77 research outputs found

    Measurements of J/psi Decays into 2(pi+pi-)eta and 3(pi+pi-)eta

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    Based on a sample of 5.8X 10^7 J/psi events taken with the BESII detector, the branching fractions of J/psi--> 2(pi+pi-)eta and J/psi-->3(pi+pi-)eta are measured for the first time to be (2.26+-0.08+-0.27)X10^{-3} and (7.24+-0.96+-1.11)X10^{-4}, respectively.Comment: 11 pages, 6 figure

    BESII Detector Simulation

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    A Monte Carlo program based on Geant3 has been developed for BESII detector simulation. The organization of the program is outlined, and the digitization procedure for simulating the response of various sub-detectors is described. Comparisons with data show that the performance of the program is generally satisfactory.Comment: 17 pages, 14 figures, uses elsart.cls, to be submitted to NIM

    Measurement of branching fractions for the inclusive Cabibbo-favored ~K*0(892) and Cabibbo-suppressed K*0(892) decays of neutral and charged D mesons

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    The branching fractions for the inclusive Cabibbo-favored ~K*0 and Cabibbo-suppressed K*0 decays of D mesons are measured based on a data sample of 33 pb-1 collected at and around the center-of-mass energy of 3.773 GeV with the BES-II detector at the BEPC collider. The branching fractions for the decays D+(0) -> ~K*0(892)X and D0 -> K*0(892)X are determined to be BF(D0 -> \~K*0X) = (8.7 +/- 4.0 +/- 1.2)%, BF(D+ -> ~K*0X) = (23.2 +/- 4.5 +/- 3.0)% and BF(D0 -> K*0X) = (2.8 +/- 1.2 +/- 0.4)%. An upper limit on the branching fraction at 90% C.L. for the decay D+ -> K*0(892)X is set to be BF(D+ -> K*0X) < 6.6%

    Study of J/ψωK+KJ/\psi \to \omega K^+K^-

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    New data are presented on J/ψωK+KJ/\psi \to \omega K^+K^- from a sample of 58M J/ψJ/\psi events in the upgraded BES II detector at the BEPC. There is a conspicuous signal for f0(1710)K+Kf_0(1710) \to K^+K^- and a peak at higher mass which may be fitted with f2(2150)KKˉf_2(2150) \to K\bar K. From a combined analysis with ωπ+π\omega \pi ^+ \pi ^- data, the branching ratio BR(f0(1710)ππ)/BR(f0(1710)KKˉ)BR(f_0(1710)\to\pi\pi)/BR(f_0(1710) \to K\bar K) is <0.11< 0.11 at the 95% confidence level.Comment: 11 pages, 5 figures. Submitted to Phys. Lett.

    Measurements of Cabibbo Suppressed Hadronic Decay Fractions of Charmed D0 and D+ Mesons

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    Using data collected with the BESII detector at e+ee^{+}e^{-} storage ring Beijing Electron Positron Collider, the measurements of relative branching fractions for seven Cabibbo suppressed hadronic weak decays D0KK+D^0 \to K^- K^+, π+π\pi^+ \pi^-, KK+π+πK^- K^+ \pi^+ \pi^- and π+π+ππ\pi^+ \pi^+ \pi^- \pi^-, D+K0ˉK+D^+ \to \bar{K^0} K^+, KK+π+K^- K^+ \pi^+ and ππ+π+\pi^- \pi^+ \pi^+ are presented.Comment: 11 pages, 5 figure

    Direct Measurement of the Pseudoscalar Decay Constant fD+

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    The absolute branching fraction of D+μ+νD^+ \to \mu^+ \nu has been directly measured by an analysis of a data sample of about 33 pb1{\rm pb^{-1}} collected around s=3.773\sqrt{s}=3.773 GeV with the BES-II at the BEPC. At these energies, DD^- meson is produced in pair as e+eD+De^+e^-\to D^{+} D^{-}. A total of 5321±149±1605321 \pm 149 \pm 160 DD^- mesons are reconstructed from this data set. In the recoil side of the tagged DD^- mesons, 2.67±1.742.67\pm1.74 purely leptonic decay events of D+μ+νD^+ \to \mu^+ \nu are observed. This yields a branching fraction of BF(D+μ+νμ)=(0.1220.053+0.111±0.010)BF(D^+ \to \mu^+ \nu_{\mu}) = (0.122^{+0.111}_{-0.053}\pm 0.010)%, and a corresponding pseudoscalar decay constant fD+=(371119+129±25)f_{D^+}=(371^{+129}_{-119}\pm 25) MeV.Comment: 7 pages, 8 figures, Submitted to Physics Letters B in October, 200

    Public Perception of Water Consumption and Its Effects on Water Conservation Behavior

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    The usual perception of consumers regarding water consumption is that their bills do not match their actual water consumption. However, this mismatch has been insufficiently studied; particularly for cases related to specific water-use patterns, water conservation practices, and user socio-demographics. In this study, a total of 776 households in 16 villages situated in the rural Wei River Basin are investigated to address the gap in the literature. Questionnaires and 3-day water diaries are used for data collection and comparison. Results show that significant relations exist between perceived water consumption and actual water consumption. Participants have different perceptions of specific water-use patterns. Participants tend to underestimate their outdoor and kitchen water consumption and overestimate their indoor water consumption. Females and elder consumers accurately estimate their water consumption, whereas consumers with high education levels and incomes underestimate their actual water consumption. The groups who can accurately estimate water consumption have better water conservation consciousness and water conservation practices than those who underestimate their water consumption. The huge disparities highlighted by the results suggest that community policies and programs to improve public water conservation consciousness or practices must be implemented to enhance consumer understanding of water consumption
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