In this talk I will review the recent progress and results concerning next-to-leading power factorization. I will mostly focus on semi-inclusive DIS process, showing the derivation of the structure functions at one-loop accuracy.
I will comment on some of the specific details that emerge at next-to-leading power, such as the cancellation of special rapidity divergences and the emergence of...
In view of the increasing precision of theoretical calculations and experimental measurements, power corrections to transverse-momentum-dependent observables have become highly important. Power corrections for TMD observables are a rich and complex subject, and are difficult to grasp even in the most simple scenarios. Our goal is to understand TMD factorization at next-to-leading power for a...
In this talk, I will show a general expression for weighted cross sections in leptonic annihilation to hadrons based on time-ordered perturbation theory (TOPT). For any infrared-safe weight, the cancellation of infrared divergences is implemented locally at the integrand level, and in principle can be evaluated numerically in four dimensions. We go on to show that it is possible to eliminate...
We propose semi-inclusive diffractive deep inelastic scattering to investigate the gluon tomography in the nucleon and nuclei at small-x. The relevant diffractive quark and gluon parton distribution functions can be computed in terms of the color dipole S-matrices in the fundamental and adjoint representations, respectively.
I'm going to review recent results for forward jests at the LHC and EIC as obtained within small-x Improved Transverse Momentum Dependent factorization (ITMD). In addition to an elementary overview of various approaches to perturbative QCD at high energy, including High Energy Factorization, Color Glass Condensate, and ITMD, we describe the Monte Carlo implementation and discuss the existing...
One of the most intriguing phenomena of strong interaction is the so-called gluon saturation in nucleons and nuclei at very small value of the Bjorken-$x$. In the saturation regime, the density of partons, per unit of transverse area, in hadronic wavefunctions becomes very large leading to non-linear effects. These latter stop the strong growth of the gluon density at small-$x$ leading to a...
We study diffractive (2+1)-jet production in photon nucleus collisions at high energy in the CGC framework. We focus in the regime in which two of the jets are hard, yet we show that large dipoles with size 1/Qs (with Qs the nucleus saturation momentum) control the cross section. These dominant contributions admit factorization in terms of parton TMDs of the Pomeron. The bulk of these TMDs is...
We introduce SKMHS22, a novel set of diffractive parton distribution functions (PDFs) and their uncertainties, computed at both next-to-leading-order and next-to-next-to-leading-order accuracy within the framework of perturbative QCD in xFitter. Our analysis comprehensively addresses diffractive deep inelastic scattering (DIS) data from HERA, encompassing the latest H1/ZEUS measurements, while...
QCD calculations for collider physics make use of perturbative solutions of renormalisation group equations (RGEs). RGE solutions can contribute significantly to systematic uncertainties of theoretical predictions for physical observables. We propose a method to express these systematic effects in terms of resummation scales, using techniques borrowed from soft-gluon resummation approaches. We...
The high level of experimental precision achieved at hadron colliders requires competitive theoretical predictions in order to extract fundamental SM parameters, such as the W boson mass.
Theoretical efforts should therefore be directed towards relevant kinematic distributions, such as the transverse momentum (pT) spectrum of the W and Z bosons and their ratio.
In this talk, essentially...
The determination of Parton Distribution Functions (PDFs) is an example of inverse problem: a model is sought knowing a finite set of experimental observations. Given the fact that the model is a continuous function, i.e. an element of an infinite dimensional space, its determination from a discrete set of data is notoriously a ill-posed problem. In the currently used methodologies for PDF...
In recent articles, the discussion on the treatment of Power Corrections in the three-jet limit, along with its influence on precision $\alpha_s$ determinations from fits to event shape experimental data, has attracted a lot of attention. On the basis of a factorization formula for the $e^+e-$ thrust distribution, derived within soft-collinear effective theory, we discuss the treatment of...
In this talk we present results for soft gluon resummation applied to the production of four top quarks in the absolute mass threshold limit. The theoretical predictions at NLO, including a full set of strong and electroweak NLO corrections, yield a relatively large error due to scale variation. We compute the resummed cross section at next-to-leading logarithmic (NLL$^\prime$) accuracy,...
We study associated production of heavy quarkonia and D mesons in the improved color evaporation model using the high-energy factorization as it is formulated in the parton Reggeization approach. The last one is based on the modified Kimber-Martin-Ryskin-Watt model for unintegrated parton distribution functions and the effective field theory of Reggezied gluons and quarks, suggested by L.N....
I will present the Next-to-next-to-leading order QCD massive corrections,
induced by a loop of top quarks, to di-photon production in proton-proton
collisions. This process is very important as a test of perturbative QCD
and as a background process for the decay of a Higgs into two photons.
All the involved partonic subprocesses are taken into account; in
particular the quark-antiquark...
The measurement of the top-quark mass in top-quark pair production using the full Run 2 dataset collected with the ATLAS experiment at √s = 13 TeV will be presented. This measurement is carried out in the dilepton channel using a template method. The talk will have a special emphasis on the theoretical uncertainties affecting experimental measurements of the top-quark mass, as more and more...
In this work we present the tools developed for the automatization of the calculation of the soft anomalous dimension matrices for the heavy-quark hadroproduction processes at one- and two-loop accuracy in QCD. The foundation of this procedure is the construction of orthogonal color basis for $2 \rightarrow n$ processes which will also be discussed. The application of these tools is...
