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Author |
Kochelev, N.I.; Vento, V. |
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Title |
Gluonic components of the pion and the transition form factor gamma*gamma* -> pi(0) |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
81 |
Issue |
3 |
Pages |
034009 - 5pp |
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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. |
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Address |
[Kochelev, N. I.] Joint Inst Nucl Res, Bogoliubov Lab Theoret Phys, Dubna 141980, Moscow Region, Russia, Email: kochelev@theor.jinr.ru |
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Publisher |
Amer Physical Soc |
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English |
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ISSN |
1550-7998 |
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Notes |
ISI:000275069000030 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
495 |
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Author |
Gomez Dumm, D.; Roig, P.; Pich, A.; Portoles, J. |
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Title |
Hadron structure in tau -> KK pi nu(tau) decays |
Type |
Journal Article |
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Year |
2010 |
Publication |
Physical Review D |
Abbreviated Journal |
Phys. Rev. D |
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Volume |
81 |
Issue |
3 |
Pages |
034031 - 17pp |
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Keywords |
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Abstract |
We analyze the hadronization structure of both vector and axial-vector currents leading to tau -> KK pi nu(tau) decays. At leading order in the 1/N-C expansion, and considering only the contribution of the lightest resonances, we work out, within the framework of the resonance chiral Lagrangian, the structure of the local vertices involved in those processes. The couplings in the resonance theory are constrained by imposing the asymptotic behavior of vector and axial-vector spectral functions ruled by QCD. In this way we predict the hadron spectra and conclude that, contrary to previous assertions, the vector contribution dominates by far over the axial-vector one in all KK pi charge channels. |
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Address |
[Gomez Dumm, D.] Univ Nacl La Plata, IFLP, CONICET, Dpto Fis, RA-1900 La Plata, Argentina |
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Publisher |
Amer Physical Soc |
Place of Publication |
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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 |
1550-7998 |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000275069000052 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
496 |
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Author |
Cirigliano, V.; Jenkins, J.P.; Gonzalez-Alonso, M. |
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Title |
Semileptonic decays of light quarks beyond the Standard Model |
Type |
Journal Article |
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Year |
2010 |
Publication |
Nuclear Physics B |
Abbreviated Journal |
Nucl. Phys. B |
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Volume |
830 |
Issue |
1-2 |
Pages |
95-115 |
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Keywords |
Semileptonic decays; CKM unitarity; Effective theory; Beyond the Standard Model |
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Abstract |
We describe non-standard contributions to semileptonic processes in a model independent way in terms of in SU(2)(L) x U(1)(Y) invariant effective lagrangian at the weak scale, front which we derive the low-energy effective lagrangian governing muon and beta decays. We find that the deviation from Cabibbo universality, Delta(CKM) equivalent to vertical bar V-ud vertical bar(2) + vertical bar V-us vertical bar(2) + vertical bar V-ub vertical bar(2) – 1, receives contributions from four effective operators. The phenomenological bound Delta(CKM) = (-1 +/- 6) x 10(-4) provides strong constraints on all four operators, corresponding to art effective scale Lambda > 11 TeV (90% CL). Depending on the operator, this constraint is at the same level or better then the Z pole observables. Conversely, precision electroweak constraints alone would allow universality violations as large as Delta(CKM) = -0.01 (90% CL). An observed Delta(CKM) not equal 0 at this level Could be explained in terms of a single four-fermion operator which is relatively poorly constrained by electroweak precision measurements. |
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Address |
[Cirigliano, Vincenzo; Jenkins, James P.; Gonzalez-Alonso, Martin] Los Alamos Natl Lab, Div Theoret, Los Alamos, NM 87545 USA, Email: cirigliano@lanl.gov |
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Publisher |
Elsevier Science Bv |
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Language |
English |
Summary Language |
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Original Title |
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Series Editor |
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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 |
0550-3213 |
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Area |
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Expedition |
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Conference |
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Notes |
ISI:000275150000003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
497 |
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Author |
Lledo, M.A.; Sommovigo, L. |
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Title |
Torsion formulation of gravity |
Type |
Journal Article |
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Year |
2010 |
Publication |
Classical and Quantum Gravity |
Abbreviated Journal |
Class. Quantum Gravity |
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Volume |
27 |
Issue |
6 |
Pages |
065014 - 16pp |
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Keywords |
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Abstract |
We explain precisely what it means to have a connection with torsion as a solution of the Einstein equations. While locally the theory remains the same, the new formulation allows for topologies that would have been excluded in the standard formulation of gravity. In this formulation it is possible to couple arbitrary torsion to gauge fields without breaking the gauge invariance. |
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Address |
[Lledo, M. A.; Sommovigo, L.] Univ Valencia, Dept Fis Teor, E-46100 Valencia, Spain, Email: Maria.Lledo@ific.uv.es |
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Publisher |
Iop Publishing Ltd |
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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 |
0264-9381 |
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:000275120600015 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
498 |
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Author |
Pierre Auger Collaboration (Abraham, J. et al); Pastor, S. |
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Title |
Trigger and aperture of the surface detector array of the Pierre Auger Observatory |
Type |
Journal Article |
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Year |
2010 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
613 |
Issue |
1 |
Pages |
29-39 |
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Keywords |
Ultra high energy cosmic rays; Auger Observatory; Extensive air showers; Trigger; Exposure |
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Abstract |
The surface detector array of the Pierre Auger Observatory consists of 1600 water-Cherenkov detectors, for the study of extensive air showers (EAS) generated by ultra-high-energy cosmic rays. We describe the trigger hierarchy, from the identification of candidate showers at the level of a single detector, amongst a large background (mainly random single cosmic ray muons), up to the selection of real events and the rejection of random coincidences. Such trigger makes the surface detector array fully efficient for the detection of EAS with energy above 3 x 10(18) eV, for all zenith angles between 0 degrees and 60 degrees, independently of the position of the impact point and of the mass of the primary particle. In these range of energies and angles, the exposure of the surface array can be determined purely on the basis of the geometrical acceptance. |
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Address |
[Boncioli, D.; Delle Fratte, C.; Di Giulio, C.; Matthiae, G.; Petrinca, P.; Salina, G.; Verzi, V.] Univ Roma Tor Vergata, I-00173 Rome, Italy, Email: giorgio.matthiae@roma2.infn.it |
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Corporate Author |
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Publisher |
Elsevier Science Bv |
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 |
0168-9002 |
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:000274772800005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
499 |
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| Permanent link to this record |
