Search

Laser Ranging is a technique used to perform accurate precision distance measurements between a laser ground station and an optical target, a Cube Corner Retroreflector (CCR). Since 1969 it is possible to realize Lunar Laser Ranging (LLR) measurements thanks to Apollo and Luna missions that placed some arrays of CCRs on the lunar surface. LLR outputs include accurate tests of General Relativity, information of the composition of the Moon, its ephemerides and its internal structure or geocentric positions and motions of ground stations: research uniquely enabled by the Moon. Despite laser ground stations have significantly improved during the years, the current limitation of the lunar optical target is due to lunar librations. In order to achieve more precise LLR measurements, MoonLIGHT project is designed by SCF_Lab joined UMD. The aim of the project is designing a next-generation of retroreflectors, prototyping, manufacturing and qualify them for the Moon’s environment. Moving from a multi small CCRs array to a single large 100 mm CCR, called MoonLIGHT, unaffected by the lunar librations. The field of view of each CCR is limited: the retroreflector needs to be pointed precisely to the ground station. The Apollo CCR arrays were manually arranged by the astronauts. In 2018 INFN proposed to ESA the MoonLIGHT Pointing Actuators (MPAc) project, able to perform unmanned pointing operation of MoonLIGHT. In 2019 ESA chose MPAc among 135 eligible scientific project proposals. In 2021 ESA agreed with NASA to launch MPAc to the Reiner Gamma region of the Moon, with a Commercial Lunar Payload Services (CLPS), which is part of the Artemis program. The lander on which MPAc will be integrated is designed by Intuitive Machines (IM). The launch expected date is in April 2024. MPAc must be able to perform two continuous perpendicular rotations to accurately point the frontal face of the CCR towards the Earth. The device is continuously evolving to ensure the success of the mission, that will take place in Ultra High Vacuum space conditions, in a wide operating temperature range. Terrestrial prototypes, with all the characteristics of the final structure, have been developed for the study of mechanical and electronics components. Qualification tests for space are being planned as the components for the Proto Flight Model (PFM) arrived to the LNF. Payload delivery is scheduled for August 2023. MPAc will contribute to attain lunar orbit range accuracy below few mm. This will improve, in turn, the precision of the Parametrized Post-Newtonian (PPN) parameters and put more stringent constraints on departures from GR predictions with observations.

We study electromagnetic properties of particles with magnetic moment and no charge using their behavior when traversing coils and solenoids. These particles via the Faraday-Lenz law create a current whose energy we calculate. We analyze both the case of very long lived, almost stable, particles and those with a finite lifetime. We use this development to study the behavior of monopolium a monopole-antimonopole bound state in its excited states., 21 pages and 16 figures. arXiv admin note: substantial text overlap with arXiv:2110.02646

Objectives Aim of the present paper is the study of the large unreported component, characterizing the SARS-CoV-2 epidemic event in Italy, taking advantage of the Istat survey. Particular attention is devoted to the sensitivity and specificity of the serological test and their effects. Methods The model satisfactory reproduces the data of the Italian survey showing a relevant predictive power and relegating in a secondary position models which do not include, in the simulation, the presence of asymptomatic groups. The corrections due to the serological test sensitivity (in particular those ones depending on the symptoms onset) are crucial for a realistic analysis of the unreported (and asymptomatic) components. Results The relevant presence of an unreported component during the second pandemic wave in Italy is confirmed and the ratio of reported to unreported cases is predicted to be roughly 1:4 in the last months of year 2020. A method to correct the serological data on the basis of the antibody sensitivity is suggested and systematically applied. The asymptomatic component is also studied in some detail and its amount quantified. A model analyses of the vaccination scenarios is performed confirming the relevance of a massive campaign (at least 80000 immunized per day) during the first six months of the year 2021, to obtain important immunization effects within August/September 2021.