In this talk, I will present an overview of heavy ion collisions. In particular, I will introduce the main phenomena in these collisions, and discuss them from the point of view of QCD, in order to highlight some of the possible approaches to tackle situations where collective phenomena play a crucial role.
Nearly ten years ago, Kang, Ma, Qiu, and Sterman derived an evolution equation for a heavy-quark pair fragmenting into a quarkonium. In this study we explore the consequence of this evolution for the color-evaporation model, focusing on $J/\psi$ transverse-momentum distributions in proton-proton collisions. In particular, I will show that it brings NLO calculations in agreement with data....
Quarkonia are perfect laboratories to study the interplay between perturbative and nonperturbative QCD, due to the different momentum scales it provides. I am going to focus on the production of quarkonia through the fragmentation of a gluon, one of the possible mechanisms to quarkonia production. I am going to talk about the factorization of the TMD in terms of the short-distance coefficients...
We calculate the production of polarized $J/\psi$ to probe the transverse momentum dependent (TMD) quark and gluon PDFs in the proton. Within the TMD framework we calculate the 18 leading order fragmentation functions for light quarks fragmenting to a $J/\psi$, considering all possible parton and hadron polarizations. We also calculate the production of $J/\psi$ from photon-gluon fusion within...
We present an updated analysis of Belle data for the transverse $\Lambda$ polarization in $e^+e^−$ annihilation processes within a TMD factorization approach. Special attention to $SU(2)$ isospin symmetry and charm quark contribution will be paid, both concerning the description of the experimental data and the extraction of the polarizing fragmentation functions.
Predictions for SIDIS...
In this talk we present the latest results about the extraction of unpolarized Transverse-Momentum-Dependent (TMD) distributions. We discuss the extraction of unpolarized quark TMD Parton Distribution Functions (TMD PDFs) in the proton, as well as TMD Fragmentation Functions (TMD FFs), from global fits of Drell-Yan and Semi-Inclusive Deep-Inelastic Scattering (SIDIS) data sets made by the MAP...
We present an extraction of unpolarized transverse momentum dependent parton distributions functions and Collins-Soper kernel from the fit of Drell-Yan and weak-vector boson production data at the N4LL order of perturbative accuracy. Based on this, Pion TMDPDFs as well as TMD fragmentation functions can be extracted, of which preliminary results are available.
In this talk, we present preliminary results about the path to a global Bayesian reweighting of TMD functions. Within an effective model as the Generalized Parton Model, and by adopting the Sivers, transversity and Collins functions as extracted from SIDIS and $e^+ e^-$ azimuthal asymmetries, we plan a simultaneous reweighting of these TMDs using data on Single-Spin Asymmetries measured at...
The quark-gluon dynamics manifests itself in a set of non-perturbative functions describing all possible spin-spin and spin-orbit correlations defining azimuthal modulations in hard scattering processes. Production of correlated hadron pairs in current, as well as target fragmentation regions, plays an increasingly important role in the interpretation of pion electroproduction data in...
Pion TMDs are not as well defined as their proton counterparts, due to the small amount of available pion scattering data. The recent measurements of unpolarized Drell Yan cross section taken at COMPASS with different targets, could improve the current understanding of pion structures. In the near future also AMBER, a new fixed-target experiment at CERN SPS, will help understand the meson...
We present a systematic formalism based on a factorization theorem in soft-collinear effective theory to describe non-global observables at hadron colliders, such as gap-between-jets cross sections. The cross sections are factorized into convolutions of hard functions, capturing the dependence on the partonic center-of-mass energy $\sqrt{\hat s}$, and low-energy matrix elements, which are...
Transverse Momentum Dependent (TMD) factorization leads to well established theorems for a restricted class of processes. In such cases, some of the effects produced by the soft radiation cancel out and the physics associated to them cannot be accessed. Extension of the factorization to non-standard processes inevitably leads to deal with the non trivial structure of the soft sector, revealing...
Track-based observables offer superior angular resolution and pile-up suppression. I developed a theoretical framework to account for the conversion to tracks using track functions, which are a kind of generalized fragmentation functions. I will discuss recent progress, including our determination of the evolution of track functions at order alpha_s^2, from which the evolution of multi-hadron...
We generalize and update our former top quark mass calibration framework for Monte Carlo event generators based on the e+e- hadron-level 2-jettiness distribution in the resonance region for boosted top production. The updated framework includes the addition of the shape variables sum of jet masses, modified jet mass and the treatment of two more gap subtraction schemes to remove the leading...
In this talk, we will talk about the high-precision fixed order results for the Drell-Yan lepton pair production as well as W boson production with the fiducial cut of CDFII at N3LO accuracy in QCD. Such high precision is achieved by the qt slicing method, which sums up the large qt contribution obtained from event-generator NNLOJET and the small qt contribution from...
Geneva is a Monte Carlo event generator that matches fixed-order NNLO predictions with higher-order (NNLL') resummation in the jet resolution variable (zero-jettiness), and further combines them with parton showers. In this talk, I will first discuss recent improvements in the Geneva framework and demonstrate their impact in selected color-singlet processes. Furthermore, I will present results...
