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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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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 |
Driencourt-Mangin, F.; Rodrigo, G.; Sborlini, G.F.R.; Torres Bobadilla, W.J. |
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Title |
Universal four-dimensional representation of H -> gamma gamma at two loops through the Loop-Tree Duality |
Type |
Journal Article |
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Year |
2019 |
Publication |
Journal of High Energy Physics |
Abbreviated Journal |
J. High Energy Phys. |
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Volume |
02 |
Issue |
2 |
Pages |
143 - 39pp |
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Keywords |
Scattering Amplitudes; Higgs Physics; Perturbative QCD |
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Abstract |
We extend useful properties of the H unintegrated dual amplitudes from one- to two-loop level, using the Loop-Tree Duality formalism. In particular, we show that the universality of the functional form regardless of the nature of the internal particle still holds at this order. We also present an algorithmic way to renormalise two-loop amplitudes, by locally cancelling the ultraviolet singularities at integrand level, thus allowing a full four-dimensional numerical implementation of the method. Our results are compared with analytic expressions already available in the literature, finding a perfect numerical agreement. The success of this computation plays a crucial role for the development of a fully local four-dimensional framework to compute physical observables at Next-to-Next-to Leading order and beyond. |
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Address |
[Driencourt-Mangin, Felix; Rodrigo, German; Sborlini, German F. R.; Bobadilla, William J. Torres] Univ Valencia, CSIC, IFIC, Apt Correus 22085, E-46071 Valencia, Spain, Email: felix.dm@ific.uv.es; |
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Publisher |
Springer |
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English |
Summary Language |
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1029-8479 |
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Conference |
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Notes |
WOS:000459485300005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3922 |
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Author |
Driencourt-Mangin, F.; Rodrigo, G.; Sborlini, G.F.R. |
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Title |
Universal dual amplitudes and asymptotic expansions for gg -> H and H -> gamma gamma in four dimensions |
Type |
Journal Article |
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Year |
2018 |
Publication |
European Physical Journal C |
Abbreviated Journal |
Eur. Phys. J. C |
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Volume |
78 |
Issue |
3 |
Pages |
231 - 7pp |
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Keywords |
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Abstract |
Though the one-loop amplitudes of the Higgs boson to massless gauge bosons are finite because there is no direct interaction at tree level in the Standard Model, a well-defined regularization scheme is still required for their correct evaluation. We reanalyze these amplitudes in the framework of the four-dimensional unsubtraction and the loop-tree duality (EDU/LTD), and show how a local renormalization solves potential regularization ambiguities. The Higgs boson interactions are also used to illustrate new additional advantages of this formalism. We show that LTD naturally leads to very compact integrand expressions in four space-time dimensions of the one-loop amplitude with virtual electroweak gauge bosons. They exhibit the same functional form as the amplitudes with top quarks and charged scalars, thus opening further possibilities for simplifications in higher-order computations. Another outstanding application is the straightforward implementation of asymptotic expansions by using dual amplitudes. One of the main benefits of the LTD representation is that it is supported in a Euclidean space. This characteristic feature naturally leads to simpler asymptotic expansions. |
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Address |
[Driencourt-Mangin, Felix; Rodrigo, German; Sborlini, German E. R.] Univ Valencia, Inst Fis Corpuscular, CSIC, Parc Cient, Valencia 46980, Spain, Email: felix.dm@ific.uv.es; |
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Springer |
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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 |
1434-6044 |
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Notes |
WOS:000427624100003 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3525 |
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Author |
Gelmini, G.B.; Huh, J.H.; Witte, S.J. |
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Title |
Unified halo-independent formalism from convex hulls for direct dark matter searches |
Type |
Journal Article |
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Year |
2017 |
Publication |
Journal of Cosmology and Astroparticle Physics |
Abbreviated Journal |
J. Cosmol. Astropart. Phys. |
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Volume |
12 |
Issue |
12 |
Pages |
039 - 33pp |
