Two-pole nature of the $Λ(1405)$ from lattice QCD
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| Main Authors: | , , , , , , , , , , |
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| Format: | Preprint |
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2023
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| _version_ | 1866915558007504896 |
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| author | Bulava, John Cid-Mora, Bárbara Hanlon, Andrew D. Hörz, Ben Mohler, Daniel Morningstar, Colin Moscoso, Joseph Nicholson, Amy Romero-López, Fernando Skinner, Sarah Walker-Loud, André |
| author_facet | Bulava, John Cid-Mora, Bárbara Hanlon, Andrew D. Hörz, Ben Mohler, Daniel Morningstar, Colin Moscoso, Joseph Nicholson, Amy Romero-López, Fernando Skinner, Sarah Walker-Loud, André |
| contents | This letter presents the first lattice QCD computation of the coupled channel $πΣ-\bar{K}N$ scattering amplitudes at energies near $1405\,{\rm MeV}$. These amplitudes contain the resonance $Λ(1405)$ with strangeness $S=-1$ and isospin, spin, and parity quantum numbers $I(J^P)=0(1/2^-)$. However, whether there is a single resonance or two nearby resonance poles in this region is controversial theoretically and experimentally. Using single-baryon and meson-baryon operators to extract the finite-volume stationary-state energies to obtain the scattering amplitudes at slightly unphysical quark masses corresponding to $m_π\approx200$ MeV and $m_K\approx487$ MeV, this study finds the amplitudes exhibit a virtual bound state below the $πΣ$ threshold in addition to the established resonance pole just below the $\bar{K}N$ threshold. Several parametrizations of the two-channel $K$-matrix are employed to fit the lattice QCD results, all of which support the two-pole picture suggested by $SU(3)$ chiral symmetry and unitarity. |
| format | Preprint |
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arxiv_https___arxiv_org_abs_2307_10413 |
| institution | arXiv |
| publishDate | 2023 |
| record_format | arxiv |
| spellingShingle | Two-pole nature of the $Λ(1405)$ from lattice QCD Bulava, John Cid-Mora, Bárbara Hanlon, Andrew D. Hörz, Ben Mohler, Daniel Morningstar, Colin Moscoso, Joseph Nicholson, Amy Romero-López, Fernando Skinner, Sarah Walker-Loud, André High Energy Physics - Lattice High Energy Physics - Phenomenology Nuclear Experiment Nuclear Theory This letter presents the first lattice QCD computation of the coupled channel $πΣ-\bar{K}N$ scattering amplitudes at energies near $1405\,{\rm MeV}$. These amplitudes contain the resonance $Λ(1405)$ with strangeness $S=-1$ and isospin, spin, and parity quantum numbers $I(J^P)=0(1/2^-)$. However, whether there is a single resonance or two nearby resonance poles in this region is controversial theoretically and experimentally. Using single-baryon and meson-baryon operators to extract the finite-volume stationary-state energies to obtain the scattering amplitudes at slightly unphysical quark masses corresponding to $m_π\approx200$ MeV and $m_K\approx487$ MeV, this study finds the amplitudes exhibit a virtual bound state below the $πΣ$ threshold in addition to the established resonance pole just below the $\bar{K}N$ threshold. Several parametrizations of the two-channel $K$-matrix are employed to fit the lattice QCD results, all of which support the two-pole picture suggested by $SU(3)$ chiral symmetry and unitarity. |
| title | Two-pole nature of the $Λ(1405)$ from lattice QCD |
| topic | High Energy Physics - Lattice High Energy Physics - Phenomenology Nuclear Experiment Nuclear Theory |
| url | https://arxiv.org/abs/2307.10413 |