NINPHA

National Initiative on Physics of Hadrons

In the last years the research activity of the NINPHA project has been devoted to four main research lines:

1) The development of a full three-dimensional (3D) tomographic picture of the nucleon [CA, PG, PV, TO]

2) QCD spectroscopy and nonperturbative models for (excited, exotic) heavy and light hadrons [GE, PG, PV]

3) Relativistic nonperturbative description of light nuclei and hadron dynamics [PG, PV]

4) Global state-of-the-art fits of collinear (and TMD) unpolarized and polarized PDFs and FFs and applications to precision physics studies at hadron colliders [CA, PV, TO]

Scientific activity of the various Research Units

INFN Section: Cagliari

The research activity of the Cagliari unit in 2025 was focused on the following main issues:

- We have contributed to the physics case for quarkonium production studies at the EIC.

Prog. Part. Nucl. Phys. 142 (2025) 104162 - e-Print: 2409.03691 [hep-ph]

- We have presented a study of azimuthal asymmetries in almost back-to-back two-hadron production in (virtual and quasi-real) photon-photon collisions at e+e- colliders.

Phys. Rev. D 112 (2025) 014013 - e-Print: 2504.12802 [hep-ph]

- We have presented a study of azimuthal asymmetries in lepton and heavy-quark pair production in ultra-peripheral collisions (UPCs) in terms of photon GTMDs.

JHEP 01 (2025) 076 - e-Print: 2410.23924 [hep-ph]

- We have performed an updated study of the Collins azimuthal asymmetries for pion-in-jet production in polarized pp collisions, focusing on the universality of the Collins function and TMD factorization.

Phys Lett. B 871 (2025) 14002 - e-Print: 2506.21959 [hep-ph]

- We have studied perturbative RGE systematics in precision observables, extending and completing a previous work on the subject and providing a method to obtain faithful estimates of perturbative uncertainties; we are actively discussing with experimental collaborations for its application to data analysis.

Phys. Rev. D 111 (2025) 074005 - e-Print: 2407.20842 [hep-ph]

- We have presented a study on the automation of NLO calculations for asymmetric hadron-hadron collisions in MadGraph5_aMC@NLO.

Eur. Phys. J. A 61 (2025) 239 - e-Print: 2501.14487 [hep-ph]

- We have presented a study on the impact of future D- and B-meson related measurements with the SMOG2 program at the LHC on the determination of the nuclear parton distributions.

Phys. Lett. B 866 (2025) 139554 - e-Print: 2503.21531 [hep-ph]

- We have presented the first implementation of resolved photoproduction processes in MadGraph5_aMC@NLO.

PoS DIS2024 (2025) 185 - e-Print: 2410.17061 [hep-ph]

- We have studied the polarization and transverse momentum effects of quarks and antiquarks in double quarkonium production in hadron-hadron collisions.

JHEP 02 (2026) 085 - e-Print: 2508.15482 [hep-ph]

- We have contributed to the technical design report of the Circular Electron Positron Collider (CEPC)

e-Print: 2510.05260 [hep-ex]

Additional publications/contributions and preprints

- We have written an invited review article for Annual Review of Particle Physics on the status of the W boson mass and the future of the electroweak fit.

e-Print: 2506.01887 [hep-ph]

- We have contributed to the Feasibility Study Report for FCC.

Eur. Phys. J. C 85 (2025) 1468, e-Print: 2505.00272 [hep-ex]; Eur. Phys. J ST 234 (2025) 5713, e-Print: 2505.00274 [physics.acc-ph]; Eur. Phys. J ST 234 (2025) 5113, e-Print: 2505.00273 [physics.acc-ph]

- We have contributed, as spokesperson, to a proposal to measure unpolarized cross sections in SIDIS on 3He target with the SoLID apparatus at JLab. The goal is to learn on TMDs by studying absolute cross sections in the region of large x, moderate Q2, and small values of the transverse momentum of the produced hadron.

