The decay of Ksub(L)0 into two muons

Preliminary results of an experiment to measure the decay rate for Ksub(L)sup(0) → μ+μ- are reported. The experiment is performed in a high-intensity Ksub(L)sup(0) beam with Ksub(L)sup(0)'s momenta between 2 and 7 GeV/c. The Ksub(L) decay products have been analyzed in a double-arm magnetic spectrometer. Mass and angular distributions of the Ksub(L)sup(0) → μ+μ- events are measured and found to agree well with those obtained for the Ksub(L)sup(0) → π+π- normalization data. Using acceptances calculated by Monte Carlo the Ksub(L)sup(0) → μ+μ- branching ratio has been determined, GITA Ksub(L)sup(0) → μsup(+)μsup(-)/GITA(Ksub(L)sup(0) → all)=(7.2sub(-1.5)sup(+2.4)x10sup(-9). Changes in each cut i.e., criteria which the events are supposed to meet) produce little effect on the result as compared to the systematic error. The results of the experiment are consistent with those previously obtained