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تسجيل مستخدم جديدSearch for the decay $D_s^+to a_0(980)^0e^+ u_e$
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Using 6.32 fb$^{-1}$ of electron-positron collision data recorded by the BESIII detector at center-of-mass energies between 4.178 and 4.226~GeV, we present the first search for the decay $D_s^+to a_0(980)^0 e^+ u_e,,a_0(980)^0rightarrow pi^0eta$, which could proceed via $a_0(980)$-$f_0(980)$ mixing. No significant signal is observed. An upper limit of $1.2 times 10^{-4}$ at the $90%$ confidence level is set on the product of the branching fractions of $D_{s}^{+}to a_0(980)^0 e^+ u_e$ and $a_0(980)^0rightarrow pi^0eta$ decays.
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Using an $e^+e^-$ collision data sample of 2.93 fb$^{-1}$ collected at a center-of-mass energy of 3.773 GeV by the BESIII detector at BEPCII, we report the observation of $D^0 to a_0(980)^- e^+ u_e$ and evidence for $D^+ to a_0(980)^0 e^+ u_e~$ wit
h significances of $6.4sigma$ and $2.9sigma$, respectively. The absolute branching fractions are determined to be $mathcal{B}(D^0 to a_0(980)^- e^+ u_e)timesmathcal{B}(a_0(980)^- to eta pi^-) = (1.33_{-0.29}^{+0.33}({rm stat})pm0.09({rm syst}))times10^{-4}~$ and $mathcal{B}(D^+ to a_0(980)^0 e^+ u_e)timesmathcal{B}(a_0(980)^0 to eta pi^0) = (1.66_{-0.66}^{+0.81}({rm stat})pm0.11({rm syst}))times10^{-4}~$. An upper limit of $mathcal{B}(D^+ to a_0(980)^0 e^+ u_e)timesmathcal{B}(a_0(980)^0 to eta pi^0)<3.0times10^{-4}~$ is also determined at the $90%~$ confidence level.
A search for the rare radiative leptonic decay $D_s^+togamma e^+ u_e$ is performed for the first time using electron-positron collision data corresponding to an integrated luminosity of 3.19 fb$^{-1}$, collected with the BESIII detector at a center-o
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Using 2.93~fb$^{-1}$ of data taken at 3.773 GeV with the BESIII detector operated at the BEPCII collider, we study the semileptonic decays $D^+ to bar K^0e^+ u_e$ and $D^+ to pi^0 e^+ u_e$. We measure the absolute decay branching fractions $mathcal B
(D^+ to bar K^0e^+ u_e)=(8.60pm0.06pm 0.15)times10^{-2}$ and $mathcal B(D^+ to pi^0e^+ u_e)=(3.63pm0.08pm0.05)times10^{-3}$, where the first uncertainties are statistical and the second systematic. We also measure the differential decay rates and study the form factors of these two decays. With the values of $|V_{cs}|$ and $|V_{cd}|$ from Particle Data Group fits assuming CKM unitarity, we obtain the values of the form factors at $q^2=0$, $f^K_+(0) = 0.725pm0.004pm 0.012$ and $f^{pi}_+(0) = 0.622pm0.012pm 0.003$. Taking input from recent lattice QCD calculations of these form factors, we determine values of the CKM matrix elements $|V_{cs}|=0.944 pm 0.005 pm 0.015 pm 0.024$ and $|V_{cd}|=0.210 pm 0.004 pm 0.001 pm 0.009$, where the third uncertainties are theoretical.
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lyzing the BESIII and {it BABAR} measurements, we conclude that the $f_0(980)$ state, dynamically generated from the $S$-wave pseudoscalar-pseudoscalar interaction, gives the dominant contribution close to the $K^+K^-$ threshold in the $K^+K^-$ invariant mass distribution of the decay $D_s^+to K^+ K^- pi^+$ in $S$-wave. On the other hand, our results imply that the lineshape adopted by BESIII and {it BABAR} for the resonances $a_0(980)$ and $f_0(980)$ is not advisable in the fit to the data close to the $K^+K^-$ threshold.
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