- We have contributed to a document on the physics case of the LHCspin project

e-Print: 2504.16034 [hep-ex]

- We have presented a phenomenological and experimental study of SIDIS unpolarized cross sections from a 3He Target with the Solenoidal Large Intensity Device at JLab

e-Print: 2512.20897 [nucl-ex]

INFN Section: Genova

During 2025 the research activity of the Genova unit was devoted to the following topics:

1) Theoretical studies of heavy flavor exotic states, their structures, decays and calculations of their production cross section at LHC [1,2,5,6]

2) Spectroscopy and decays of heavy flavor hadrons at LHC [3, 4,11]

3) Development of theory framework for the INFN experiment NUMEN at LNS Catania [7]

4) Implementation of the Genoa spectroscopy amplitudes in the NUMEN - LNS reaction code [7]

5) Theory developments for LHCb [2]

6) Theory support for future experiments at CERN [8,9,10]

7) Research on analytical or quasi-analytical solutions of the neutron transport equation and applications [12,13]

8) Study of the eigenvalues of the neutron transport equation with a high-precision calculation [14]

9) Regge models for descriptions of background to hybrid searches at JLab [15,16,17]

10) Study of opportunities for hadron spectroscopy at the EIC and at an upgraded JLab Facility [18,19]

Published or submitted Articles ( 2025 up to March 2026 ):

1. Quarks in 'exotic' quartets prefer to stick together, E. Santopinto, NATURE 648, 48 (2025)

2. Fully charmed tetraquark production at the LHC experiments, E. Santopinto et al., JHEP 01 (2025) 093.

3. Ξc(2790)+/0 and Ξc(2815)+/0 radiative decays, E. Santopinto et al., Phys. Lett. B 868 (2025) 139666.

4. Radiative decays of the second shell Λb and Ξb bottom baryons, Ailier Rivero-Acosta, H. García-Tecocoatzi, A. Ramirez-Morales, E. Santopinto, Carlos Alberto Vaquera-Araujo, Phys. Rev. D 112 (2025) 072014.

5. Strong decays of the DK∗ and D-bar K∗ molecular states, Zi-Li Yue, Cheng-Jian Xiao, H. García-Tecocoatzi, Dian-Yong Chen, Elena Santopinto, Eur. Phys. J. C 85 (2025) 1367.

6. Determining the width of 𝐷∗(2317) by using 𝑇0cs0(2327) in a molecular frame, Zi-Li Yue, Quan-Yun Guo, Dian-Yong Chen, Elena Santopinto, Eur. Phys. J. C 86 (2026) 33.

7. Status of the NUMEN Construction, D. Pierroutsakou, E. Santopinto, et al. (NUMEN Collaboration), EPJ Web Conf. 333 (2025) 03006.

8. Future Circular Collider Feasibility Study Report: Volume 3 - Civil Engineering, Implementation and Sustainability, FCC Collaboration, M. Benedikt, ...E. Santopinto, et al., Eur. Phys. J. ST 234 (2025) 5113-5383.

9. Future Circular Collider Feasibility Study Report: Volume 2 - Accelerators, Technical Infrastructure and Safety, FCC Collaboration, M. Benedikt...E. Santopinto, et al., Eur. Phys. J. ST 234 (2025) 5713- 6197.

10. Future Circular Collider Feasibility Study Report: Volume 1 - Physics, Experiments, Detectors, FCC Collaboration, M. Benedikt...E. Santopinto, et al., Eur. Phys. J. C 85 (2025) 1468.

11. Radiative decays of the Σc, Ξ′c and Ωc charmed baryons, A. DÅlavila-Rivera, E. Santopinto, et al., e-Print: :2512.03008 [hep-ph]

12. A review of the scientific contributions by Barry Ganapol, P. Ravetto and P. Saracco, Annals of Nuclear Energy 217 (2025) 111253.

