اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدFeasibility study of measuring $bto sgamma$ photon polarisation in $D^0rightarrow K_1(1270)^- e^+ u_e$ at STCF
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We report a sensitive study of measuring $bto sgamma$ photon polarisation in $D^{0}to K_1(1270)^-e^+ u_e$ with an integrated luminosity of $mathcal L$ = 1 ab$^{-1}$ at a center-of-mass energy of 3.773 GeV at future Super Tau Charm Facility. More than 61,000 signals of $D^{0}to K_1(1270)^-e^+ u_e$ are expected. Based on a fast simulation software package, the statistical sensitivity for the ratio of up-down asymmetry is estimated to be $1.5times 10^{-2}$ by performing a two-dimensional angular analysis in $D^{0}to K_1(1270)^-e^+ u_e$. Combining with measurements of up-down asymmetry in $Bto K_1gamma$, the photon polarisation in $bto sgamma$ can be determined model-independently.
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Using 2.93 fb$^{-1}$ of $e^+e^-$ collision data taken with the BESIII detector at a center-of-mass energy of 3.773 $rm ,GeV$, the observation of the $D^0to K_1(1270)^- e^+ u_e$ semileptonic decay is presented. The statistical significance of the deca
y $D^0to K_1(1270)^- e^+ u_e$ is greater than $10sigma$. The branching fraction of $D^0to K_1(1270)^- e^+ u_e$ is measured to be $(1.09pm0.13^{+0.09}_{-0.16} pm 0.12)times10^{-3}$. Here, the first uncertainty is statistical, the second is systematic, and the third originates from the assumed branching fraction of $K_1(1270)^- rightarrow K^-pi^+pi^-$. The fraction of longitudinal polarization in $D^0to K_1(1270)^- e^+ u_e$ is determined for the first time to be $0.50pm0.19_{rm stat}pm0.08_{rm syst}$.
We report a study of the decay $D^0 rightarrow bar{K}^0pi^-e^+ u_{e}$ based on a sample of $2.93~mathrm{fb}^{-1}$ $e^+e^-$ annihilation data collected at the center-of-mass energy of 3.773~GeV with the BESIII detector at the BEPCII collider. The tota
l branching fraction is determined to be $mathcal{B}(D^0rightarrow bar{K}^0pi^-e^+ u_{e})=(1.434pm0.029({rm stat.})pm0.032({rm syst.}))%$, which is the most precise to date. According to a detailed analysis of the involved dynamics, we find this decay is dominated with the $K^{*}(892)^-$ contribution and present an improved measurement of its branching fraction to be $mathcal{B}(D^0rightarrow K^{*}(892)^-e^+ u_e)=(2.033pm0.046({rm stat.})pm0.047({rm syst.}))%$. We further access their hadronic form-factor ratios for the first time as $r_{V}=V(0)/A_1(0)=1.46pm0.07({rm stat.})pm0.02({rm syst.})$ and $r_{2}=A_2(0)/A_1(0)=0.67pm0.06({rm stat.})pm0.01({rm syst.})$. In addition, we observe a significant $bar{K}^0pi^-$ $S$-wave component accounting for $(5.51pm0.97({rm stat.})pm0.62({rm syst.}))%$ of the total decay rate.
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