Observation of charmed strange meson pair production in ϒð2SÞ decays and in e + e − annihilation at s=10.52 GeV
Abstrakt
We observe the process ϒð2SÞ RIGHTWARDS ARROW DðÞþ s D- sJ and continuum production eþe- RIGHTWARDS ARROW DðÞþ s D- sJ at ffiffiffi s p 1/4 10.52 GeV (and their charge conjugates) using the data samples collected by the Belle detector at KEKB, where D- sJ is Ds1
ð2536Þ- or D s2
ð2573Þ-. Both D- sJ states are identified through their decay into K- D- ðÞ.
We measure the products of branching fractions Bðϒð2SÞ RIGHTWARDS ARROW DðÞþ s D- sJ
ÞBðD- sJ RIGHTWARDS ARROW K- D- ðÞÞ and the Born cross sections σBornðeþe- RIGHTWARDS ARROW DðÞþ s D- sJ
ÞBðD- sJ RIGHTWARDS ARROW K- D- ðÞÞ, and then compare the ratios R1
IDENTICAL TO Bðϒð2SÞ RIGHTWARDS ARROW
DðÞþ s D- sJ
Þ=Bðϒð2SÞ RIGHTWARDS ARROW μþμ-Þ for ϒð2SÞ decays and R2
IDENTICAL TO σBornðeþe- RIGHTWARDS ARROW DðÞþ s D- sJ
Þ=σBornðeþe- RIGHTWARDS ARROW
μþμ-Þ for continuum production. We obtain R1=R2 1/4 9.7 2.3 1.1, 6.8 2.1 0.8, 10.2 3.3 2.5, and 3.4 2.1 0.8 for the Dþs
Ds1
ð2536Þ-, Dþ s Ds1
ð2536Þ-, Dþs
D s2
ð2573Þ-, and
Dþ s D s2
ð2573Þ- final states in the D- sJ RIGHTWARDS ARROW K-D- ðÞ0 modes, respectively. The measured R1=R2 values indicate that the strong decay dominates in ϒð2SÞ RIGHTWARDS ARROW DðÞþ s D- sJ processes. We also measure the ratios of branching fractions BðDs1
ð2536Þ- RIGHTWARDS ARROW K0
SDð2010Þ-Þ=BðDs1
ð2536Þ- RIGHTWARDS ARROW K-Dð2007Þ0Þ 1/4 0.48 0.07 0.02 and BðD s2
ð2573Þ- RIGHTWARDS ARROW K0
SD-Þ=BðD s2
ð2573Þ- RIGHTWARDS ARROW K-D0Þ 1/4 0.49 0.10 0.02, which are consistent with isospin symmetry. The second ratio is the first measurement of this quantity. Here, the first uncertainties are statistical and the second are systematic.