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arXiv · 2509.00838

$S$-wave kaon-nucleon interactions from lattice QCD at the physical point

Kotaro Murakami·Sinya Aoki·Takumi Doi·Yan Lyu·Wren Yamada
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Abstract

We investigate S-wave kaon-nucleon ($KN$) interactions with strangeness $S=+1$ in lattice QCD using the time-dependent HAL QCD method. Employing the $(2+1)$-flavor gauge configuration with $m_{\pi}\approx 137~\textrm{MeV}$ and $m_{K}\approx 502~\textrm{MeV}$, we calculate the $KN$ potentials at the leading order in the derivative expansion. The potentials in both isospin channels ($I=1$ and $I=0$) exhibit repulsion at short distances, while only the $I=0$ potential has a small attractive pocket at intermediate distances. From these potentials, we compute the phase shifts as well as the low-energy scattering parameters. The obtained phase shifts show no signals corresponding to resonances or bound states in both isospin channels, suggesting the absence of the $\Theta^{+}(1540)$ pentaquark in the S-wave $KN$ systems. The results for $I=0$ suggest that the scattering amplitudes in this channel are dominated by P-wave components rather than S-wave.

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Kotaro Murakami, Sinya Aoki, Takumi Doi, Yan Lyu, Wren Yamada. 2025-08-31. $S$-wave kaon-nucleon interactions from lattice QCD at the physical point. https://arxiv.org/abs/2509.00838

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