Publications (65)
Heavy Quark Fragmentation in Collisions to NNLO+NNLL Accuracy in Perturbative QCD
Leonardo Bonino, Matteo Cacciari, Giovanni Stagnitto
Fragmentation of heavy quarks into heavy-flavoured hadrons receives both perturbative and non-perturbative contributions. We consider perturbative QCD corrections to heavy quark pr…
QCD Predictions for Charm and Bottom Production at RHIC
Matteo Cacciari
We present up-to-date QCD predictions for open charm and bottom production at RHIC in nucleon-nucleon collisions at \sqrt{S} = 200 GeV. The electron spectrum resulting from heavy f…
Onium Production
Matteo Cacciari
The present status of our understanding of onium production is reviewed. Different models are described and comparisons of theoretical predictions with experimental data are given.
Inclusive open charm photoproduction in ultraperipheral collisions at the LHC with GA-FONLL
Matteo Cacciari, Gian Michele Innocenti, Anna M. StaÅto
We compute the inclusive production cross section in ultraperipheral Pb-Pb collisions at the LHC as a function of the transverse momentum and rapidity. These calcul…
Constraint fitting of experimental data with a jet quenching model embedded in a hydrodynamical bulk medium
Nestor Armesto, Matteo Cacciari, Tetsufumi Hirano +2
We present a global fit to single- and double-inclusive suppression data of high- particles in central Au+Au collisions at top RHIC energy. We also include in this analysis da…
Gluon PDF constraints from the ratio of forward heavy quark production at the LHC at \sqrt{S}=7 and 13 TeV
Matteo Cacciari, Michelangelo L. Mangano, Paolo Nason
We discuss production of charm and bottom quarks at forward rapidity in pp collisions at the LHC, updating the QCD predictions for the run at \sqrt{S}=13 TeV. We show that, while t…
Quantifying the performance of jet definitions for kinematic reconstruction at the LHC
Matteo Cacciari, Juan Rojo, Gavin P. Salam +1
We present a strategy to quantify the performance of jet definitions in kinematic reconstruction tasks. It is designed to make use exclusively of physical observables, in contrast…
Fully differential VBF Higgs production at NNLO
Matteo Cacciari, Frédéric A. Dreyer, Alexander Karlberg +2
We calculate the fully differential next-to-next-to-leading-order (NNLO) corrections to vector-boson fusion (VBF) Higgs production at proton colliders, in the limit in which there…
FastJet: a code for fast k_t clustering, and more
Matteo Cacciari
Two main classes of jet clustering algorithms, cone and k_t, are briefly discussed. It is argued that the former can be often cumbersome to define and implement, and difficult to a…
A Study of Heavy Flavoured Meson Fragmentation Functions in e+ e- annihilation
Matteo Cacciari, Paolo Nason, Carlo Oleari
We compare QCD theoretical predictions for heavy flavoured mesons fragmentation spectra in e+ e- annihilation with data from CLEO, BELLE and LEP. We include several effects in our…
Perturbative and non-perturbative aspects of heavy-quark fragmentation
Einan Gardi, Matteo Cacciari
We describe a new approach to heavy-quark fragmentation which is based on a resummed perturbative calculation and parametrization of power corrections, concentrating on the z -> 1…
FastJet user manual
Matteo Cacciari, Gavin P. Salam, Gregory Soyez
FastJet is a C++ package that provides a broad range of jet finding and analysis tools. It includes efficient native implementations of all widely used 2-to-1 sequential recombinat…
SoftKiller, a particle-level pileup removal method
Matteo Cacciari, Gavin P. Salam, Gregory Soyez
Existing widely-used pileup removal approaches correct the momenta of individual jets. In this article we introduce an event-level, particle-based pileup correction procedure, Soft…
HL-LHC Computing Review: Common Tools and Community Software
HEP Software Foundation, :, Thea Aarrestad +107
Common and community software packages, such as ROOT, Geant4 and event generators have been a key part of the LHC's success so far and continued development and optimisation will b…
A note on the CDF high-p_t charged particle excess
Matteo Cacciari, Gavin P. Salam, Matthew J. Strassler
It has recently been pointed out that CDF data for the cross section of high-p_t charged particles show an excess of up to three orders of magnitude over QCD predictions, a feature…
Soft-Gluon Resummation in Heavy Quarkonium Physics
Matteo Cacciari
Soft-gluon resummation within the framework of heavy quarkonium hadroproduction is considered. A few selected cases are studied in detail. A sizeable increase of the cross sections…
