Spectral parameters of the $ρ$ resonance from lattice QCD

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Auteurs principaux: Wang, Zhengli, Leinweber, Derek B., Liu, Chuan, Liu, Liuming, Sun, Peng, Thomas, Anthony W., Wu, Jia-jun, Xing, Hanyang, Yu, Kang
Format: Preprint
Publié: 2025
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author Wang, Zhengli
Leinweber, Derek B.
Liu, Chuan
Liu, Liuming
Sun, Peng
Thomas, Anthony W.
Wu, Jia-jun
Xing, Hanyang
Yu, Kang
author_facet Wang, Zhengli
Leinweber, Derek B.
Liu, Chuan
Liu, Liuming
Sun, Peng
Thomas, Anthony W.
Wu, Jia-jun
Xing, Hanyang
Yu, Kang
contents We present a lattice QCD investigation of the $ρ$ resonance using nine $N_f = 2 + 1$ Wilson-Clover ensembles with three lattice spacings and various pion masses ranging from $135$ to $320$ MeV. For each ensemble, a large number of finite volume energy levels are determined and the energy dependence of the phase shift obtained from Lüscher's finite volume method. The mass and width of the $ρ$ resonance are then extracted by assuming the Breit-Wigner form. The mass and width are extrapolated to the physical pion mass and continuum limit ($\mathcal{O}(a^2)$) using a linear function of $a^2$ and $m^2_π$. The extrapolated values for the mass and width in the Breit-Wigner form are $(m_ρ,\,Γ_ρ) = (781.6\pm10.0,\, 146.5\pm 9.9)$ MeV, which are in good agreement with experiment. An alternative method of analysis, based on Hamiltonian effective field theory, involves directly fitting the lattice energy levels and accounting for the quark mass dependence of the hadronic loop diagrams which yield the leading and next-to-leading non-analytic behaviour. This approach also yields consistent $ρ$ parameters at the physical point. This represents the most precise determination to date of the mass and width of a hadron which is unstable under strong decay, achieved through comprehensive lattice QCD calculations and methods of analysis.
format Preprint
id arxiv_https___arxiv_org_abs_2502_03700
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Spectral parameters of the $ρ$ resonance from lattice QCD
Wang, Zhengli
Leinweber, Derek B.
Liu, Chuan
Liu, Liuming
Sun, Peng
Thomas, Anthony W.
Wu, Jia-jun
Xing, Hanyang
Yu, Kang
High Energy Physics - Lattice
High Energy Physics - Phenomenology
We present a lattice QCD investigation of the $ρ$ resonance using nine $N_f = 2 + 1$ Wilson-Clover ensembles with three lattice spacings and various pion masses ranging from $135$ to $320$ MeV. For each ensemble, a large number of finite volume energy levels are determined and the energy dependence of the phase shift obtained from Lüscher's finite volume method. The mass and width of the $ρ$ resonance are then extracted by assuming the Breit-Wigner form. The mass and width are extrapolated to the physical pion mass and continuum limit ($\mathcal{O}(a^2)$) using a linear function of $a^2$ and $m^2_π$. The extrapolated values for the mass and width in the Breit-Wigner form are $(m_ρ,\,Γ_ρ) = (781.6\pm10.0,\, 146.5\pm 9.9)$ MeV, which are in good agreement with experiment. An alternative method of analysis, based on Hamiltonian effective field theory, involves directly fitting the lattice energy levels and accounting for the quark mass dependence of the hadronic loop diagrams which yield the leading and next-to-leading non-analytic behaviour. This approach also yields consistent $ρ$ parameters at the physical point. This represents the most precise determination to date of the mass and width of a hadron which is unstable under strong decay, achieved through comprehensive lattice QCD calculations and methods of analysis.
title Spectral parameters of the $ρ$ resonance from lattice QCD
topic High Energy Physics - Lattice
High Energy Physics - Phenomenology
url https://arxiv.org/abs/2502.03700