objectivesAugust 3rd, 2020, the Italian National Institute of Statistics (ISTAT) presented preliminary results of seroprevalence survey on the percentage of individuals affected by Covid-19. The survey aims to define (within the entire population of Italy) the portion of individuals that developed an antibody response against SARS-CoV-2. For the first time one has an estimate of the asymptomatic infected population and the possibility to acknowledge its potential rôle in the infection spread in Italy, one of the most affected areas in Europe. The information obtained allow a particularly sensitive validation of epidemiological models which include the asymptomatic class.methodsThe present study is devoted to the construction of a model able to simulate, in a systematic way, the asymptomatic group whose relevance in the, SARS-CoV-2 epidemic, has been recently investigated and discussed. The investigation involves the description of the first epidemic outbreak in Italy as well as the predictive analysis of the ongoing second wave. In particular the possible correction to the data of the serological tests because of their sensitivity and specificity.resultsThe model: taken as an example of the models presently used, satisfactory reproduces the data of the ISTAT survey showing a relevant predictive power and relegating in a secondary position models which do not include, in the simulation, the presence of asymptomatic groups. The corrections due to the serological test sensitivity (in particular those ones depending on the symptoms onset) make the comparison between data and models less accurate.conclusionsThe predictions of the model confirm a relevant presence of asymptomatic individuals also during the second pandemic wave in Italy. The ratio of reported to unreported cases is predicted to be roughly 1:4. A more detailed knowledge of the results of the survey could allow to correct, in a relevant way, the data by means of the experimental evidences on the antibodies sensibility. The model analyses of the vaccination strategies, confirms the relevance of a massive administration with the beginning of the year to arrive at the end of the infection within August 2021.

BackgroundThe outbreak of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has led to 101739 confirmed cases, in Italy, as of March 30th, 2020. While the analogous event in China appears to be under control at the moment, the outbreaks in western countries are still at an early stage of development. Italy, at present, is playing a major role in understanding the transmission dynamics of these new infections and evaluating the effectiveness of control measures in a western social context.MethodsWe combined a quarantined model with early-stage development data in Italy (during the period February 20th - March 30th) to predict longer-term progression (up to March 30th, and till June 25th, 2020 in a longterm view) with different control measures. Due to significant variations in the control strategies, which have been changing over time, and thanks to the introduction of detection technologies leading to faster confirmation of the SARS-CoV-2 infections, we made use of time-dependent contact and diagnosis rates to estimate when the effective daily reproduction ratio can fall below 1. Within the same framework, we analyze the possible secondary infection event after relaxing the isolation measures.Outcomes and interpretationWe study two simplified scenarios compatible with the observation data and the effects of two stringent measures on the evolution of the epidemic. On one side, the contact rate must be kept as low as possible, but it is also clear that, in a modern developed country, it cannot fall under certain minimum levels and for a long time. The complementary parameter tuned is the transition rate of the symptomatic infected individuals to the quarantined class, a parameter δI connected with the time tI = 1/δI needed to perform diagnostic tests. Within the conditions of the outbreak in Italy, this time must fall under 12-8 hours in order to make the reproduction number less than 1 to minimize the case numbers. Moreover, we show how the same parameter plays an even more important role in mitigating the effects of a possible secondary infection event.FundingNo funding has been provided by private or public actors beyond the current clinical practice (National Health Service).

An analysis of the time evolution of the 2019-nCoV outbreak event in Italy is proposed and is based on the preliminary data at disposal (till March 11th, 2020) on one side, and on an epidemiological model recently used to describe the same epidemic event in the Wuhan region (February 2020) on the other side. The equations of the model include the description of compartments like Susceptible (S), exposed (E), infectious but not yet symptomatic (pre-symptomatic) (A), infectious with symptoms (I), hospitalized (H) and recovered (R). Further stratification includes quarantined susceptible (Sq), isolated exposed (Eq) and isolated infected (Iq) compartments. The equations are numerically solved for boundary (initial) conditions tuned on the Italian event. The rôle of quarantine is specifically emphasized and supports the strategies adopted providing a numerical description of the effects.