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Keywords |
dark matter experiments; dark matter theory |
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Abstract |
Using the Fenchel-Eggleston theorem for convex hulls (an extension of the Caratheodory theorem), we prove that any likelihood can be maximized by either a dark matter 1-speed distribution F(v) in Earth's frame or 2-Galactic velocity distribution f(gal) ((u) over right arrow), consisting of a sum of delta functions. The former case applies only to time-averaged rate measurements and the maximum number of delta functions is (N-1), where N is the total number of data entries. The second case applies to any harmonic expansion coefficient of the time-dependent rate and the maximum number of terms is N. Using time-averaged rates, the aforementioned form of F(v) results in a piecewise constant unmodulated halo function (eta) over tilde (BF)-B-0 (v(min)) (which is an integral of the speed distribution) with at most (N-1) downward steps. The authors had previously proven this result for likelihoods comprised of at least one extended likelihood, and found the best-fit halo function to be unique. This uniqueness, however, cannot be guaranteed in the more general analysis applied to arbitrary likelihoods. Thus we introduce a method for determining whether there exists a unique best-fit halo function, and provide a procedure for constructing either a pointwise con fi dence band, if the best-fit halo function is unique, or a degeneracy band, if it is not. Using measurements of modulation amplitudes, the aforementioned form of f(gal) ((u) over right arrow), which is a sum of Galactic streams, yields a periodic time-dependent halo function (eta) over right arrow BF (v(min); t) which at any fixed time is a piecewise constant function of v(min) with at most N downward steps. In this case, we explain how to construct pointwise confidence and degeneracy bands from the time-averaged halo function. Finally, we show that requiring an isotropic Galactic velocity distribution leads to a Galactic speed distribution F(u)that is once again a sum of delta functions, and produces a time-dependent (eta) over tilde BF (v(min); t) function (and a time-averaged (eta) over tilde (0) BF (v(min))) that is piecewise linear, di ff ering significantly from best-fit halo functions obtained without the assumption of isotropy. |
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Address |
[Gelmini, Graciela B.; Witte, Samuel J.] Univ Calif Los Angeles, Dept Phys & Astron, 475 Portola Plaza, Los Angeles, CA 90095 USA, Email: gelmini@physics.ucla.edu; |
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Publisher |
Iop Publishing Ltd |
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English |
Summary Language |
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Original Title |
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Abbreviated Series Title |
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ISSN |
1475-7516 |
ISBN |
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Notes |
WOS:000418922000002 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
3440 |
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Author |
Bordes, J.; Chan, H.M.; Tsou, S.T. |
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Title |
Unified FSM treatment of CP physics extended to hidden sector giving (i) delta(CP) for leptons as prediction, (ii) new hints on the material content of the universe |
Type |
Journal Article |
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Year |
2021 |
Publication |
International Journal of Modern Physics A |
Abbreviated Journal |
Int. J. Mod. Phys. A |
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Volume |
36 |
Issue |
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Pages |
2150238 - 19pp |
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Keywords |
Phenomenology beyond the Standard Model; framed Standard Model; CP physics; dark matter |
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Abstract |
A unified treatment of CP physics for quarks and leptons in the framed Standard Model (FSM) is extended to include the predicted hidden sector giving as consequences: (i) that an earlier part estimate of the Jarlskog invariant J' for leptons is turned into a prediction for its actual value, i.e. J' similar to -0.012 (delta(CP)' similar to 1.11 pi), which is of the right order of magnitude, of the right sign, and in the range of values favoured by the present experiment, (ii) some novel twists to the effects of CP-violation on the material content of the universe. |
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Address |
[Bordes, Jose] Univ Valencia, Ctr Mixto CSIC, Dept Fis Teor, Calle Dr Moliner 50, E-46100 Burjassot, Valencia, Spain, Email: jose.m.bordes@uv.es; |
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Corporate Author |
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Publisher |
World Scientific Publ Co Pte Ltd |
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 |
0217-751x |
ISBN |
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Conference |
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Notes |
WOS:000732963000005 |
Approved |
no |
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Is ISI |
yes |
International Collaboration |
yes |
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Call Number |
IFIC @ pastor @ |
Serial |
5059 |
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