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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 (up) 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 Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1126-6708 ISBN Medium
Area Expedition Conference
Notes WOS:000313123800038 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 1346
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Author Campanario, F.; Kerner, M.; Zeppenfeld, D.
Title Z gamma production in vector-boson scattering at next-to-leading order QCD Type Journal Article
Year 2018 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 01 Issue 1 Pages 160 - 19pp
Keywords NLO Computations; Phenomenological Models
Abstract (up) Cross sections and differential distributions for Z gamma production in association with two jets via vector boson fusion are presented at next-to-leading order in QCD. The leptonic decays of the Z boson with full off-shell effects and spin correlations are taken into account. The uncertainties due to different scale choices and pdf sets are studied. Furthermore, we analyze the effect of including anomalous quartic gauge couplings at NLO QCD.
Address [Campanario, Francisco] Univ Valencia, CSIC, IFIC, Theory Div, E-46980 Valencia, Spain, Email: francisco.campanario@ific.uv.es;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000423794800002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3469
Permanent link to this record
 

 
Author Cieri, L.; Sborlini, G.F.R.
Title Exploring QED Effects to Diphoton Production at Hadron Colliders Type Journal Article
Year 2021 Publication Symmetry-Basel Abbreviated Journal Symmetry-Basel
Volume 13 Issue 6 Pages 994 - 17pp
Keywords diphoton production; QCD corrections; NLO calculations; QED effects
Abstract (up) In this article, we report phenomenological studies about the impact of O(alpha) corrections to diphoton production at hadron colliders. We explore the application of the Abelianized version of the qT-subtraction method to efficiently compute NLO QED contributions, taking advantage of the symmetries relating QCD and QED corrections. We analyze the experimental consequences due to the selection criteria and we find percent-level deviations for M-gamma gamma > 1TeV. An accurate description of the tail of the invariant mass distribution is very important for new physics searches which have the diphoton process as one of their main backgrounds. Moreover, we emphasize the importance of properly dealing with the observable photons by reproducing the experimental conditions applied to the event reconstruction.
Address [Cieri, Leandro] Ist Nazl Fis Nucl, Sez Firenze, I-50019 Sesto Fiorentino, Italy, Email: cieri@fi.infn.it;
Corporate Author Thesis
Publisher Mdpi Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN ISBN Medium
Area Expedition Conference
Notes WOS:000666940900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4898
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Author Becchetti, M.; Bonciani, R.; Cieri, L.; Coro, F.; Ripani, F.
Title Full top-quark mass dependence in diphoton production at NNLO in QCD Type Journal Article
Year 2024 Publication Physics Letters B Abbreviated Journal Phys. Lett. B
Volume 848 Issue Pages 138362 - 7pp
Keywords Collider phenomenology; Diphoton; Top quark; NNLO
Abstract (up) In this paper we consider the diphoton production in hadronic collisions at the next-to-next-to-leading order (NNLO) in perturbative QCD, taking into account for the first time the full top quark mass dependence up to two loops (full NNLO). We show selected numerical distributions, highlighting the kinematic regions where the massive corrections are more significant. We make use of the recently computed two-loop massive amplitudes for diphoton production in the quark annihilation channel. The remaining massive contributions at NNLO are also considered, and we comment on the weight of the different types of contributions to the full and complete result.
Address [Becchetti, Matteo] Univ Torino, Dipartimento Fis, Via Pietro Giuria 1, I-10125 Turin, Italy, Email: matteo.becchetti@unito.it;
Corporate Author Thesis
Publisher Elsevier Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 0370-2693 ISBN Medium
Area Expedition Conference
Notes WOS:001131862200001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5873
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Author Campanario, F.; Kerner, M.; Ninh, L.D.; Rosario, I.
Title Diphoton production in vector-boson scattering at the LHC at next-to-leading order QCD Type Journal Article
Year 2020 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 06 Issue 6 Pages 072 - 25pp
Keywords NLO Computations
Abstract (up) In this paper, we present results at next-to-leading order (NLO) QCD for photon pair production in association with two jets via vector boson scattering within the Standard Model (SM), and also in an effective field theory framework with anomalous gauge coupling effects via bosonic dimension-6 and 8 operators. We observe that, com- pared to other processes in the class of two electroweak (EW) vector boson production in association with two jets, more exclusive cuts are needed in order to suppress the SM QCD-induced background channel. As expected, the NLO QCD corrections reduce the scale uncertainties considerably. Using a well-motivated dynamical scale choice, we find moderate K -factors for the EW-induced process while the QCD-induced channel receives much larger corrections. Furthermore, we observe that applying a cut of Delta phi(cut)(j2 gamma 1) <2.5 for the second hardest jet and the hardest photon helps to increase the signal significance and reduces the impact of higher-order QCD corrections.
Address [Campanario, Francisco; Rosario, Ivan] Univ Valencia, CSIC, IFIC, Div Theory, E-46980 Valencia, Spain, Email: francisco.campanario@ific.uv.es;
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000541147600003 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 4433
Permanent link to this record