Sabrina Sacerdoti is a Ph.D. student from Universidad de Buenos Aires, on a three-month MCnet studentship in the Durham team.
Simone Amoroso is a Ph.D. student from the University of Freiburg, on the ATLAS experiment, on a three-month MCnet studentship in the CERN team.
Colour reconnections have emerged as one of the main uncertain aspects of soft hadron-hadron collider physics, with significant implications for minimum-bias and underlying-event physics, as well as for precision measurements, most importantly the determination of the top quark mass in hadronic final states. We argue that a vital missing ingredient in current models is an understanding of the implications of QCD coherence on the process of hadronization, especially in the context of multiple parton interactions (MPI).
We describe the implementation of supersymmetric models in PYTHIA 8, including production and decay of superparticles and allowing for violation of flavour, CP, and R-parity. We also present a framework for importing generic new-physics matrix elements into PYTHIA 8, in a way suitable for use with automated tools. We emphasize that this possibility should not be viewed as the only way to implement new-physics models in PYTHIA 8, but merely as an additional possibility on top of the already existing ones.
Measurements of inclusive observables, such as particle multiplicities and momentum spectra, have already delivered important information on soft-inclusive ("minimum-bias") physics at the Large Hadron Collider. In order to gain a more complete understanding, however, it is necessary to include also observables that probe the structure of the studied events. We argue that forward-backward (FB) correlations and event-shape observables may be particulary useful first steps in this respect.