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Author |
Aguilera-Verdugo, J.J.; Hernandez-Pinto, R.J.; Rodrigo, G.; Sborlini, G.F.R.; Torres Bobadilla, W.J. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Causal representation of multi-loop Feynman integrands within the loop-tree duality |
Type |
Journal Article |
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Year |
2021 |
Publication ![sorted by Publication field, ascending order (up)](img/sort_asc.gif) |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
01 |
Issue |
1 |
Pages |
69 - 26pp |
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Keywords |
Duality in Gauge Field Theories; Perturbative QCD; Scattering Amplitudes |
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Abstract |
The numerical evaluation of multi-loop scattering amplitudes in the Feynman representation usually requires to deal with both physical (causal) and unphysical (non-causal) singularities. The loop-tree duality (LTD) offers a powerful framework to easily characterise and distinguish these two types of singularities, and then simplify analytically the underling expressions. In this paper, we work explicitly on the dual representation of multi-loop Feynman integrals generated from three parent topologies, which we refer to as Maximal, Next-to-Maximal and Next-to-Next-to-Maximal loop topologies. In particular, we aim at expressing these dual contributions, independently of the number of loops and internal configurations, in terms of causal propagators only. Thus, providing very compact and causal integrand representations to all orders. In order to do so, we reconstruct their analytic expressions from numerical evaluation over finite fields. This procedure implicitly cancels out all unphysical singularities. We also interpret the result in terms of entangled causal thresholds. In view of the simple structure of the dual expressions, we integrate them numerically up to four loops in integer space-time dimensions, taking advantage of their smooth behaviour at integrand level. |
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Address |
[Jesus Aguilera-Verdugo, J.; Rodrigo, German; Sborlini, German F. R.; Torres Bobadilla, William J.] Univ Valencia, Inst Fis Corpuscular, CSIC, Parc Cientif, E-46980 Valencia, Spain, Email: jesus.aguilera@ific.uv.es; |
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Springer |
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English |
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ISSN |
1029-8479 |
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Expedition |
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Conference |
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Notes |
WOS:000609437600001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4697 |
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Permanent link to this record |
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Author |
Ramirez-Uribe, S.; Hernandez-Pinto, R.J.; Rodrigo, G.; Sborlini, G.F.R.; Torres Bobadilla, W.J. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Universal opening of four-loop scattering amplitudes to trees |
Type |
Journal Article |
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Year |
2021 |
Publication ![sorted by Publication field, ascending order (up)](img/sort_asc.gif) |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
04 |
Issue |
4 |
Pages |
129 - 22pp |
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Keywords |
Duality in Gauge Field Theories; Perturbative QCD; Scattering Amplitudes |
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Abstract |
The perturbative approach to quantum field theories has made it possible to obtain incredibly accurate theoretical predictions in high-energy physics. Although various techniques have been developed to boost the efficiency of these calculations, some ingredients remain specially challenging. This is the case of multiloop scattering amplitudes that constitute a hard bottleneck to solve. In this paper, we delve into the application of a disruptive technique based on the loop-tree duality theorem, which is aimed at an efficient computation of such objects by opening the loops to nondisjoint trees. We study the multiloop topologies that first appear at four loops and assemble them in a clever and general expression, the (NMLT)-M-4 universal topology. This general expression enables to open any scattering amplitude of up to four loops, and also describes a subset of higher order configurations to all orders. These results confirm the conjecture of a factorized opening in terms of simpler known subtopologies, which also determines how the causal structure of the entire loop amplitude is characterized by the causal structure of its subtopologies. In addition, we confirm that the loop-tree duality representation of the (NMLT)-M-4 universal topology is manifestly free of noncausal thresholds, thus pointing towards a remarkably more stable numerical implementation of multiloop scattering amplitudes. |
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Address |
[Ramirez-Uribe, Selomit; Rodrigo, German; Sborlini, German F. R.; Bobadilla, William J. Torres] Univ Valencia, Inst Fis Corpuscular, CSIC, Parc Cient, E-46980 Valencia, Spain, Email: norma.selomit.ramirez@ific.uv.es; |
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Springer |
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English |
Summary Language |
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Series Volume |
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ISSN |
1029-8479 |
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Expedition |
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Conference |
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Notes |
WOS:000641467800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4787 |
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Permanent link to this record |
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Author |
Ramirez-Uribe, S.; Renteria-Olivo, A.E.; Rodrigo, G.; Sborlini, G.F.R.; Vale Silva, L. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Quantum algorithm for Feynman loop integrals |
Type |
Journal Article |
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Year |
2022 |
Publication ![sorted by Publication field, ascending order (up)](img/sort_asc.gif) |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
05 |
Issue |
5 |
Pages |
100 - 32pp |
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Keywords |
Duality in Gauge Field Theories; Perturbative QCD; Scattering Amplitudes |
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Abstract |
