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Author Wang, Y.F.; Yao, D.L.; Zheng, H.Q. url  doi
openurl 
  Title On the existence of N*(890) resonance in S-11 channel of N scatterings Type Journal Article
  Year 2019 Publication Frontiers of Physics Abbreviated Journal Front. Phys.  
  Volume 14 Issue 2 Pages 24501 - 6pp  
  Keywords (up) dispersion relations; N scatterings; nucleon resonance  
  Abstract Low-energy partial-wave N scattering data is reexamined with the help of the production representation of partial-wave S matrix, where branch cuts and poles are thoroughly under consideration. The left-hand cut contribution to the phase shift is determined, with controlled systematic error estimates, by using the results of O(p(3)) chiral perturbative amplitudes obtained in the extended-onmass- shell scheme. In S-11 and P-11 channels, severe discrepancies are observed between the phase shift data and the sum of all known contributions. Statistically satisfactory fits to the data can only be achieved by adding extra poles in the two channels. We find that a S-11 resonance pole locates at zr = (0:895-0:081)-(0:164-0:023)i GeV, on the complex s-plane. On the other hand, a P-11 virtual pole, as an accompanying partner of the nucleon bound-state pole, locates atzv = (0:966-0:018) GeV, slightly above the nucleon pole on the real axis below threshold. Physical origin of the two newly established poles is explored to the best of our knowledge. It is emphasized that the O(p(3)) calculation greatly improves the fit quality comparing with the previous O(p(2)) one.  
  Address [Wang, Yu-Fei; Zheng, Han-Qing] Peking Univ, Dept Phys, Beijing 100871, Peoples R China, Email: deliang.yao@ific.uv.es  
  Corporate Author Thesis  
  Publisher Higher Education Press Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 2095-0462 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000454564100001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3857  
Permanent link to this record
 

 
Author Wang, Y.F.; Yao, D.L.; Zheng, H.Q. url  doi
openurl 
  Title New insights on low energy pi N scattering amplitudes: comprehensive analyses at O (p(3)) level Type Journal Article
  Year 2019 Publication Chinese Physics C Abbreviated Journal Chin. Phys. C  
  Volume 43 Issue 6 Pages 064110 - 22pp  
  Keywords (up) dispersion relations; pion-nucleon scattering; chiral perturbation theory  
  Abstract A production representation of partial-wave S matrix is utilized to construct low-energy elastic pion-nucleon scattering amplitudes from cuts and poles on complex Riemann sheets. Among them, the contribution of left-hand cuts is estimated using the O (p(3)) results obtained in covariant baryon chiral perturbation theory within the extendedon-nass-shell scheme. By fitting to data on partial-wave phase shifts, it is indicated that the existences of hidden poles in S-11 and P-11 channels, as conjectured in our previous paper [Eur. Phys. J. C, 78(7): 543 (2018)], are firmly established. Specifically, the pole mass of the S-11 hidden resonance is determined to be (895 +/- 81)-(164 +/- 23)i MeV, whereas, the virtual pole in the P-11 channel locates at (966 +/- 18) MeV. It is found that analyses at the O (p(3)) level improves significantly the fit quality, comparing with the previous O (p(2)) one. Quantitative studies with cautious physical discussions are also conducted for the other S- and P-wave channels.  
  Address [Wang, Yu-Fei; Zheng, Han-Qing] Peking Univ, Dept Phys, Beijing 100871, Peoples R China, Email: yaodeliang@pku.edu.cn  
  Corporate Author Thesis  
  Publisher Iop Publishing Ltd Place of Publication Editor  
  Language English Summary Language Original Title  
  Series Editor Series Title Abbreviated Series Title  
  Series Volume Series Issue Edition  
  ISSN 1674-1137 ISBN Medium  
  Area Expedition Conference  
  Notes WOS:000468501700013 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4020  
Permanent link to this record
 

 
Author Aguilera-Verdugo, J.J.; Driencourt-Mangin, F.; Plenter, J.; Ramirez-Uribe, S.; Rodrigo, G.; Sborlini, G.F.R.; Torres Bobadilla, W.J.; Tracz, S. url  doi
openurl 
  Title Causality, unitarity thresholds, anomalous thresholds and infrared singularities from the loop-tree duality at higher orders Type Journal Article
  Year 2019 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 12 Issue 12 Pages 163 - 12pp  
  Keywords (up) Duality in Gauge Field Theories; Perturbative QCD; Scattering Amplitudes  
  Abstract We present the first comprehensive analysis of the unitarity thresholds and anomalous thresholds of scattering amplitudes at two loops and beyond based on the loop- tree duality, and show how non-causal unphysical thresholds are locally cancelled in an efficient way when the forest of all the dual on-shell cuts is considered as one. We also prove that soft and collinear singularities at two loops and beyond are restricted to a compact region of the loop three-momenta, which is a necessary condition for implementing a local cancellation of loop infrared singularities with the ones appearing in real emission; without relying on a subtraction formalism.  
  Address [Aguilera-Verdugo, J. Jesus; Driencourt-Mangin, Felix; Plenter, Judith; Ramirez-Uribe, Selomit; Rodrigo, German; Sborlini, German F. R.; Torres Bobadilla, William J.; Tracz, Szymon] Univ Valencia, Consejo Super Invest Cient, Inst Fis Corpuscular, Parc Cient, E-46980 Valencia, Spain, Email: jesus.aguilera@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:000513535500003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4288  
Permanent link to this record
 

