P-wave nucleon-pion scattering amplitude in the Δ(1232) channel from lattice QCD

Giorgio Silvi, Srijit Paul, Constantia Alexandrou, Stefan Krieg, Luka Leskovec, Stefan Meinel, John Negele, Marcus Petschlies, Andrew Pochinsky, Gumaro Rendon, Sergey Syritsyn, Antonino Todaro

Research output: Contribution to journalArticlepeer-review

Abstract

We determine the Δ(1232) resonance parameters using lattice QCD and the Lüscher method. The resonance occurs in elastic pion-nucleon scattering with JP= 3/2+in the isospin I = 3/2, P-wave channel. Our calculation is performed with Nf= 2 + 1 flavors of clover fermions on a lattice with L ≈ 2.8 fm. The pion and nucleon masses are mπ= 255.4 (1.6) MeV and mN= 1073 (5) MeV, espectively, and the strong decay channel Δ πNis found to be above the threshold. To thoroughly map out the energy dependence of the nucleon-pion scattering amplitude, we compute the spectra in all relevant irreducible representations of the lattice symmetry groups for total momenta up to P= 2π/L (1, 1, 1), including irreps that mix S and P waves. We perform global fits of the amplitude parameters to up to 21 energy levels, using a Breit-Wigner model for the P-wave phase shift and the effective-range expansion for the S-wave phase shift. From the location of the pole in the P-wave scattering amplitude, we obtain the resonance mass mΔ= 1378(7)(9) MeV and the coupling gΔ-πN= 23.8(2.7)(0.9).

Original languageEnglish (US)
Article number094508
JournalPhysical Review D
Volume103
Issue number9
DOIs
StatePublished - May 1 2021

ASJC Scopus subject areas

  • Physics and Astronomy (miscellaneous)

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