the down- and up-type quarks. It happens if we have several zeros in the quark mass matrices. We proceed a systematic construction of texture zeros for the quark sector in the T^2/Z3 orbifold compactification. We also extend the mass construction to the neutrino sector and derive predictions on the CP violating parameter in the neutrino oscillation and the mass parameter of neutrinoless double beta decay. We can naturally explain the positive sign of the baryon asymmetry in the present universe.

Speaker: Morimitsu Tanimoto (Niigata University)

12:30 Free time for lunch

Parallel session

16:00 Coffee break

Parallel session

Wednesday, 2 July

08:30 Registration

Morning session

17 MonoHiggsology

Flavor symmetry and other ideas beyond the standard model may be achieved using the dark sector, while keeping only the one SM Higgs doublet.

Speaker: Ernest Ma (University of California, Riverside)

18 TBA

Speaker: Salvador Centelles Chuliá (Instituto de Física Corpuscular (IFIC) / Universidad de Valencia (UV))

19 TBA

Speaker: Claudia Cornella (CERN)

20 TBA

Speaker: Sebastian Jaeger (University of Sussex)

11:00 Coffee break

11:30 Group photo

Morning session

21 TBA

Speaker: Enrico Nardi (Istituto Nazionale di Fisica Nucleare)

22 TBA

Speaker: Marco Nardecchia (Istituto Nazionale di Fisica Nucleare)

12:45 Free afternoon

20:00 Conference Dinner

Thursday, 3 July

08:30 Registration

Morning session

23 Quark and Lepton Mass Hierarchies from Modular Flavour Symmetry with Weightons

Speaker: Steve King (University of Southampton)

24 TBA

Speaker: Myriam Mondragon (Instituto de Fisica, UNAM)

25 TBA

Speaker: Thomas Kephart (Vanderbilt University)

26 TBA

Speaker: Giulia Ricciardi (Istituto Nazionale di Fisica Nucleare)

11:00 Coffee break

Morning session

27 TBA

Speaker: Silvia Pascoli (University of Bologna)

28 TBA

Speaker: Stefan Antusch (University of Basel)

12:30 Free time for lunch

Parallel session

16:00 Coffee break

Parallel session

Friday, 4 July

08:30 Registration

Morning session

29 Quantum Gravity and Flavor: Probing New Frontiers with Neutrinos

Quantum gravitational effects are expected to reveal themselves at extreme energies, cosmological distances, in a break-down of standard quantum mechanics, or in the breaking of global symmetries. Neutrinos offer a unique potential to probe such effects: they are perfect quantum probes, their masses may be related to lepton number or flavor and thus global symmetry breaking and extra-galactic neutrinos have been observed at energies up to the PeV scale. We discuss Lepton Number Violation, Quantum-Gravitational Decoherence, Altered Dispersion Relations, Holographic Scaling and Entanglement Measures and assess the future perspectives of such experimental probes of quantum gravity.

Speaker: Heinrich Päs

30 TBA

Speaker: Gustavo Burdman

31 TBA

Speaker: Jessica Turner (Durham University)

32 TBA

Speaker: Arsenii Titov (University of Padua and INFN)

11:00 Coffee break

Morning session

33 Selection rules for cLFV processes from residual flavour groups

We systematically investigate the possible phenomenological impact of residual flavour groups in the charged lepton sector. We consider all possible flavour charge assignments for abelian residual symmetries up to Z8. The allowed flavour structures of operators in Standard Model Effective Field Theory (up to dimension six) lead to distinctive and observable patterns of cLFV processes. We illustrate the relevance of such selection rules displaying the current bounds on and the future sensitivities to the new physics scale. These results demonstrate, in particular, the importance and discriminating power of searches for cLFV tau lepton decays and muonium to antimuonium conversion.

Speaker: Claudia Hagedorn (IFIC - UV/CSIC)

34 TBA

Speaker: Ivo de Medeiros Varzielas (CFTP, IST)

12:30 Free time for lunch

Afternoon session

35 TBA

Speaker: Monojit Ghosh (Ruđer Bošković Institute, Zagreb, Croatia)

36 Goofy Symmetries

Speaker: Andreas Trautner

37 Spontaneous CP Violation in an Axion Model: Implications for Leptonic Flavor and the Minimal Seesaw

We investigate an extension of the Dine–Fischler–Srednicki–Zhitnitsky (DFSZ) axion model that realizes spontaneous CP violation and explores its implications for leptonic flavor structure within the framework of the minimal seesaw mechanism. By introducing singlet heavy Majorana neutrinos and an additional complex singlet scalar, we construct the extended Yukawa and scalar sectors necessary for radiatively generating the CP-violating quartic couplings at the 1-loop level. We demonstrate that the CP phase arising from the spontaneous breaking of symmetry propagates into the lepton sector, influencing the Dirac neutrino mass matrix and, consequently, the CP-violating phases of the Pontecorvo–Maki–Nakagawa–Sakata (PMNS) matrix. A benchmark numerical analysis confirms the compatibility of the model with current neutrino oscillation data and illustrates how low-energy leptonic CP violation can originate from the extended scalar dynamics. This framework offers a coherent link between axion physics, spontaneous CP violation, and the flavor structure of neutrinos.

Speaker: Sin Kyu Kang (Seoul National University of Science and Technolofy)

16:00 Coffee break

16:30 End