اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدHigher-order multipole amplitude measurement in $psi(2S)togammachi_{c2}$
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BESIII Collaboration
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Using $106times10^6$ $psi(2S)$ events collected with the BESIII detector at the BEPCII storage ring, the higher-order multipole amplitudes in the radiative transition $psi(2S)togammachi_{c2}togammapipi/gamma KK$ are measured. A fit to the $chi_{c2}$ production and decay angular distributions yields $M2=0.046pm0.010pm0.013$ and $E3=0.015pm0.008pm0.018$, where the first errors are statistical and the second systematic. Here $M2$ denotes the normalized magnetic quadrupole amplitude and $E3$ the normalized electric octupole amplitude. This measurement shows evidence for the existence of the $M2$ signal with $4.4sigma$ statistical significance and is consistent with the charm quark having no anomalous magnetic moment.
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Using 106~million $psi(3686)$ events collected with the BESIII detector, we measure multipole amplitudes for the decay $psi(3686)rightarrowgammachi_{c1,2}togammagamma J/psi$ beyond the dominant electric-dipole amplitudes. The normalized magnetic-quad
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re obtained, which allows a proper estimation of the detection efficiency using helicity amplitude information. In addition, the sensitivities of measurement of hyperon asymmetry decay parameters for these processes are discussed.
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