RT Journal Article
T1 Relevance of fermion loops for W plus W- scattering at the LHC
A1 Quezada Calonge, Carlos Ariel
A1 Dobado González, Antonio
A1 Sanz Cillero, Juan José
AB We study the one-loop corrections to W+W- elastic scattering within the framework of effective theories. Rescattering via intermediate electroweak would-be-Goldstone bosons dominate at high energies, as the corresponding loop diagrams with these intermediate bosons scale like O(s2/v4) in the chiral effective counting. In the present article, we focus our attention on the usually neglected fermion-loop corrections which scale like O(M2fers/v4) in the Higgs effective field theory (HEFT). Although this dependency is formally suppressed for s → ∞  with respect to the ones from boson loops, the large top mass can lead to a numerical competition between fermion and boson loops at intermediate energies of the order of a few TeV. The central goal of the present study is to assess the importance of these fermion loops. For this, since the fermion contribution scales with the mass of the fermions, we have calculated the imaginary part induced by loops of the heaviest fermions, top and bottom quarks, in W+W- -W+W- elastic scattering and compared them with the loop contributions from purely bosonic loops, as a large imaginary part would be a clear indicator of large fermion-loop effects. We have examined the dependence of both amplitudes on the effective couplings, allowing an O(10%) deviation from the Standard Model. In some cases, boson loops dominate over top and bottom corrections, as expected. However, we find that there are regions in the space of effective parameters that yield a significant-and even dominant-imaginary contribution from fermion loops. In addition to our conclusions for the general HEFT, we also provide analyses particularized to some benchmark points in the SO(5)/SO(4) minimal composite Higgs model.
PB American Physical Society
SN 2470-0010
YR 2023
FD 2023-05-18
LK https://hdl.handle.net/20.500.14352/135018
UL https://hdl.handle.net/20.500.14352/135018
LA eng
NO Quezada-Calonge, Carlos, et al. «Relevance of Fermion Loops for W + W − Scattering at the LHC». Physical Review D, vol. 107, n.o 9, mayo de 2023, p. 093006. DOI.org (Crossref), https://doi.org/10.1103/PhysRevD.107.093006
NO CA16108,BES-2017-082408.
NO Ministerio de Ciencia, Innovación y Universidades (España)
NO Agencia Estatal de Investigación (España)
NO European Commission
NO Ministerio de Economía y Competividad (España)
DS Docta Complutense
RD 28 abr 2026