arXiv subjects

K. Fischer

Publications and source records attributed to K. Fischer.

At least 19 recordsLinked to original sources

arXiv2025

Measurement of Born Cross Sections and Effective Form Factors of $e^+e^-\to \Omega^{-}\bar{\Omega}^{+}$ from$\sqrt{s}$ = 3.7 to 4.7 GeV

Using $e^+e^-$ collision data corresponding to an integrated luminosity of 22.7 fb$^{-1}$, collected at center-of-mass energies between 3.7 and 4.7 GeV with the BESIII detector at the BEPCII storage ring, we measure the energy-dependent Born cross sections of $e^+e^-\to \Omega^{-}\bar{\Omega}^+$ and the effective form factors of the $\Omega^-$ baryon. The analysis employs a single baryon tagging method, and the results are consistent with theoretical predictions, providing critical constraints on the electromagnetic structure of the $\Omega^-$ hyperon. No significant signal of charmonium or charmonium-like states decaying to $\Omega^{-}\bar{\Omega}^+$ is observed in the investigated energy range.

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arXiv2025

Test of local realism via entangled $\Lambda\bar\Lambda$ system

The non-locality of quantum correlations is a fundamental feature of quantum theory. The Bell inequality serves as a benchmark for distinguishing between predictions made by quantum theory and local hidden variable theory (LHVT). Recent advancements in photon-entanglement experiments have addressed potential loopholes and have observed significant violations of variants of Bell inequality. However, examples of Bell inequalities violation in high energy physics are scarce. In this study, we utilize $(10.087\pm0.044)\times10^{9}$ $J/\psi$ events collected with the BES-III detector at the BEPCII collider, performing non-local correlation tests using the entangled hyperon pairs. The massive-entangled $\Lambda\bar\Lambda$ systems are formed and decay through strong and weak interactions, respectively. Through measurements of the angular distribution of $p\bar{p}$ in $J/\psi\to \gamma\eta_c$ and subsequent $\eta_c\to\Lambda(p\pi^-)\bar\Lambda(\bar{p}\pi^{+})$ cascade decays, a significant violation of LHVT predictions is observed. The exclusion of LHVT is found to be statistically significant at a level exceeding $5.2\sigma$ in the testing of three Bell-like inequalities.

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arXiv2025

Observation of resonant contribution to the $e^+e^-\to \Omega^{-}\bar{\Omega}^{+}$ around 4.2 GeV and evidence of $\psi(3770)\to \Omega^{-}\bar{\Omega}^{+}$

Using $e^+e^-$ collision data corresponding to a total integrated luminosity of 22.7 fb$^{-1}$, collected at center-of-mass energies between 3.7 and 4.7 GeV with the BESIII detector, we present a measurement of energy-dependent cross sections and effective form factors for the process of $e^+e^-\to \Omega^{-}\bar{\Omega}^+$. By conducting a fit to the cross sections of $e^+e^-\to \Omega^{-}\bar{\Omega}^+$ considering the continuum and resonant contributions, a clear resonant structure in the spectrum around 4.2 GeV is observed for the first time with a statistical significance exceeding 10$\sigma$, and it can be well described with the line shape of the $Y(4230)$ and $Y(4320)$ observed in $e^+e^-\to \pi^{+}\pi^{-}J/\psi$. Evidence for the decay $\psi(3770) \to \Omega^-\bar{\Omega}^{+}$ is observed with a statistical significance of 4.4$\sigma$ by analyzing the measured cross sections together with earlier BESIII results, and the branching fraction is firstly measured to be $(4.0\pm1.0\pm0.6)$ $\times$ $10^{-5}$, where the first uncertainty is statistical and the second is systematic.

