Marco Radici | University of Pavia (original) (raw)

Papers by Marco Radici

arXiv (Cornell University), Sep 25, 2014

This study is part of a project to investigate the transverse momentum dependence in parton distr... more This study is part of a project to investigate the transverse momentum dependence in parton distribution and fragmentation functions, analyzing (semi-)inclusive high-energy processes within a proper QCD framework. We calculate the transverse-momentum-dependent (TMD) multiplicities for e + e − annihilation into two hadrons (considering different combinations of pions and kaons) aiming to investigate the impact of intrinsic and radiative partonic transverse momentum and their mixing with flavor. Different descriptions of the non-perturbative evolution kernel (see, e.g., Refs. [1-5]) are available on the market and there are 200 sets of flavor configurations for the unpolarized TMD fragmentation functions (FFs) resulting from a Monte Carlo fit of Semi-Inclusive Deep-Inelastic Scattering (SIDIS) data at Hermes (see Ref. [6]). We build our predictions of e + e − multiplicities relying on this rich phenomenology. The comparison of these calculations with future experimental data (from Belle and BaBar collaborations) will shed light on non-perturbative aspects of hadron structure, opening important insights into the physics of spin, flavor and momentum structure of hadrons.

We calculate the transverse momentum dependence in the production of two back-to-back hadrons in ... more We calculate the transverse momentum dependence in the production of two back-to-back hadrons in electron-positron annihilations at the medium/large energy scales of Bes-III and Belle experiments. We use the parameters of the transverse-momentumdependent (TMD) fragmentation functions that were recently extracted from the semiinclusive deep-inelastic-scattering multiplicities at low energy from Hermes. TMD evolution is applied according to different approaches and using different parameters for the nonperturbative part of the evolution kernel, thus exploring the sensitivity of our results to these different choices and to the flavor dependence of parton fragmentation functions. We discuss how experimental measurements could discriminate among the various scenarios.

Journal of physics, May 1, 2009

Results for the proton and neutron electric and magnetic form factors as well as the nucleon axia... more Results for the proton and neutron electric and magnetic form factors as well as the nucleon axial form factor are presented for constituent quark models, based on either one-gluon-exchange and Goldstone-boson-exchange dynamics. The calculations are performed in a covariant framework using the point-form approach to relativistic quantum mechanics. The only input to the calculations is the nucleon wave function of the corresponding constituent quark model. A comparison is given to results of the instanton-induced constituent quark model treated with the Bethe-Salpeter equation.

Journal of High Energy Physics, Oct 19, 2022

We present an extraction of unpolarized transverse-momentum-dependent parton distribution and fra... more We present an extraction of unpolarized transverse-momentum-dependent parton distribution and fragmentation functions based on more than two thousand data points from several experiments for two different processes: semi-inclusive deep-inelastic scattering and Drell-Yan production. The baseline analysis is performed using the Monte Carlo replica method and resumming large logarithms at N 3 LL accuracy. The resulting description of the data is very good (χ 2 /N dat = 1.06). For semi-inclusive deep-inelastic scattering, predictions for multiplicities are normalized by factors that cure the discrepancy with data introduced by higher-order perturbative corrections.

arXiv (Cornell University), Nov 2, 2021

arXiv (Cornell University), Jan 25, 2022

We present exploratory studies of the 3D proton tomography through polarized T-odd gluon TMDs at ... more We present exploratory studies of the 3D proton tomography through polarized T-odd gluon TMDs at leading twist, obtained in a spectator-model framework. We embody in our approach a flexible parameterization for the spectator-mass spectral function, suited to catch both small-and moderate-x effects. All these studies are relevant to unveil the gluon dynamics inside hadrons, which represents a core research line of studies at new-generation colliders, such as the Electron-Ion Collider, NICA-SPD, the High-Luminosity LHC, and the Forward Physics Facility.

arXiv (Cornell University), Nov 5, 2021

We present preliminary results on the leading-twist transverse-momentum-dependent (TMD) gluon lin... more We present preliminary results on the leading-twist transverse-momentum-dependent (TMD) gluon linearity function, which is directly connected to nucleon transverse-spin asymmetries originating from the density of linearly-polarized gluons. The function is calculated in a spectatormodel framework for the parent proton and for the-type gauge-link structure. Our work represents a further step toward the definition of a complete set of gluon TMD distributions at twist-2 that can be used to access the gluon dynamics inside nucleons and nuclei at new-generation colliders.

