Sökresultat

The top quark pair production and decay are considered in the framework of the smeared-mass unstable particles model. The results for total and differential cross-sections in vicinity of t (t) over bar threshold are in good agreement with the previous ones in the literature. The strategy of calculations of the higher order corrections in the framework of the model is discussed. Suggested approach

We discuss new diffractive mechanism of central exclusive production of W+W- pairs in proton-proton collisions at the LHC. We include diagrams with intermediate virtual Higgs boson as well as quark box diagrams. Several observables related to this process are calculated. Predictions for the total cross section and differential distributions in W-boson rapidity and transverse momentum as well as WW

A systematic study of the odd-intrinsic parity sector of QCD is presented. We briefly describe different applications including pi(0) -> gamma gamma decay, muonic g -2 factor and test of new holographic conjectures.

We review Buchler and Colangelo's result that leading divergences at any loop order can be calculated using only one-loop calculations and we provide an alternative proof. We then use this method to calculate the leading divergences of and thus the leading logarithmic corrections to the meson mass in the massive $O(N)$ nonlinear sigma model to five-loop order. We also calculate the all-loop result

We report lifetime measurements of the five levels in the 3d(4)(a(5)D)5s e(6)D term in Cr II at an energy around 83 000 cm(-1), and log(gf) values for 38 transitions from the investigated levels. The lifetimes are obtained using time-resolved, laser-induced fluorescence on ions from a laser-produced plasma. Since the levels have the same parity as the low-lying states directly populated in the pla

Based on the chiral perturbation theory, we investigate the low-energy dynamics of nucleon parton distributions. We show that in different regions of the momentum fraction x the chiral expansion is significantly different. For nucleon parton distributions these regions are characterized by x similar to 1, x similar to m(pi)/M-N and x similar to (m(pi)/M-N)(2). We derive extended counting rules for

Medium-induced gluon radiation gives rise to the strong energy loss observed in single hadron spectra in heavy ion collisions. Its angular structure, leading e.g. to intra-jet correlations, is only known for the one-gluon inclusive case. In the vacuum, properties such as angular ordering appear when considering less inclusive distributions due to destructive interference effects. We present a calc