We elaborate on the method of parametric annihilators for deriving relations among integrals. Annihilators are differential operators that annihilate multi-valued integration kernels appearing in suitable integral representations of special functions and Feynman integrals. We describe a method for computing parametric annihilators based on efficient linear solvers and show how to use them to...
The associated production of a top-antitop quark pair with a $W$ boson is one of the heaviest signatures probed at the LHC. The corresponding rates have been found to be consistently higher than the Standard Model predictions, calling for improved theoretical predictions.
In this talk I will discuss one of the main bottlenecks for the exact computation of the two-loop QCD amplitude, namely...
In order to match the increasing precision of modern particle colliders, it is essential to have accurate theoretical predictions for the cross sections of physical processes and their associated distributions. These predictions are often obtained via Monte Carlo event generators which combine the fixed-order calculation, computed as a perturbative expansion in the coupling constants, with a...
Recent experimental results from the Atomki collaboration have reported the observation of anomalous effects in Beryllium, Helium and Carbon nuclear transitions that could hint at physics beyond the Standard Model. However, the MEG-II experiment has recently found no significant anomalous signal in the Beryllium transition $^8$Be$^⋆$ → $^8$Be + $e^+e^-$. In view of this result, we critically...
It is well known that the Standard Model (SM) is not a complete theory, but rather an effective one, describing particle phenomenology in some energy range. Different ways of extending the SM have been formulated, among these there is the class of the so-called 331 extensions. These depend ona free parameter $\beta$.It is well known that 331 models with $\beta =\sqrt{3}$ predict the existence...
We consider models in which the Standard Model is extended with dark quarks that belong to fragments of vector-like representations of the grand-unifying group SU(5), and are charged under a new confining non-Abelian interaction. We consider both strongly-coupled and weakly-coupled régimes, corresponding to the dark quarks being lighter or heavier than the confinement scale, respectively. We...
