Measurement of the branching ratio for Υ(1S) state intoπ+π− andsearch for decaysΥ(1S)→π+π−,K+K−,p <img src="/fullt

In the experiment withe⁺e⁻-beams performed at the VEPP-4 storage ring with the MD-1 detector we have measuredB_μμ, the branching ratio for the decay of Υ(1S) state intoμ⁺μ⁻. We obtainedB_μμ=(2.12+0.20+0.10)%. It is shown that the continuum and resonance interference should be taken into account. For the first time the upper limits on the branching ratio for the decaysΥ→π⁺π⁻,K⁺K⁻,p <img src="/fulltext-image.asp?format=htmlnonpaginated&src=P27N147HM13Q365K_html\10052_2005_Article_BF01566650_TeX2GIFIE2.gif" border="0" alt=" $$\bar p$$ " /> have been measured: Br(Υ→π⁺π⁻)<5·10⁻⁴, Br(Υ→K⁺K⁻)<5·10⁻⁴, Br(Υ→p <img src="/fulltext-image.asp?format=htmlnonpaginated&src=P27N147HM13Q365K_html\10052_2005_Article_BF01566650_TeX2GIFIE3.gif" border="0" alt=" $$\bar p$$ " /><9·10⁻⁴ (90% CL).