Suplemento de la revista mexicana de física, Jun 8, 2022

We present exploratory studies of the 3D proton tomography through polarized T-odd gluon TMDs at ... more We present exploratory studies of the 3D proton tomography through polarized T-odd gluon TMDs at leading twist, obtained in a spectator-model framework. We embody in our approach a flexible parameterization for the spectator-mass spectral function, suited to catch both small-and moderate-x effects. All these studies are relevant to unveil the gluon dynamics inside hadrons, which represents a core research line of studies at new-generation colliders, such as the Electron-Ion Collider, NICA-SPD, the High-Luminosity LHC, and the Forward Physics Facility.

SciPost physics proceedings, Jul 12, 2022

We present exploratory analyses of the 3D gluon content of the proton via a study of unpolarized ... more We present exploratory analyses of the 3D gluon content of the proton via a study of unpolarized and polarized gluon TMDs at twist-2, calculated in a spectator model for the parent nucleon. Our approach embodies a flexible parametrization for the spectatormass function, suited to describe both moderate and small-x effects. All these studies can serve as a useful guidance in the investigation of the gluon dynamics inside nucleons and nuclei, which constitutes one of the major goals of new-generation colliding machines, as the EIC, the HL-LHC, NICA, and the FPF.

arXiv (Cornell University), Jun 7, 2023

We include strong parity-violating contributions to inclusive deep inelastic scattering (DIS) of ... more We include strong parity-violating contributions to inclusive deep inelastic scattering (DIS) of longitudinally polarized leptons off an unpolarized target. At variance with standard results, we obtain nonvanishing parity-violating structure functions in the case of pure photon exchange. The addition of these strong parity-violating contributions improves the description of existing experimental data on DIS parity-violating asymmetries. We find the size of these contributions small but exhibiting a deviation from zero of about 1.5 σ. The associated p-value is 0.063, indicating that the probability of making an error by rejecting the hypothesis of no parity-violating contributions is 6.3%, which is small but not negligible. Further improvement on the limit of the strong parity-violation can be expected from the future SoLID program at Jefferson Lab.

Physical Review D

We describe the formal analogies in the description of the inclusive production in hard processes... more We describe the formal analogies in the description of the inclusive production in hard processes of hadron pairs (based on dihadron fragmentation functions) and of a single hadron inside a jet (based on hadron-in-jet fragmentation functions). Since several observables involving dihadron fragmentation functions have been proposed in the past, we are able to suggest new interesting observables involving hadron-in-jet fragmentation functions, in lepton-hadron deep-inelastic scattering and hadronic collisions.

Progress in Particle and Nuclear Physics

FIG. 1. The EIC concept at Brookhaven National Laboratory [9]. The electron and the ion beams are... more FIG. 1. The EIC concept at Brookhaven National Laboratory [9]. The electron and the ion beams are clearly identified. There are several beam intersection points, one at the o'clock (IP6) location and at the 8 o'clock (IP8) location are suitable for the installation and operation of large scale detector systems. Interaction point IP8 may be most suitable for high-luminosity optimization at low to intermediate center-of-mass energies as well as for the installation of a secondary focus for forward processes requiring high momentum resolution. The electron beam energy ranges from 2.5 GeV to 18 GeV, while for protons the ion beam allows selected energies between 41 GeV and 275 GeV covering a collision center-mass energy from 20 GeV to 140 GeV. The ion beam is circulating counter clockwise, and the new electron ring with electrons circling clockwise. Both beams will be highly polarized with both electron and proton polarizations greater than 70%. The EIC will benefit from two existing large detector halls in IP6 and in IR8, both fully equipped with infrastructure.