We present a novel benchmark application of a quantum algorithm to Feynman loop integrals. The two on-shell states of a Feynman propagator are identified with the two states of a qubit and a quantum algorithm is used to unfold the causal singular configurations of multiloop Feynman diagrams. To identify such configurations, we exploit Grover's algorithm for querying multiple solutions over unstructured datasets, which presents a quadratic speed-up over classical algorithms when the number of solutions is much smaller than the number of possible configurations. A suitable modification is introduced to deal with topologies in which the number of causal states to be identified is nearly half of the total number of states. The output of the quantum algorithm in IBM Quantum and QUTE Testbed simulators is used to bootstrap the causal representation in the loop-tree duality of representative multiloop topologies. The algorithm may also find application and interest in graph theory to solve problems involving directed acyclic graphs. |
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Address |
[Ramirez-Uribe, Selomit; Renteria-Olivo, Andres E.; Rodrigo, German; Sborlini, German F. R.; Vale Silva, Luiz] Univ Valencia, Inst Fis Corpuscular, CSIC, Parc Cient, E-46980 Valencia, Spain, Email: norma.selomit.ramirez@ific.uv.es; |
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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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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 |
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Area |
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Expedition |
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Conference |
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Notes |
WOS:000796990400007 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5230 |
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Permanent link to this record |
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Author |
Ayala, C.; Cvetic, G.; Kogerler, R. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Lattice-motivated holomorphic nearly perturbative QCD |
Type |
Journal Article |
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Year |
2017 |
Publication ![sorted by Publication field, ascending order (up)](img/sort_asc.gif) |
Journal of Physics G |
Abbreviated Journal |
J. Phys. G |
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Volume |
44 |
Issue |
7 |
Pages |
075001 - 30pp |
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Keywords |
perturbative QCD; lattice QCD; QCD phenomenology; resummation |
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Abstract |
Newer lattice results indicate that, in the Landau gauge at low spacelike momenta, the gluon propagator and the ghost dressing function are finite non-zero. This leads to a definition of the QCD running coupling, in a specific scheme, that goes to zero at low spacelike momenta. We construct a running coupling which fulfills these conditions, and at the same time reproduces to a high precision the perturbative behavior at high momenta. The coupling is constructed in such a way that it reflects qualitatively correctly the holomorphic (analytic) behavior of spacelike observables in the complex plane of the squared momenta, as dictated by the general principles of quantum field theories. Further, we require the coupling to reproduce correctly the nonstrange semihadronic decay rate of tau lepton which is the best measured low-momentum QCD observable with small higher-twist effects. Subsequent application of the Borel sum rules to the V + A spectral functions of tau lepton decays, as measured by OPAL Collaboration, determines the values of the gluon condensate and of the V + A six-dimensional condensate, and reproduces the data to a significantly higher precision than the usual (MS) over bar running coupling. |
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Address |
[Ayala, Cesar] Univ Valencia, Dept Theoret Phys, E-46100 Valencia, Spain, Email: Gorazd.Cvetic@usm.cl |
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Publisher |
Iop Publishing Ltd |
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English |
Summary Language |
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Abbreviated Series Title |
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Edition |
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ISSN |
0954-3899 |
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Conference |
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Notes |
WOS:000402509800001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3167 |
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Permanent link to this record |
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Author |
ATLAS Collaboration (Aad, G. et al); Amoros, G.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Escobar, C.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Kaci, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Miñano, M.; Mitsou, V.A.; Moles-Valls, R.; Moreno Llacer, M.; Oliver Garcia, E.; Perez Garcia-Estañ, M.T.; Ros, E.; Salt, J.; Solans, C.A.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Villaplana Perez, M.; Vos, M.; Wildauer, A. |
![goto web page (via DOI) doi](img/doi.gif)
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Title |
Measurement of the transverse momentum distribution of Z/gamma* bosons in proton-proton collisions at sqrt(s)=7 TeV with the ATLAS detector |
Type |
Journal Article |
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Year |
2011 |
Publication ![sorted by Publication field, ascending order (up)](img/sort_asc.gif) |
Physics Letters B |
Abbreviated Journal |
Phys. Lett. B |
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Volume |
705 |
Issue |
5 |
Pages |
415-434 |
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Keywords |
Z bosons; Differential cross section; Perturbative QCD; Event generators; Monte Carlo models |
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Abstract |
A measurement of the Z/gamma* transverse momentum (p(T)(Z)) distribution in proton-proton collisions at sqrt(s) = 7 TeV is presented using Z/gamma* -> e(+)e(-) and Z/gamma* -> mu(+)mu(-) decays collected with the ATLAS detector in data sets with integrated luminosities of 35 pb(-1) and 40 pb(-1), respectively. The normalized differential cross sections are measured separately for electron and muon decay channels as well as for their combination up to pi of 350 GeV for invariant dilepton masses 66 GeV < m(ll) < 116 GeV. The measurement is compared to predictions of perturbative QCD and various event generators. The prediction of resummed QCD combined with fixed order perturbative QCD is found to be in good agreement with the data. |
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Address |
[Akdogan, T.; Arik, E.; Arik, M.; Istin, S.; Ozcan, V. E.; Rador, T.] Bogazici Univ, Dept Phys, Istanbul, Turkey |
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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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Notes |
WOS:000297490400001 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
840 |
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Permanent link to this record |