Precise Measurements of Branching Fractions for Ds+D_s^+ Meson Decays to Two Pseudoscalar Mesons

We measure the branching fractions for seven $D_{s}^{+}$ two-body decays to pseudo-scalar mesons, by analyzing data collected at $\sqrt{s}=4.178\sim4.226$ GeV with the BESIII detector at the BEPCII collider. The branching fractions are determined to be $\mathcal{B}(D_s^+\to K^+\eta^{\prime})=(2.68\pm0.17\pm0.17\pm0.08)\times10^{-3}$, $\mathcal{B}(D_s^+\to\eta^{\prime}\pi^+)=(37.8\pm0.4\pm2.1\pm1.2)\times10^{-3}$, $\mathcal{B}(D_s^+\to K^+\eta)=(1.62\pm0.10\pm0.03\pm0.05)\times10^{-3}$, $\mathcal{B}(D_s^+\to\eta\pi^+)=(17.41\pm0.18\pm0.27\pm0.54)\times10^{-3}$, $\mathcal{B}(D_s^+\to K^+K_S^0)=(15.02\pm0.10\pm0.27\pm0.47)\times10^{-3}$, $\mathcal{B}(D_s^+\to K_S^0\pi^+)=(1.109\pm0.034\pm0.023\pm0.035)\times10^{-3}$, $\mathcal{B}(D_s^+\to K^+\pi^0)=(0.748\pm0.049\pm0.018\pm0.023)\times10^{-3}$, where the first uncertainties are statistical, the second are systematic, and the third are from external input branching fraction of the normalization mode $D_s^+\to K^+K^-\pi^+$. Precision of our measurements is significantly improved compared with that of the current world average values

Updated measurements of the M1 transition ψ(3686)→γηc(2S)\psi(3686) \to \gamma \eta_{c}(2S) with ηc(2S)→KKˉπ\eta_{c}(2S) \to K \bar{K} \pi

Based on a data sample of $(27.08 \pm 0.14 ) \times 10^8~\psi(3686)$ events collected with the BESIII detector at the BEPCII collider, the M1 transition $\psi(3686) \to \gamma \eta_{c}(2S)$ with $\eta_{c}(2S) \to K\bar{K}\pi$ is studied, where $K\bar{K}\pi$ is $K^{+} K^{-} \pi^{0}$ or $K_{S}^{0}K^{\pm}\pi^{\mp}$. The mass and width of the $\eta_{c}(2S)$ are measured to be $(3637.8 \pm 0.8 (\rm {stat}) \pm 0.2 (\rm {syst}))$ MeV/$c^{2}$ and $(10.5 \pm 1.7 (\rm {stat}) \pm 3.5 (\rm {syst}))$ MeV, respectively. The product branching fraction $\mathcal{B}\left(\psi(3686) \rightarrow \gamma \eta_{c}(2 S)\right) \times \mathcal{B}(\eta_{c}(2 S) \rightarrow K \bar{K} \pi)$ is determined to be $(0.97 \pm 0.06 (\rm {stat}) \pm 0.09 (\rm {syst})) \times 10^{-5}$. Using $\mathcal{BR}(\eta_{c}(2S)\to K\bar{K}\pi)=(1.86^{+0.68}_{-0.49})\%$, we obtain the branching fraction of the radiative transition to be $\mathcal{BR}(\psi(3686) \to \gamma \eta_{c}(2S)) = (5.2 \pm 0.3 (\rm {stat}) \pm 0.5 (\rm {syst}) ^{+1.9}_{-1.4} (extr)) \times 10^{-4}$, where the third uncertainty is due to the quoted $\mathcal{BR}(\eta_{c}(2S) \to K\bar{K}\pi)$

Updated measurement of the branching fraction of Ds+→τ+ντD_s^+\to \tau^+\nu_\tau via τ+→π+νˉτ\tau^+\to\pi^+\bar{\nu}_\tau

