Speakers
Sergey Podolsky
(UCL (Louvain-la-Neuve))
Siarhei Padolski
(Universite Catholique de Louvain (BE))
Description
A precision measurement of the ratio RK of the rates of kaon leptonic decays
K+- --> e+- nu and K+- --> mu+- nu with the full minimum bias data sample
collected with low intensity 75 GeV/c beam by the NA62 experiment at CERN in
2007-2008 is reported. The result, obtained by analyzing ~150,000
reconstructed K+- --> e+- nu candidates with 11%
background contamination, has a record precision of 0.4% and is in agreement
with the Standard Model expectation.
The sensitivity of the NA62 experiment at CERN to charged kaon decays
violating lepton number conservation, neutral pion decays forbidden in the
Standard Model and heavy sterile neutrinos is discussed. An upper limit on
the lepton number violating K+- --> pi-+ mu+- mu+- decay rate from the
NA48/2 experiment is presented.
A precision lepton universality test by measurement of the helicity suppressed ratio of leptonic decay rates of the charged kaon with ~10^5 K+- --> e+- nu decays collected by the NA62 experiment in 2007-08 is presented. The record accuracy of 0.4% constrains the parameter space of new physics models with extended Higgs sector, a fourth generation of quarks and leptons or sterile neutrinos. An improved upper limit on the rate of the lepton number violating decay K+- --> pi-+ mu+- mu+- from the NA48/2 experiment, which probes the resonant enhancement of the rate in the presence of heavy Majorana neutrinos in the ~100 MeV range, is presented. The prospects for the searches of lepton number and flavour violating decays of the charged kaon with an improved sensitivity down to ~10^{-12} during the forthcoming main phase of the NA62 experiment are discussed: these would probe new physics scenarios involving heavy Majorana neutrinos or R-parity violating SUSY.
Author
Cristina Lazzeroni
(University of Birmingham (GB))
