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Author |
Ramirez-Uribe, S.; Hernandez-Pinto, R.J.; Rodrigo, G.; Sborlini, G.F.R.; Torres Bobadilla, W.J. |
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Title |
Universal opening of four-loop scattering amplitudes to trees |
Type |
Journal Article |
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Year |
2021 |
Publication |
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 |
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ISSN |
1029-8479 |
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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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Author |
Ljungvall, J.; Perez-Vidal, R.M.; Lopez-Martens, A.; Michelagnoli, C.; Clement, E.; Dudouet, J.; Gadea, A.; Hess, H.; Korichi, A.; Labiche, M.; Lalovic, N.; Li, H.J.; Recchia, F. |
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Title |
Performance of the Advanced GAmma Tracking Array at GANIL |
Type |
Journal Article |
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Year |
2020 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
955 |
Issue |
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Pages |
163297 - 13pp |
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Keywords |
AGATA spectrometer; GANIL facility; gamma-ray tracking; Nuclear structure; HPGe detectors |
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Abstract |
The performance of the Advanced GAmma Tracking Array (AGATA) at GANIL is discussed, on the basis of the analysis of source and in-beam data taken with up to 30 segmented crystals. Data processing is described in detail. The performance of individual detectors are shown. The efficiency of the individual detectors as well as the efficiency after gamma-ray tracking are discussed. Recent developments of gamma-ray tracking are also presented. The experimentally achieved peak-to-total is compared with simulations showing the impact of back-scattered gamma rays on the peak-to-total in a gamma-ray tracking array. An estimate of the achieved position resolution using the Doppler broadening of in-beam data is also given. Angular correlations from source measurements are shown together with different methods to take into account the effects of gamma-ray tracking on the normalization of the angular correlations. |
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Address |
[Ljungvall, J.; Lopez-Martens, A.; Dudouet, J.; Korichi, A.] Univ Paris Saclay, Univ Paris Sud, CNRS IN2P3, CSNSM, F-91405 Orsay, France, Email: joa.ljungvall@csnsm.in2p3.fr |
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Elsevier |
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English |
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ISSN |
0168-9002 |
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Conference |
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Notes |
WOS:000508940400029 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
4276 |
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Author |
Andricek, L. et al; Lacasta, C.; Marinas, C.; Vos, M. |
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Title |
Intrinsic resolutions of DEPFET detector prototypes measured at beam tests |
Type |
Journal Article |
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Year |
2011 |
Publication |
Nuclear Instruments & Methods in Physics Research A |
Abbreviated Journal |
Nucl. Instrum. Methods Phys. Res. A |
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Volume |
638 |
Issue |
1 |
Pages |
24-32 |
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Keywords |
Silicon pixel detector; Detector resolution; Spatial resolution; DEPFET; Beam test |
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Abstract |
The paper is based on the data of the 2009 DEPFET beam test at CERN SPS. The beam test used beams of pions and electrons with energies between 40 and 120 GeV, and the sensors tested were prototypes with thickness of 450 μm and pixel pitch between 20 and 32 μm. Intrinsic resolutions of the detectors are calculated by disentangling the contributions of measurement errors and multiple scattering in tracking residuals. Properties of the intrinsic resolution estimates and factors that influence them are discussed. For the DEPFET detectors in the beam test, the calculation yields intrinsic resolutions of approximate to 1 μm, with a typical accuracy of 0.1 μm. Bias scan, angle scan, and energy scan are used as example studies to show that the intrinsic resolutions are a useful tool in studies of detector properties. With sufficiently precise telescopes, detailed resolution maps can be constructed and used to study and optimize detector performance. |
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Address |
[Dolezal, Z.; Drasal, Z.; Kodys, P.; Kvasnicka, P.; Malina, L.; Scheirich, J.] Charles Univ Prague, Fac Math & Phys, Inst Particle & Nucl Phys, CR-18000 Prague, Czech Republic, Email: peter.kodys@mff.cuni.cz |
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Publisher |
Elsevier Science Bv |
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English |
Summary Language |
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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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ISSN |
0168-9002 |
ISBN |
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Notes |
ISI:000290082600005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
618 |
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Author |
n_TOF Collaboration (Mendoza, E. et al); Giubrone, G.; Tain, J.L. |
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Title |
Improved Neutron Capture Cross Section Measurements with the n_TOF Total Absorption Calorimeter |
Type |
Journal Article |
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Year |
2011 |
Publication |
Journal of the Korean Physical Society |
Abbreviated Journal |
J. Korean Phys. Soc. |
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Volume |
59 |
Issue |
2 |
Pages |
1813-1816 |
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Keywords |
ND2010; Nuclear data; n_TOF; Background; Monte Carlo; Neutron; Time of flight; Cross section; Calorimeter; Shielding; Simulation; Total absorption; Gamma ray; Neutron capture |
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Abstract |
The n_TOF collaboration operates a Total Absorption Calorimeter (TAC) [1] for measuring neutron capture cross-sections of low-mass and/or radioactive samples. The results obtained with the TAC have led to a substantial improvement of the capture cross sections of (237)Np and (240)Pu [2]. The experience acquired during the first measurements has allowed us to optimize the performance of the TAC and to improve the capture signal to background ratio, thus opening the way to more complex and demanding measurements on rare radioactive materials. The new design has been reached by a series of detailed Monte Carlo simulations of complete experiments and dedicated test measurements. The new capture setup will be presented and the main achievements highlighted. |
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Address |
[Mendoza, E; Becares, V; Casado, A; Cano-Ott, D; Fernandez-Ordonez, M; Gonzalez-Romero, E; Guerrero, C; Martinez, T; Vidriales, JJ] Ctr Invest Energet Medioambientales & Tecnol, Madrid 28040, Spain, Email: emilio.mendoza@ciemat.es |
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Korean Physical Soc |
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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 |
0374-4884 |
ISBN |
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Conference |
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Notes |
WOS:000294080700086 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ elepoucu @ |
Serial |
738 |
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Author |
Aguilera-Verdugo, J.J.; Hernandez-Pinto, R.J.; Rodrigo, G.; Sborlini, G.F.R.; Torres Bobadilla, W.J. |
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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 |
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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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: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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