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arXiv2024

Observation of an axial-vector state in the study of $\psi(3686) \to \phi \eta \eta'$ decay

Using (2712.4 $\pm$ 14.3)$\times 10^{6}$ $\psi(3686)$ events collected with the BESIII detector at BEPCII, a partial wave analysis of the decay $\psi(3686) \to \phi \eta \eta' $ is performed with the covariant tensor approach. An axial-vector state with a mass near 2.3 $\rm GeV/c^2$ is observed for the first time. Its mass and width are measured to be 2316 $\pm 9_{\mathrm{stat}} \pm 30_{\mathrm{syst}}\,\rm MeV/c^2$ and 89 $\pm 15_{\mathrm{stat}} \pm 26_{\mathrm{syst}}\,\rm MeV$, respectively. The product branching fractions of $\mathcal{B}(\psi(3686) \to X(2300) \eta') \mathcal{B}(X(2300)\to \phi \eta)$ and $\mathcal{B}(\psi(3686) \to X(2300) \eta)\mathcal{B}(X(2300)\to \phi \eta')$ are determined to be (4.8 $\pm 1.3_{\mathrm{stat}} \pm 0.7_{\mathrm{syst}})\times 10^{-6}$ and (2.2 $\pm 0.7_{\mathrm{stat}} \pm 0.7_{\mathrm{syst}})\times 10^{-6}$, respectively. The branching fraction $\mathcal{B}(\psi(3686) \to \phi \eta \eta')$ is measured for the first time to be (3.14$\pm0.17_{\mathrm{stat}}\pm0.24_{\mathrm{syst}})\times10^{-5}$. The first uncertainties are statistical and the second are systematic.

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arXiv2024

Search for the Rare Decays $D_s^+\to h^+(h^{0})e^+e^-$

Using 7.33~fb$^{-1}$ of $e^{+}e^{-}$ collision data collected by the BESIII detector at center-of-mass energies in the range of $\sqrt{s}=4.128 - 4.226$~GeV, we search for the rare decays $D_{s}^+\to h^+(h^{0})e^{+}e^{-}$, where $h$ represents a kaon or pion. By requiring the $e^{+}e^{-}$ invariant mass to be consistent with a $\phi(1020)$, $0.98<M(e^{+}e^{-})<1.04$ ~GeV/$c^2$, the decay $D_s^+\to\pi^+\phi,\phi\to e^{+}e^{-}$ is observed with a statistical significance of 7.8$\sigma$, and evidence for the decay $D_s^+\to\rho^+\phi,\phi\to e^{+}e^{-}$ is found for the first time with a statistical significance of 4.4$\sigma$. The decay branching fractions are measured to be $\mathcal{B}(D_s^+\to\pi^+\phi, \phi\to e^{+}e^{-} )=(1.17^{+0.23}_{-0.21}\pm0.03)\times 10^{-5}$, and $\mathcal{B}(D_s^+\to\rho^+\phi, \phi\to e^{+}e^{-} )=(2.44^{+0.67}_{-0.62}\pm 0.16)\times 10^{-5}$, where the first uncertainties are statistical and the second systematic. No significant signal for the three four-body decays of $D_{s}^{+}\to \pi^{+}\pi^{0}e^{+}e^{-},\ D_{s}^{+}\to K^{+}\pi^{0}e^{+}e^{-}$, and $D_{s}^{+}\to K_{S}^{0}\pi^{+}e^{+}e^{-}$ is observed. For $D_{s}^{+}\to \pi^{+}\pi^{0}e^{+}e^{-}$, the $\phi$ mass region is vetoed to minimize the long-distance effects. The 90$\%$ confidence level upper limits set on the branching fractions of these decays are in the range of $(7.0-8.1)\times 10^{-5}$.

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arXiv2024

Search for di-photon decays of an axion-like particle in radiative $J/\psi$ decays

We search for the di-photon decay of a light pseudoscalar axion-like particle, $a$, in radiative $J/\psi$ decays, using 10 billion $J/\psi$ events collected with the BESIII detector. We find no evidence of a signal and set upper limits at the $95\%$ confidence level on the product branching fraction $\mathcal{B}(J/\psi \to \gamma a) \times \mathcal{B}(a \to \gamma \gamma)$ and the axion-like particle photon coupling constant $g_{a \gamma \gamma}$ in the ranges of $(3.7-48.5) \times 10^{-8}$ and $(2.2 -101.8)\times 10^{-4}$ GeV$^{-1}$, respectively, for $0.18 \le m_a \le 2.85$ GeV/$c^2$. These are the most stringent limits to date in this mass region.

