Related papers: K -> pi nu nubar from standard to new physics

We review some recent theoretical results on rare kaon decays. Particular attention is devoted to find Standard Model tests. This is theoretically easy in $K\to \pi \nu \bar{\nu}$, while a careful study of the long distance contributions is…

Exploring correlations between the CP asymmetries of $B^0_d\to\pi^0K_{\rm S}$ following from an isospin relation, we uncover new tensions with the Standard Model in data for neutral $B\to\pi K$ decays. Should this intriguing picture…

With the first measurements of the branching ratios and the direct CP asymmetries of $B_s\to K^{-}K^{+}$, $K^{-}\pi^{+}$ decays by the CDF collaboration, we constrain the relevant parameter space of the Minimal Supersymmetric Standard Model…

The long-term goal of NA62 is to measure the ultra rare K+/- -> pi+/- nu anti-nu decay with a sensitivity of 10^-12 per event. This is done by using the decay - in - flight technique which allows a signal acceptance of ~10% . The aim is to…

We consider the impact of R-parity violating suprsymmetry in the nonleptonic decay B --> pi+ pi-. This is one of the rare instances where new physics contributes to both B-Bbar mixing and B --> pi+ pi- decay. We do a numerical analysis to…

Using data collected with the HyperCP (E871) spectrometer during the 1997 fixed-target run at Fermilab, we report the first observation of the decay K- -> pi- mu+ mu- and new measurements of the branching ratios for K+/- -> pi+/- mu+ mu- .…

In a global analysis of the latest parity-violating electron scattering measurements on nuclear targets, we demonstrate a significant improvement in the experimental knowledge of the weak neutral-current lepton-quark interactions at low…

We present measurements of the flavor-changing neutral current decays B -> Kl+l- and B -> K*l+l-, where l+l- is either an e+e- or mu+mu- pair. The data sample comprises 229 X 10^6 Y(4S) -> BBbar decays collected with the BaBar detector at…

We report on a search for the flavor-changing neutral current decays $\Dz\to e^+e^-$ and $\Dz\to\mu^+\mu^-$, and the lepton-flavor violating decay $\Dz\to e^\pm\mu^\mp$. The measurement is based on $122 {fb}^{-1}$ of data collected by the…

Rare decays provide a complementary window to direct collider searches as probes of physics beyond the Standard Model. We present an overview of the New Physics sensitivity provided by existing and future measurements of rare leptonic and…

The ultra-rare decay $K^+\to\pi^+\nu\bar\nu$ is a golden mode in flavor physics. The Standard Model prediction for its branching ratio is below $10^{-10}$. This decay mode is highly sensitive to new physics models at mass scales up to…

Bounds on R-parity violating couplings in the supersymmetric standard model are reviewed, and some new bounds arising from non-observation of certain rare B-decays (such as $B \rightarrow K^+K^-$) are presented. The focus is on…

An analysis of the rare B decays $B\to K^{(*)}\nu\bar\nu$ is presented both within the SM and beyond. The SM predictions for the branching ratios are updated and uncertainties reduced. For the NP analysis both a model independent approach…

In the Standard Model extended by sterile neutrinos, modified W-l-nu couplings arise, which are able to induce a tree-level enhancement to lepton flavour universality violation in kaon decays. The additional mixing between the active…

In the Standard Model (SM), the rare transitions where a bottom quark decays into a strange quark and a pair of light leptons exhibit a potential sensitivity to physics beyond the SM. In addition, the SM embeds Lepton Flavour Universality…

An extensive model-independent analysis of B->DD decays is carried out employing SU(3) flavour symmetry, including symmetry-breaking corrections. Several theoretically clean observables are identified which allow for testing the Standard…

Motivated by flavour symmetry models, we construct theories based on a low-energy limit featuring lepton flavour triality that have the flavour-violating decays $\tau^\pm \to \mu^\pm \mu^\pm e^\mp$ and $\tau^\pm \to e^\pm e^\pm \mu^\mp$ as…

Motivated by a recent Belle~II measurement that suggests an excess in the rare decay $B \to K\, E_{\rm miss}$, and building upon our recent differential decay rate likelihood analysis of the existing experimental information, we investigate…

In the light of new experimental results on $B \to K\pi$ decays, we study the decay processes $B \to K \pi$ in the framework of both R-parity conserving (SUGRA) and R-parity violating supersymmetric models. We find that any possible…

The measured B -> pi pi, pi K branching ratios exhibit puzzling patterns. We point out that the B -> pi pi hierarchy can be nicely accommodated in the Standard Model (SM) through non-factorizable hadronic interference effects, whereas the B…