相关论文: Results from the NA62 2014 Commissioning Run

A search for the rare decays $B^0_s\to\mu^+\mu^-$ and $B^0\to\mu^+\mu^-$ is performed at the LHCb experiment using data collected in $pp$ collisions corresponding to a total integrated luminosity of 4.4 fb$^{-1}$. An excess of…

We present the estimate of the branching ratio for the rare decay $\bar B^0\to D^*\gamma$. We use QCD factorization approach in order to compute the amplitude of the process. The calculation is carried out with the leading order accuracy. %…

I present some of the most recent BaBar measurements for rare B decays. These include rate asymmetries in the B decays to K(*) l+ l- and K+ pi- and branching fractions in the B decays to l+ nu_l, K_1(1270)+ pi- and K_1(1400)+ pi-. I also…

The NA48/2 Collaboration at CERN has accumulated unprecedented statistics of rare kaon decays in the Ke4 modes: Ke4(+-) ($K^\pm \to \pi^+ \pi^- e^\pm \nu$) and Ke4(00) ($K^\pm \to \pi^0 \pi^0 e^\pm \nu$) with nearly one percent background…

We report preliminary measurements of the branching fractions for B+ -> J/psi phi K+, B0 -> J/psi phi K0S, B0 -> J/psi phi, B0 -> J/psi eta and B -> J/psi eta' using 56 million BBbar events collected at the Y(4S) resonance with the BABAR…

In the standard model (SM), we re-investigate the rare decay $B\to \phi\pi$, which has been viewed as an ideal probe to detect the new physics signals beyond the SM. Contributions in the naive factorization method, the radiative…

A new measurement of $B_{\pi e2}$, the $\pi^+ \to e^+\nu(\gamma)$ decay branching ratio, is currently under way at the Paul Scherrer Institute. The present experimental result on $B_{\pi e2}$ constitutes the most accurate test of lepton…

New results on radiative K+- decays from the NA48/2 experiment are presented. In the channel K+- -> pi+- pi0 gamma more than 1 million decays were reconstructed, leading to the first measurement of the interference between direct photon…

From 56 days of data taking in 2002, the NA48/1 experiment observed 6316 Xi0 --> Sigma+ e- nubar candidates (with the subsequent Sigma+ --> p pi0 decay) and 555 anti-Xi0 --> anti-Sigma+ e+ nu candidates with background contamination of…

Using 226 million $\Upsilon(4S)\to B\bar{B}$ events collected with the BaBar detector at the PEP-II $e^+e^-$ storage ring at the Stanford Linear Accelerator Center, we measure the branching fraction for $B^0\to \bar{D}^0 K^+\pi^-$,…

The NA61/SHINE experiment aims to discover the critical point of strongly interacting matter and study properties of the onset of deconfinement. These goals are to be achieved by performing a twodimensional phase diagram (T - {\mu}B) scan…

The NA62 experiment is designed to measure the ultra-rare decay $K^+ \rightarrow \pi^+ \nu \bar{\nu}$ branching ratio with a precision of $\sim 10\%$ at the CERN Super Proton Synchrotron (SPS). The trigger system of NA62 consists in three…

We present a method for measuring branching fractions for the decay of $J = 1/2$ atomic energy levels to lower-lying states based on time-resolved recording of the atom's fluorescence during a series of population transfers. We apply this…

We compute the branching fraction of the decays $B \to K \nu \bar\nu$ and $B \to K^* \nu \bar\nu$ in the Standard Model. We also comment on the experimental difficulties and procedures to detect such modes at B factories.

In this paper, I study the branching ratio of the rare radiative decay $B_s \to \nu \bar{\nu} \gamma$ in the framework of the Fourth-Generation Standard Model and the Two-Higgs-Doublet Model. It is shown that this quantity is a very…

We report a measurement of the branching fraction of $B \to K^{\ast}(892)\ell^+\ell^-$ decays, where $\ell^+\ell^- = \mu^+\mu^-$ or $e^+e^-$, using electron-positron collisions recorded at an energy at or near the $\Upsilon(4S)$ mass and…

The rare decay B^+ \to D_s^+ \bar K^{*0} can occur only via annihilation diagrams in the Standard Model. We calculate the branching ratio in perturbative QCD approach based on k_T factorization theorem. We found that the branching ratio of…

We establish improved upper limits on branching fractions for $B^{0}$ decays to final states where the decay products are purely invisible (i.e., no observable final state particles) and for final states where the only visible product is a…

We report preliminary measurements of the branching fractions of the decays $\tau \to K\, n\pi^0\, \nu$ ($n = 0,1,2,3$) and $\tau \to \pi\, n\pi^0\, \nu$ ($n = 3,4$), excluding the contributions that proceed through the decay of…

The ratio of the leptonic charged kaon decays $R_K= \Gamma(K^{\pm} \to e^{\pm}\nu) / \Gamma(K^{\pm} \to \mu^{\pm}\nu)$ is sensitive to the structure of the week interactions and can be precisely calculated within the Standard Model.…