This paper reports the study of $D_s^+\to \tau^+\nu$ via $\tau^+\to\pi^+\bar{\nu}_\tau$ using a boosted decision tree method, with $7.33$ fb$^{-1}$ of $e^{+}e^{-}$ collision data collected by the BESIII detector at center-of-mass energies between $4.128$ and $4.226$~GeV. The branching fraction of $D_s^+\to \tau^+\nu_\tau$ is determined to be $(5.44\pm0.17_{\rm stat}\pm0.13_{\rm syst})\%$. The product of the $D_s^+$ decay constant $f_{D_s^+}$ and the CKM matrix element $|V_{cs}|$ is $f_{D_s^+}|V_{cs}| = (248.3\pm3.9_{\rm stat}\pm3.1_{\rm syst}\pm1.0_{\rm input})~\mathrm{MeV}$. Combining with the $|V_{cs}|$ value obtained from the Standard Model global fit or the $f_{D_s^+}$ from the lattice quantum chromodynamics, we determine $|V_{cs}| = 0.993\pm0.015_{\rm stat}\pm0.012_{\rm syst}\pm0.004_{\rm input}$ and $f_{D_s^+} = (255.0\pm4.0_{\rm stat}\pm3.2_{\rm syst}\pm1.0_{\rm input})~\text{MeV}$. The first uncertainty is statistical, the second one is systematic and the third one is due to the input parameters, mainly the lifetime of $D_s^+$. All results obtained in this work supersede the BESIII previous results based on 6.32 fb$^{-1}$ of $e^+e^-$ collision data taken at center-of-mass energies between $4.178$ and $4.226$~GeV

Partial Wave Analysis of J/ψ→γγϕJ/\psi\rightarrow \gamma \gamma \phi

Using a sample of $(10087\pm44)\times10^{6}$ $J/\psi$ events collected with the BESIII detector at the BEPCII collider, a partial wave analysis on the decay $\gamma\gamma\phi$ is performed to investigate the intermediate resonances in $J/\psi\rightarrow\gamma X, X\rightarrow\gamma\phi$. The resonances $f_{1}(1285)$, $\eta(1405)$, $f_{1}(1420)$, $f_{1}(1510)$, $f_{2}(1525)$, $X(1835)$, $f_{2}(1950)$, $f_{2}(2010)$, $f_{0}(2200)$ and $\eta_{c}$ are observed with statistical significance greater than 5$\sigma$. The product branching fractions $\mathcal{B}(J/\psi\rightarrow\gamma X, X\rightarrow \gamma \phi)$ are reported. The resonance parameters of $\eta(1405)$ and $X(1835)$ are also measured

Investigating the ΔI=1/2\Delta I = 1/2 rule and CP violation through the measurement of decay asymmetry parameters in Ξ−\Xi^- decays

Using $(10087\pm44)\times 10^{6}$ $J/\psi$ events collected with the BESIII detector, numerous $\Xi^-$ and $\Lambda$ decay asymmetry parameters are simultaneously determined from the process $J/\psi \to \Xi^- \bar{\Xi}^+ \to \Lambda(p\pi^-) \pi^- \bar{\Lambda}(\bar{n} \pi^0) \pi^+$ and its charge-conjugate channel. The precisions of $\alpha_0$ for $\Lambda \to n\pi^0$ and $\bar{\alpha}_0$ for $\bar{\Lambda} \to \bar{n}\pi^0$ compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decay asymmetry parameters of $\Lambda \to n\pi^0$ to that of $\Lambda \to p\pi^-$, $\langle \alpha_0 \rangle/ \langle \alpha_{\Lambda -} \rangle$, is determined to be $0.873 \pm 0.012^{+0.011}_{-0.010}$, where the first and the second uncertainties are statistical and systematic, respectively. The ratio is smaller than unity, which is predicted by the $\Delta I = 1/2$ rule, with a statistical significance of more than $5\sigma$. We test for CP violation in $\Xi^- \to \Lambda \pi^-$ and in $\Lambda \to n \pi^{0}$ with the best precision to date.Comment: 8 pages, 2 figures, 1 tabl

Measurement of e+e−→ϕη′e^{+}e^{-}\to\phi\eta' cross sections at center-of-mass energies from 3.508 to 4.951 GeV and search for the decay ψ(3770)→ϕη′\psi(3770)\to\phi\eta'

The cross sections of the $e^{+}e^{-}\to\phi\eta'$ process at center-of-mass energies from 3.508 to 4.951 GeV are measured with high precision using 26.1 fb$^{-1}$ data collected with the BESIII detector operating at the BEPCII storage ring. The cross sections are of the order of a few picobarn, and decrease as the center-of-mass energy increases as $s^{-n/2}$ with $n=4.35\pm 0.14$. This result is in agreement with the Nambu-Jona-Lasinio model prediction of $n=3.5\pm 0.9$. In addition, the charmless decay $\psi(3770)\to\phi\eta'$ is searched for by fitting the measured cross sections, yet no significant signal is observed. The upper limit of ${\cal B}(\psi(3770)\to\phi\eta')$ at the 90\% confidence level is determined to be $2.3\times 10^{-5}$

Measurement of the absolute branching fraction of the three-body decay Λc+→Ξ0K+π0\Lambda_{c}^+ \to \Xi^{0}K^{+}\pi^{0} and search for Λc+→nK+π0\Lambda_{c}^+ \to nK^+\pi^0, Σ0K+π0\Sigma^{0}K^{+}\pi^{0} and ΛK+π0\Lambda K^{+}\pi^{0}

