相关论文: The s-d Transition in Heavy Mesons

Current data on semileptonic charged- and neutral-current $B$ decays show deviations from the predictions of the Standard Model. It is well known that a charged Higgs boson, belonging to the two-Higgs doublet model without $Z_2$ symmetry,…

A systematic calculation for the transition form factors of heavy to light mesons ($B,B_s,D,D_s \to \pi, K, \eta, \rho, K^*, \omega, \phi$) is carried out by using light-cone sum rules in the framework of heavy quark effective field theory.…

Wave functions and the screening mass spectrum in the 3D SU(2)-Higgs model near to the phase transition line below the endpoint and in the crossover region are calculated. In the crossover region the changing spectrum versus temperature is…

We report a comprehensive set of results for B-meson heavy-to-light transition form factors calculated using a truncation of, and expression for, the transition amplitudes in which all elements are motivated by the study of Dyson-Schwinger…

Measurements of the branching fractions of the semileptonic decays $B\to D^{(*)}\tau\bar\nu_\tau$ and $B_c\to J/\psi\tau\bar\nu_\tau$ systematically exceed the Standard Model (SM) predictions, pointing to possible signals of new physics…

The rare $B \to K^{(*)} \bar{\ell} \ell$ decays exhibit a long-standing tension with Standard Model (SM) predictions, which can be attributed to a lepton-universal short-distance $b \to s \bar{\ell} \ell$ interaction. We present two novel…

The new narrow mesons observed recently in the final states Ds+ pi0 and Ds*+ pi0 are pointed out to be naturally assigned as the ground-state scalar and axial-vector chiralons in the c sbar system, which would newly appear in the covariant…

We study the form factor f_+^H (H=D,B) involved in H-\pi transitions. We use data on D^0 \to \pi^- l^+ \nu to find f_+^D at low recoil. Then we use perturbative QCD methods to calculate at larger recoil the contributions to f_+^H that break…

We compute for the first time QCD corrections to the rare decays B -> X_{d,s} nu nubar, B_{d,s} -> l^+ l^-, K -> pi nu nubar and K_L -> mu^+ mu^-, where l=e or mu, in the context of a supersymmetric extension of the Standard Model (SM) with…

We observe a new D_s meson with mass (2856.6 +/- 1.5_{stat.} +/- 5.0_{syst.}) MeV/c^2 and width (48 +/- 7_{stat.} +/- 10_{syst.}) MeV decaying into D^0 K^+ and D^+K^0_S. In the same mass distributions we also observe a broad structure with…

The discovery of New Physics, using weak decays of mesons is difficult due to intractable strong interaction effects needed to describe it. We show how the multitude of "related observables" obtained from B\to K^* \ell^+\ell^-, can provide…

We reconsider observables for discovering and measuring the mass of a Higgs boson via its di-leptonic decays: H --> WW* --> l nu l nu. We define an observable generalizing the transverse mass that takes into account the fact that one of the…

We reconsider the complete set of four-quark operators in the Weak Effective Theory (WET) for non-leptonic $\Delta F=1$ decays that govern $s\to d$ and $b\to d, s$ transitions in the Standard Model (SM) and beyond, at the Next-to-Leading…

We study the crossover between the mean-field and critical behavior of the two-dimensional Bose gas throughout the fluctuation region of the Berezinskii--Kosterlitz--Thouless phase transition point. We argue that this crossover is described…

Based on the short-distance expansion of currents in the heavy quark effective theory, we derive the exact expressions for the heavy-to-heavy meson and baryon weak decay form factors to order $1/m_Q$ in the heavy quark expansion, and to all…

We analyze the semileptonic $ B_{s} \rightarrow D_{s2}^{*}(2573)\ell\bar{\nu }_{\ell}$ transition, where $\ell=\tau,~\mu$ or $e$, within the standard model. We apply the QCD sum rule approach to calculate the transition form factors…

We analyse the constraints on dimension-six Delta F=1 effective operators in models respecting the MFV hypothesis, both in the one-Higgs doublet case and in the two-Higgs doublet scenario with large tan beta. The constraints are derived…

This article summarizes the latest results on the proton-to-electron mass ratio $\mu$ derived from H$_2$ observations at high redshift in the light of possible variations of fundamental physical constants. The focus lies on UVES…

We present preliminary results for heavy to light transitions of pseudoscalar mesons, induced by the vector and tensor operators. This lattice study is performed in quenched approximation, by using the nonperturbatively improved Wilson…

Spin-singlet and spin-triplet internal transitions of quasi-two-dimensional, negatively charged magneto-excitons (X-) and their evolution with excess electron density have been studied in GaAs/AlGaAs quantum-wells by optically detected…