The Large Hadron Collider is reaching energies never achieved before allowing the search for exotic particles in the TeV mass range. In a continuing effort to find monopoles we discuss the effect of the magnetic dipole field created by a pair of monopole-anti-monopole or monopolium on the successive bunches of charged particles in the beam at LHC., 14 pages, 11 figures

Fluctuations play an important role in diffractive production of vector mesons. It was in particular recently suggested, based on the Impact-Parameter dependent Saturation model (IPSat), that geometrical fluctuations triggered by the motion of the constituent quarks within the protons could explain incoherent diffractive processes observed at HERA. We propose a variant of the IPSat model which includes spatial and symmetry correlations between constituent quarks, thereby reducing the number of parameters needed to describe diffractive vector meson production to a single one, the size of the gluon cloud around each valence quark. The application to $J/\Psi$, $\rho$ and $\phi$ diffractive electron and photon production cross sections reveal the important role of geometrical fluctuations in incoherent channels, while other sources of fluctuations are needed to fully account for electroproduction of light mesons, as well as photo production of $J/\Psi$ mesons at small momentum transfer., Comment: 17 pages, 15 figures, major revision, title changed, new sections included , figures added to discuss vector meson electroproduction, new references, version accepted for publication in EPJ C

Double parton scattering, occurring in high energy hadron-hadron collisions, e.g. at the LHC, is usually investigated through model dependent analyses of the so called effective cross section $\sigma_{eff}$. We present a dynamic approach to this fundamental quantity making use of a Light-Front model treatment. Within such a framework $\sigma_{eff}$ is initially evaluated at low energy scale using the model and then, through QCD evolution, at high energy scale to reach the experimental conditions. Our numerical outcomes are consistent with the present experimental analyses of data in kinematical region we investigate. An important result of the present work is the $x_i$ dependence of $\sigma_{eff}$, a feature directly connected to double parton correlations and which could unveil new information on the three dimensional structure of the proton., Comment: 5 pages, 2 figures, invited talk at the Conference "Light-Cone 2015", 21-25 September 2015, Frascati, Italy; Few-Body Systems, in press

Two-parton correlations in the pion are investigated in terms of double parton distribution functions. A Poincar\'e covariant Light-Front framework has been adopted. As non perturbative input, the pion wave function obtained within the so-called soft-wall AdS/QCD model has been used. Results show how novel dynamical information on the structure of the pion, not accessible through one-body parton distribution, are encoded in double parton distribution functions., Comment: 14 pages, 8 figures

Double parton distribution functions (dPDF), accessible in high energy proton-proton and proton nucleus collisions, encode information on how partons inside a proton are correlated among each other and could represent a tool to explore the 3D proton structure. In recent papers, double parton correlations have been studied in the valence quark region, by means of constituent quark models. This framework allows to understand clearly the dynamical origin of the correlations and to establish which, among the features of the results, are model independent. Recent relevant results, obtained in a relativistic light-front scheme, able to overcome some drawbacks of previous calculations, such as the poor support, will be presented. Peculiar transverse momentum correlations, generated by the correct treatment of the boosts, are obtained. The role of spin correlations will be also shown. In this covariant approach, the symmetries of the dPDFs are unambiguously reproduced. The study of the QCD evolution of the model results has been performed in the valence sector, showing that, in some cases, the effect of evolution does not cancel that of correlations., Comment: 6 pages, 3 figures, invited talk at the Conference "Light Cone 2014 (LC2014)", Raleigh, North Carolina, May 26-30, 2014. Submitted to Few-Body Systems

Generalized Parton Distributions are investigated within a holographic approach where the string modes in the fifth dimension describe the nucleon in a bottom-up or AdS/QCD framework. The aim is to bring the AdS/QCD results in the realm of phenomenology in order to extract consequences and previsions. Two main aspects are studied: i) the role of the confining potential needed for breaking conformal invariance and introducing confinement (both: classic Soft-Wall and recent Infra-Red potentials are investigated); ii) the extension of the predicted GPDs to the entire range of off-forward kinematics by means of Double-Distributions. Higher Fock states are included describing the nucleon as a superposition of three valence quarks and quark-antiquark pairs and gluons., 16 pages, 11 figures, major revision, title changed, new sections included, figures added, new references, version accepted for publication in EPJ C

