相关论文: QCD Calculations of Decays of Heavy Flavor Hadrons

In decay modes $B^0 \to D_s^{(*)+} D_s^{(*)-}$ and $B_s^0 \to D^{(*)+} D^{(*)-}$, none of quarks in final states is the same as one of $B$ meson. They can occur only via annihilation diagrams in the Standard Model. In the heavy quark limit,…

We propose a new method for precise determination of |V_{td} / V_{ub}| from the ratios of branching ratios BR(B -> \rho \nu \bar \nu ) / BR(B ->\rho l \nu ) and BR(B -> \pi \nu \bar \nu ) / BR(B -> \pi l \nu ). These ratios depend only on…

Using the QCD sum rules approach and the complete leading--logarithmic short--distance coefficients determining the penguin--amplitude, we obtain $B(B\to K^*\gamma) = (6.8\pm 2.4)\cdot 10^{-5}$ for top--quark masses in the range (150--200)…

We have developed a new technique for inclusive reconstruction of the energy of B hadrons. The excellent efficiency and resolution of this technique allow us to make the most precise determination of the b-quark fragmentation function,…

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.

It is demonstrated that charm is systematically undercounted in various experiments. Via a process of elimination, $B(D^0 \rightarrow K^- \pi^+ )$ is identified as the culprit. It calibrates essentially all charmed meson production and…

We report a measurement of the branching fraction $B(D^+ \rightarrow \mu^+ \nu_{\mu}) = [3.71 \pm 0.19 (\rm stat) \pm 0.06 (\rm sys)]\times 10^{-4}$ based on 2.92 ${\rm fb^{-1}}$ of data accumulated at $\sqrt{s}=3.773$ GeV with the BESIII…

The quenching of light and heavy flavor hadrons in relativistic heavy-ion collisions probes the color and flavor dependences of parton energy loss through a color-deconfined quark-gluon plasma (QGP), and thus reveals the properties of QCD…

In view of new precise measurements of the $\bar B\to D^*\ell \bar\nu$ decay rate near zero recoil, we reconsider the theoretical uncertainties in the extraction of $| V_{cb}|$ using heavy quark symmetry. In particular, we combine our…

At the LHC, bottom baryons are being produced in unprecedented quantities, which opens up a new field for flavor physics. For example, the decay $\Lambda_b \to p \mu^- \bar{\nu}$ can be used to obtain a novel determination of the CKM matrix…

We perform global fits to the moments of semileptonic B decay distributions and extract |V_cb|, the heavy quark masses, and the non-perturbative parameters of the heavy quark expansion. We include NNLO perturbative corrections and recent…

In the last decade, the LEP and SLD experiments played a central role in the study of B hadrons (hadrons containing a b quark). New B hadrons have been observed ($B^0_s$, \Lambda_b$, $\Xi_b$ and $B^{**}$) and their production and decay…

We present a sum-rule extraction of heavy-meson decay constants from the two-point correlator of heavy-light pseudoscalar currents. Our main concern is to control the uncertainties of the decay constants, induced by both input QCD…

Rare decays mediated by $b \to s \nu \bar \nu$ transitions have been reported by the Belle II experiment. The branching ratio of the decay $B^+ \to K^+ \nu \bar \nu$ is found to be enhanced with respect to the standard model value. If taken…

We present Standard Model predictions for lepton flavour universality ratios of inclusive $B\to X_{(c)} \ell \bar\nu_\ell$. For the $\ell=\mu,e$, these ratios are very close to unity as expected. For the $\tau$ mode, we update the SM…

We examine the prospects for observing weak flavour-changing neutral current (FCNC) decays of \B\ mesons at hadron colliders, including effects of anomalous $WWZ$~vertices. Since it is very difficult to measure the inclusive rate $B…

We present a search for the rare flavor-changing neutral-current decay $B^+ \to K^+ \nu \bar{\nu}$ based on data sample of 82 fb$^{-1}$ collected with the BABAR detector at the PEP-II B-factory. Signal events are selected by examining the…

In these lectures, I present several important applications of QCD sum rules to the decay processes involving heavy-flavour hadrons. The first lecture is introductory. As a study case, the sum rules for decay constants of the heavy-light…

We present a lattice QCD calculation of form factors for the decay $\Lambda_b \to p \mu^- \bar{\nu}$, which is a promising channel for determining the CKM matrix element $|V_{ub}|$ at the Large Hadron Collider. In this initial study we work…

I review the status of the modern theoretical approach to weak decays of heavy flavor hadrons based on the 1/m_Q expansion in QCD. The qualitative features are explained and the subtleties in simultaneously incorporating perturbative and…