相关论文: Triangulating an exotic T quark

Motivated by evidence that the top quark mass lies near the $bWZ$ threshold, we compute the decay rate for $t\rightarrow bWZ$ in the Standard Model, including the effects of the finite widths of the $W$ and $Z$ bosons. In the limit where…

If the $R_b$ excess at LEP is real, then any explanation in terms of renormalizable loop corrections leads to important new decay modes of the $t$ quark and suppresses the $t \to bW$ branching ratio. In the two-Higgs-doublet model, the…

In this work, we calculate the top quark rare decays t-cgamma and t-cg in the framework where the standard model is embedded in a warped extra dimension with the custodial symmetry SU(3)c*SU(2)L*SU(2)R*U(1)x*PLR. Adopting reasonable…

We study the $p\bar p$ production and decay of exotic quarks that are predicted by the SU(3)$\times$U(1) extension of the Standard Model. We show that recent experimental searches for SUSY particles at the Tevatron limit the mass of these…

In the framework of the color-magnetic interaction, we systematically investigate the mass splittings of the $QQ\bar{Q}\bar{q}$ tetraquark states and estimated their rough masses in this work. These systems include the explicitly exotic…

Many standard model extensions that address the hierarchy problem contain Dirac-fermion partners of the top quark, which are typically expected around the TeV scale. Searches for these vector-like quarks mostly focus on their decay into…

The conventional loosely bound molecule interpretation of the $X(3872)$ is not compatible with the recent LHCb experimental measurement of the ratio of branching fractions…

We calculate in the framework of two Higgs doublet models the differential decay rate for inclusive $\bar B\to\tau\,\bar\nu\,X$ transitions to order $1/m_b^2$ in the heavy quark expansion, for both polarized and unpolarized tau leptons. In…

The latest results from the CDF and D0 collaborations on the top-quark pair-production cross section and limits on electroweak production are presented. Included are measurements of properties of the top quark such as charge, lifetime, and…

Recently, some progresses have been made on the double-heavy tetraquarks in the experiments, such as $T_{cc}$ reported by LHCb Collaboration, and $X_{cc\bar{s}\bar{s}}$ reported by the Belle Collaboration. Coming on the heels of our…

Scrutinizing the scattering of ordinary mesons in the limiting case of the number of colour degrees of freedom $N_{\rm c}$ of quantum chromodynamics approaching infinity, we formulate Feynman-diagram selection criteria and from these deduce…

Precision studies of top quark properties are currently underway at the LHC and Tevatron colliders with the prospect of probing anomalous t-W -b interactions. In the mean time, recent experimental results for the B_{d,s} - \bar{B}_{d,s}…

We calculate the typical size of loop corrections to electroweak observables arising from non-standard $Z {\overline t } t$ and $W t b$ vertices. We use an effective Lagrangian formalism based on the electroweak gauge group $SU(2)_L\times…

The mass and coupling of the axial-vector tetraquark $T_{bc;\bar{u}\bar{d} }^{0}$ (in a short form $T_{bc}^{0}$) are calculated by means of the QCD two-point sum rule method. In computations we take into account contributions arising from…

With the deeper study of Higgs particle, Higgs precision measurements can be served to probe new physics indirectly. In many new physics models, vector-like quarks $T_L,~T_R$ occur naturally. It is important to probe their couplings with…

A search for new exotic particles decaying to the VZ final state is performed, where V is either a W or a Z boson decaying into two overlapping jets and the Z decays into a pair of electrons, muons or neutrinos. The analysis uses a data…

Deviations of the top electroweak couplings from their Standard Model values imply that certain amplitudes for the scattering of third generation fermions and longitudinally polarized vector bosons or Higgses diverge quadratically with…

We studied properties of the strange axial mesons in the relativized quark model. We calculated the $K_1$ decay constant in the quark model and showed how it can be used to extract the $K_1 (^3P_1) - K_1 (^1P_1)$ mixing angle ($\theta_K$)…

The flavor changing neutral top quark decay t -> c X is computed, where X is a neutral standard model particle, in a extended model with a single extra dimension. The cases for the photon, X= \gamma$, and a Standard Model Higgs boson, X =…

We study $B\to \phi K$ and $B\to \phi X_s$ decays in the heavy quark limit using perturbative QCD. The next leading order corrections introduce substantial modifications to the naive factorization results (more than 50%). The branching…