ICHEP 2022

A new KS→πeν branching fraction measurement from KLOE-2

7 Jul 2022, 18:08

17m

Room 9 (Indaco)

Parallel Talk Quark and Lepton Flavour Physics Quark and Lepton Flavour Physics

Speaker

Antonio Passeri (Istituto Nazionale di Fisica Nucleare)

Description

The KLOE-2 Collaboration continues the KLOE long-standing tradition of flavour physics precision measurements in the kaon sector with a new $K_S\to \pi e\nu$ branching fraction measurement.
Based on a sample of 300 million $K_S$ mesons produced in $\varphi \to K_L{K}_S$ decays recorded by the KLOE experiment
at the DA$\mathrm{\Phi }$NE $e^{+}{e}^{-}$ collider, the $K_S\to \pi e\nu$ signal selection exploits a boosted decision tree built with kinematic variables together with time-of-flight
measurements.
A fit to the reconstructed electron mass distribution provides the signal yield, then normalised to $K_S\to {\pi }^{+}{\pi }^{-}$ decays. Data control samples of $K_L\to \pi e\nu$ decays are used to evaluate signal selection efficiencies.
The combination with our previous BR($K_S\to \pi e\nu$) measurement, based on an
independent data sample, allows the total precision to be improved by almost a factor of two, and a new derivation of $f_{+}(0)|V_{us}|$.

Presentation materials

ICHEP22_Kse3_Passeri.pdf