13. Impact of energy collapsing on the effective neutron lifetime, P. Saracco et al., Annals of Nuclear Energy 222 (2025) 111550.

14. High-precision eigenvalues of the neutron transport equation by the Carlvik method, P. Saracco et al., Annals of Nuclear Energy 224 (2025) 111672.

15. Nonperturbative aspects of the electromagnetic pion form factor at high energies, A. Pilloni et al. (JPAC Collaboration), Phys. Rev. D 111 (2025) 054034.

16. Studying pi+pi- photoproduction beyond Pomeron exchange, A. Pilloni et al. (JPAC Collaboration), Phys. Rev. D 111 (2025) 014002.

17. High-energy η(‘)π photoproduction and the nature of exotic waves, G. Montaña, V. Mathieu, V. Shastry, Ł. Bibrzycki, C. Fernández-Ramírez, N. Hammoud, R. J. Perry, A. Pilloni, A. Rodas, W. A. Smith, A. P. Szczepaniak, D. Winney, Phys. Lett. B 872 (2026) 140101.

18. Hadron Physics Opportunities at FAIR, J. G. Messchendorp, A. Pilloni et al., e-Print: 2512.15986 [hep-ex].

19. Frascati 22 GeV Workshop Summary, A. Accardi, A. Pilloni et al., e-Print: 2601.05773 [nucl-ex].

INFN Section: Pavia

The research activity of the Pavia unit in 2025 was focused on the following main issues:

Within the ongoing effort of the MAP collaboration (Multidimensional Analyses of Partonic distributions) to perform studies of hadron structure using modern nonperturbative tools, we achieved the following goals:

- Within out fitting framework named "NangaParbat", we completed the extraction of the transverse-momentum dependent parton distributions (TMDs) for longitudinally polarized quarks by fitting HERMES data for spin asymmetries on longitudinally polarized protons, consistently using our results for the unpolarized quark TMDs in the denominator of the asymmetry.

- Within the same framework, we extended to the pion our flavor-sensitive extraction of quark TMDs by consistently analyzing available data for pion-proton Drell-Yan processes.

L. Rossi, A. Bacchetta, M. Cerutti, and M. Radici

e-Print: 2509.25098 [hep-ph]; submitted to Phys. Lett. B

- We completed the first extraction of unpolarised quark TMDs from Drell-Yan data using neural networks to parametrise the TMD nonperturbative part, confirming the feasibility of using machine-learning techniques to study the multi-dimensional partonic structure, and showing that neural networks provide a more accurate description of data.

- We contributed to the physics proposal of LHCspin, a polarized gas fixed-target experiment at LHCb for studies of 3-dimensional hadronic structure in unexplored kinematic regimes.

A. Accardi, A. Bacchetta,.., B. Pasquini,.., M. Radici, et al.

e-Print: 2504.16034 [hep-ex]

- We continued our studies of the impact on the uncertainty of unpolarized quark TMDs in the proton produced by simulations of projected uncertainties for SIDIS pseudodata with unpolarized protons at the Electron-Ion Collider (EIC), in particular in the so-called "Early Science" conditions; these results will be included in the EIC Early Science Report in preparation.

- We performed the same kind of impact studies for the possible 22 GeV energy upgrade at Jefferson Lab, and contributed also to other topics about the nucleon like its spatial structure, mechanical properties, form factors and emergent mass, that are part of the main program of the white paper on the 22 GeV JLab upgrade published in

A. Accardi,.., A.C. Alvaro,.., F. Delcarro,.., M. Radici, et al.

e-Print: :2601.05773 [nucl-ex]

- We completed the exploration of tensor TMDs in the deuteron through the possible measurement at Hall B of Jefferson Lab of tensor-polarized structure functions, which enable the direct access to quark and gluon distributions in light nuclei that cannot be naively constructed from the proton and the neutron.

