Speaker
Description
We measured double-strangeness systems produced in the $^{12}C(K^{-},K^{+})X$ reaction which involves a $\Xi^{-}$ hyperon and a $\Lambda\Lambda$ hyperon pair at the J-PARC using 1.8 GeV/$\mathit{c}$ $K^{-}$ beam.
The E42 experiment which has a primary goal to search for the H-dibaryon collected 300K $^{12}C(K^{-}, K^{+})X$ reaction events containing thousands of $\Lambda\Lambda$ events which is two orders of magnitude larger then ever.
In the high-momentum region of outgoing $K^{+}$ particles, low-momentum $\Xi^{-}$ hyperons are produced in the $(K^{-}, K^{+})$ reaction. Such a slow $\Xi^{-}$ hyperon may have high probability to stick up to the nucleus. It will be ended up with $\Xi N$ elastic scattering, $\Xi^{-}p\rightarrow\Xi^{0}n$ charge exchange reaction, or $\Xi^{-}p\rightarrow\Lambda\Lambda$ conversion process, unless the $\Xi^{-}$ escapes from the nucleus.
The cross-section measurement of $^{12}C(K^{-}, K^{+}\Xi^{-})$ and $^{12}C(K^{-}, K^{+}\Lambda\Lambda)$ reactions will provide crucial information on the $\Xi^{-}-N$ potential strengths and the cross-section ratio of individual processes. This talk will report the first cross-section measurement results for $^{12}C(K^{-}, K^{+}\Xi^{-})$ and $^{12}C(K^{-}, K^{+}\Lambda\Lambda)$ reactions at 1.8 GeV/$\mathit{c}$.
