Search for D⁰ → γγ and Improved Measurement of the Branching Fraction for D⁰ → π⁰π⁰
Date
2015-06-26
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Amer Physical Soc
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Abstract
Using 2.92 fb⁻¹ of electron-positron annihilation data collected at √s̅ = 3.773 GeV with the BESIII detector, we report the results of a search for the flavor-changing neutral current process D⁰ → γγ using a double-tag technique. We find no signal and set an upper limit at 90% confidence level for the branching fraction of ℬ(D⁰ → γγ) < 38 x 10⁻⁶. W also investigate D⁰ meson decay into two neutral pions, obtaining a branching fraction of ℬ{D⁰ → π⁰π⁰ = (8.24 ± 0.21(stat) ± 0.30(syst)) x 10⁻⁴, the most precise measurement to date and consistent with the current world average.
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Quantum flavor dynamics, Branching fractions (Nuclear physics), Causality (Physics), Quantum flavor dynamics, Radioactive decay, Mesons, Photons
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This work is supported in part by National Key Basic Research Program of China under Contract No. 2015CB856700; National Natural Science Foundation of China (NSFC) under Contracts Nos. 11125525, 11235011, 11322544, 11335008, 11425524; Joint Large-Scale Scientific Facility Funds of the NSFC and CAS under Contracts Nos. 11179007, 11179014, U1232201, U1332201; CAS under Contracts Nos. KJCX2-YW-N29, KJCX2-YW-N45; German Research Foundation DFG under Contract No. Collaborative Research Center CRC-1044; Ministry of Development of Turkey under Contract No. DPT2006K-120470; Russian Foundation for Basic Research under Contract No. 14-07-91152; U.S. Department of Energy under Contracts Nos. DE-FG02-04ER41291, DE-FG02-05ER41374, DE-FG02-94ER40823, DESC0010118; WCU Program of National Research Foundation of Korea under Contract No. R32-2008-000-10155-0.
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©2015 American Physical Society