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arXiv2024

Search for the production of deuterons and antideuterons in e^+e^- annihilation at center-of-mass energies between 4.13 and 4.70 GeV

Using a data sample of $e^+e^-$ collision data corresponding to an integrated luminosity of 19 fb$^{-1}$ collected with the BESIII detector at the BEPCII collider, we search for the production of deuterons and antideuterons via $e^+e^-\to pp\pi^-\bar{d}+c.c.$ for the first time at center-of-mass energies between 4.13 and 4.70 GeV. No significant signal is observed and the upper limit of the $e^+e^-\to pp\pi^-\bar{d}+c.c.$ cross section is determined to be from 9.0 to 145 fb depending on the center-of-mass energy at the $90\%$ confidence level.

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arXiv2024

Measurement of the Electromagnetic Transition Form-factors in the decays $\eta'\rightarrow\pi^+\pi^-l^+l^-$

With a sample of $(10087\pm44)\times10^{6}$ $J/\psi$ events accumulated with the BESIII detector, we analyze the decays $\eta'\rightarrow\pi^+\pi^-l^+l^-(l=e,$ $\mu)$ via the process $J/\psi\rightarrow\gamma\eta'$. The branching fractions are measured to be $\mathcal{B}(\eta'\rightarrow\pi^+\pi^-e^+e^-)=(2.45\pm0.02(\rm{stat.})\pm0.08(\rm{syst.})) \times10^{-3}$ and $\mathcal{B}(\eta'\rightarrow\pi^+\pi^-\mu^+\mu^-)=(2.16\pm0.12(\rm{stat.})\pm0.06(\rm{syst.}))\times10^{-5}$, and the ratio is $\frac{\mathcal{B}(\eta'\rightarrow\pi^{+}\pi^{-}e^{+}e^{-})}{\mathcal{B}(\eta'\rightarrow\pi^{+}\pi^{-}\mu^{+}\mu^{-})} = 113.4\pm0.9(\rm{stat.})\pm3.7(\rm{syst.})$. In addition, by combining the $\eta'\rightarrow\pi^+\pi^-e^+e^-$ and $\eta'\rightarrow\pi^+\pi^-\mu^+\mu^-$ decays, the slope parameter of the electromagnetic transition form factor is measured to be $b_{\eta'}=1.30\pm0.19\ (\mathrm{GeV}/c^{2})^{-2}$, which is consistent with previous measurements from BESIII and theoretical predictions from the VMD model. The asymmetry in the angle between the $\pi^+\pi^-$ and $l^+l^-$ decay planes, which has the potential to reveal the $CP$-violation originating from an unconventional electric dipole transition, is also investigated. The asymmetry parameters are determined to be $\mathcal{A}_{CP}(\eta'\rightarrow\pi^+\pi^-e^+e^-)=(-0.21\pm0.73(\rm{stat.})\pm0.01(\rm{syst.}))\%$ and $\mathcal{A}_{CP}(\eta'\rightarrow\pi^+\pi^-\mu^+\mu^-)=(0.62\pm4.71(\rm{stat.})\pm0.08(\rm{syst.}))\%$, implying that no evidence of $CP$-violation is observed at the present statistics. Finally, an axion-like particle is searched for via the decay $\eta'\rightarrow\pi^+\pi^-a, a\rightarrow e^+e^-$, and upper limits of the branching fractions are presented for the mass assumptions of the axion-like particle in the range of $0-500\ \mathrm{MeV}/c^{2}$.

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arXiv2024

First measurements of the absolute branching fraction of $\Lambda_{c}(2625)^{+}\to \Lambda^{+}_{c}\pi^+\pi^-$ and upper limit on $\Lambda_{c}(2595)^{+}\to \Lambda^{+}_{c}\pi^+\pi^-$

The absolute branching fraction of the decay $\Lambda_{c}(2625)^{+}\to \Lambda^{+}_{c}\pi^+\pi^-$ is measured for the first time to be $(50.7 \pm 5.0_{\rm{stat.}} \pm 4.9_{\rm{syst.}} )\%$ with 368.48 pb$^{-1}$ of $e^+e^-$ collision data collected by the BESIII detector at the center-of-mass energies of $\sqrt{s} = 4.918$ and $4.950$ GeV. This result is lower than the naive prediction of 67\%, obtained from isospin symmetry, by more than $2\sigma$, thereby indicating that the novel mechanism referred to as the \textit{threshold effect}, proposed for the strong decays of $\Lambda_{c}(2595)^{+}$, also applies to $\Lambda_{c}(2625)^{+}$. This measurement is necessary to obtain the coupling constants for the transitions between $s$-wave and $p$-wave charmed baryons in heavy hadron chiral perturbation theory. In addition, we search for the decay $\Lambda_{c}(2595)^{+}\to \Lambda^{+}_{c}\pi^+\pi^-$. No significant signal is observed, and the upper limit on its branching fraction is determined to be 80.8\% at the 90\% confidence level.

