Timelike meson form-factors beyond the elastic region from lattice QCD
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arXiv
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| Format: | Preprint |
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2024
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| _version_ | 1866929441818542080 |
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| author | Ortega-Gama, Felipe Dudek, Jozef Edwards, Robert |
| author_facet | Ortega-Gama, Felipe Dudek, Jozef Edwards, Robert |
| contents | We present a calculation of the vector-isovector timelike form-factors of the pion and the kaon using lattice quantum chromodynamics. We calculate two-point correlation functions with $m_π\sim 280$ MeV, extracting both the finite-volume spectrum and matrix elements for these states created from the vacuum by a vector current. After determining the coupled-channel $ππ, K\overline{K}$ scattering amplitudes, we perform the necessary correction for the significant finite-volume effects present in the current matrix elements, leading to the timelike form-factors. We find these to be dominated by the presence of the $ρ$ resonance, and we extract its decay constant by an analytic continuation of the amplitudes to the resonance pole. In addition, the spacelike pion form-factor is determined on the same lattice configurations, and a dispersive parameterization is used to simultaneously describe the spacelike and elastic timelike regions. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2407_20617 |
| institution | arXiv |
| publishDate | 2024 |
| record_format | arxiv |
| spellingShingle | Timelike meson form-factors beyond the elastic region from lattice QCD Ortega-Gama, Felipe Dudek, Jozef Edwards, Robert High Energy Physics - Lattice High Energy Physics - Phenomenology We present a calculation of the vector-isovector timelike form-factors of the pion and the kaon using lattice quantum chromodynamics. We calculate two-point correlation functions with $m_π\sim 280$ MeV, extracting both the finite-volume spectrum and matrix elements for these states created from the vacuum by a vector current. After determining the coupled-channel $ππ, K\overline{K}$ scattering amplitudes, we perform the necessary correction for the significant finite-volume effects present in the current matrix elements, leading to the timelike form-factors. We find these to be dominated by the presence of the $ρ$ resonance, and we extract its decay constant by an analytic continuation of the amplitudes to the resonance pole. In addition, the spacelike pion form-factor is determined on the same lattice configurations, and a dispersive parameterization is used to simultaneously describe the spacelike and elastic timelike regions. |
| title | Timelike meson form-factors beyond the elastic region from lattice QCD |
| topic | High Energy Physics - Lattice High Energy Physics - Phenomenology |
| url | https://arxiv.org/abs/2407.20617 |