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arXiv · 1909.02973

$I = 3$ three-pion scattering amplitude from lattice QCD

Tyler D. Blanton·Fernando Romero-López·Stephen R. Sharpe
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Abstract

We analyze the spectrum of two- and three-pion states of maximal isospin obtained recently for isosymmetric QCD with pion mass $M\approx 200\;$MeV in Ref. [1]. Using the relativistic three-particle quantization condition, we find $\sim 2 σ$ evidence for a nonzero value for the contact part of the three-$π^+$ ($I=3$) scattering amplitude. We also compare our results to leading-order chiral perturbation theory. We find good agreement at threshold, and some tension in the energy dependent part of the three-$π^+$scattering amplitude. We also find that the two-$π^+$ ($I=2$) spectrum is fit well by an $s$-wave phase shift that incorporates the expected Adler zero.

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Tyler D. Blanton, Fernando Romero-López, Stephen R. Sharpe. 2021-03-15. $I = 3$ three-pion scattering amplitude from lattice QCD. https://doi.org/10.1103/physrevlett.124.032001

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