arXiv subjects

Federico Silvetti

Publications and source records attributed to Federico Silvetti.

8 recordsLinked to original sources

arXiv2026

LHC Constraints on Resonant Kaluza-Klein Gravitons

The signature prediction of extra-dimensional theories is the appearance of a tower of massive gravitons. In this work, we study the constraints on resonant heavy spin-2 particles at the Large Hadron Collider (LHC), with focus on the entire tower of gravitons, beyond the traditional single-resonance analysis. Since several states of the tower can lie within the same accessible mass window, the combined signal is enhanced, and the resulting constraints can be significantly stronger than those obtained from a single resonance alone. We first update the current constraints on single graviton searches stemming from diphoton and dilepton data from ATLAS and CMS, using datasets collected above $\sim 200\,{\rm GeV}$, and then consider the impact on the bounds of the full tower of states for different extra-dimensional scenarios. This allows us to extend the reach of current searches to lower mass regions than typically considered, paving the way for future analyses by experimental collaborations.

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arXiv2026

Boosted Higgs-strahlung off a $W$ boson at next-to-next-to-next-to-leading order in QCD

The production of a boosted Higgs boson in association with a charged weak ($W$) boson is a key process to scrutinize the electroweak symmetry breaking mechanism at hadron colliders. This reaction constitutes the dominant Higgs production channel at large transverse momentum, providing unique sensitivity to Higgs-boson interactions with other Standard Model particles as well as to physics beyond the Standard Model. In this Letter, we present the first fully differential calculation of this important scattering process at next-to-next-to-next-to-leading order (N$^3$LO) in perturbative Quantum Chromodynamics (QCD). We find that the N$^3$LO corrections, amounting to approximately $+2\%$ in the boosted regime, generally lie at the edge of or outside the standard scale variation band of the previous perturbative order. The residual dependence of the N$^3$LO prediction on perturbative scales is reduced to below the percent level, marking a milestone for the Higgs precision program.

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arXiv2026

Event generation for future DIS experiments

In this contribution we discuss state-of-the-art hadron-level predictions for the deep-inelastic scattering process at next-to-leading-order precision for several multiplicities, consistently merged in one sample. We focus on the physics at (potential) future colliders, the Electron-Ion Collider planned at BNL as well as the higher energy experiments discussed as future options at CERN, a LHeC and a DIS phase of the Future Circular Collider dubbed FCC-eh.

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arXiv2025

Event generation at MEPS@NLO accuracy in neutral and charged current DIS at the EIC

We present state-of-the-art hadron-level predictions for the deep-inelastic scat- tering process at next-to-leading-order precision for several multiplicities, con- sistently merged in one sample. For the first time at this level of accuracy, we consider both neutral and charged current deep-inelastic scattering at the Electron-Ion Collider, and present the first application of consistent next-to- leading-order merging to charged current deep-inelastic scattering in general. We critically examine inclusive predictions using multileg merging techniques, contrasting perturbative and nonperturbative uncertainties. Further, we study typical kinematic deep-inelastic scattering observables as well as jet measure- ments and 1-jettiness with realistic cuts implied by expected and past detector resolution. On the perturbative side, we see large corrections toward small vir- tualities and Bjorken-x, which can be captured by higher-multiplicity matrix elements and the merging procedure. Nonperturbative effects, while negligible in most jet observables, can reach similar size as the perturbative uncertainties around the peak of the 1-jettiness distributions especially at low values of $Q^2$ .

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arXiv2024

Resummation phenomenology and PDF determination for precision QCD at the LHC

With the ongoing Run 3 of the LHC and its upcoming High-Luminosity upgrade, there is a growing need to study observables with high precision both experimentally and theoretically. To increase precision on the theory side, improvements of fixed-order perturbative predictions, resummation of logarithmic enhancements and accurate determination of proton structure are required. This thesis explores the latter two topics. We discuss high-energy logarithms and their resummation techniques, introducing an extension of the HELL formalism for multi-differential distributions in transverse momentum, rapidity and invariant mass. We apply this framework to heavy-quark pair production at the LHC, studying the kinematics of both a single quark and the final-state pair. An additional discussion is dedicated to a possible extension of the kt-factorisation framework, which underlies high-energy resummation, to capture next-to-leading logarithmic corrections. To test this hypothesis, we delve into the computation of a NLO off-shell coefficient function using Higgs-induced DIS in the infinite top mass limit as a benchmark process and report a partial result. Beside high-energy logarithms, we consider the determination of transverse-momentum distributions from a high mass system with additional QCD radiation and exclusive production cuts. Specifically, we focus on $HW^+$ production with a jet veto and analyse the Higgs transverse momentum spectrum at NNLO, using qt-subtraction. We complement the fixed order study with NNLL resummation of jet-veto logarithms and linear power correction in ptHW using the RadISH formalism. Finally, in the last project pertaining to this thesis we consider the problem of Parton Distribution Function determination. We propose a minimal parametrisation guided by physical arguments and investigate its performance in fitting the HERA dataset with NLO QCD theory predictions.

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arXiv2023

Analysis of HERA data with a PDF parametrization inspired by quantum statistical mechanics

We present a determination of the parton distribution functions (PDFs) of the proton from HERA data using a PDF parametrization inspired by a quantum statistical model of the proton dynamics. This parametrization is characterised by a very small number of parameters, yet it leads to a reasonably good description of the data, comparable with other parametrizations on the market. It may thus provide an alternative to standard parametrizations, useful for studying parametrization bias and to possibly simplify the fit procedure thanks to the small number of parameters. Interestingly, the model reproduces key physical features, such as a $\bar d$ distribution larger than $\bar u$, that HERA data alone are not able to constrain when using more flexible parametrizations. Moreover, polarized distributions are described in the model by the same parameters of the unpolarized ones, giving us the possibility of extracting both types of distributions within the same fit.

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arXiv2023

Small-$x$ resummation in coefficient function for differential heavy-quarks production

High-energy logarithmic correction are enhanced when the ratio, $x = \frac{Q^2}{s}$ between the typical energy scale of a scattering process $Q$ and the total centre of mass energy available $s$ is small. We discuss recent developments on their resummation in differential cross sections in rapidity, transverse momentum and invariant mass and their application to heavy flavour production at the LHC.

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arXiv2022

Differential heavy quark pair production at small $x$

We consider the production of a heavy quark pair in proton-proton collisions. For bottom and charm quarks, the final state invariant mass is typically much smaller than the collider energy (e.g. at the LHC), so that high-energy logarithms may spoil the perturbativity of the theoretical prediction at fixed order. The resummation of these logarithms to all orders is thus needed to obtain reliable predictions. In this work, we extend previous results on high-energy (or small-$x$) resummation to differential distributions in rapidity, transverse momentum and invariant mass, and implement them in the public code HELL.

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