Conveners
Resummation, Parton Showers and Monte-Carlo
- Carlo Oleari (Istituto Nazionale di Fisica Nucleare)
Resummation, Parton Showers and Monte-Carlo
- Leonardo Vernazza (INFN, Torino)
Resummation, Parton Showers and Monte-Carlo
- Emanuele Re (Istituto Nazionale di Fisica Nucleare)
The matching between fixed-order calculations and parton shower simulations represents one of the key building blocks for the construction of accurate and fully-differential predictions at colliders. While NLO matching with leading logarithmic accurate parton showers has been a solved problem for many years, there is currently no standard matching procedure with next-to-logarithmic (NLL)...
As experimental precision continues to improve, it becomes increasingly important for the theory community to incorporate electroweak corrections alongside higher-order QCD effects in our predictions. In this talk, I will introduce the QED-MC@NLO method, which matches a QED parton shower with an NLO electroweak calculation. I will discuss some implementation details and present results from...
The increasingly high accuracy of top-quark studies at the LHC calls for a theoretical description of $t\bar t$ production and decay in terms of exact matrix elements for the full $2 \to 6$ process that includes the off-shell production and the chain decays of $t\bar t$ and $tW$ intermediate states, together with their quantum interference. Corresponding NLO QCD calculations matched to parton...
We introduce a forthcoming extension to MadGraph5_aMC@NLO, enabling the automated computation of cross sections for processes involving quarkonium particles within the non-relativistic QCD (NRQCD) factorization framework. To achieve next-to-leading order (NLO) accuracy in the strong coupling constant $\alpha_s$, we have refined the FKS subtraction formalism. Our approach is applicable to the...
Calculations in perturbative QCD suffer from large logarithms that appear at all orders in the perturbation theory, endangering the perturbative description. In pursuit of precise predictions for (differential) cross sections, factorisation theorems have been established with the benefit to sum these large logarithms to all orders in perturbation theory, improving the predictive power of the...
Power corrections are crucial for the frontier precision study at colliders, and soft quarks play an important role starting from next-to-leading power. However, renormalizing soft-quark functions and, hence, deriving their anomalous dimensions are hard and have only received progress recently. In this talk, I will show how to renormalize soft-quark functions entering the light-quark-induced...
The higher-order behavior of logarithmically enhanced contributions in non-global LHC observables is very intricate, in particular as double-logarithmic corrections -- so-called super-leading logarithms (SLLs) -- arise first at high orders in perturbation theory.
Their all-order resummation has been understood recently by means of a factorization formula in soft-collinear EFT.
In this talk,...
Perturbative calculations for processes that involve heavy flavours can be performed in two approaches: the massive scheme and the massless one. The former enables one to fully account for the heavy-quark kinematics, while the latter allows one to resum potentially-large mass logarithms. Furthermore, the two schemes can be combined to take advantage of the virtues of each of them. Both massive...
Accurate and fully differential predictions are crucial inputs for the precise experimental analyses at collider experiments and are typically provided by parton shower Monte Carlo programs. The event generator Sherpa with its focus on the inclusion of higher-order EW and QCD effects is available in a new version 3.0 this year and we will summarise its new features and current developments for...
Time-like matching threshold conditions are an ingredient of the DGLAP evolution for Fragmentation Functions in the Variable-Flavour-Number-Scheme. We introduce the theoretical framework by revising the next-to-leading order derivation. An extension of the formalism in electron-positron annihilation is derived at next-to-next-to leading order (NNLO) accuracy. We present an analytical form of...
We extend the class of factorization theorems for non-global observables from fixed angular constraints to cross sections defined in terms of sequential jet clustering. The associated hard and soft functions depend not only on the directions of the hard partons, but also on their energy fractions. We derive the one-loop anomalous dimension of the hard functions that drives the...
In this talk, I will present the first calculation of open bottom production at hadron colliders at NNLO+NNLL, i.e. a next-to-next-to-leading-order calculation that resums collinear mass logarithms at next-to-next-to-leading-logarithmic accuracy. This new computation achieves significantly reduced scale uncertainties compared to previous calculations, with errors of just a few percent at high...
We propose an event generation for LHC multi-jet processes (up to 10 external particles) in a two-step procedure based on the colour expansion of the tree-level matrix-element. In this way, in the first step the phase-space integration is performed on the leading-colour accurate expansion of the amplitudes. At this step, we compare several choices of the integration variables. In a second...
