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I=32 πK s-wave scattering length from lattice QCD

Ziwen Fu1,*, Qu-Zhi Li2,†, and Jun Wang1,‡

  • 1Key Laboratory of Radiation Physics and Technology of Education Ministry; Institute of Nuclear Science and Technology, Sichuan University, Chengdu 610064, People’s Republic of China
  • 2College of Physics, Sichuan University, Chengdu, Sichuan 610064, People’s Republic of China

  • *Contact author: fuziwen@scu.edu.cn
  • †Contact author: liquzhi@scu.edu.cn
  • ‡Contact author: wangjun@scu.edu.cn
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Phys. Rev. D 113, 034501 – Published 4 February, 2026

DOI: https://doi.org/10.1103/c66h-96wh

Abstract

The I=32 πK s-wave scattering phase shift is computed by lattice quantum chromodynamics with Nf=3 flavors of Asqtad-improved staggered fermions. The energy-eigenvalues of πK systems at one center of mass frame and six moving frames using moving wall source technique are used to get phase shifts by Lüscher’s formula and its extensions. The calculations are good enough to acquire effective range expansion parameters: scattering length a, effective range r, and shape parameter P, which are in good agreement with our explicit analytical predictions in three-flavor chiral perturbation theory at next-to-leading order. All results are fairly consistent with experimental measurements, phenomenological studies, and lattice estimations. Numerical computations are implemented at a fine (a≈0.082  fm, L3T=40396) lattice ensemble with physical quark masses.

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Phys. Rev. D 113, 034501– Published 4 February, 2026
  • Received 8 December 2025
  • Accepted 9 January 2026
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