- We have been invited to write an introduction to parton distribution functions and their generalizations which describe the quark and gluon structure of hadrons, and can be measured in various high-energy scattering processes.

C. Lorcé, A. Metz, B. Pasquini

e-Print: 2507.12664 [hep-ph]; in press on "Encyclopedia of Particle Physics", Elsevier.

- We extended our previous work on the non-conserved axial current for a gluon target by investigating the leading-twist matrix elements of the nonlocal light-like flavor-singlet vector current, which is parametrized in terms of twist-2 unpolarized generalized parton distributions (GPDs) of quarks for an on-shell gluon target; we computed them at one-loop accuracy in perturbation theory using a quark mass and dimensional regularization as infrared regulators, discussing also the limit of vanishing momentum transfer.

A.C. Alvaro,.., B. Pasquini, and S. Rodini

e-Print: 2512.23563 [hep-ph]; submitted to Phys. Lett. B.

- We presented a once-subtracted dispersion relation (DR) formalism for the virtual Compton scattering (VCS) process from threshold up to the Δ(1232) energy region; the formalism aims at extracting the nucleon's electric and magnetic generalized polarizabilities in view of the precision goals of the present and near future experiments at Jefferson Lab, and improves upon the existing unsubtracted DR formalism in several ways; we compare our results to VCS data and show the sensitivity of the observables to the nucleon's scalar generalized polarizabilities, which enter the present formalism as subtraction constants.

- We reconsidered the derivation of the factorization theorem for unpolarized semi-inclusive electron-positron annihilation cross sections confirming that, contrary to some recent claims in the literature, the standard operator definition for single-hadron fragmentation remains valid also for the case of small-mass n hadrons with the same hard perturbative parts and evolution kernel; this result reaffirms in particular the reliability of past phenomenological studies with Di-hadron Fragmentation Functions (DiFFs).

T.C. Rogers, T. Rainaldi, M. Radici, A. Courtoy

Phys. Rev. D 113 (2026) 038902 - e-Print: 2602.09211 [hep-ph]

- We have improved our old extraction of DiFFs from Belle data on electron-positron annihilations into back-to-back di-hadron pairs by increasing the accuracy in the description of perturbative corrections to the unpolarized DiFF up to next-to-next-to-leading order (NNLO), and by performing for the first time the extraction parametrizing the nonperturbative part with a neural network.

V. Mahaut, L. Polano, A. Bacchetta,.., M. Radici, et al.

JHEP 02 (2026) 051 - e-Print: 2509.11855 [hep-ph]

Other Recent preprints not yet published

1) LHCspin: a Polarized Gas Target for the LHC

A. Accardi, A. Bacchetta,.., B. Pasquini,.., M. Radici, et al.

e-Print: 2504.16034

2) S. Diehl,.., M. Radici et al. (ePIC Coll. and EIC Users Group),

Synergies between a U.S.-based Electron-Ion Collider and European Research in Particle Physics

e-Print: 2504.01236 [hep-ex]

3) Parton Distribution Functions and their Generalizations

C. Lorcé, A. Metz, B. Pasquini

e-Print: 2507.12664 [hep-ph]

Contribution to "Encyclopedia of Particle Physics", Elsevier, in press

4) Frascati 22 GeV Workshop Summary

A. Accardi,.., A.C. Alvaro,.., F. Delcarro,.., M. Radici, et al.

e-Print: 2601.05773 [nucl-ex]

INFN Section: Perugia

During 2025, the nuclear group of the NINPHA-Perugia node has investigated how to properly define nuclear double parton distributions (DPDs) which enter the nuclear double parton scattering (DPS) cross-section. These quantities encode novel fundamental information on the partonic structure of hadrons and nuclei, such as the possible impact of double parton correlations and the mean transverse distance between two partons. To this aim, we made use of the Poincaré covariant approach, based on Light-front Relativistic Hamiltonian Dynamic. We proved that there are two main contributions: 1) The two active partons belong to the same nucleon in the nucleus (DPS1) and 2) The two partons belong to two different nucleons (DPS2). The latter is an effect beyond the usual impulse approximation. We evaluated the DPDs corresponding to these two mechanisms for 2H by using the associated realistic wave-functions [1]. We also started a new investigation to prove that fundamental information that could shed some light on the still open problem of the nuclear EMC effect could be obtained from future nuclear DPS processes [2].