Proceedings of 41st International Conference on High Energy physics — PoS(ICHEP2022), Dec 16, 2022

We present a recent extraction of unpolarised transverse-momentum-dependent (TMD) parton distribu... more We present a recent extraction of unpolarised transverse-momentum-dependent (TMD) parton distribution functions and TMD fragmentation functions from experimental data sets of Semi-Inclusive Deep-Inelastic Scattering, Drell-Yan and Z boson production. The global fit is performed at the N 3 LL logarithmic accuracy and is based on flexible non-perturbative functions, allowing to reach a very good agreement with data

Journal of High Energy Physics

We present an extraction of unpolarized transverse-momentum-dependent parton distribution and fra... more We present an extraction of unpolarized transverse-momentum-dependent parton distribution and fragmentation functions based on more than two thousand data points from several experiments for two different processes: semi-inclusive deep-inelastic scattering and Drell-Yan production. The baseline analysis is performed using the Monte Carlo replica method and resumming large logarithms at N3LL accuracy. The resulting description of the data is very good (χ2/Ndat = 1.06). For semi-inclusive deep-inelastic scattering, predictions for multiplicities are normalized by factors that cure the discrepancy with data introduced by higher-order perturbative corrections.

arXiv (Cornell University), Oct 4, 2022

We map the distribution of unpolarized quarks inside a unpolarized pion as a function of the quar... more We map the distribution of unpolarized quarks inside a unpolarized pion as a function of the quark's transverse momentum, encoded in unpolarized Transverse Momentum Distributions (TMDs). We extract the pion TMDs from available data of unpolarized pion-nucleus Drell-Yan processes, where the cross section is differential in the lepton-pair transverse momentum. In the cross section, pion TMDs are convoluted with nucleon TMDs that we consistently take from our previous studies. We obtain a fairly good agreement with data. We present also predictions for pion-nucleus scattering that is being measured by the COMPASS Collaboration. * The MAP acronym stands for "Multi-dimensional Analyses of Partonic distributions". It refers to a collaboration aimed at studying the three-dimensional structure of hadrons. The public codes released by the collaboration are available at https://github.com/MapCollaboration.

Journal of Instrumentation

ATHENA has been designed as a general purpose detector capable of delivering the full scientific ... more ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges.

arXiv (Cornell University), Sep 25, 2014

This study is part of a project to investigate the transverse momentum dependence in parton distr... more This study is part of a project to investigate the transverse momentum dependence in parton distribution and fragmentation functions, analyzing (semi-)inclusive high-energy processes within a proper QCD framework. We calculate the transverse-momentum-dependent (TMD) multiplicities for e + e − annihilation into two hadrons (considering different combinations of pions and kaons) aiming to investigate the impact of intrinsic and radiative partonic transverse momentum and their mixing with flavor. Different descriptions of the non-perturbative evolution kernel (see, e.g., Refs. [1-5]) are available on the market and there are 200 sets of flavor configurations for the unpolarized TMD fragmentation functions (FFs) resulting from a Monte Carlo fit of Semi-Inclusive Deep-Inelastic Scattering (SIDIS) data at Hermes (see Ref. [6]). We build our predictions of e + e − multiplicities relying on this rich phenomenology. The comparison of these calculations with future experimental data (from Belle and BaBar collaborations) will shed light on non-perturbative aspects of hadron structure, opening important insights into the physics of spin, flavor and momentum structure of hadrons.

We calculate the transverse momentum dependence in the production of two back-to-back hadrons in ... more We calculate the transverse momentum dependence in the production of two back-to-back hadrons in electron-positron annihilations at the medium/large energy scales of Bes-III and Belle experiments. We use the parameters of the transverse-momentumdependent (TMD) fragmentation functions that were recently extracted from the semiinclusive deep-inelastic-scattering multiplicities at low energy from Hermes. TMD evolution is applied according to different approaches and using different parameters for the nonperturbative part of the evolution kernel, thus exploring the sensitivity of our results to these different choices and to the flavor dependence of parton fragmentation functions. We discuss how experimental measurements could discriminate among the various scenarios.

Journal of physics, May 1, 2009

Results for the proton and neutron electric and magnetic form factors as well as the nucleon axia... more Results for the proton and neutron electric and magnetic form factors as well as the nucleon axial form factor are presented for constituent quark models, based on either one-gluon-exchange and Goldstone-boson-exchange dynamics. The calculations are performed in a covariant framework using the point-form approach to relativistic quantum mechanics. The only input to the calculations is the nucleon wave function of the corresponding constituent quark model. A comparison is given to results of the instanton-induced constituent quark model treated with the Bethe-Salpeter equation.

