I consider the effect on MSTW partons distribution functions (PDFs) due to changes in the choices of theoretical procedure used in the fit. I first consider using the 3-flavour fixed flavour number scheme instead of the standard general mass variable flavour number scheme used in the MSTW analysis. This results in the light quarks increasing at all relatively small x values, the gluon distribut...

We generate fixed three-and four-light-flavour sets of partons using MRST2004 par-tons as input. We show that it is important to set n f = 3 in the strong coupling, as well as in the splitting and coefficient functions, in order to obtain a consistent set of fixed-flavour partons. We compare the description of data using partons in both variable-and fixed-flavour-number-schemes. In deep inelast...

We propose the new mechanism of neutrino flavour relaxation to explain the experimentally observed changes of initial neutrino flavour fluxes. The test of neutrino relaxation hypothesis is presented, using the data of modern reactor, solar and accelerator experiments. The final choice between the standard neutrino oscillations and the proposed neutrino flavour relaxation model can be done in fu...

Flavour physics plays a crucial role in the search for physics beyond the Standard Model (SM). While B physics offers many observables to look for deviations from the SM, the highest new physics sensitivity can be obtained in the rare kaon decays K → πνν. Of particular interest are correlations between various flavour violating observables that allow to test the symmetries and the operator stru...

Though it is widely taken for granted that it makes sense to separately discuss quark and gluon jets, normal jet algorithms lead to a net parton-level jet flavour that is infrared (IR) unsafe. This writeup illustrates the problem and explains how the kt algorithm can be modified to provide an IR safe parton-level flavour. As well as being of use in theoretical calculations that require a projec...