The correct description of Double Parton Scattering (DPS), which represents a background in several channels for the search of new Physics at the LHC, requires the knowledge of double parton distribution functions (dPDFs). These quantities represent also a novel tool for the study of the three-dimensional nucleon structure, complementary to the possibilities offered by electromagnetic probes. In this paper we analyze dPDFs using Poincar\'e covariant predictions obtained by using a Light-Front constituent quark model proposed in a recent paper, and QCD evolution. We study to what extent factorized expressions for dPDFs, which neglect, at least in part, two-parton correlations, can be used. We show that they fail in reproducing the calculated dPDFs, in particular in the valence region. Actually measurable processes at existing facilities occur at low longitudinal momenta of the interacting partons; to have contact with these processes we have analyzed correlations between pairs of partons of different kind, finding that, in some cases, they are strongly suppressed at low longitudinal momenta, while for other distributions they can be sizeable. For example, the effect of gluon-gluon correlations can be as large as 20 $\%$. We have shown that these behaviors can be understood in terms of a delicate interference of non-perturbative correlations, generated by the dynamics of the model, and perturbative ones, generated by the model independent evolution procedure. Our analysis shows that at LHC kinematics two-parton correlations can be relevant in DPS, and therefore we address the possibility to study them experimentally., Comment: 34 pages, 20 figures

Charge and isospin symmetry violations to valence and sea distribution functions in the nucleon are evaluated (at low resolution scale) by means of a meson cloud model and light-cone quark wave functions. Their perturbative evolution are implemented at Next-to-next-to-leading order (NNLO) using an original evolution code in order to include the perturbatively generated strange - anti-strange asymmetry typical of the three loop evolution expansion. Charge symmetry violating QED effects are also added and the distributions, evolved at the experimental scale, are compared with available information. The role of non-perturbative effects is emphasized in the interpretation of the, so called, NuTeV anomaly and new experiments at very-high energy., Comment: revtex4, 7 pages, 3 figures; text improved, new comments and references

An explicit evaluation of the double parton distribution functions (dPDFs), within a relativistic Light-Front approach to constituent quark models, is presented. dPDFs encode information on the correlations between two partons inside a target and represent the non-perturbative QCD ingredient for the description of double parton scattering in proton-proton collisions, a crucial issue in the search of new Physics at the LHC. Valence dPDFs are evaluated at the low scale of the model and the perturbative scale of the experiments is reached by means of QCD evolution. The present results show that the strong correlation effects present at the scale of the model are still sizable, in the valence region, at the experimental scale. At the low values of x presently studied at the LHC the correlations become less relevant, although they are still important for the spin-dependent contributions to unpolarized proton scattering., Comment: 21 pages, 11 figures. Minor revisions. References added. Final version accepted for publication in JHEP

Helicity-dependent generalized parton distributions of the nucleon are derived from the overlap representation of generalized parton distributions using light-cone wave functions obtained in constituent quark models. Results from two different quark models are used also to study the angular momentum sum rule and the spin asymmetry in polarized electron scattering., 20 pages, 5 figures, 2 tables

The link between the nucleon generalized parton distributions and the non-diagonal one-body density matrix in momentum space is studied. Attention is focussed on the region where quark generalized parton distributions (GPD's) describe emission and reabsorption of a single active quark by the target nucleon. The correct covariant connection with wave functions used in any constituent quark model is established. Results obtained with different constituent quark models are presented for the unpolarized quark GPD's., Comment: 2 new figures included and references added, conclusions unchanged. Version to appear in Nucl. Phys. B

Generalized parton distributions (GPDs) are studied at the hadronic (nonperturbative) scale within different assumptions based on a relativistic constituent quark model. In particular, by means of a meson-cloud model we investigate the role of nonperturbative antiquark degrees of freedom and the valence quark contribution. A QCD evolution of the obtained GPDs is used to add perturbative effects and to investigate the GPDs' sensitivity to the nonperturbative ingredients of the calculation at larger (experimental) scale., Comment: 17 pages, 10 figures; submitted to Phys. Rev. D

