Records |
Author |
Gomez Dumm, D.; Noguera, S.; Scoccola, N.N. |
Title |
Pion radiative weak decays in nonlocal chiral quark models |
Type |
Journal Article |
Year |
2011 |
Publication |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
Volume |
698 |
Issue |
3 |
Pages |
236-242 |
Keywords |
Nonlocal quark models; Pion radiative weak decays |
Abstract |
We analyze the radiative pion decay pi(+) -> e(+) nu(e)gamma within nonlocal chiral quark models that include wave function renormalization. In this framework we calculate the vector and axial-vector form factors F-V and F-A at q(2) = 0 – where q(2) is the e(+) nu(e) squared invariant mass – and the slope a of F-V (q(2)) at q(2) -> 0. The calculations are carried out considering different nonlocal form factors, in particular those taken from lattice QCD evaluations, showing a reasonable agreement with the corresponding experimental data. The comparison of our results with those obtained in the (local) NJL model and the relation of F-V and a with the form factor in pi(0) -> gamma*gamma decays are discussed. |
Address |
[Gomez Dumm, D.] Univ Nacl La Plata, CONICET, Dept Fis, IFLP, RA-1900 La Plata, Buenos Aires, Argentina, Email: dumm@fisica.unlp.edu.ar |
Corporate Author |
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Thesis |
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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 |
0370-2693 |
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:000289543700008 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
609 |
Permanent link to this record |
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Author |
Catani, S.; de Florian, D.; Rodrigo, G. |
Title |
Space-like (vs. time-like) collinear limits in QCD: is factorization violated? |
Type |
Journal Article |
Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
Volume |
07 |
Issue |
7 |
Pages |
026 - 88pp |
Keywords |
NLO Computations; Hadronic Colliders |
Abstract |
We consider the singular behaviour of QCD scattering amplitudes in kinematical configurations where two or more momenta of the external partons become collinear. At the tree level, this behaviour is known to be controlled by factorization formulae in which the singular collinear factor is universal (process independent). We show that this strict (process-independent) factorization is not valid at one-loop and higher-loop orders in the case of the collinear limit in space-like regions (e. g., collinear radiation from initial-state partons). We introduce a generalized version of all-order collinear factorization, in which the space-like singular factors retain some dependence on the momentum and colour charge of the non-collinear partons. We present explicit results on one-loop and two-loop amplitudes for both the two-parton and multiparton collinear limits. At the level of squared amplitudes and, more generally, cross sections in hadron-hadron collisions, the violation of strict collinear factorization has implications on the non-abelian structure of logarithmically-enhanced terms in perturbative calculations (starting from the next-to-next-to-leading order) and on various factorization issues of mass singularities (starting from the next-to-next-to-next-to-leading order). |
Address |
[Catani, Stefano] Univ Florence, Sez Firenze, Ist Nazl Fis Nucl, I-50019 Florence, Italy, Email: catani@fi.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 |
1126-6708 |
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:000307298400026 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
1160 |
Permanent link to this record |
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Author |
Alioli, S.; Fuster, J.; Irles Quiles, A.; Moch, S.; Uwer, P.; Vos, M. |
Title |
A new observable to measure the top quark mass at hadron colliders |
Type |
Journal Article |
Year |
2012 |
Publication |
Pramana-Journal of Physics |
Abbreviated Journal |
Pramana-J. Phys. |
Volume |
79 |
Issue |
4 |
Pages |
809-812 |
Keywords |
Top quark; mass; pole mass; NLO; cross-section; t(t)over-bar plus jet; POWHEG; perturbative QCD |
Abstract |
The t (t) over bar + jet + X differential cross-section in proton-proton collisions at 7 TeV centre of mass energy is investigated with respect to its sensitivity to the top quark mass. The analysis includes higher order QCD corrections at NLO. The impact of the renormalization scale (mu(R)), the factorization (mu(F)) scale and of the choice of different proton's PDF (parton distribution function) has been evaluated. In this study it is concluded that differential jet rates offer a promising option for alternative mass measurements of the top quark, with theoretical uncertainties below 1 GeV. |
Address |
[Fuster, Juan; Irles, Adrian; Vos, Marcel] Univ Valencia, Ctr Mixte, CSIC, IFIC, E-46071 Valencia, Spain, Email: airqui@ific.uv.es |
Corporate Author |
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Thesis |
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Publisher |
Indian Acad Sciences |
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 |
0304-4289 |
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:000310875900021 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
1200 |
Permanent link to this record |
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Author |
Kleiss, R.H.P.; Malamos, I.; Papadopoulos, C.G.; Verheyen, R. |
Title |
Counting to one: reducibility of one- and two-loop amplitudes at the integrand level |
Type |
Journal Article |
Year |
2012 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
Volume |
12 |
Issue |
12 |
Pages |
038 - 24pp |
Keywords |
QCD Phenomenology; NLO Computations |
Abstract |
Calculation of amplitudes in perturbative quantum field theory involve large loop integrals. The complexity of those integrals, in combination with the large number of Feynman diagrams, make the calculations very difficult. Reduction methods proved to be very helpful, lowering the number of integrals that need to be actually calculated. Especially reduction at the integrand level improves the speed and set-up of these calculations. In this article we demonstrate, by counting the numbers of tensor structures and independent coefficients, how to write such relations at the integrand level for one-and two-loop amplitudes. We clarify their connection to the so-called spurious terms at one loop and discuss their structure in the two-loop case. This method is also applicable to higher loops, and the results obtained apply to both planar and non-planar diagrams. |
Address |
[Kleiss, Ronald H. P.; Verheyen, Rob] Radboud Univ Nijmegen, NL-6525 ED Nijmegen, Netherlands, Email: R.Kleiss@science.ru.nl; |
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 |
1126-6708 |
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:000313123800038 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
1346 |
Permanent link to this record |
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Author |
Bierenbaum, I.; Buchta, S.; Draggiotis, P.; Malamos, I.; Rodrigo, G. |
Title |
Tree-loop duality relation beyond single poles |
Type |
Journal Article |
Year |
2013 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
Volume |
03 |
Issue |
3 |
Pages |
025 - 24pp |
Keywords |
QCD Phenomenology; NLO Computations |
Abstract |
We develop the Tree-Loop Duality Relation for two- and three-loop integrals with multiple identical propagators (multiple poles). This is the extension of the Duality Relation for single poles and multi-loop integrals derived in previous publications. We prove a generalization of the formula for single poles to multiple poles and we develop a strategy for dealing with higher-order pole integrals by reducing them to single pole integrals using Integration By Parts. |
Address |
Univ Hamburg, Inst Theoret Phys 2, D-22761 Hamburg, Germany, Email: isabella.bierenbaum@desy.de; |
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 |
1029-8479 |
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:000317521200025 |
Approved |
no |
Is ISI |
yes |
International Collaboration |
yes |
Call Number ![sorted by Call Number field, descending order (down)](img/sort_desc.gif) |
IFIC @ pastor @ |
Serial |
1418 |
Permanent link to this record |