Pileup subtraction using jet areas
Matteo Cacciari, Gavin P. Salam
One of the major challenges for the LHC will be to extract precise information from hadronic final states in the presence of the large number of additional soft pp collisions, pile…
Power corrections for jets at hadron colliders
Matteo Cacciari, Mrinal Dasgupta, Lorenzo Magnea +1
We discuss non-perturbative QCD corrections to jet distributions in hadron collisions, focussing on hadronisation and underlying event contributions. Using soft gluon resummation a…
Updated predictions for the total production cross sections of top and of heavier quark pairs at the Tevatron and at the LHC
Matteo Cacciari, Stefano Frixione, Michelangelo L. Mangano +2
We present updated predictions for the total production cross section of top-quark pairs at the Tevatron and at the LHC, and, at the LHC, of heavy-quark pairs with mass in the rang…
An improved description of charm fragmentation data
Matteo Cacciari, Andrea Ghira, Simone Marzani +1
We consider the fragmentation of heavy quarks into heavy-flavoured hadrons, specifically the production of charmed mesons in collisions, at different centre-of-mass energi…
Phenomenology of quarkonia production in fixed target experiments and at the Tevatron and HERA colliders
Matteo Cacciari
The phenomenology of heavy quarkonia production in fixed target experiments and at the Tevatron and HERA colliders is reviewed. The latest theoretical results are presented and com…
Charm Cross Sections for the Tevatron Run II
Matteo Cacciari, Paolo Nason
We present a calculation of the D^{*+}, D^+ and D^0 meson single inclusive production cross section for the Tevatron Run II. We use the FONLL approach in perturbative QCD, which, b…
Prospects for Quarkonium Physics at HERA
Matteo Cacciari, Michael Krämer
We work out and review prospects for future quarkonium physics at HERA. We focus on the impact of color-octet contributions and discuss how measurements at HERA can be used to test…
A note on the fate of the Landau-Yang theorem in non-Abelian gauge theories
Matteo Cacciari, Luigi Del Debbio, José R. Espinosa +2
Using elementary considerations of Lorentz invariance, Bose symmetry and BRST invariance, we argue why the decay of a massive color-octet vector state into a pair of on-shell massl…
Soft-Gluon Resummation for Bottom Fragmentation in Top Quark Decay
Matteo Cacciari, Gennaro Corcella, Alexander D. Mitov
We study soft-gluon radiation in top quark decay within the framework of perturbative fragmentation functions. We present results for the b-quark energy distribution, accounting fo…
Jet Areas, and What They are Good For
Matteo Cacciari
We introduce the concept of the area of a jet, and show how it can be used to perform the subtraction of even a large amount of diffuse noise from hard jets.
Heavy-Quark Fragmentation
Matteo Cacciari, Einan Gardi
We study perturbative and non-perturbative aspects of heavy-quark fragmentation into hadrons, emphasizing the large-x region, where x is the energy fraction of the detected hadron.…
Novel tools and observables for jet physics in heavy-ion collisions
Harry Arthur Andrews, Liliana Apolinario, Redmer Alexander Bertens +25
Studies of fully-reconstructed jets in heavy-ion collisions aim at extracting thermodynamical and transport properties of hot and dense QCD matter. Recently, a plethora of new jet…
Associated J/psi + gamma Photoproduction as a Probe of the Colour-Octet Mechanism
Matteo Cacciari, Mario Greco, Michael Krämer
The associated production of a J/psi and a photon in photon-hadron collisions is considered, and shown to be a good probe of the presence of colour-octet mediated channels in quark…
Dispelling the N^3 myth for the Kt jet-finder
Matteo Cacciari, Gavin P. Salam
At high-energy colliders, jets of hadrons are the observable counterparts of the perturbative concepts of quarks and gluons. Good procedures for identifying jets are central to exp…
Charm Production via Fragmentation
Matteo Cacciari, Mario Greco
The next-to-leading open charm production in collisions is calculated within the Perturbative Fragmentation Functions formalism, to allow resummation of $\as\log(\pt^2/m^2)$…
Top-pair production at hadron colliders with next-to-next-to-leading logarithmic soft-gluon resummation
Matteo Cacciari, Michal Czakon, Michelangelo L. Mangano +2
Incorporating all recent theoretical advances, we resum soft-gluon corrections to the total cross-section at hadron colliders at the next-to-next-to-leading logarithmic (…