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arXiv2024

Improved measurements of the Dalitz decays $\eta/\eta'\rightarrow\gamma e^{+}e^{-}$

Based on a data sample of 10 billion $J/\psi$ events collected with the BESIII detector, improved measurements of the Dalitz decays $\eta/\eta'\rightarrow\gamma e^+e^-$ are performed, where the $\eta$ and $\eta'$ are produced through the radiative decays $J/\psi\rightarrow\gamma \eta/\eta'$. The branching fractions of $\eta\rightarrow\gamma e^+e^-$ and $\eta'\rightarrow\gamma e^+e^-$ are measured to be $(7.07 \pm 0.05 \pm 0.23)\times10^{-3}$ and $(4.83\pm0.07\pm0.14)\times10^{-4}$, respectively. Within the single pole model, the parameter of electromagnetic transition form factor for $\eta\rightarrow\gamma e^+e^-$ is determined to be $\Lambda_{\eta}=(0.749 \pm 0.027 \pm 0.007)~ {\rm GeV}/c^{2}$. Within the multi-pole model, we extract the electromagnetic transition form factors for $\eta'\rightarrow\gamma e^+e^-$ to be $\Lambda_{\eta'} = (0.802 \pm 0.007\pm 0.008)~ {\rm GeV}/c^{2}$ and $\gamma_{\eta'} = (0.113\pm0.010\pm0.002)~ {\rm GeV}/c^{2}$. The results are consistent with both theoretical predictions and previous measurements. The characteristic sizes of the interaction regions for the $\eta$ and $\eta'$ are calculated to be $(0.645 \pm 0.023 \pm 0.007 )~ {\rm fm}$ and $(0.596 \pm 0.005 \pm 0.006)~ {\rm fm}$, respectively. In addition, we search for the dark photon in $\eta/\eta^\prime\rightarrow\gamma e^{+}e^{-}$, and the upper limits of the branching fractions as a function of the dark photon are given at 90\% confidence level.

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arXiv2024

First observation of the decay $\Lambda^+_c\to nK^{0}_{S}\pi^+\pi^0$

Based on 4.5 fb$^{-1}$ of $e^{+}e^{-}$ collision data accumulated at center-of-mass energies between $4599.53$ MeV and $4698.82$ MeV with the BESIII detector, the decay $\Lambda_{c}^{+}\to nK_{S}^{0}\pi^+\pi^0$ is observed for the first time with a significance of $9.2\sigma$. The branching fraction is measured to be $(0.85\pm0.13\pm0.03)\%$, where the first uncertainty is statistical and the second systematic, which differs from the theoretical prediction based on isospin by 4.4$\sigma$. This indicates that there may be resonant contributions or some unknown dynamics in this decay.

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arXiv2024

Partial Wave Analysis of $J/\psi\rightarrow \gamma \gamma \phi$

Using a sample of $(10087\pm44)\times10^{6}$ $J/\psi$ events collected by the BESIII detector at the BEPCII collider, a partial-wave analysis of the decay $\gamma\gamma\phi$ is performed to investigate the intermediate resonances in $J/\psi\rightarrow\gamma R, R\ar\gamma\phi$. Resonances including $f_{1}(1285)$, $\eta(1405)$, $f_{1}(1420)$, $f_{1}(1510)$, $f_{2}(1525)$, $X(1835)$, $f_{2}(1950)$, $f_{2}(2010)$, $f_{0}(2200)$ and $\eta_{c}$ have been detected with statistical significance greater than 5$\sigma$. The product branching fractions $\mathcal{B}(J/\psi\rightarrow\gamma R, R\ar \gamma \phi)$ are reported, and the resonance parameters of $\eta(1405)$ and $X(1835)$ have been precisely determined. It is more probable that $\eta(1405)$ and $X(1835)$ act as the first - and second - excited states of $\eta^{\prime}$, respectively. The observation of $\eta_{c}\rightarrow\gamma\phi$ holds great significance for the in depth study of charmonium properties. No evidence of $\eta(1295)$, $\eta_{1}(1855)$ or X(2370) is found. The measured upper limits of relevant BF products do not conflict with theoretical expectations for X(2370) as a pseudoscalar glueball and $\eta_{1}(1855)$ as a hybrid state.