 
Author Aguilera-Verdugo, J.J.; Hernandez-Pinto, R.J.; Rodrigo, G.; Sborlini, G.F.R.; Torres Bobadilla, W.J. url  doi
openurl 
  Title Causal representation of multi-loop Feynman integrands within the loop-tree duality Type Journal Article
  Year 2021 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 01 Issue 1 Pages 69 - 26pp  
  Keywords (up) Duality in Gauge Field Theories; Perturbative QCD; Scattering Amplitudes  
  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.  
  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;  
  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:000609437600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4697  
Permanent link to this record
 

 
Author Ramirez-Uribe, S.; Hernandez-Pinto, R.J.; Rodrigo, G.; Sborlini, G.F.R.; Torres Bobadilla, W.J. url  doi
openurl 
  Title Universal opening of four-loop scattering amplitudes to trees Type Journal Article
  Year 2021 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 04 Issue 4 Pages 129 - 22pp  
  Keywords (up) Duality in Gauge Field Theories; Perturbative QCD; Scattering Amplitudes  
  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.  
  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;  
  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:000641467800001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 4787  
Permanent link to this record
 

 
Author Ramirez-Uribe, S.; Renteria-Olivo, A.E.; Rodrigo, G.; Sborlini, G.F.R.; Vale Silva, L. url  doi
openurl 
  Title Quantum algorithm for Feynman loop integrals Type Journal Article
  Year 2022 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 05 Issue 5 Pages 100 - 32pp  
  Keywords (up) Duality in Gauge Field Theories; Perturbative QCD; Scattering Amplitudes  
  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.  
  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;  
  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:000796990400007 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5230  
Permanent link to this record
 

 
Author LHCb Collaboration (Aaij, R. et al); Martinez-Vidal, F.; Oyanguren, A.; Ruiz Valls, P.; Sanchez Mayordomo, C. url  doi
openurl 
  Title Measurement of the forward-backward asymmetry in Z/gamma* -> mu(+)mu(-) decays and determination of the effective weak mixing angle Type Journal Article
  Year 2015 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 11 Issue 11 Pages 190 - 19pp  
  Keywords (up) Electroweak interaction; Forward physics; Hadron-Hadron Scattering  
  Abstract The forward-backward charge asymmetry for the process q (q) over bar -> Z/gamma* -> mu(+)mu(-) is measured as a function of the invariant mass of the dimuon system. Measurements are performed using proton proton collision data collected with the LHCb detector at root s = 7 and 8 TeV, corresponding to integrated luminosities of 1 fb(-1) and 2 fb(-2) respectively. Within the Standard Model the results constrain the effective electroweak mixing angle to be  
  Address [Bediaga, I.; De Miranda, J. M.; Ferreira Rodrigues, F.; Gomesla, A.; Massafferri, A.; Osorio Rodrigues, B.; dos Reis, A. C.; Rodrigues, A. B.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil, Email: jprice@hep.ph.liv.ac.uk  
  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:000368080000001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2529  
Permanent link to this record
 

 
Author LHCb Collaboration (Aaij, R. et al); Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Valls, P.; Sanchez Mayordomo, C. url  doi
openurl 
  Title Measurement of forward W and Z boson production in association with jets in proton-proton collisions at root s=8 TeV Type Journal Article
  Year 2016 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 05 Issue 5 Pages 131 - 23pp  
  Keywords (up) Electroweak interaction; Forward physics; Hadron-Hadron scattering (experiments); Jet physics; QCD  
  Abstract The production of W and Z bosons in association with jets is studied in the forward region of proton-proton collisions collected at a centre-of-mass energy of 8 TeV by the LHCb experiment, corresponding to an integrated luminosity of 1.98 +/- 0.02 fb(-1). The W boson is identified using its decay to a muon and a neutrino, while the Z boson is identified through its decay to a muon pair. Total cross-sections are measured and combined into charge ratios, asymmetries, and ratios of W+jet and Z+jet production cross-sections. Differential measurements are also performed as a function of both boson and jet kinematic variables. All results are in agreement with Standard Model predictions.  
  Address [Archilli, F.; Bediaga, I.; De Miranda, J. M.; Ferreira Rodrigues, F.; Gomes, A.; Massafferri, A.; dos Reis, A. C.; Rodrigues, A. B.; Vieira, D.] Ctr Brasileiro Pesquisas Fis, Rio De Janeiro, Brazil, Email: stephen.farry@cern.ch  
  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:000377450500001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 2723  
Permanent link to this record
 