A detailed study of nucleon parton distribution functions is performed within a radiative next-to-next-to-leading-order (NNLO) parton model whose low-scale input is rigidly described by wave functions which include quarks and dressing a meson cloud. The light-front Hamiltonian dynamics fixes the three-quark wave functions, and the meson cloud is introduced by means of high-order Fock components in time-ordered perturbation theory in the infinite momentum frame. Nonstrange as well as strange meson-baryon fluctuations are considered ($\ensuremath{\pi}$, $\ensuremath{\rho}$, $\ensuremath{\omega}$, $K$, and ${K}^{*}$, together with $N$, $\mathrm{\ensuremath{\Delta}}$, $\mathrm{\ensuremath{\Lambda}}$, and $\mathrm{\ensuremath{\Sigma}}$) and the effects on strange and nonstrange parton distributions investigated showing the large effects due to (nonstrange) sea asymmetries and the delicate balance of the strange asymmetry. The nonstrange and the strange components, the valence as well as the gluon distributions, are compared with available experimental data confirming the need of both nonperturbative degrees of freedom and perturbative (NNLO) radiative effects.

The role of the effective momentum approximation to disentangle Coulomb distortion effects in quasielastic $(e,e')$ reactions is investigated. The separation of the cross section in longitudinal and transverse components is discussed including higher order DWBA corrections due to the focusing of the electron waves.The experimental studies performed, in the last few years, making use of different approximate treatments are shown to be sometime inconsistent. As a consequence some of the longitudinal and transverse responses, extracted from the inclusive cross sections cannot be considered reliable. A separation procedure based on the effective momentum approximation is discussed in connection with the recent experimental data on electron/positron quasielastic scattering on $^{12}$C and $^{208}$Pb., Comment: latex, no figures, submitted to Nucl. Phys. A

We show that a light-front covariant treatment of the spin in the nucleon gives rise to significant differences between transverse and longitudinal polarized parton distributions at low energies. These differences survive evolution to higher Q2 scales and the importance of these relativistic spin effects can be assessed by measuring double-spin asymmetries in lepton pair production in polarized hadron-hadron collisions.

We study the response of the nucleon, as a system of three bound (constituent) non relativistic quarks, to external (quasi static) electric and magnetic fields. The approach, based on a sum rule technique, is applied to a large class of two and three-body interquark potentials. Lower and upper bounds to the electric polarizability and para-magnetic susceptibility are explicitly calculated within a large variety of constituent models and their values related to the features of the interquark interaction picture. The r\^ole of three-body forces is investigated in details as well as the effects of SU(6) breaking terms in the potential model. Our results can be used to extract the mesonic contributions to the static polarizabilty and susceptibility. The quark degrees of freedom give a quite sizeable contributions to both and the meson cloud accounts roughly for 30% and 60% of the electric proton and neutron polarizability respectively. The quark contribution to the paramagnetic susceptibility is even higher and the mesonic effects are rather uncertain., Comment: 21 pages, no figures, LaTEX

Dispersive effects have been investigated by comparing elastic scattering of electrons and positrons from {sup 12}C at the Saclay Linear Accelerator. The results demonstrate that dispersive effects at energies of 262 MeV and 450 MeV are less than 2% below the first diffraction minimum [0.95 < q{sub eff} (fm{sup -1}) < 1.66] in agreement with the prediction of Friar and Rosen. At the position of this minimum (q{sub eff} = 1.84 fm{sup -1}), the deviation between the positron scattering cross section and the cross section derived from the electron results is -44% {+-} 30%.

Using a simple picture of the constituent quark as a composite system of point-like partons, we construct the parton distributions by a convolution between constituent quark momentum distributions and constituent quark structure functions. We evaluate the latter at a low hadronic scale with updated phenomenological information, and we build the momentum distributions using well-known quark models. The resulting parton distributions and structure functions are evolved to the experimental scale and good agreement with the available DIS data is achieved. When compared with a similar calculation using non-composite constituent quarks, the accord with experiment of the present calculation becomes impressive. We therefore conclude that DIS data are consistent with a low energy scenario dominated by composite, mainly non-relativistic constituents of the nucleon., 13 pages; latex; 5 postscript figures included in submission

We propose a quark model description of the nucleon which includes, in a unified picture, valence quarks and a core of q q pairs and gluons at the hadronic (non-perturbative) scale. The resulting parton distributions are evolved to high ¢Q 2 by means of an appropriate next-to-leading order evolution and compared with the data. The procedure is carried out for several, rather different, quark model pictures to analyze the model dependence. We conclude that there is not a smooth transition between the degrees of freedom of low-energy nuclear physics (baryons and mesons) and a description in terms of quarks and gluons.