- The Gravitational Form Factors of the pion have been evaluated from the corresponding generalized parton distribution functions calculated within the holographic graviton soft-wall model [3].

- Simone Pacetti and collaborators published a manuscript about isospin violation in J/psi and psi(2S) decay in Lambda-Sigma-bar^0+c.c. [4]. In collaboration with the BESIII Uppsala group, electromagnetic form factors (EMFFs) of hyperons based on dispersion relations have been studied [5]. The NINPHA group also contributed to the manuscript: “Tests of CP Symmetry in Entangled Hyperon Antihyperon Pairs at BESIII” [6]. The J/psi decay in the Omega-pi^0 state has been also investigated together with the decay of charmonium states in the barionic octet pairs by means of the optical theorem. The group published 3 national and international conference proceedings [7]-[9].

- Members of the NINPHA group of Perugia proposed and followed a master thesis entitled "Quantum Computing for hadronic physics: the meson spectrum via Variational Quantum Algorithms exploitation". The expected results from classical computation methods are well reproduced and the study is presently ongoing.

- In collaboration with Prof. Mark Strikman (Penn State, USA) and Dr. Vadim Guzey (University of Jyväskylä, Finlandia) a model for the number distribution of forward neutrons emitted in inelastic proton-nucleus collisions has been developed [10]. M. Alvioli joined a study on the understanding of the observation of collisions involving isobaric nuclei at RHIC for low and high energy physics investigations [11].

REFERENCES

[1] F.A. Ceccopieri, F. Fornetti, E. Pace, M. Rinaldi, G. Salmè and N. Iles, Eur. Phys. J. C 85 (2025) 1265

[2] F.A. Ceccopieri, F. Fornetti, E. Pace, M. Rinaldi, G. Salmè, in preparation

[ 3] F. Fornetti and M. Rinaldi, in preparation

[4] F. Rosini and S. Pacetti, Eur. Phys. J. C 85 (2025) 236

[5] BESIII Collaboration, ..., F. Rosini,..., et al., Phys. Rev. Lett. 135 (2025) 191902

[6] W. Zheng, A. Kupsc, S. Pacetti, F. Rosini, N. Salone, X. Wang and S. s. Fang, Chin. Phys. Lett. 42 (2025) 041201

[7] F. Rosini and S. Pacetti, PoS FAIRness2024 (2026) 031

[8] F. Rosini, Nuovo Cim. C 49 (2026) 47

[9] F. Rosini and S. Pacetti, PoS WIFAI2024 (2025) 041

[10] M. Alvioli, V. Guzey and M. Strikman, Phys. Rev. C 112 (2025) 034901

[11] G. Giacalone,..., M. Alveoli..., et al, Nuclear physics confronts relativistic collisions of isobars, e-Print: 2507.01454 [nucl-ex]

INFN Section: Torino

In 2025, the Torino group continued its research activity on the three-dimensional structure of nucleons in partonic momentum space, with particular focus on Transverse Momentum Dependent (TMD) parton distribution and fragmentation functions and their properties. The large-transverse-momentum regime of TMD distributions, relevant for the consistency between TMD and collinear factorization, was also investigated.

Parallel lines of research were pursued and several related issues were studied:

- A phenomenological tool, referred to as “affinity”, was developed to quantify the proximity of experimental kinematic bins to specific hadron production regions, such as those associated with TMD factorization. This tool has been employed to provide simulations and kinematic diagnostics for the proposed upgrade of the CEBAF accelerator at Jefferson Lab (USA) to a center-of-mass energy of 22 GeV. Further developments, carried out in collaboration with Dr. Yushkevych and members of the experimental community, aim at refining the method through the inclusion of Monte Carlo inputs. The corresponding analysis was completed in 2025, and the results are expected to be released in the first semester of 2026.

