| Records |
Author  |
Mateu, V.; Rodrigo, G. |
| Title |
Oriented event shapes at (NLL)-L-3 + O(alpha(2)(S)) |
Type |
Journal Article |
| Year |
2013 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
11 |
Issue |
11 |
Pages |
030 - 29pp |
| Keywords |
Jets; NLO Computations |
| Abstract |
We analyze oriented event-shapes in the context of Soft-Collinear Effective Theory (SCET) and in fixed-order perturbation theory. Oriented event-shapes are distributions of event-shape variables which are differential on the angle theta(T) that the thrust axis forms with the electron-positron beam. We show that at any order in perturbation theory and for any event shape, only two angular structures can appear: F-0 = 3/8 (1+cos(2) theta(T)) and F-1 = (1 – 3 cos(2) theta(T)). When integrating over theta(T) to recover the more familiar event-shape distributions, only F-0 survives. The validity of our proof goes beyond perturbation theory, and hence only these two structures are present at the hadron level. The proof also carries over massive particles. Using SCET techniques we show that singular terms can only arise in the F-0 term. Since only the hard function is sensitive to the orientation of the thrust axis, this statement applies also for recoil-sensitive variables such as Jet Broadening. We show how to carry out resummation of the singular terms at (NLL)-L-3 for Thrust, Heavy-Jet Mass, the sum of the Hemisphere Masses and C-parameter by using existing computations in SCET. We also compute the fixed-order distributions for these event-shapes at O(alpha(S)) analytically and at O(alpha(2)(S)) with the program Event2. |
| Address |
[Mateu, Vicent; Rodrigo, German] Univ Valencia, Consejo Super Invest Cient, Inst Fis Corpuscular, E-46980 Paterna, Valencia, Spain, Email: mateu@ific.uv.es; |
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Thesis |
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| Publisher |
Springer |
Place of Publication |
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| Language |
English |
Summary Language |
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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:000326699400001 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
1675 |
| Permanent link to this record |
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| Author |
Llanes Jurado, J.; Rodrigo, G.; Torres Bobadilla, W.J. |
| Title |
From Jacobi off-shell currents to integral relations |
Type |
Journal Article |
| Year |
2017 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
12 |
Issue |
12 |
Pages |
122 - 22pp |
| Keywords |
NLO Computations; QCD Phenomenology |
| Abstract |
In this paper, we study off-shell currents built from the Jacobi identity of the kinematic numerators of gg -> X with X = ss, q (q) over bar, gg. We find that these currents can be schematically written in terms of three-point interaction Feynman rules. This representation allows for a straightforward understanding of the Colour-Kinematics duality as well as for the construction of the building blocks for the generation of higher-multiplicity tree-level and multi-loop numerators. We also provide one-loop integral relations through the Loop-Tree duality formalism with potential applications and advantages for the computation of relevant physical processes at the Large Hadron Collider. We illustrate these integral relations with the explicit examples of QCD one-loop numerators of gg -> ss. |
| Address |
[Llanes Jurado, Jose; Rodrigo, German; Torres Bobadilla, William J.] Univ Valencia, Inst Fis Corpuscular, CSIC, Parc Cient, E-46980 Valencia, Spain, Email: jollaju@alumni.uv.es; |
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Thesis |
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| Publisher |
Springer |
Place of Publication |
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| Language |
English |
Summary Language |
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Original 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:000418560700004 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
no |
| Call Number |
IFIC @ pastor @ |
Serial |
3431 |
| 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; |
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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 Title |
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Abbreviated Series Title |
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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 |
IFIC @ pastor @ |
Serial |
1346 |
| Permanent link to this record |
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| Author |
Hernandez-Pinto, R.J.; Sborlini, G.F.R.; Rodrigo, G. |
| Title |
Towards gauge theories in four dimensions |
Type |
Journal Article |
| Year |
2016 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
| Volume |
02 |
Issue |
2 |
Pages |
044 - 14pp |
| Keywords |
NLO Computations |
| Abstract |
The abundance of infrared singularities in gauge theories due to unresolved emission of massless particles (soft and collinear) represents the main difficulty in perturbative calculations. They are typically regularized in dimensional regularization, and their subtraction is usually achieved independently for virtual and real corrections. In this paper, we introduce a new method based on the loop-tree duality (LTD) theorem to accomplish the summation over degenerate infrared states directly at the integrand level such that the cancellation of the infrared divergences is achieved simultaneously, and apply it to reference examples as a proof of concept. Ultraviolet divergences, which are the consequence of the point-like nature of the theory, are also reinterpreted physically in this framework. The proposed method opens the intriguing possibility of carrying out purely four-dimensional implementations of higher-order perturbative calculations at next-to-leading order (NLO) and beyond free of soft and final-state collinear subtractions. |
| Address |
[Hernandez-Pinto, Roger J.; Sborlini, German F. R.; Rodrigo, German] Univ Valencia, Inst Fis Corpuscular, Consejo Super Invest Cient, Pare Cient, E-46980 Valencia, Spain, Email: rogerjose.hernandez@ific.uv.es; |
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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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Abbreviated Series Title |
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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:000375270700002 |
Approved |
no |
| Is ISI |
yes |
International Collaboration |
yes |
| Call Number |
IFIC @ pastor @ |
Serial |
2661 |
| Permanent link to this record |
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| 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 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 |
IFIC @ pastor @ |
Serial |
609 |
| Permanent link to this record |