Journal of High Energy Physics, Oct 19, 2022

We present an extraction of unpolarized transverse-momentum-dependent parton distribution and fra... more We present an extraction of unpolarized transverse-momentum-dependent parton distribution and fragmentation functions based on more than two thousand data points from several experiments for two different processes: semi-inclusive deep-inelastic scattering and Drell-Yan production. The baseline analysis is performed using the Monte Carlo replica method and resumming large logarithms at N 3 LL accuracy. The resulting description of the data is very good (χ 2 /N dat = 1.06). For semi-inclusive deep-inelastic scattering, predictions for multiplicities are normalized by factors that cure the discrepancy with data introduced by higher-order perturbative corrections.

arXiv (Cornell University), Nov 2, 2021

arXiv (Cornell University), Jan 25, 2022

We present exploratory studies of the 3D proton tomography through polarized T-odd gluon TMDs at ... more We present exploratory studies of the 3D proton tomography through polarized T-odd gluon TMDs at leading twist, obtained in a spectator-model framework. We embody in our approach a flexible parameterization for the spectator-mass spectral function, suited to catch both small-and moderate-x effects. All these studies are relevant to unveil the gluon dynamics inside hadrons, which represents a core research line of studies at new-generation colliders, such as the Electron-Ion Collider, NICA-SPD, the High-Luminosity LHC, and the Forward Physics Facility.

arXiv (Cornell University), Nov 5, 2021

We present preliminary results on the leading-twist transverse-momentum-dependent (TMD) gluon lin... more We present preliminary results on the leading-twist transverse-momentum-dependent (TMD) gluon linearity function, which is directly connected to nucleon transverse-spin asymmetries originating from the density of linearly-polarized gluons. The function is calculated in a spectatormodel framework for the parent proton and for the-type gauge-link structure. Our work represents a further step toward the definition of a complete set of gluon TMD distributions at twist-2 that can be used to access the gluon dynamics inside nucleons and nuclei at new-generation colliders.

Suplemento de la revista mexicana de física, Jun 8, 2022

We present exploratory studies of the 3D proton tomography through polarized T-odd gluon TMDs at ... more We present exploratory studies of the 3D proton tomography through polarized T-odd gluon TMDs at leading twist, obtained in a spectator-model framework. We embody in our approach a flexible parameterization for the spectator-mass spectral function, suited to catch both small-and moderate-x effects. All these studies are relevant to unveil the gluon dynamics inside hadrons, which represents a core research line of studies at new-generation colliders, such as the Electron-Ion Collider, NICA-SPD, the High-Luminosity LHC, and the Forward Physics Facility.

SciPost physics proceedings, Jul 12, 2022

We present exploratory analyses of the 3D gluon content of the proton via a study of unpolarized ... more We present exploratory analyses of the 3D gluon content of the proton via a study of unpolarized and polarized gluon TMDs at twist-2, calculated in a spectator model for the parent nucleon. Our approach embodies a flexible parametrization for the spectatormass function, suited to describe both moderate and small-x effects. All these studies can serve as a useful guidance in the investigation of the gluon dynamics inside nucleons and nuclei, which constitutes one of the major goals of new-generation colliding machines, as the EIC, the HL-LHC, NICA, and the FPF.

arXiv (Cornell University), Jun 7, 2023

We include strong parity-violating contributions to inclusive deep inelastic scattering (DIS) of ... more We include strong parity-violating contributions to inclusive deep inelastic scattering (DIS) of longitudinally polarized leptons off an unpolarized target. At variance with standard results, we obtain nonvanishing parity-violating structure functions in the case of pure photon exchange. The addition of these strong parity-violating contributions improves the description of existing experimental data on DIS parity-violating asymmetries. We find the size of these contributions small but exhibiting a deviation from zero of about 1.5 σ. The associated p-value is 0.063, indicating that the probability of making an error by rejecting the hypothesis of no parity-violating contributions is 6.3%, which is small but not negligible. Further improvement on the limit of the strong parity-violation can be expected from the future SoLID program at Jefferson Lab.