The Cabbibo-favored decay $\Lambda_{c}^+ \to \Xi^{0}K^{+}\pi^{0}$ is studied for the first time using 6.1 fb$^{-1}$ of $e^+e^-$ collision data at center-of-mass energies between 4.600 and 4.840 GeV, collected with the BESIII detector at the BEPCII collider. With a double-tag method, the branching fraction of the three-body decay $\Lambda_{c}^+ \to \Xi^{0}K^{+}\pi^{0}$ is measured to be $(7.79 \pm 1.46 _{\rm} \pm0.71 _{\rm}) \times 10^{ - 3}$, where the first and second uncertainties are statistical and systematic, respectively. The branching fraction of the two-body decay $\Lambda_{c}^+ \to \Xi(1530)^{0}K^+$ is $(5.99\pm1.04\pm0.29)\times10^{-3}$, which is consistent with the previous result of $(5.02\pm0.99\pm0.31)\times 10^{-3}$. In addition, the upper limit on the branching fraction of the doubly Cabbibo-suppressed decay $\Lambda_{c}^+ \to nK^+\pi^0$ is $7.1 \times 10^{-4}$ at the 90$\%$ confidence level. The upper limits on the branching fractions of $\Lambda_{c}^+ \to \Sigma^{0}K^{+}\pi^{0}$ and $\Lambda K^{+}\pi^{0}$ are also determined to be $1.8\times 10^{-3}$ and $2.0 \times 10^{-3}$, respectively.Comment: 15 pages, 20 figure

Cross section measurements of e+e−→ΦK+K−e^+e^- \to \Phi K^+ K^- and e+e−→ΦKS0KS0e^+ e^- \to \Phi K_S^0 K_S^0 at center-of-mass energies between 3.7730 GeV and 4.7008 GeV

Based on 22.7 fb$^{-1}$ of $e^+e^-$ annihilation data collected at 33 different center-of-mass energies between 3.7730 GeV and 4.7008 GeV with the BESIII detector at the BEPCII collider, Born cross sections of the two processes $e^+e^-\to \phi K^+ K^-$ and $e^+ e^- \to \phi K_{S}^{0} K_{S}^{0}$ are measured for the first time. No indication of resonant production through an intermediate vector state $V$ is observed, and the upper limits on the product of the electronic width $\Gamma_{e^+e^-}$ and the branching fraction $Br(V\rightarrow \phi K \bar{K})$ of the processes $e^+e^- \to V \to \phi K^+ K^-$ and $e^+e^- \to V \to \phi K_S^0K_S^0$ at the $90\%$ confidence level are obtained for a large parameter space in resonance masses and widths. For the current world average mass and width of the $\psi(4230)$ of $m=4.2187$ GeV$/c^2$ and $\Gamma=44$ MeV, we set upper limits on the $\phi K^+ K^-$ and $\phi K_S^0K_S^0$ final states of 1.75 eV and 0.47 eV at the $90\%$ confidence level, respectively

Measurement of the e+e−→KS0KL0π0e^{+}e^{-} \to K_{S}^{0} K_{L}^{0} \pi^{0} cross sections from s=\sqrt{s}= 2.000 to 3.080 GeV

Based on $e^{+}e^{-}$ collision data collected at center-of-mass energies from 2.000 to 3.080 GeV by the BESIII detector at the BEPCII collider, a partial wave analysis is performed for the process $e^{+}e^{-}\to K_{S}^{0} K_{L}^{0} \pi^{0}$. The results allow the Born cross sections of the process $e^{+}e^{-}\to K_{S}^{0} K_{L}^{0} \pi^{0}$, as well as its subprocesses $e^{+}e^{-}\to K^{*}(892)^{0}\bar{K}$ and $K^{*}_{2}(1430)^{0}\bar{K}$ to be measured. The Born cross sections for $e^{+}e^{-}\to K_{S}^{0} K_{L}^{0}\pi^{0}$ are consistent with previous measurements by BaBar and SND, but with substantially improved precision. The Born cross section lineshape of the process $e^{+}e^{-}\to K^{*}(892)^{0}\bar{K}$ is consistent with a vector meson state around 2.2 GeV with a statistical significance of 3.2$\sigma$. A Breit-Wigner fit determines its mass as $M_Y=(2164.1\pm9.6\pm3.1)~{\rm{MeV}}/c^{2}$ and its width as $\Gamma_{Y}=(32.4\pm21.1\pm1.5)~\rm{MeV}$, where the first uncertainties are statistical and the second ones are systematic, respectively