Described here is the study of lambda-b polarization in the LHC-ATLAS experiment I have done with Prof. Homer Neal this summer. Our work has three main focuses, including predicting lambda polarization from quark-quark scattering models applied to p-p elastic collisions, modeling lambda polarization saturation, and simulating lambda-b events and polarization measurements in ATLAS using the λ0J/...

Top-quark physics is one of the main fields of investigation at the Tevatron accelerator and, ultimately, at the LHC. We perform a phenomenological analysis of tt̄ events at hadron colliders, with a focus on observables relying on bottom-quark fragmentation in top-quark decay. In particular, we investigate the B-lepton invariant-mass distribution in the dilepton channel and give an estimate of t...

The heavy-quark expansion for inclusive semi-leptonic B decays introduces Λ̄ and λ1, which are matrix elements in heavy-quark effective field theory. We review how they can be obtained from an analysis of the heavy quark mass dependence of heavy-light meson masses in lattice QCD. We present preliminary results for the bottom quark mass, mb, using Λ̄ and λ1 for the Bs meson from a 2+1 sea-flavor u...

We show that because of the milder GIM suppression, the four-quark dipenguin operator contributes to the short distance piece of the D − D̄ mixing amplitude at the same order of magnitude as the box diagram. In addition, we put an upper bound ∆m D ≤ 5 ×∆mbox D on a long-distance resonant contribution induced by the penguin mixing. The phenomenon of meson mixing has been studied for a long time. ...

Apart from the low-energy regime of the strong interaction, flavour physics is the least tested part of the SM. This is reflected in the rather large error bars of several flavour parameters such as the mixing parameters at the twenty percent level [1]. However, the experimental situation concerning B physics will drastically change in the near future. There are several B physics experiments su...

The primary goal of this talk will be to summarize in a unified way the predictions of the constituent interchange theory192 (CIM) of high transverse momenta phenomena. A unified approach is possible due to the nature of the theory to be described in which predictions for all such processes are determined by a few simple assumptions. Success in the exclusive realm of hadron physics must go hand...

We discuss a model-independent framework for the analysis of the radiative B-meson decays B → K * γ and B → ργ based on the heavy-quark limit of QCD. We present a factorization formula for the treatment of B → V γ matrix elements involving charm (or up-quark) loops, which contribute at leading power in ΛQCD/mB to the decay amplitude. Annihilation topologies are power suppressed, but still calcu...

The integrated branching fraction of the process B → Xs l+l− is dominated by resonance background from narrow charmonium states, such as B → Xsψ → Xs l +l−, which exceeds the non-resonant charm-loop contribution by two orders of magnitude. The origin of this fact is discussed in view of the general expectation of quark-hadron duality. The situation in B → Xs l+l− is contrasted with charmpenguin...

We calculate the radiative corrections to the nonleptonic inclusive B decay mode b → cūd taking into account the charm quark mass. Compared to the massless case, corrections resulting from a nonvanishing c quark mass increase the nonleptonic rate by (4–8)%, depending on the renormalization point. As a by–product of our calculation, we obtain an analytic expression for the radiative correction t...

We compute non-perturbative contributions to B → Xs l+l− that are not explicitly suppressed by powers of the b-quark mass. They are proportional to 〈B|hσ·Gh|B〉 and arise from an interference between the free-quark amplitude and higher order terms in the matrix element of the four-quark operator sγ(1 − γ5)cα cγμ(1 − γ5)bβ . This correction is found to be small over most of the dalitz plot except...