Related papers: Rare Kaon Decays
We search for decays of a B meson into a neutral D meson and a kaon, with the D meson decaying into K+pi-pi0. This final state can be reached through the b --> c transition B- -> D0K- followed by the doubly Cabibbo-suppressed D0 -->…
The study of the rare decays $B\to K^{(*)} \nu \bar\nu$ offers a window into the dynamics operating at the electroweak scale, allowing studies of the Standard Model and searches for heavy new physics. However, the analysis of these decays…
The NA62 experiment at CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar collecting O(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to…
The NA62 experiment at CERN SPS aims to measure the Branching Ratio of the very rare kaon decay K+ -> pi+ nu nubar collecting O(100) events with a 10% background to make a stringent test of the Standard Model. One of the main backgrounds to…
The NA62 experiment at CERN reports searches for $K^+\to\mu^+N$ and $K^+\to\mu^+\nu X$ decays, where $N$ and $X$ are massive invisible particles, using the 2016-2018 data set. The $N$ particle is assumed to be a heavy neutral lepton, and…
We report on results of a search for the decay mode K_L -> pi^0 gamma e^+ e^- conducted by the E162 experiment at KEK. We observed no events and set a 90% confidence level upper limit of Br(K_L -> pi^0 gamma e^+ e^-)< 7.1x10^{-7} for its…
We search for decays of a B meson into a neutral D meson and a kaon, with the D meson decaying into K+pi-pi0. This final state can be reached through the b --> c transition B- -> D0K- followed by the doubly Cabibbo-suppressed D0 -->…
We present results of a search for proton decays, $p \to \bar{\nu} K^+$, using data from a 33 kton$\cdot$year exposure of the Super-Kamiokande detector. Two decay modes of the kaon, $K^+ \to \mu^+ \nu_{\mu}$ and $K^+ \to \pi^+ \pi^0$, were…
Rare meson decays are among the most sensitive probes of both heavy and light new physics. Among them, new physics searches using kaons benefit from their small total decay widths and the availability of very large datasets. On the other…
After $CP$ violation was discovered in the $K_L \to \pi^+\pi^-$ decay, many theories were proposed to explain it, and the Kobayashi-Maskawa model and the Superweak model lasted for many years as strong candidates. High-precision kaon…
Recent results from a rare kaon decay experiment E787 at the BNL-AGS on K^+ \to \pi^+ \nu \bar\nu, K^+ \to \mu^+ \nu \gamma, and K^+ \to \pi^+ \pi^0 \gamma decays are reported.
The availability of high-intensity kaon beams at the J-PARC Hadron Experimental Facility and the CERN SPS North Area, together with the abundant forward production of kaons at the LHC, gives rise to unique possibilities for sensitive tests…
We present a search for the decay of a B0 or B0bar meson to a K*0bar K0 or K*0 K0bar final state, using a sample of approximately 232 million BBbar events collected with the BABAR detector at the PEP-II asymmetric energy e+e- collider at…
The KOTO ($K^0$ at Tokai) experiment aims to observe the CP-violating rare decay $K_L \rightarrow \pi^0 \nu \bar{\nu}$ by using a long-lived neutral-kaon beam produced by the 30 GeV proton beam at the Japan Proton Accelerator Research…
Precise measurements of the branching ratios for the $K\to\pi\nu\bar{\nu}$ decays can provide unique constraints on CKM unitarity and, potentially, evidence for new physics. It is important to measure both decay modes,…
The NA62 experiment at CERN is designed to measure precisely the rare decay $K^{+} \rightarrow \pi^+ \nu \bar{\nu}$. The intensity and energy of the SPS proton beam used to produce the $K^+$, as well as the hermetic detector coverage and…
Searches for lepton flavour and lepton number violation in kaon decays by the NA48/2 and NA62 experiments at CERN are presented. A precision measurement of the helicity-suppressed ratio RK of the K --> e nu and K --> mu nu decay rates has…
Rare decays of K mesons are reviewed from the perspective of testing the ``ones'' and ``zeros'' of the standard model. Decays K^+ -> pi^+ nu anti-nu and K_L -> pi^0 nu anti-nu probe the one-loop effective Hamiltonian for s -> d nu anti-nu,…
A search for the D0 to \pi+ \pi- \mu+ \mu- decay, where the muon pair does not originate from a resonance, is performed using proton-proton collision data corresponding to an integrated luminosity of 1.0 fb-1 recorded by the LHCb experiment…
Theoretical aspects of kaon and muon decays are reviewed. In particular, three topics on kaon and muon decays, namely $K \to \pi\nu \bar{\nu}$ processes, T violation in $K^+ \to \pi^0\mu^+ \nu$ decay and lepton flavor violation in muon…