| Records |
| Author |
Noguera, S.; Vento, V. |
| Title |
The pion transition form factor and the pion distribution amplitude |
Type |
Journal Article |
| Year |
2010 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
| Volume |
46 |
Issue |
2 |
Pages |
197-205 |
Keywords  |
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| Abstract |
Recent BaBar data on the pion transition form factor, whose Q(2)-dependence is much steeper then predicted by asymptotic Quantum Chromodynamics (QCD), have caused a renewed interest in its theoretical description. We present here a formalism based on a model-independent description for low photon virtuality and a high photon virtuality description based on QCD, which match at a scale Q(0). The high photon virtuality description incorporates a flat pion distribution amplitude, phi(x) = 1, at the matching scale Q(0) and QCD evolution from Q(0) to Q > Q(0). The flat pion distribution is connected, through soft pion theorems and chiral symmetry, to the pion valence parton distribution at the same low scale Q(0). The procedure leads to a good description of the data, and by incorporating additional twist-three effects, to an excellent description of the data. |
| Address |
[Noguera, S.] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Valencia, Spain, Email: Santiago.Noguera@uv.es |
| Corporate Author |
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Thesis |
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| Publisher |
Springer |
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 |
1434-6001 |
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 |
ISI:000284869600005 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ elepoucu @ |
Serial |
312 |
| Permanent link to this record |
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| Author |
Kiesewetter, S.; Vento, V. |
| Title |
eta-eta '-glueball mixing |
Type |
Journal Article |
| Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
82 |
Issue |
3 |
Pages |
034003 - 13pp |
| Keywords |
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| Abstract |
We have revisited glueball mixing with the pseudoscalar mesons in the MIT bag model scheme. The calculation has been performed in the spherical cavity approximation to the bag using two different fermion propagators, the cavity and the free propagators. We obtain probabilities of mixing for the eta at the level of 0.006%-2.0%, while for the eta' one at the level of 0.6%-40%, depending on the choice of bag radius and, therefore, of the strong coupling constant. Our results differ from previous calculations. The origin of our difference stems from the treatment of the time integrations. The comparison of our calculation with experimental data, which is consistent with small eta – eta' – G mixing, implies that the pseudoscalar glueball is small, R similar to 0.5-0.6 fm and has a large mass, M-G similar to 2000-2500 MeV. |
| Address |
[Kiesewetter, Simon] Univ Valencia, Dept Fis Teor, CSIC, E-46100 Burjassot, Valencia, Spain |
| 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 |
ISI:000280611800007 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ elepoucu @ |
Serial |
399 |
| Permanent link to this record |
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| Author |
Mathieu, V.; Vento, V. |
| Title |
Pseudoscalar glueball and eta-eta ' mixing |
Type |
Journal Article |
| Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
81 |
Issue |
3 |
Pages |
034004 - 12pp |
| Keywords |
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| Abstract |
We have performed a dynamical analysis of the mixing in the pseudoscalar channel with the goal of understanding the existence and behavior of the pseudoscalar glueball. Our philosophy has not been to predict precise values of the glueball mass but to exploit an adequate effective theory to the point of breaking and to analyze which kind of mechanisms restore compatibility with data. Our study has led to analytical solutions which allow a clear understanding of the phenomena. The outcome of our calculation leads to a large mass glueball M-Theta > 2000 MeV, to a large glue content of the eta ', and to mixing angles in agreement with previous numerical studies. |
| Address |
[Mathieu, Vincent] Univ Mons, Serv Phys Nucl & Subnucl, Acad Univ Wallonie Bruxells, B-7000 Mons, Belgium, Email: vincent.mathieu@umons.ac.be |
| 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 |
ISI:000275069000025 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
494 |
| Permanent link to this record |
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| Author |
Kochelev, N.I.; Vento, V. |
| Title |
Gluonic components of the pion and the transition form factor gamma*gamma* -> pi(0) |
Type |
Journal Article |
| Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
| Volume |
81 |
Issue |
3 |
Pages |
034009 - 5pp |
| Keywords |
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| Abstract |
We propose an effective Lagrangian for the coupling of the neutral pion with gluons whose strength is determined by a low-energy theorem. We calculate the contribution of the gluonic components arising from this interaction to the pion transition form factor gamma*gamma* -> pi(0) using the instanton liquid model to describe the quantum chromodynamics vacuum. We find that this contribution is large and might explain the anomalous behavior of the form factor at large virtuality of one of the photons, a feature which was recently discovered by the BABAR Collaboration. |
| Address |
[Kochelev, N. I.] Joint Inst Nucl Res, Bogoliubov Lab Theoret Phys, Dubna 141980, Moscow Region, Russia, Email: kochelev@theor.jinr.ru |
| 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 |
ISI:000275069000030 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ elepoucu @ |
Serial |
495 |
| Permanent link to this record |
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| Author |
Courtoy, A.; Scopetta, S.; Vento, V. |
| Title |
Non-perturbative momentum dependence of the coupling constant and hadronic models |
Type |
Journal Article |
| Year |
2011 |
Publication |
European Physical Journal A |
Abbreviated Journal |
Eur. Phys. J. A |
| Volume |
47 |
Issue |
4 |
Pages |
49 - 7pp |
| 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. |
| Address |
[Courtoy, A.] Ist Nazl Fis Nucl, Sez Pavia, I-27100 Pavia, Italy, Email: Aurore.Courtoy@pv.infn.it |
| Corporate Author |
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Thesis |
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| Publisher |
Springer |
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 |
1434-6001 |
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 |
ISI:000291659500003 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
657 |
| Permanent link to this record |