Physical Review D

We describe the formal analogies in the description of the inclusive production in hard processes... more We describe the formal analogies in the description of the inclusive production in hard processes of hadron pairs (based on dihadron fragmentation functions) and of a single hadron inside a jet (based on hadron-in-jet fragmentation functions). Since several observables involving dihadron fragmentation functions have been proposed in the past, we are able to suggest new interesting observables involving hadron-in-jet fragmentation functions, in lepton-hadron deep-inelastic scattering and hadronic collisions.

Progress in Particle and Nuclear Physics

FIG. 1. The EIC concept at Brookhaven National Laboratory [9]. The electron and the ion beams are... more FIG. 1. The EIC concept at Brookhaven National Laboratory [9]. The electron and the ion beams are clearly identified. There are several beam intersection points, one at the o'clock (IP6) location and at the 8 o'clock (IP8) location are suitable for the installation and operation of large scale detector systems. Interaction point IP8 may be most suitable for high-luminosity optimization at low to intermediate center-of-mass energies as well as for the installation of a secondary focus for forward processes requiring high momentum resolution. The electron beam energy ranges from 2.5 GeV to 18 GeV, while for protons the ion beam allows selected energies between 41 GeV and 275 GeV covering a collision center-mass energy from 20 GeV to 140 GeV. The ion beam is circulating counter clockwise, and the new electron ring with electrons circling clockwise. Both beams will be highly polarized with both electron and proton polarizations greater than 70%. The EIC will benefit from two existing large detector halls in IP6 and in IR8, both fully equipped with infrastructure.

Proceedings of 41st International Conference on High Energy physics — PoS(ICHEP2022), Dec 16, 2022

We present a recent extraction of unpolarised transverse-momentum-dependent (TMD) parton distribu... more We present a recent extraction of unpolarised transverse-momentum-dependent (TMD) parton distribution functions and TMD fragmentation functions from experimental data sets of Semi-Inclusive Deep-Inelastic Scattering, Drell-Yan and Z boson production. The global fit is performed at the N 3 LL logarithmic accuracy and is based on flexible non-perturbative functions, allowing to reach a very good agreement with data

Journal of High Energy Physics

We present an extraction of unpolarized transverse-momentum-dependent parton distribution and fra... more We present an extraction of unpolarized transverse-momentum-dependent parton distribution and fragmentation functions based on more than two thousand data points from several experiments for two different processes: semi-inclusive deep-inelastic scattering and Drell-Yan production. The baseline analysis is performed using the Monte Carlo replica method and resumming large logarithms at N3LL accuracy. The resulting description of the data is very good (χ2/Ndat = 1.06). For semi-inclusive deep-inelastic scattering, predictions for multiplicities are normalized by factors that cure the discrepancy with data introduced by higher-order perturbative corrections.

arXiv (Cornell University), Oct 4, 2022

We map the distribution of unpolarized quarks inside a unpolarized pion as a function of the quar... more We map the distribution of unpolarized quarks inside a unpolarized pion as a function of the quark's transverse momentum, encoded in unpolarized Transverse Momentum Distributions (TMDs). We extract the pion TMDs from available data of unpolarized pion-nucleus Drell-Yan processes, where the cross section is differential in the lepton-pair transverse momentum. In the cross section, pion TMDs are convoluted with nucleon TMDs that we consistently take from our previous studies. We obtain a fairly good agreement with data. We present also predictions for pion-nucleus scattering that is being measured by the COMPASS Collaboration. * The MAP acronym stands for "Multi-dimensional Analyses of Partonic distributions". It refers to a collaboration aimed at studying the three-dimensional structure of hadrons. The public codes released by the collaboration are available at https://github.com/MapCollaboration.

Journal of Instrumentation

ATHENA has been designed as a general purpose detector capable of delivering the full scientific ... more ATHENA has been designed as a general purpose detector capable of delivering the full scientific scope of the Electron-Ion Collider. Careful technology choices provide fine tracking and momentum resolution, high performance electromagnetic and hadronic calorimetry, hadron identification over a wide kinematic range, and near-complete hermeticity. This article describes the detector design and its expected performance in the most relevant physics channels. It includes an evaluation of detector technology choices, the technical challenges to realizing the detector and the R&D required to meet those challenges.