We perform a next-to-leading order study of polarized parton distributions as predicted by quark models. The approach allows a detailed investigation of the anomalous contributions as well as angular momentum effects of the partons. Higher-order effects are large in the region 0.01 ⩽ x ⩽ 0.2, where also the introduction of gluon polarization at the hadronic scale plays a crucial role.

The high energy parton distribution when evolved to a low energy scale appears to indicate that a valence picture of hadron structure arises. We have developed a formalism based on a laboratory partonic description which connects the parton distributions with the momentum distributions of a quark model. The formalism uses Next to Leading Order evolution and has been defined to produce the right support for the parton distributions. In this scheme we have analyzed the polarized and unpolarized data and shown that well-known Quark Models lead to a qualitative description of the data. However, if one aims at a quantitative agreement, these conventional low energy models have to be changed to include higher momentum and angular momentum components. Moreover, if the present gluon distributions, despite their indirect extraction, are taken to be an accurate description of nature, the need of primordial gluons or constituent quark substructure is an outcome of our calculation.

Bjorken scaling is violetd. At large $x$-values ($0.7 \lesssim x \leq 1$) the violation is mainly attributed to $\propto 1/Q^2$ (higher-twist) corrections. We discuss how to incorporate such corrections by using a new scaling variable $\bar x(x,Q^2)$ which accounts for the non-perturbative effects due to the confining parton interaction in the final state. The approach can accomodate also the remaining QCD logarithmic corrections and the behaviour of the $F_2(x,Q^2)$ structure functions is reproduced, in a quite natural way, within a wide kinematical range., 10 pages, 5 figures

The sum rule technique is introduced in the context of the interaction of atoms with electromagnetic radiation and is used to study rigorous bounds to the electric dipole polarizability of the hydrogen atom. Riassunto. La tecnica delle regole di somma viene introdotta nel contesto dell'interazione degli atomi con la radiazione elettromagnetica ed utilizzata per studiare dei limiti rigorosi per la polarizzabilia elettrica di dipolo dell'atomo di idrogeno.

We use a laboratory frame description based on quark model wave functions to study the parton distributions in the nucleon. The present approach incorporates two major improvements, namely, it has the correct support and the renormalization group evolution is carried out to next-to-leading order. We obtain initially the parton distributions arising from the Isgur-Karl wave function. The failure of the latter to reproduce, even approximately, the data motivates us to analyze different scenarios, i.e. additional high momentum components and nonvanishing gluon distributions at the initial scale. We conclude that in order to understand data at various scales complex models simultaneously, it is necessary to include high momentum components and/or valence gluons.

The inclusive quasi-elastic electron scattering off16O,40Ar,208Pb and238U is studied including the distortion of the incoming and outgoing electron wave due to Coulomb interaction with the nuclear charge. The total cross-section, containing a new term due to the interference between the longitudinal and transverse structure functions, is discussed within the impulse approximation where final-state interaction and binding effects are included by using sum rules techniques. The quasi-elastic scattering induced by positrons is also investigated.

A systematic study of the polarized-parton distributions is presented and related to the properties of the constituent quarks. The effects of breaking SU(6) symmetry are emphasized and the Isgur-Karl constituent model is discussed in detail. The results on the proton, neutron and deuteron structure functions are compared with the recent experimental data, and the role of the gluon polarization is pointed out. The role of the D-state admixture in the nucleon ground state is also investigated.

The utility of ([ital e],[ital e][prime][ital d]) reactions in providing information about dynamical correlations in nuclei is discussed. The breakup of [sup 4]He into two deuterons is taken as a model case. We show how two-nucleon dynamics of both short range and tensor nature affects the ([ital e],[ital e][prime][ital d]) cross section in different kinematical regions. The role of final state interactions is also discussed. Within our model, kinematical conditions can be chosen to emphasize the sensitivity to a particular aspect of the ground state dynamics thereby suggesting promoting avenues for experiment.

