Alfonso Albero, AlejandroCalvo Gómez, MíriamCamboni, AlessandroCoquereau, SamuelGarrido Beltrán, LluísGascón Fora, DavidGironella Gironell, PereGraciani Díaz, RicardoGraugés Pous, EugeniVilasis-Cardona, XavierLHCb Collaboration2021-03-092021-03-092020-01-212470-0010https://hdl.handle.net/2445/174766The results of an amplitude analysis of the charmless three-body decay B+→π+π+π−, in which CP-violation effects are taken into account, are reported. The analysis is based on a data sample corresponding to an integrated luminosity of 3  fb−1 of pp collisions recorded with the LHCb detector. The most challenging aspect of the analysis is the description of the behavior of the π+π−  S-wave contribution, which is achieved by using three complementary approaches based on the isobar model, the K-matrix formalism, and a quasi-model-independent procedure. Additional resonant contributions for all three methods are described using a common isobar model, and include the ρ(770)0, ω(782) and ρ(1450)0 resonances in the π+π− P-wave, the f2(1270) resonance in the π+π− D-wave, and the ρ3(1690)0 resonance in the π+π− F-wave. Significant CP-violation effects are observed in both S- and D-waves, as well as in the interference between the S- and P-waves. The results from all three approaches agree and provide new insight into the dynamics and the origin of CP-violation effects in B+→π+π+π− decays.46 p.application/pdfeng(c) American Physical Society, 2020Gran Col·lisionador d'HadronsFísica de partículesLarge Hadron Collider (France and Switzerland)Particle physicsinfo:eu-repo/semantics/article7062182021-03-09info:eu-repo/semantics/openAccess