Crossing Heavy-Flavour Thresholds in Fragmentation Functions
Matteo Cacciari, Paolo Nason, Carlo Oleari
In analogy with parton distribution functions, also parton fragmentation functions obey matching conditions when crossing heavy-flavour thresholds. We compute these matching condit…
Phenomenology of ``Onium'' Production
Matteo Cacciari
The phenomenology of heavy quarkonia production in hadron collisions is reviewed. The theoretical predictions are compared to data. Commonly used production models are shown to fai…
The LEP Trail to Non-Perturbative QCD
Matteo Cacciari
This talk summarizes the presentations given in the Hadronic Physics session at the LEPTRE meeting, emphasizing the importance of LEP data in our quest for a successful approach to…
On the characterisation of the underlying event
Matteo Cacciari, Gavin P. Salam, Sebastian Sapeta
The measurement of the underlying event (UE) and its separation from hard interactions in hadron-collider events is a conceptually and practically challenging task. We develop a si…
On the use of charged-track information to subtract neutral pileup
Matteo Cacciari, Gavin P. Salam, Gregory Soyez
The use of charged pileup tracks in a jet to predict the neutral pileup component in that same jet could potentially lead to improved pileup removal techniques, provided there is a…
Hadronic Production of Heavy Quarks
Matteo Cacciari
We review the status of theoretical evaluations of heavy quark and heavy quarkonium hadroproduction cross sections and their comparisons with experimental data.
Top production at large p_t at NLO+NLL accuracy
Matteo Cacciari
We introduce a new version of the FONLL code, now capable of calculating differential distributions for top quark production with next-to-leading-log resummation of log(p_t/m) term…
An extensive survey of the estimation of uncertainties from missing higher orders in perturbative calculations
Emanuele Bagnaschi, Matteo Cacciari, Alberto Guffanti +1
We consider two approaches to estimate and characterise the theoretical uncertainties stemming from the missing higher orders in perturbative calculations in Quantum Chromodynamics…
The anti-k_t jet clustering algorithm
Matteo Cacciari, Gavin P. Salam, Gregory Soyez
The k_t and Cambridge/Aachen inclusive jet finding algorithms for hadron-hadron collisions can be seen as belonging to a broader class of sequential recombination jet algorithms, p…
Heavy Quark Production: Theory vs. Experiment
Matteo Cacciari
The current status of the comparisons between some experimental results and theoretical predictions for heavy quark production is reviewed. It is shown that the combination of new…
Color-Octet Contributions to Photoproduction
Matteo Cacciari, Michael Krämer
We have calculated the leading color-octet contributions to the production of particles in photon-proton collisions. Using the values for the color-octet matrix elements ext…
Perturbative and Non-Perturbative Issues in Heavy Quark Fragmentation
Matteo Cacciari
We review the state-of-the-art of our understanding of heavy quark fragmentation. Recent e^+e^- data for B mesons are compared to the most up-to-date theoretical predictions, and t…
Heavy Flavoured Meson Fragmentation Functions in annihilation up to NNLO + NNLL
Leonardo Bonino, Matteo Cacciari, Giovanni Stagnitto
In this contribution, we make use of the QCD perturbative fragmentation function formalism to describe the one-particle inclusive fragmentation of a heavy quark produced in $e^+e^-…
On Heavy Quarks Photoproduction and c -> D* Fragmentation Functions
Matteo Cacciari
The state of the art of the theoretical calculations for heavy quarks photoproduction is reviewed. The full fixed order next-to-leading order massive calculation and the resummatio…
Fluctuations and asymmetric jet events in PbPb collisions at the LHC
Matteo Cacciari, Gavin P. Salam, Gregory Soyez
Recent LHC results concerning full jet-quenching in PbPb collisions have been presented in terms of a jet asymmetry parameter, measuring the imbalance between the transverse moment…
Power-suppressed effects in heavy quark fragmentation functions
Matteo Cacciari, Paolo Nason, Carlo Oleari
This talk summarizes the results of a phenomenological analysis of heavy quark fragmentation data published by the CLEO and BELLE collaborations at \sqrt{s} = 10.6 GeV and by the L…
Jet Fragmentation Function Moments in Heavy Ion Collisions
Matteo Cacciari, Paloma Quiroga-Arias, Gavin P. Salam +1