Longitudinal and transverse response functions, R L and R T , have been obtained in inclusive quasi-elastic electron scattering from 4 He and 208 Pb, for momentum transfers between 300 and 650 MeV/ c and energy transfers up to 350 MeV. A quenching of R L , ∼ 14% in 4 He and ∼ 50% in 208 Pb has been observed. Interpretations in terms of correlations and modification of nucleon form factors in the nuclear medium are discussed.

A study of deep inelastic electron-nucleus scattering is presented. The approach assumes that the non-perturbative component of the parton distributions can be approximated by constituent quark model wave functions for both free and bound nucleons. The perturbative contribution is evaluated by using the renormalization group evolution equations. Results are obtained for a large class of nuclei and the effects of conventional short-range nuclear dynamics included in the discussion. The dynamically generated sea and gluon content of the nucleus is investigated and rescaling and change in confinement scale are discussed in connection with the evolution procedure. Results in the regionx>1 are also presented.

We study the link between the constituent quark masses and the parton distributions extracted from high-energy deep inelastic lepton-nucleon scattering. To this end the valence distributions at low-resolution scale are evaluated within a constituent quark model while the solution of the QCD evolution equations is discussed in terms of an effective-quark-mass approximation. The results are compared with the experimental data and the influence of the one-gluon-exchange mechanism discussed.

We study the effects of final state rescattering on the cross section for the 4 He(e, eD)D reaction. We find that for the kinematicla region in which there exists published data these effects are especially important for the L =0 and L =2 partial waves. The L =0 rescattering is mainly important for ensuring orthogonality thereby giving the cross section the correct low q -dependence. We show that reasonable models of the rescattering bring the calculated cross section much closer to experiment than previous published calculations. Transverse current contributions to the cross section are also discussed.

The Coulomb sum rule is evaluated for a large class of nuclei up to the heavy ones. Beyond mean-field effects, short-range correlations are taken into account. The latter decrease the sum rule in the whole considered momentum range. The size of the reduction increases with the average proton density reaching its maximum for medium heavy nuclei.

The momentum distributions of constituent quarks in nucleons are studied within the framework of non-relativistic quark models for baryons. The corrections due to one-gluon-exchange effects are discussed comparing different quark-quark potential approximations. Applications to deep inelastic lepton-nucleon scattering are discussed within a quark-parton model in the laboratory frame.

The nucleon momentum distribution is studied with particular emphasis on heavy nuclei. The effects of both the mean-field and short-range correlations are discussed. The latter are included using a method based on the local density approximation. A systematic comparison with the predictions of other theoretical approaches is presented.

We use the interacting instanton liquid model (IILM) as a tool to study the role played by the chiral interactions in the lowest-lying vector and axial-vector meson resonances. We find that narrow a{sub 1} and {rho} meson resonances can be generated by instanton-induced chiral forces, even in the absence of confinement. In the IILM, these hadrons are found to have masses only about 30% larger than the experimental value and small width < or approx. 10-50 MeV. This result suggests that chiral interactions are very important in these systems and provide most of their mass. We explore the decaying patterns of the {rho} meson, in the absence of confinement. We argue that, in our model where only chiral forces are switched on, this meson decays dissociating into its quark-antiquark constituents.

Double parton distribution functions (dPDF) represent a tool to explore the 3D proton structure. They can be measured in high energy proton-proton and proton nucleus collisions and encode information on how partons inside a proton are correlated among each other. dPFDs are studied here in the valence quark region, by means of a constituent quark model, where two particle correlations are present without any additional prescription. This framework allows to understand the dynamical origin of the correlations and to clarify which, among the features of the results, are model independent. Use will be made of a relativistic light-front scheme, able to overcome some drawbacks of the previous calculation. Transverse momentum correlations, due to the exact treatment of the boosts, are predicted and analyzed. The role of spin correlations is also shown. Due to the covariance of the approach, some symmetries of the dPDFs are seen unambigously. For the valence sector, the study of the QCD evolution of the model results, which can be performed safely thanks to the property of good support, has been also completed., 8 pages, 12 figures, invited talk at the "XLIV ISMD Conference", Bologna, Italy, 8-12 September 2014. Submitted to EPJ Web of Conferences