Conveners
Plenary
- Simon David Badger (Istituto Nazionale di Fisica Nucleare)
Plenary
- Gudrun Heinrich (Karlsruhe Institute of Technology)
Plenary
- Richard Keith Ellis
Plenary
- Paolo Torrielli (Istituto Nazionale di Fisica Nucleare)
Plenary
- Alessandro Vicini (Istituto Nazionale di Fisica Nucleare)
Plenary
- Massimiliano Grazzini (Istituto Nazionale di Fisica Nucleare)
We present computations of the even-N moments of the flavour-singlet four-loop splitting functions to N=20. These results, obtained using off-shell operator matrix elements (OMEs). We construct approximations based on our moments for the OMEs and endpoint constraints. These approximations facilitate an approximate N3LO evolution of parton distributions which are sufficiently accurate for...
Fragmentation of heavy quarks into heavy-flavoured hadrons receives both perturbative and non-perturbative contributions. We consider perturbative QCD corrections to heavy quark production in $e^+e^-$ collisions to next-to-next-to-leading order accuracy in QCD with next-to-next-to-leading-logarithmic resummation of quasi-collinear and soft emissions.
We study multiple matching schemes, and...
Understanding the singularity structure of Feynman integrals in parameter space is useful both for formulating numerical procedures for their evaluation (e.g. sector decomposition) and for understanding their asymptotic behaviour, as captured by the method of regions. A promising direction of exploration in this regard is the geometric description of Feynman integrals in parameter space....
Parton shower event generators are essential tools for establishing the quantitative connection between theory and experiment. However, their flexibility comes with a trade-off: they generally offer lower formal accuracy compared to state-of-the-art analytic calculations, which in turn have more limited applicability. The poor accuracy of the inevitably employed parton shower generators...
Overview of ATLAS precision measurements and Monte Carlo generators usage
I will show how expansion methods can be used to analytically evaluate multi-scale gluon fusion processes at two-loop order. In particular, an expansion for small transverse momentum covers most of the phase space for the gg-> ZZ, gg-> HZ and gg-> HH processes. When combined with a high-energy expansion the whole phase space is covered. Since this approach allows to express the amplitudes...
We present ongoing work towards the development of an automated NLO generator in the OpenLoops framework. This new algorithm combines key features of the Loop Tree Duality (LTD) and OpenLoops methods. In particular, virtual and real corrections are combined in a way that enables the local cancellation of IR singularities. To this end we introduce a new technique that supports the calculation...
We present the first results for the next-to-next-to leading order (NNLO) corrections to the semi-inclusive deep-inelastic scattering process in perturbative quantum chromodynamics. We consider scattering with polarized and unpolarized protons and obtain the complete contributions analytically for all parton channels. All relevant virtual and real emission Feynman diagrams have been computed...
I elaborate on the vector space structures of Euler-Mellin-Feynman Integrals, emerging from the application of Intersection Theory of (twisted) De Rahm Co-homology, and discuss the crucial role of the intersection numbers as fundamental mathematical quantities, ruling linear relations (integration-by-parts identities or contiguity relations, differential and difference equations), as well as...
We extend the existing next-to-next-to-leading order (NNLO) NNPDF4.0 sets of parton distribution functions (PDFs) to approximate next-to-next-to-next-to-leading order (aN$^3$LO).
We construct an approximation to the N3LO splitting functions that includes all available partial information from both fixed-order computations and from small and large x resummation, and estimate the uncertainty on...
I will briefly review the GENEVA framework, which combines the resummation of a jet resolution variable
up to N3LL with the NNLO fixed-order corrections into a single event generator, eventually matched to the parton shower.
This provides the highest accuracy in the strong coupling constant at both small and large jet resolution scales.
I will focus on the recent progress and challenges in...
We discuss a methodology for calculating second-order cross sections based on the use of local subtractions for soft and collinear singularities and built implementing suitable momentum mappings and well known universal limiting formulae. With appropriate adjustments, it is possible to carry out the analytical calculation of the integrated version of the subtractions, which brings reliable...
In this talk I will present recent progress in the generalisation of the nested soft-collinear subtraction scheme to multi-parton final state processes. The scheme has already been successfully applied to scatterings involving a limited number of coloured partons, and it has shown remarkable flexibility and good numerical performances. I will discuss how to overcome the difficulties that arise...
In this talk I present a strategy to optimally disentangle multi-parton interactions from the primary scattering in a collision. The strategy enables probes of multi-parton interactions significantly beyond the state of the art, including their characteristic momentum scale, the interconnection between primary and secondary scatters, and the pattern of three and potentially even more...
Geometric formalisms have been long employed to describe QFTs of scalar fields and, in the past few years, they have been successfully applied to the study of SM EFT and Higgs EFTs.
The talk will first give an overview of these methods, highlighting their power and their shortcomings. It will then introduce a novel geometric formalism that aims at resolving some of the latter, which is based...
