Article is made available in accordance with the publisher's policy and may be subject to US copyright law. Please refer to the publisher's site for terms of use. The MIT Faculty has made this article openly available. Please share how this access benefits you. Your story matters. We establish the existence of the top quark using a 67 pb ' data sample of pp collisions at ~s = 1.8 TeV collected ...

Top quark events in hadron collisions often contain additional hadronic jets from gluon bremsstrahlung off the quarks and gluons in the hard subprocesses. Such extra jets must be taken into account in attempts to reconstruct the momentum of the top quark from those of its decay products. We have performed a complete calculation of gluon radiation in top production and decay at the Fermilab Teva...

We present our study on B → πlν semileptonic decay form factors using NRQCD action for heavy quark. In the analysis, we use the form factors f1(v · kπ) and f2(v · kπ) defined in the context of heavy quark effective theory by Burdman et al.. Since the NRQCD action for heavy quark respects the heavy quark symmetry, our results are described by the HQET form factors most naturally. From a quenched...

We investigate spin properties of single top quark production at hadron colliders. Based on an analogy with single top production and polarized top quark decay, we reproduce in a simple way the results by G. Mahlon and S. Parke on the existence of preferred axes for the decomposition of the top quark spin. For the W ∗and W-g-fusion production modes these axes are related to the down-type quark ...

The top quark, which completes the quark sector of the SM, was discovered in 1995 at the Tevatron by the CDF and DØ Collaborations [1]. Being the heaviest of all quarks with a mass of 178.0 ± 4.3 GeV/c [2], it couples most strongly to the Higgs boson, and its lifetime of ≈ 4 · 10 s means that it is the only quark that decays before it can hadronise, preserving spin information, and providing a ...

We present our study on B → πlν semileptonic decay form factors using NRQCD action for heavy quark. In the analysis, we use the form factors f1(v · kπ) and f2(v · kπ) defined in the context of heavy quark effective theory by Burdman et al.. Since the NRQCD action for heavy quark respects the heavy quark symmetry, our results are described by the HQET form factors most naturally. From a quenched...

Since the observation of the top quark in 1995, considerable progress has been made by the CDF and D0 collaborations in measuring top quark production and decay properties. The combined top quark mass from both experiments is mt = 174:3 5:1 GeV/c . With this determination of the top quark mass, the remaining properties of the top quark are predicted by the standard model, allowing for many new ...

The B̄ → Kγ branching fraction is predicted using heavy quark spin symmetry at large recoil to relate the tensor and (axial-)vector form factors, using heavy quark flavor symmetry to relate the B decay form factors to the measured D → Kl̄ν form factors, and extrapolating the semileptonic B decay form factors to large recoil assuming nearest pole dominance. This prediction agrees with data surpris...

Improved staggered fermions are a numerically efficient formulation of the fermion action in lattice QCD. They are used for nonperturbative theoretical calculations of the QCD form factors appearing in the decay rates for radiative and semileptonic meson transitions. The constituent quarks are bound inside hadrons by the strong interaction, so the decay rate depends on the interactions between ...

The constituent quark model can explain the strong selectivity of the Nη decay branching ratios of the nucleon resonances if the fine structure interaction between the constituent quarks is described in terms of Goldstone boson exchange. This chiral quark model predicts that the S wavefunctions in lowest order, should have large Nη branching ratios, while Nη decay of the other resonances that h...