The nature of a jet's fragmentation in heavy-ion collisions has the potential to cast light on the mechanism of jet quenching. However the presence of the huge underlying event com…
pQCD Calculations of Heavy Quark and J/psi Production
Matteo Cacciari
We review the present status of theoretical predictions for both closed (J/psi) and open heavy quark production in high energy collisions, and their comparisons to experimental dat…
Jet Reconstruction in Heavy Ion Collisions
Matteo Cacciari, Juan Rojo, Gavin P. Salam +1
We examine the problem of jet reconstruction at heavy-ion colliders using jet-area-based background subtraction tools as provided by FastJet. We use Monte Carlo simulations with an…
Theoretical predictions for charm and bottom production at the LHC
Matteo Cacciari, Stefano Frixione, Nicolas Houdeau +3
We present predictions for a variety of single-inclusive observables that stem from the production of charm and bottom quark pairs at the 7 TeV LHC. They are obtained within the FO…
Event isotropy in perturbative QCD
Daniele Atzori, Matteo Cacciari, Simone Marzani +1
It has recently been proposed that collider events can be equipped with a metric, the Energy Mover's Distance (EMD), which allows one to rephrase multiple aspects of collider physi…
Heavy quarks, from discovery to precision
Matteo Cacciari
The discoveries of the heavy quarks are briefly reviewed, with a focus on the role played by Mario Greco in the interpretation of the experimental observations, and on his contribu…
D^* production from e^+e^- to ep collisions in NLO QCD
Matteo Cacciari, Mario Greco
Fragmentation functions for D mesons, based on the convolution of a perturbative part, related to the heavy quark perturbative showering, and a non-perturbative model for its hadro…
Challenges in Monte Carlo event generator software for High-Luminosity LHC
The HSF Physics Event Generator WG, :, Andrea Valassi +38
We review the main software and computing challenges for the Monte Carlo physics event generators used by the LHC experiments, in view of the High-Luminosity LHC (HL-LHC) physics p…
Meaningful characterisation of perturbative theoretical uncertainties
Matteo Cacciari, Nicolas Houdeau
We consider the problem of assigning a meaningful degree of belief to uncertainty estimates of perturbative series. We analyse the assumptions which are implicit in the conventiona…
The single-jet inclusive cross-section and its definition
Matteo Cacciari, Stefano Forte, Davide Napoletano +2
We investigate some well-known problematic aspects of the single-jet inclusive cross-section, specifically its non-unitarity and the possibly related issue of apparent perturbative…
The Catchment Area of Jets
Matteo Cacciari, Gavin P. Salam, Gregory Soyez
The area of a jet is a measure of its susceptibility to radiation, like pileup or underlying event (UE), that on average, in the jet's neighbourhood, is uniform in rapidity and azi…
Pileup subtraction for jet shapes
Gregory Soyez, Gavin P. Salam, Jihun Kim +2
Jet shapes have the potential to play a role in many LHC analyses, for example in quark-gluon discrimination or jet substructure analyses for hadronic decays of boosted heavy objec…
A thrust to trust minimum thrust
Matteo Cacciari
We determine the minimum value of thrust for a number of N-particle configurations. For N=5 in three dimensions an exact result is found for the first time. For larger N we obtain…
Phenomenological and theoretical developments in jet physics at the LHC
Matteo Cacciari
We review the history of jets in high energy physics, and describe in more detail the developments of the past ten years, discussing new algorithms for jet finding and their main c…
Recent Progress in Jet Algorithms and Their Impact in Underlying Event Studies
Matteo Cacciari
Recent developments in jet clustering are reviewed. We present a list of fast and infrared and collinear safe algorithms, and also describe new tools like jet areas. We show how th…
QCD Predictions for Charm and Bottom Production at RHIC
Matteo Cacciari, Paolo Nason, Ramona Vogt
We make up-to-date QCD predictions for open charm and bottom production at RHIC in nucleon-nucleon collisions at \sqrt{S} = 200 GeV. We also calculate the electron spectrum resulti…
Rise and Fall of the Bottom Quark Production Excess
Matteo Cacciari
We review the history of comparisons between bottom production measurements and QCD predictions. We challenge the existence of a `significant discrepancy', and argue that standard…