Pseudoscalar Mass and Decay Constant in Lattice QCD with Exact Chiral Symmetry

TL;DR

This paper calculates the masses and decay constants of pseudoscalar mesons D, D_s, and K using quenched lattice QCD with exact chiral symmetry, providing results consistent with experimental data.

Contribution

The study presents the first determination of pseudoscalar meson decay constants in quenched lattice QCD with exact chiral symmetry, fixing quark masses and lattice spacing through experimental inputs.

Findings

Calculated decay constants: f_K=152(6)(10) MeV, f_D=235(8)(14) MeV, f_{D_s}=266(10)(18) MeV.

Results agree with recent experimental measurements.

Determined quark masses and lattice spacing consistent with physical meson masses.

Abstract

The masses and decay constants of pseudoscalar mesons $ D $, $ D_s $, and $ K $ are determined in quenched lattice QCD with exact chiral symmetry. For 100 gauge configurations generated with single-plaquette action at $ \beta = 6.1 $ on the $ 20^3 \times 40 $ lattice, we compute point-to-point quark propagators for 30 quark masses in the range $ 0.03 \le m_q a \le 0.80 $, and measure the time-correlation functions of pseudoscalar and vector mesons. The inverse lattice spacing $ a^{-1} $ is determined with the experimental input of $ f_\pi $, while the strange quark bare mass ($ m_s a = 0.08 $), and the charm quark bare mass ($ m_c a = 0.80 $) are fixed such that the masses of the corresponding vector mesons are in good agreement with $ \phi(1020) $ and $ J/\psi(3097) $ respectively. Our results of pseudoscalar-meson decay constant are: $ f_K = 152(6)(10) $ MeV, $ f_D = 235(8)(14)$ MeV, and $ f_{D_s} = 266(10)(18) $ MeV [hep-ph/0506266]. The latest experimental result of $ f_{D^+} $ from CLEO [hep-ex/0508057] is in good agreement with our prediction.