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Author |
Courtoy, A.; Scopetta, S.; Vento, V. |
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Title |
Non-perturbative momentum dependence of the coupling constant and hadronic models |
Type |
Journal Article |
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Year |
2011 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
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Volume |
47 |
Issue |
4 |
Pages |
49 - 7pp |
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Keywords  |
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Abstract |
Models of hadron structure are associated with a hadronic scale which allows by perturbative evolution to calculate observables in the deep inelastic region. The resolution of Dyson-Schwinger equations leads to the freezing of the QCD running coupling (effective charge) in the infrared, which is best understood as a dynamical generation of a gluon mass function, giving rise to a momentum dependence which is free from infrared divergences. We use this new development to understand why perturbative treatments are working reasonably well despite the smallness of the hadronic scale. |
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Address |
[Courtoy, A.] Ist Nazl Fis Nucl, Sez Pavia, I-27100 Pavia, Italy, Email: Aurore.Courtoy@pv.infn.it |
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Thesis |
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Publisher |
Springer |
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Language |
English |
Summary Language |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1434-6001 |
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Notes |
ISI:000291659500003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
657 |
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Author |
Noguera, S.; Scopetta, S. |
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Title |
Eta-photon transition form factor |
Type |
Journal Article |
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Year |
2012 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
85 |
Issue |
5 |
Pages |
054004 - 12pp |
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Keywords |
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Abstract |
The eta-photon transition form factor is evaluated in a formalism based on a phenomenological description at low values of the photon virtuality, and a QCD-based description at high photon virtualities, matching at a scale Q(0)(2). The high photon virtuality description makes use of a distribution amplitude calculated in the Nambu-Jona-Lasinio model with Pauli-Villars regularization at the matching scale Q(0)(2), and QCD evolution from Q(0)(2) to higher values of Q(2). A good description of the available data is obtained. The analysis indicates that the recent data from the BABAR collaboration on pion and eta transition form factor can be well reproduced, if a small contribution of higher twist is added to the dominant twist-two contribution at the matching scale Q(0)(2). |
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Address |
[Noguera, S.] Univ Valencia, CSIC, Dept Fis Teor, E-46100 Burjassot, Spain, Email: Santiago.Noguera@uv.es |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1550-7998 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000300972300001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
924 |
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Author |
Rinaldi, M.; Scopetta, S.; Vento, V. |
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Title |
Double parton correlations in constituent quark models |
Type |
Journal Article |
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Year |
2013 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
87 |
Issue |
11 |
Pages |
114021 - 9pp |
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Keywords |
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Abstract |
Double parton correlations, having effects on the double parton scattering processes occurring in high-energy hadron-hadron collisions, for example at the LHC, are studied in the valence quark region by means of constituent quark models. In this framework, two particle correlations are present without any additional prescription, at variance with what happens, for example, in independent particle models, such as the MIT bag model in its simplest version. From the present analysis, conclusions similar to the ones obtained recently in a modified version of the bag model can be drawn: correlations in the longitudinal momenta of the active quarks are found to be sizable, while those in transverse momentum are much smaller. However, the framework used allows us to understand clearly the dynamical origin of the correlations. In particular, it is shown that the small size of the correlations in transverse momentum is a model-dependent result, which would not occur if models with sizable quark orbital angular momentum were used to describe the proton. Our analysis permits us, therefore, to clarify the dynamical origin of the double parton correlations and to establish which, among the features of the results, are model independent. The possibility of testing the studied effects experimentally is discussed. |
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Address |
[Rinaldi, M.; Scopetta, S.] Univ Perugia, Dipartimento Fis, I-06100 Perugia, Italy, Email: matteo.rinaldi@pg.infn.it; |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1550-7998 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000321001100004 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1509 |
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Author |
Gomez Dumm, D.; Noguera, S.; Scoccola, N.N.; Scopetta, S. |
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Title |
Pion distribution amplitude and the pion-photon transition form factor in a nonlocal chiral quark model |
Type |
Journal Article |
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Year |
2014 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
89 |
Issue |
5 |
Pages |
054031 - 14pp |
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Keywords |
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Abstract |
We study the pion distribution amplitude (pi DA) in the context of a nonlocal chiral quark model. The corresponding Lagrangian reproduces the phenomenological values of the pion mass and decay constant, as well as the momentum dependence of the quark propagator obtained in lattice calculations. It is found that the obtained pi DA has two symmetric maxima, which arise from the new contributions generated by the nonlocal character of the interactions. This pi DA is applied to leading order and next-to-leading order calculations of the pion-photon transition form factor. Implications of the results are discussed. |
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Address |
[Gomez Dumm, D.] Univ Nacl La Plata, CONICET, IFLP, Dept Fis, RA-1900 La Plata, Argentina |
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Corporate Author |
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Thesis |
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Publisher |
Amer Physical Soc |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
1550-7998 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000334304700006 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
1775 |
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Author |
Rinaldi, M.; Scopetta, S.; Traini, M.; Vento, V. |
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Title |
Double Parton Distributions in Light-Front Constituent Quark Models |
Type |
Journal Article |
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Year |
2015 |
Publication |
Few-Body Systems |
Abbreviated Journal |
Few-Body Syst. |
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Volume |
56 |
Issue |
6-9 |
Pages |
515-521 |
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Keywords |
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Abstract |
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. |
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Address |
[Rinaldi, Matteo; Scopetta, Sergio] Univ Perugia, Dipartimento Fis & Geol, I-06100 Perugia, Italy, Email: matteo.rinaldi@pg.infn.it |
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Corporate Author |
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Thesis |
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Publisher |
Springer Wien |
Place of Publication |
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Editor |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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Series Title |
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Abbreviated Series Title |
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Series Volume |
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Series Issue |
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Edition |
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ISSN |
0177-7963 |
ISBN |
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Medium |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000360435800042 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
2370 |
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