- A compatibility analysis between cross-section data differential in qT, and lattice QCD calculations of the Collins–Soper kernel was completed in 2025, in collaboration with Dr. Pucci (PhD student in co-tutelle with Charles University, Prague). The manuscript is currently in preparation and is expected to be submitted in the first semester of 2026.

- A computational tool for analysis of TMD distributions within the novel HSO approach, developed by members of our group in collaboration with colleagues from Old Dominion University & the University of Connecticut, has been released for public use. This tool enables the nuclear physics community to verify our recently published results as well as perform independent analysis on selected Drell-Yan data. (https://github.com/joghdr/hso_dy)

- In collaboration with our INFN postdoctoral researcher Dr. Jennifer Rittenhouse West, we have carried out next-to-leading-order QCD calculations of antiproton and antineutron production cross sections in proton–proton collisions, covering center-of-mass energies from 17.2 GeV up to 13 TeV. The availability of precise theoretical predictions for these hadronic production cross sections is crucial for a reliable determination of the Standard Model background in cosmic ray antiproton measurements, thereby improving the interpretative power of indirect dark matter searches. Within this framework, we have determined the antineutron-to-antiproton production ratio, finding a value close to unity with controlled theoretical uncertainties, in tension with earlier experimental claims of a large enhancement.

- In collaboration with the Theory Center at Jefferson Lab and INFN Rome, the factorization theorem for deep-inelastic scattering at large x was investigated, highlighting the emergence of a jet function related to the quark propagator in the threshold region and of the Collins-Soper kernel. The analysis was completed and submitted for publication in 2025:

“Unveiling the Collins–Soper kernel in inclusive DIS at threshold”

A. Simonelli et al.,

e-Print 2502.15033 [hep-ph]

- Along the same lines, a more comprehensive manuscript has been prepared in 2025 and will be submitted for publication in 2026:

“Factorization of DIS at large-x revisited”

A. Simonelli et al.

- Additional activity concerned the study of the relation between quark propagation and hadronization. In collaboration with Poonam Choudary, postdoc at IIT Mumbai, we also focused on model calculations for higher-twist fragmentation functions connected to the chiral-odd “jet mass” and on the impact of the latter in polarized hadron production from electron-positron annihilation. Publication of these results, mainly obtained in 2025, is expected in 2026.

- Furthermore, work has been carried out in order to devise a version of the Sivers effect in the context of atomic physics, combining Quantum Mechanics and Quantum Electrodynamics (QED). This might result in a cleaner experimental investigation of the interplay between the time reversal symmetry and the gauge symmetry with respect to the case of Quantum Chromodynamics (QCD). The topic is the subject of two dissertations, a B.Sc. thesis at the University of Torino and a Ph.D. thesis at the University of Michigan. Both dissertations have been successfully completed and defended. The analysis is now complete and publication is expected in 2026.

- In collaboration with colleagues at Penn State University (Berks) and Argonne National Laboratory, an investigation of the impact of nuclear uncertainties on the extraction of pion and proton TMDs from Drell–Yan data is ongoing. The publication of the results is expected in the first semester of 2026.

- In collaboration with Kamil Laurent (Ph.D. student at NIKHEF, NL), we are conducting closure tests on the minimization frameworks used by the MAP collaboration to determine TMD distributions from experimental data. The developed code has been integrated into the MAP framework to ensure broader applicability. The analysis, largely carried out in 2025, is currently being finalized, with publication expected in 2026.