 
Author LHCb Collaboration (Aaij, R. et al); Garcia Martin, L.M.; Henry, L.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J.; Sanchez Mayordomo, C. url  doi
openurl 
  Title Measurement of Z -> tau(+)tau(-) production in proton-proton collisions at root s=8 TeV Type Journal Article
  Year 2018 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 09 Issue 9 Pages 159 - 19pp  
  Keywords (up) Electroweak interaction; Forward physics; Hadron-Hadron scattering (experiments); Lepton production; Tau Physics  
  Abstract A measurement of Z -> tau(+)tau(-) production cross-section is presented using data, corresponding to an integrated luminosity of 2 fb(-1), from pp collisions at root s = 8 TeV collected by the LHCb experiment. The tau(+)tau(-)candidates are reconstructed in final states with the first tau lepton decaying leptonically, and the second decaying either leptonically or to one or three charged hadrons. The production cross-section is measured for Z bosons with invariant mass between 60 and 120 GeV/c(2), which decay to tau leptons with transverse momenta greater than 20 GeV/c and pseudorapidities between 2.0 and 4.5. The cross-section is determined to be sigma(pp -> Z -> tau+tau-)= 95.8 +/- 2.1 +/- 4.6 +/- 0.2 +/- 1.1 pb, where the first uncertainty is statistical, the second is systematic, the third is due to the LHC beam energy uncertainty, and the fourth to the integrated luminosity uncertainty. This result is compatible with NNLO Standard model predictions. The ratio of the cross-sections for Z -> tau(+)tau(- )to Z -> mu(+)mu(-) (Z -> e(+)e(-)), determined to be 1.01 +/- 0.05 (1.02 +/- 0.06), is consistent with the lepton-universality hypothesis in Z decays.  
  Address [Bediaga, I; Cruz Torres, M.; De Miranda, J. M.; Gomes, A.; Massafferri, A.; Molina Rodriguez, J.; dos Reis, A. C.; Soares Lavra, L.; Tourinho Jadallah Aoude, R.] CBPF, Rio De Janeiro, Brazil, Email: chitsanu.khurewathanakul@cern.ch  
  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:000446181600001 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 3757  
Permanent link to this record
 

 
Author LHCb Collaboration (Aaij, R. et al); Jashal, B.K.; Martinez-Vidal, F.; Oyanguren, A.; Remon Alepuz, C.; Ruiz Vidal, J. url  doi
openurl 
  Title Precision measurement of forward Z boson production in proton-proton collisions at root s=13 TeV Type Journal Article
  Year 2022 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.  
  Volume 07 Issue 7 Pages 026 - 57pp  
  Keywords (up) Electroweak Interaction; Forward Physics; Hadron-Hadron Scattering; Particle and Resonance Production  
  Abstract A precision measurement of the Z boson production cross-section at root s = 13 TeV in the forward region is presented, using pp collision data collected by the LHCb detector, corresponding to an integrated luminosity of 5.1 fb(-1). The production cross-section is measured using Z -> mu(+)mu(-) events within the fiducial region defined as pseudorapidity 2.0 < eta < 4.5 and transverse momentum p(T) > 20 GeV/c for both muons and dimuon invariant mass 60 < M-mu μ< 120 GeV/c(2). The integrated cross-section is determined to be sigma(Z -> mu(+)mu(-)) = 196.4 +/- 0.2 +/- 1.6 +/- 3.9 pb, where the first uncertainty is statistical, the second is systematic, and the third is due to the luminosity determination. The measured results are in agreement with theoretical predictions within uncertainties.  
  Address [de Souza Leite, J. Baptista; Bediaga, I; Torres, M. Cruz; De Miranda, J. M.; dos Reis, A. C.; Falcao, L. N.; Gomes, A.; Massafferri, A.; Machado, D. Torres] Ctr Brasileiro Pesquisas Fis CBPF, Rio De Janeiro, Brazil, Email: hang.yin@cern.ch  
  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:000825333400003 Approved no  
  Is ISI yes International Collaboration yes  
  Call Number IFIC @ pastor @ Serial 5299  
Permanent link to this record
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