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arXiv2023

Measurements of $\Sigma$ electromagnetic form factors in the time-like region using the untagged initial-state radiation technique

The process $e^{+}e^{-}\to\Sigma^{+}\bar{\Sigma}^{-}$ is studied from threshold up to 3.04 GeV/$c^2$ via the initial-state radiation technique using data with an integrated luminosity of 12.0 fb$^{-1}$, collected at center-of-mass energies between 3.773 and 4.258 GeV with the BESIII detector at the BEPCII collider. The pair production cross sections and the effective form factors of $\Sigma$ are measured in eleven $\Sigma^{+}\bar{\Sigma}^{-}$ invariant mass intervals from threshold to 3.04 GeV/$c^2$. The results are consistent with the previous results from Belle and BESIII. Furthermore, the branching fractions of the decays $J/\psi\to\Sigma^{+}\bar{\Sigma}^{-}$ and $\psi(3686)\to\Sigma^{+}\bar{\Sigma}^{-}$ are determined and the obtained results are consistent with the previous results of BESIII.

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arXiv2023

Measurements of Born Cross Sections for $e^+e^-\to \Lambda_{c}^+ \bar{\Lambda}_{c}(2595)^- + {\rm c.c.}$ and $e^+e^-\to \Lambda_{c}^+ \bar{\Lambda}_{c}(2625)^- + {\rm c.c.}$ at $\sqrt{s}=$4918.0 and 4950.9 MeV

Using $e^+e^-$ collision data collected with the BESIII detector operating at the BEPCII collider, the Born cross sections of $e^+e^-\to \Lambda_{c}^+ \bar{\Lambda}_{c}(2595)^- + \rm{c.c.}$ and $e^+e^-\to \Lambda_{c}^+ \bar{\Lambda}_{c}(2625)^- + \rm{c.c.}$ are measured for the first time at center-of-mass energies of $\sqrt{s}=4918.0$ and 4950.9 MeV. Non-zero cross sections are observed very close to the production threshold. The measured Born cross sections of $e^+e^-\to \Lambda_{c}^+ \bar{\Lambda}_{c}(2625)^- + \rm{c.c.}$ are about $2\sim3$ times greater than those of $e^+e^-\to \Lambda_{c}^+ \bar{\Lambda}_{c}(2595)^- + \rm{c.c.}$, thereby indicating that the exotic structure potentially exists in the excited charmed baryons. The Born cross sections are $15.6\pm3.1\pm0.9$ pb and $29.4\pm3.7\pm2.7$ pb for $e^+e^-\to \Lambda_{c}^+ \bar{\Lambda}_{c}(2595)^- + \rm{c.c.}$, and are $43.4\pm4.0\pm4.1$ pb and $76.8\pm6.5\pm4.2$ pb for $e^+e^-\to \Lambda_{c}^+ \bar{\Lambda}_{c}(2625)^- +\rm{c.c.}$ at $\sqrt s=4918.0$ and 4950.9 MeV, respectively. Based on the polar angle distributions of the $\bar{\Lambda}_{c}(2625)^-$ and $\Lambda_{c}(2625)^+$, the form-factor ratios $\sqrt{|G_{E}|^2 + 3|G_{M}|^2}/|G_{C}|$ are determined for $e^+e^-\to \Lambda_{c}^+ \bar{\Lambda}_{c}(2625)^- + \rm{c.c.}$ for the first time, which are $5.95\pm4.07\pm0.15$ and $0.94\pm0.32\pm0.02$ at $\sqrt s=4918.0$ and 4950.9 MeV, respectively. All of these first uncertainties are statistical and second systematic.