- Our local group and the MAP collaboration started investigating the role of the flavor dependence of unpolarized TMDs in the determination of the W boson mass from hadronic collisions. This work, carried out in collaboration with Sara Pontina, graduate student at the University of Turin, is a spin-off of the recent MAP flavor-dependent fits and generalizes the results obtained in 2018 and 2019 on the same topic.

This research line started in late 2025. Results will be finalized in 2026.

- In collaboration with P. Torrielli and L. Rottoli, the impact of including non-perturbative effects in the Radish framework is assessed. The aim of the project is to improve the calculation of Drell-Yan qT-differential spectra at small transverse momenta. The novelty lies in the fact that resummation and the associated non-perturbative effects are directly implemented in momentum space. The analysis, largely carried out in 2025, is expected to culminate in a publication in 2026.

- M. Boglione is author of a document which summarizes the outcomes of the “Science at the Luminosity Frontier: Jefferson Lab at 22 GeV” workshop, held at the INFN Laboratori Nazionali di Frascati in December 2024 and made public in 2025. This document provides a critical assessment of the scientific case for a proposed energy upgrade of the Continuous Electron Beam Accelerator Facility (CEBAF) to 22 GeV.

"Frascati 22 GeV Workshop Summary"

A. Accardi et al.

e-Print: 2601.05773 [nucl-ex]

- M. Boglione, E.R. Nocera and A. Signori authored a document assessing and promoting the LHCSpin program at LHCB - CERN

"LHCspin: a Polarized Gas Target for LHC"

A. Accardi et al.

e-Print: 2504.16034 [hep-ex]

- Our research activity on the three-dimensional structure of the nucleons was complemented with topics related to precision physics at colliders with collinear parton distribution functions (PDFs). This line of research was pursued mainly within the NNPDF collaboration in the following directions:

- The determination of the collinear helicity PDFs, including next-to-next-to-leading order (NNLO) corrections has been tackled as part of a major effort from members of the NNPDF Collaboration. The determination included an analysis of polarised inclusive deep-inelastic scattering and jet, dijet, and gauge boson production data in polarised proton-proton collisions. A systematic treatment of missing higher order uncertainties was deployed for the first time. The corresponding paper has been published as

“NNPDFpol2.0: a global determination of polarised PDFs and their uncertainties at next-to-next-to-leading order”

J. Cruz Martinez et al.,

JHEP 07(2025) 168 - e-Print 2503.11814 [hep-ph]

- A further line of research is being pursued to study the interplay between specific data sets and PDFs. Specifically, we have investigated the generalisation power of various PDF sets to predict measurements that were not included in their determination.

“Parton distributions confront LHC Run II data: a quantitative appraisal”

A. Chiefa et al.,

JHEP07 (2025) 067 - e-Print: 2501.10359 [hep-ph]

- A determination of the strong coupling from a global analysis of hard scattering has been completed. In this context, new statistical techniques, which take advantage of correlations between Standard Model parameters, PDFs, and data, have been developed to simplify the task of determining the first from the last. Validation tests against common techniques have been studied.

“A determination of alpha_s(MZ) at aN3LOQCD x NLOQED accuracy from a global PDF analysis “

R.D. Ball et al.,

Eur. Phys. J. C 85 (2025) 1001 - e-Print: 2506.13871 [hep-ph]

- In collaboration with P. Torrielli, L. Rottoli and J.M. Cruz-Martinez, the impact of including resummation of small transverse momenta in Drell Yan measurements is being assessed, in particular when these measurements are incorporated into a global determination of PDFs. The analysis, largely carried out in 2025, is expected to culminate in a publication in the first semester of 2026.

- In collaboration with the group led by S. Brodsky (SLAC), the problem of unambiguous scale setting in perturbative QCD has been addressed. A scheme-independent determination of the QCD running coupling has been achieved by applying the Principle of Maximum Conformality in its infinite-order formulation, combined with intrinsic conformality. The analysis is based on jet observables (thrust and C-parameter) in e+e− annihilation at the Z0 peak and employs a maximum-likelihood approach, leading to a precise determination of αs(MZ), consistent with the world average and with reduced systematic uncertainties.

