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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.

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).

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

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

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

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

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

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.

In this presentation we review our recent attempt to address two questions concerning dynamical correlations inside the nucleon: (i) is the non-perturbative quark-quark interaction particularly attractive in the color antitriplet 0+ diquark channel? (ii) are such correlations induced by instantons? We define appropriate ratios of Euclidean three-point functions which encode specific information about two-body correlations and can be computed on the lattice. We analyze such correlations functions in different models with very different diquark content: a naive non-relativistic SU(6) quark model, the Random Instanton Liquid Model and the Quark Chiral Soliton Model. We show that such models lead to radically different predictions. We conclude that a lattice QCD calculation of such correlation functions can determine which picture is most realistic.

This work is devoted to the study of diquark correlations inside the nucleon. We analyze some matrix elements which encode information about the non-perturbative forces, in different color anti-triplet diquark channels. We suggest a lattice calculation to check the quark-diquark picture and clarify the role of instanton-mediated interactions. We study in detail the physical properties of the 0+ diquark, using the Random Instanton Liquid Model. We find that instanton forces are sufficiently strong to form a diquark bound-state, with a mass of ~500 MeV, which is compatible with earlier estimates. We also compute its electro-magnetic form factor and find that the diquark is a broad object, with a size comparable with that of the proton., Final version, accepted for publication on Phys. Rev. D

I report on the research activities performed under the (italian) MURST-PRIN project "Fisica Teorica del Nucleo e dei sistemi a pi\'u corpi" covering part of the topics on hadronic degrees of freedom. The most recent achievements in the field are summarized focusing on the specific role of the nuclear physics community., Comment: To appear in the Proceedings of 8th Convegno su Problemi di Fisica Nucleare Teorica (Cortona 2000), Cortona, Italy, 18-21 Oct. 2000, uses ws-p8-50x6-00.cls

Modifications to the nucleon electric polarizability induced by pion and sigma exchange in the q-q potentials are studied by means of sum rule techniques within a non-relativistic quark model. Contributions from meson exchange interactions are found to be small and in general reduce the quark core polarizability for a number of hybrid and one-boson-exchange q-q models. These results can be explained by the constraints that the baryonic spectrum impose on the short range behavior of the mesonic interactions., 11 pages, 1 figure added, expanded discussion

Using a simple picture of the constituent quark as a composite system of point-like partons, we construct the polarized parton distributions by a convolution between constituent quark momentum distributions and constituent quark structure functions. Using unpolarized data to fix the parameters we achieve good agreement with the polarization experiments for the proton, while not so for the neutron. By relaxing our assumptions for the sea distributions, we define new quark functions for the polarized case, which reproduce well the proton data and are in better agreement with the neutron data. When our results are compared with similar calculations using non-composite constituent quarks the accord with the experiments of the present scheme is impressive. We conclude that, also in the polarized case, DIS data are consistent with a low energy scenario dominated by composite constituents of the nucleon., 18 pages; latex; 4 ps figures. Final version to appear in Phys. Lett. B; discussion about the polarized sea slightly changed

Sum rule techniques are used to predict average excitation energy and total capture rates for inclusive radiative pion and muon capture in N = Z nuclei. The processes under consideration are shown to exhibit different excitation features because of the strong dependence on the orbit of the captured particle. Results are given for 16 O and 40 Ca. A semi-quantitative agreement with experimental data is found, amenable to the approximations in the treatment of nuclear dynamics.