KEK Theory Meeting on Particle Physics Phenomenology (KEK-PH2026winter)

Session

parallel session B: Flavor

17 Feb 2026, 16:40

meeting room

Conveners

parallel session B: Flavor

• Kohsaku Tobioka

33. Possible scenarios for baryogenesis in the presence of a lepton number violating operator in the rare meson decays

Yushi Mura

17/02/2026, 16:40

We discuss lepton number violating operators motivated by the flavor-changing rare meson decays, B -> Kvv and K ->πvv.
They can erase a pre-existing baryon asymmetry via electroweak sphaleron, and we analyze their impacts on baryon number washout in the early Universe,
We also discuss other topics related to the lepton number violation, the Majorana masses of the active neutrinos and the...

34. Rare meson decay constraints on dark photon and the like

Osamu Seto

17/02/2026, 17:00

We evaluate constraints from flavor changing rare meson decays to a light vector boson X, followed by the decay of the on-shell X into the SM fermions. Our theoretical evaluation of the branching ratio of charged B meson decay and charged kaon decay is compared to experimental results, and we derive new constraints for dark photon, U(1)B−L​ and U(1)R​ models.

35. Radiative Corrections to $D_s \to \ell \nu$ and CKM Unitarity Test

Kota Sasaki

17/02/2026, 17:20

Recently, a violation of the CKM unitarity condition has been reported in the latest charm-meson data and the latest lattice results, once the universal electroweak correction is taken into account. In this talk, we analytically derive for the first time the complete one-loop electroweak (EW) and QED corrections to the $D_{s}^+ \to \ell^+ \nu_\ell$ decays for $\ell = \mu, \tau$. Our analysis...