We use the heavy quark expansion to investigate the width difference ∆Γ Bs between the B s mass eigenstates. The corrections of O(Λ QCD /m b) and O(m s /m b) to the leading order expression in the operator product expansion are derived and estimated to yield a sizable reduction of the leading result for ∆Γ Bs by typically 30%. For completeness we also quantify small effects due to penguin opera...

We discuss lattice methods to obtain the derivatives of a lattice meson mass with respect to the bare sea and valence quark masses. Applications are made to quenched and dynamical fermion configurations. We find evidence for significant differences between quenched and dynamical fermion configurations. We discuss how to relate dependence on the bare lattice parameters to more phenomenologically...

It has been found that recent results on forward jet production from deep inelastic scattering can neither be reproduced by models which are based on leading order αs QCD matrix elements and parton showers nor by next-toleading order calculations. The measurement of forward jet cross sections has been suggested as a promising probe of new small x parton dynamics and the question is whether thes...

Diffraction is an old subject which has received much interest in recent years due to the advent of diffractive hard scattering. We discuss some theoretical models and experimental results that have shown new striking effects, e.g. rapidity gaps in jet and W production and in deep inelastic scattering. Many aspects can be described through the exchange of a pomeron with a parton content, but th...

ππ scattering at low energy is sensitive to the structure of the QCD vacuum. I review the calculations of the ππ scattering lengths and phases, and group them in three cathegories: 1. those based on very general theoretical constraints (like dispersion relations and crossing symmetry) and phenomenology, 2. those which in addition make explicit use of chiral symmetry, 3. the firstprinciple ones,...

Long-term preservation of data and software of large experiments and detectors in high energy physics is of utmost importance to secure the heritage of (mostly unique) data and to allow advanced physics (re-)analyses at later times. Summarising the work of an international study group, motivation, use cases and technical details are given for an organised effort to secure and enable future use ...

We compute the supersymmetric QCD corrections to the decay distribution of polarized top quarks for the semileptonic decay mode t(↑) → blνl . As a byproduct, we reinvestigate the SUSY-QCD corrections to the total decay width Γ(t → W +b) and resolve a discrepancy between two previous results in the literature.

We present the results of a quenched lattice QCD study of the coupling g, in the static heavy quark limit. After combining this with our previous results obtained by using propagating heavy quarks with a mass around the physical charm quark, we are able to interpolate to the b-quark sector. Our results are g ∞ = 0.48 ± 0.

Recent progress in extending finite temperature lattice QCD simulations from the T axis into the finite density plane is reviewed. The covered topics are a calculation of the transition line by multidimensional reweighting, screening mass calculations in dimensionally reduced QCD and simulations at imaginary μ.

We present a new NLO QCD analysis of the world data on inclusive polarized deep inelastic scattering. Comparing to our previous analysis: i) the values of gA and a8 = 3F −D are updated ii)the MRST’99 instead of the MRST’98 parametrization for the input unpolarized parton densities is used and iii) the recent SLAC E155 proton data on the spin asymmetry A1 are included in the analysis. A new set ...