相关论文: Limit on a Right-Handed Admixture to the Weak $b \…
The Left-Right model is a popular extension of the Standard Model that features three new neutral gauge bosons, $W^{\pm}_R$ and $Z_R$. Collider searches for a Left-Right symmetry are often concentrated on the charged right-handed current,…
Using a data sample of $(10087 \pm 44) \times 10^6$ $J/\psi$ events collected with the BESIII detector at a centre-of-mass energy of $\sqrt{s}=3.097\ \textrm{GeV}$, a dedicated search for the charmonium semileptonic weak decay…
Recent lattice QCD calculations of direct CP violation in $K_L \to \pi \pi$ decays indicate tension with the experimental results. Assuming this tension to be real, we investigate a possible beyond-the-Standard Model explanation via…
It has been known that there exists a disagreement emerged between the determination of $|V_{ub}|$ from inclusive $B \to X_u\ell\nu$ decays and exclusive $B \to \pi\ell\nu$ decays. In order to solve the mismatch, we investigate the…
The measured $\bar{B}\to D^{(*)} l \bar\nu$ decay rates for light leptons ($l=e,\mu$) constrain all $\bar{B}\to D^{(*)}$ semileptonic form factors, by including both the leading and ${\cal O}(\Lambda_{\text{QCD}}/m_{c,b})$ subleading…
We propose an approach for measuring the moments of the hadronic invariant mass distribution in semileptonic $B_{s}^{0}$ meson decays using a sum-of-exclusive technique. Using the present and foreseen knowledge about exclusive semileptonic…
We study violation of quark-hadron duality for $\bar{B}\to X_ul\nu$ and $D\to X_dl\nu$ decays in the presence of the right-handed current operator. For this case, we show that duality violation has some aspects different from the standard…
Bauer, Ligeti and Luke have recently proposed a new method for measuring |V_{ub}| in inclusive semileptonic B decays, using a cut on the lepton invariant mass to discriminate against b->c transitions. We investigate the structure of the…
We apply a recently proposed mechanism -- in which an SU(3) symmetry predicts the weak mixing angle -- to construct realistic theories with composite quarks and leptons at a TeV. Although the models are strongly coupled, they are reliably…
The inclusive and exclusive semileptonic decay distributions for b -> c decay are computed in the Shifman-Voloshin limit. The inclusive decay distributions (computed using an operator product expansion) depend on quark masses, and the…
We provide upper and lower bounds on the semileptonic weak decay form factors for $B \to D^(*)$ and $\Lambda_b \to \Lambda_c$ decays by utilizing inclusive heavy quark effective theory sum rules. These bounds are calculated to second order…
We investigate CP violation in the purely right-handed b quark to c- and u- quark coupling model under the constraint of right-handed W-gauge boson mass M_R > 720 GeV , which is experimentally obtained recently by D0 Collaboration at…
We report the OPE-based predictions for a number of lepton energy and hadronic mass moments in the inclusive semileptonic B -> X_c \ell\nu decays with a lower cut on the charged lepton energy. We rely on the direct OPE approach where no…
We report on a search for right-handed $W$ bosons ($W_R$). We used data collected with the D{\O} detector at the Fermilab Tevatron $p\bar p$ collider at $\sqrt{s}=$1.8 TeV to search for $W_R$ decays into an electron and a massive…
The $b \to c$ semileptonic sum rules provide relations between the decay rates of $B \to D^{(*)} \tau\bar\nu$ and $\Lambda_b \to \Lambda_c \tau\bar\nu$. Starting from the heavy quark and zero-recoil limits, we revisit the derivation of the…
Heavy-meson semileptonic decays calculations on the lattice are reviewed. The focus is upon obtaining reliable matrix elements. Errors that depend upon the lattice spacing, $a$, are an important source of systematic error. Full $O(a)$…
An explicit relativistic light-front quark model is presented which gives the momentum transfer dependent form factors of weak hadronic currents among heavy pseudoscalar and vector mesons in the whole accessible kinematic region $ 0\leq q^2…
We report an upper limit on the fraction of V+A current, $f_{V+A}$, in top quark decays, using approximately 700 pb$^{-1}$ of $p\bar{p}$ collisions at $\sqrt{s}$=1.96 TeV acquired by the upgraded Collider Detector at Fermilab. For the decay…
Clean tests of a small admixture of right-handed quark currents directly coupled to the standard W are still lacking. We show that such non-standard couplings can be significantly constrained measuring the value of the scalar Kpi form…
We find the effective neutral current in the heavy top quark limit up to and including the terms of order $\alpha_s^3$. The result is then employed to compute the correction of the same order to the axial part of the Z decay rate into…