“Scheme-independent determination of the QCD running coupling at all scales from jet observables using the Principle of Maximum Conformality and infinite-order scale setting”

L. Di Giustino, S.J. Brodsky, P.G. Ratcliffe, S.-Q. Wang and X.-G. Wu

Phys. Lett. B 869 (2025) 139884 - e-Print: 2407.08570 [hep-ph]

“The Principle of Maximum Conformality correctly resolves the renormalization-scheme-dependence problem”

J. Yan, S. J. Brodsky, L.D. Giustino, P.G. Ratcliffe, S.-Q. Wang and X.-G. Wu

Symmetry 17 (2025) 411 - e-Print: 2311.17360 [hep-ph]

- Philip Ratcliffe has also published a book

“An Introduction to Elementary Particle Phenomenology (Second Edition)”, IOP Publishing Ltd, Jan. 2025.

Short summary of NINPHA scientific activity in 2024

Below, a short list of the main achievements of the NINPHA project in 2024 is reported.

CA-1) We have extended the Bayesian reweighting procedure to the case of multiple independent extractions of TMD parton distributions, leading to a simultaneous reweighting of the quark Sivers, transversity and Collins TMD functions.

Phys. Lett. B 854 (2024) 138712 - e-print: 2402.12322 [hep-ph]

CA-2) We have studied charmonium and bottomonium production in hadronic collisions within the TMD approach and NRQCD, focusing on quarkonium states with even charge conjugation, as a tool for the extraction of unpolarized and linearly polarized gluon TMDs.

Phys. Rev. D 110 (2024) 034038 - e-print: 2403.20017[hep-ph]

GE-1) The formalism for the production of fully charmed tetraquarks at the LHC was developed and applied to the calculation of pp->T4c +X cross sections.

Our results demonstrate the dominance of the T4c(2++) production rate relative to that of T4c(0++), and are supported by preliminary CMS results.

JHEP 01 (2025) 093 - e-print: 2409.12070 [hep-ph]

GE-2) We have performed extensive and detailed studies of opportunities for hadron spectroscopy at the EIC and an upgraded JLab Facility.

PG-1) We have performed a realistic calculation of the different parton distributions for light-nuclei within a Poincaré approach, needed for the next generation of experiments at EIC and JLab.

PG-2) We have also completed the development of a code aimed to solve a generalized eigenvalue problem with a quantum annealer. This project won a call from INFN and CINECA.

PV-1) We implemented in our fitting framework the formalism to separately study the intrinsic transverse momentum distribution of each unpolarized quark flavor from the extraction of the corresponding TMD in a global fit of SIDIS and Drell-Yan data at colliders

JHEP 08 (2024) 232, e-Print: :2405.13833 [hep-ph]

PV-2) We performed the first extraction of unpolarised quark TMDs from Drell-Yan data using neural networks to parametrise the TMD nonperturbative part, confirming the feasibility of using machine-learning techniques to study the multi-dimensional partonic structure, and showing that neural networks provide a more accurate description of data

e-Print: 2502.04166 [hep-ph]

TO) The Torino node is actively engaged in the study of hadron structure, focusing on two complementary aspects of QCD.

TO-1) On one side, we work on Transverse Momentum Dependent (TMD) physics, investigating TMD factorization theorems, TMD parton densities, and their scale evolution, with particular emphasis on describing the full qT pectrum of unpolarized cross sections, while maintaining a close connection to spin-dependent phenomena and transverse spin asymmetries.

TO-2) On the other side, we address collinear physics, studying parton distribution functions (PDFs) and fragmentation functions (FFs) within the collinear framework, where transverse momentum effects are integrated out.

Together, these activities provide a comprehensive understanding of the partonic structure of hadrons, from multidimensional, transverse, and longitudinal perspectives.