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Search: authors:"Valerio Bertone"

12 papers found.
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Neutrino telescopes as QCD microscopes

Abstract We present state-of-the-art predictions for the ultra-high energy (UHE) neutrino-nucleus cross-sections in charged- and neutral-current scattering. The calculation is performed in the framework of collinear factorisation at NNLO, extended to include the resummation of small-x BFKL effects. Further improvements are made by accounting for the free-nucleon PDF constraints...

Parton distributions with small-x resummation: evidence for BFKL dynamics in HERA data

We present a determination of the parton distribution functions of the proton in which NLO and NNLO fixed-order calculations are supplemented by NLLx small-x resummation. Deep-inelastic structure functions are computed consistently at \(\hbox {NLO+NLL}x\) or \(\hbox {NNLO+NLL}x\), while for hadronic processes small-x resummation is included only in the PDF evolution, with...

A determination of the fragmentation functions of pions, kaons, and protons with faithful uncertainties

We present NNFF1.0, a new determination of the fragmentation functions (FFs) of charged pions, charged kaons, and protons/antiprotons from an analysis of single-inclusive hadron production data in electron–positron annihilation. This determination, performed at leading, next-to-leading, and next-to-next-to-leading order in perturbative QCD, is based on the NNPDF methodology, a...

Impact of low-x resummation on QCD analysis of HERA data

Fits to the final combined HERA deep-inelastic scattering cross-section data within the conventional DGLAP framework of QCD have shown some tension at low x and low \(Q^2\). A resolution of this tension incorporating \(\ln (1/x)\)-resummation terms into the HERAPDF fits is investigated using the xFitter program. The kinematic region where this resummation is important is...

A determination of the charm content of the proton

We present an unbiased determination of the charm content of the proton, in which the charm parton distribution function (PDF) is parametrized on the same footing as the light quarks and the gluon in a global PDF analysis. This determination relies on the NLO calculation of deep-inelastic structure functions in the FONLL scheme, generalized to account for massive charm-initiated...

A determination of m c (m c ) from HERA data using a matched heavy-flavor scheme

The charm quark mass is one of the fundamental parameters of the Standard Model Lagrangian. In this work we present a determination of the \( \overline{\mathrm{MS}} \) charm mass from a fit to the inclusive and charm HERA deep-inelastic structure function data. The analysis is performed within the xFitter framework, with structure functions computed in the FONLL general-mass...

On the impact of lepton PDFs

In this paper we discuss the effect of the complete leading-order QED corrections to the DGLAP equations that govern the perturbative evolution of parton distribution functions (PDFs). This requires the extension of the purely QCD DGLAP evolution including a PDF for the photons and, consistently, also for the charged leptons e ±, μ ± and τ ±. We present the implementation of the...

Reference results for time-like evolution up to \( \mathcal{O}\left({\alpha}_s^3\right) \)

We present high-precision numerical results for time-like Dokshitzer-Gribov-Lipatov-Altarelli-Parisi evolution in the \( \overline{\mathrm{MS}} \) factorisation scheme, for the first time up to next-to-next-to-leading order accuracy in quantum chromodynamics. First, we scrutinise the analytical expressions of the splitting functions available in the literature, in both x and N...

aMCfast: automation of fast NLO computations for PDF fits

We present the interface between MadGraph5_aMC@NLO, a self-contained program that calculates cross sections up to next-to-leading order accuracy in an automated manner, and APPLgrid, a code that parametrises such cross sections in the form of look-up tables which can be used for the fast computations needed in the context of PDF fits. The main characteristic of this interface...

Parton distributions from high-precision collider data

We present a new set of parton distributions, NNPDF3.1, which updates NNPDF3.0, the first global set of PDFs determined using a methodology validated by a closure test. The update is motivated by recent progress in methodology and available data, and involves both. On the methodological side, we now parametrize and determine the charm PDF alongside the light-quark and gluon ones...

Parton distributions for the LHC run II

We present NNPDF3.0, the first set of parton distribution functions (PDFs) determined with a methodology validated by a closure test. NNPDF3.0 uses a global dataset including HERA-II deep-inelastic inclusive cross-sections, the combined HERA charm data, jet production from ATLAS and CMS, vector boson rapidity and transverse momentum distributions from ATLAS, CMS and LHCb, W +c...