1. Search for a bound state of kaon and pion
- Author
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Kishimoto, T., Khanam, F., Hayakawa, T., Ajimura, S., Itabashi, T., Matsuoka, K., Minami, S., Mitoma, Y., Sakaguchi, A., Shimizu, Y., Terai, K., Sato, T., Noumi, H., Sekimoto, M., Takahashi, H., Fukuda, T., Imoto, W., and Mizoi, Y.
- Subjects
High Energy Physics - Experiment ,Nuclear Experiment - Abstract
We have searched for a bound state of kaon and pion denoted by $X$. The $X$ was conjectured to explain the so-called $\Theta^+$ resonance as a bound state of kaon, pion and nucleon. This model explains almost all properties of the $\Theta^+$, however, the model works only if the $K \pi$ interaction is strongly attractive. It is so strong that it could make a bound state $X$. Here we report a result of the search for the $X$ by using the $K^+ + N \rightarrow X^+ + N$ reaction at P$_K\sim$ 1.2 GeV/c. The $X^+ \rightarrow K^+ \gamma \gamma$ decay produces $K^+$ in momentum region where other processes cannot fill. We observed signature of the $X^+$ with statistical significance of 2 $\sigma$. Production cross section of $X$ with respect to that of $\pi^0$ is 1$\pm$0.5% if we take it as an evidence and 1.5% if we set an upper limit., Comment: 7 pages, 3 figures
- Published
- 2012