Related papers: Kaon decays shedding light on massless dark photon…
We present a systematic QCD sum-rule analysis of the in-medium properties of the charged kaon doublet $K^{\pm}$ over the full $(T,\rho)$ plane relevant to current and forthcoming heavy-ion experiments. Working within the QCD sum-rule…
We suggest that the decay modes of kaons with a pion and a pionium ($\pi^+\pi^-$ atom) in the final state can constitute a not yet considered background to the very rare decay $K\to\pi\nu\bar\nu$. In fact, a part of pioniums may escape the…
We report the first observation of a b -> u type charmless baryonic B decay, B+ -> p pbar pi+, as well as b -> s type B0 -> p pbar K0 and B+ -> p pbar K*+ decays. The analysis is based on a 78fb^{-1} data sample recorded on the Upsilon(4S)…
Over the next years, the Flavour Physics community will be looking for inconsistencies of the Standard Model (SM) by exploiting new and precise measurements. In these ``indirect new physics'' searches, the key strategy is to concentrate on…
The rare kaon decays $K\to\pi\ell^+\ell^-$ and $K\to\pi\nu\bar{\nu}$ are flavor changing neutral current (FCNC) processes and hence promising channels with which to probe the limits of the standard model and to look for signs of new…
The ratio $\mathcal{B}(K_L\to\pi^0\nu\bar\nu)/\mathcal{B}(K^+\to\pi^+\nu\bar\nu)$ of the branching fractions of kaon decays $K_L\to\pi^0\nu\bar\nu$ and $K^+\to\pi^+\nu\bar\nu$ has a maximum of about 4.3 under the assumption that the…
We study the weak radiative decays of ${\bf B}_b \to {\bf B}_n \gamma$ with ${\bf B}_{b(n)} $ the anti-triplet-bottom (octet) baryons in the light front quark model. We obtain that ${\cal B}(\Lambda_b \to \Lambda \gamma)= (7.1 \pm 0.3…
Precision measurements of the branching ratios (BRs) for rare kaon decays can provide unique constraints on CKM unitarity and may reveal the existence of new physics. The BRs for two of these decays, $K^+\to\pi^+\nu\bar{\nu}$ and…
A theoretical model of the reactions e+ e- --> K+ K- gamma and e+ e- --> K0 K0bar gamma has been derived. The strong interaction between kaons is taken into account using a general form of the K Kbar scattering amplitude. It is shown that…
We have studied two-body charmless hadronic decays of B mesons into the final states $\pi\pi$, $K \pi$, and $KK$. Using 3.3 million $B\bar{B}$ pairs collected with the CLEO-II detector, we have made the first observation of the decays…
Motivated by experimental results on $\bar B\to D^{(*)}K^-K^{0}$, we use a factorization approach to study these decays. Two mechanisms concerning kaon pair production arise: current-produced (from vacuum) and transition (from the $B$…
A sizable strong-interaction phase shift in weak two-body nonleptonic baryon decay would enhance the possibility of discovering charge-conjugation parity ($CP$) violation in the baryon sector, which might help in the quest for understanding…
In this study, we have investigated the two-body hadronic decay of the charged kaon, $ K^{+}\rightarrow\pi^{+}+\pi^{0} $, in the presence of a laser field with circular polarization. We have derived, by analytical techniques, the…
The radiative decay $K^+ \to \pi^+ \pi^0 \gamma$ ($K_{\pi 2 \gamma}$) has been measured with stopped positive kaons. A $K_{\pi 2 \gamma}$ sample containing 4k events was analyzed, and the $K_{\pi 2 \gamma}$ branching ratio of the direct…
Heavy neutral leptons ($N$) below the kaon mass are severely constrained by cosmology and lab-based searches for their decays in flight. If $N$ interacts via an additional force, $N\to\nu e^+e^-$ decays are enhanced and cosmological limits…
The standard model (SM) of particle physics is spectacularly successful, yet the measured value of the muon anomalous magnetic moment $(g-2)_\mu$ deviates from SM calculations by 3.6$\sigma$. Several theoretical models attribute this to the…
The long-distance and non-local parts of the form factors describing the single-photon mediated $K_{S,L}\to\pi^0\gamma^*\to\pi^0\ell^+\ell^-$ ($\ell = e, \mu$) transitions in the standard model are addressed in QCD in the limit where the…
Recent results and future prospects in the rare kaon-decay experiments at KEK, BNL, CERN and FNAL are reviewed. Emphasis is placed on the quark flavor dynamics in the flavor-changing neutral current processes. Experimental and data-analysis…
Some applications of the elementary kaon photoproduction process are discussed: the investigation of missing resonances in the p(gamma,K+)Lambda channel, the role of the P_{13}(1720) state in the p(gamma,K0)Sigma+ channel, and the…
A massless particle beyond the Standard Model is searched for in the two-body decay $\Sigma^+\rightarrow p+{\rm invisible}$ using $(1.0087\pm0.0044)\times10^{10}$ $J/\psi$ events collected at a center-of-mass energy of $\sqrt{s}=3.097$ GeV…