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arXiv2023

Amplitude Analysis of the Decays $D^0\to\pi^+\pi^-\pi^+\pi^-$ and $\pi^+\pi^-\pi^0\pi^0$

Using $e^+e^-$ annihilation data corresponding to an integrated luminosity of 2.93 $\rm fb^{-1}$ taken at the center-of-mass energy $\sqrt{s}=3.773$~GeV with the BESIII detector, a joint amplitude analysis is performed on the decays $D^0\to\pi^+\pi^-\pi^+\pi^-$ and $D^0\to\pi^+\pi^-\pi^0\pi^0$(non-$\eta$). The fit fractions of individual components are obtained, and large interferences among the dominant components of $D^{0}\to a_{1}(1260)\pi$, $D^{0}\to\pi(1300)\pi$, $D^{0}\to\rho(770)\rho(770)$ and $D^{0}\to2(\pi\pi)_{S}$ are found in both channels. With the obtained amplitude model, the $CP$-even fractions of $D^0\to \pi^+\pi^-\pi^+\pi^-$ and $D^0\to\pi^+\pi^-\pi^0\pi^0$(non-$\eta$) are determined to be $(75.2\pm1.1_{\rm stat.}\pm1.5_{\rm syst.})\%$ and $(68.9\pm1.5_{\rm stat.}\pm 2.4_{\rm syst.})\%$, respectively. The branching fractions of $D^0\to \pi^+\pi^-\pi^+\pi^-$ and $D^0\to\pi^+\pi^-\pi^0\pi^0$(non-$\eta$) are measured to be $(0.688\pm0.010_{\rm stat.}\pm 0.010_{\rm syst.})\%$ and $(0.951\pm0.025_{\rm stat.}\pm 0.021_{\rm syst.})\%$, respectively. The amplitude analysis provides an important model for binning strategy in the measurements of the strong phase parameters of $D^0 \to 4\pi$ when used to determine the CKM angle $\gamma (\phi_{3})$ via the $B^{-}\to D K^{-}$ decay.

hep-ex↗

arXiv2023

Measurement of Branching Fractions for $\Lambda_{c}^{+} \rightarrow n K_{S}^{0} \pi^{+}$ and $\Lambda_{c}^{+} \rightarrow n K_{S}^{0} K^{+}$

Based on 4.5 fb$^{-1}$ of $e^{+}e^{-}$ collision data accumulated at center-of-mass energies between $4.600\,\mathrm{GeV}$ and $4.699\,\mathrm{GeV}$ with the BESIII detector, we measure the absolute branching fraction of the Cabibbo-favored decay $\Lambda_{c}^{+} \rightarrow n K_{S}^{0} \pi^{+}$ with the precision improved by a factor of 2.8 and report the first evidence for the singly-Cabibbo-suppressed decay $\Lambda_{c}^{+} \rightarrow n K_{S}^{0} K^{+}$. The branching fractions for $\Lambda_{c}^{+} \rightarrow n K_{S}^{0} \pi^{+}$ and $\Lambda_{c}^{+} \rightarrow n K_{S}^{0} K^{+}$ are determined to be $(1.86\pm0.08\pm0.04)\times10^{-2}$ and $\left(3.9^{+1.7}_{-1.4}\pm0.3\right)\times10^{-4}$, respectively, where the first uncertainties are statistical and the second ones are systematic.

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arXiv2023

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

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.

hep-ex↗

arXiv2023

Study of the doubly Cabibbo-suppressed decays $D^+_s\to K^+K^+\pi^-$ and $D^+_s\to K^+K^+\pi^-\pi^0$

Based on 7.33 fb$^{-1}$ of $e^+e^-$ collision data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, the experimental studies of the doubly Cabibbo-suppressed decays $D^+_s\to K^+K^+\pi^-$ and $D^+_s\to K^+K^+\pi^-\pi^0$ are reported. We determine the absolute branching fraction of $D^+_s\to K^+K^+\pi^-$ to be (${1.23^{+0.28}_{-0.25}}({\rm stat})\pm0.06({\rm syst})$) $\times 10^{-4}$. No significant signal of $D^+_s\to K^+K^+\pi^-\pi^0$ is observed and the upper limit on its decay branching fraction at 90\% confidence level is set to be $1.7\times10^{-4}$.

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