The systematic combination of perturbative QCD with parton-shower resummation is achieved at NLO by a small, but growing, number of 'NLO matching' methods.
Among them, the KrkNLO method is unique in exploiting a modification of the PDF factorisation scheme, from the conventional $\overline{\mathrm{MS}}$ scheme, to a scheme (the 'Krk' scheme) in which the NLO corrections can be applied as a...
In this talk, we present steps towards automated matching of the Alaric parton shower to NLO QCD matrix elements for lepton collisions in Sherpa. We validate our implementation against jet production in $e^+e^- \to$ jets for up to five jets. We show numerical tests of the subtraction in the infrared limit, benchmarking against the Catani-Seymour subtraction. We then present first hadron-level...
In this talk, I will present a new decomposition of QCD splitting functions, carried out systematically up to second order in the strong coupling. The core idea is to separate the splitting functions into two components: scalar dipole radiator functions and pure remainders. Unlike conventional approaches, our construction does not rely on any soft or collinear approximations. The splitting...
Spin correlations between QCD emissions have so far been neglected in most of the parton shower algorithms commonly used for LHC predictions. However, their inclusion is crucial to achieve NLL accuracy or to include NLO contributions in these algorithms.
In this talk, we present a new algorithm for incorporating spin correlations into parton shower algorithms. Instead of using spin density...
We perform the threshold resummation for massive vector boson pair production processes ($ZZ$ and $W^{+}W^{-}$) in hadron collisions to Next to Next Leading Log accuracy. The resummed cross-sections are then matched with NNLO fixed order results, which are obtained using the MATRIX code. We present our results for the invariant mass distribution to NNLO+NNLL accuracy in QCD for the current LHC...
In this talk, I discuss the resummation of leading logarithmic contributions to the collinear matching coefficients of Transverse Momentum Dependent distributions (TMDs) in the large-$x$ regime. Resummation is performed directly at the level of TMDs, preserving their process-independence and, for the first time, covering distributions that match onto twist‑three collinear Parton Distribution...
At energies above the Electroweak (EW) scale, higher-order EW corrections exhibit a logarithmic enhancement which is driven by the ratio of the typical scattering energy to the gauge-boson mass. At next-to-leading order (NLO) these corrections lead to factors amounting to several tens of percent in tails of kinematic distributions of crucial LHC processes, and still contribute a few percent at...
We review the state of the art in applying the small-x resummation to parton distribution functions in the proton, with particular emphasis on the gluon content. In the first part, we briefly discuss small-x resummed 1D collinear distributions, highlighting their connections with the 3D transverse-momentum dependent counterparts at both small and moderate x, including the effects of...
We update a previous N$^3$LL$^\prime$+${\cal O}(\alpha_s^3)$ determination of the strong coupling from a global fit to thrust data. Detailed discussions are provided concerning the stability of the results under variations of the fit range and the importance of summing up higher-order logarithmic terms for convergence and stability. We also demonstrate that a number of additional effects...
We present the first calculation of high-energy corrections to the
process of photon+dijet production. The high-energy corrections stabilise
the fixed-order perturbative behaviour and lead to a significant
improvement in the description of data.
Factorization theorems for non-global observables at hadron colliders can be used to resum super-leading logarithms (SLLs) and we present a phenomenological analysis of their numerical impact in pp -> 2 jets.
SLLs are closely related to collinear factorization breaking and are driven by a double-logarithmic evolution equation in an effective field theory. The compatibility of this...
Using renormalization group arguments in dQCD, I derive an analytic resummation formula for the threshold resummation of differential distributions with fixed longitudinal partonic kinematics. By matching to existing fixed-order NNLO computations I obtain NLL resummation for the Drell-Yan rapidity distribution with fixed partonic rapidity and for semi-inclusive deep-inelastic scattering. For...
In this talk, I will present our research on the substructure of jets containing heavy flavour. Our main goal is to better understand these jets from a theoretical perspective, using resummed perturbative techniques that are specially designed for jets coming from heavy quarks. In particular, we provide analytical predictions for several key jet substructure observables, including jet...
The distribution of transverse energy flow into an azimuthal strip presents novel theoretical features and accompanying challenges in its all-order description. Its resummation structure depends non-trivially on the axis definition, with the standard thrust axis breaking naive double-logarithmic exponentiation. Moreover it receives non-global logarithmic (NGL) enhancements that start with...
The Koba-Nielsen-Olesen (KNO) scaling of hadron multiplicity distributions, empirically confirmed to hold approximately in $e^+e^-$ collisions and Deep Inelastic Scattering, has been observed to be violated in hadron-hadron collisions. In this work, we show that the universality of KNO scaling can be extended to hadron-hadron collisions when restricted to QCD jets. We present a comprehensive...
