arXiv subjects

P. T. Ge

Publications and source records attributed to P. T. Ge.

At least 19 recordsLinked to original sources

arXiv2025

Measurement of the hyperon weak radiative decay $\Xi^0\to\gamma\Sigma^0$ at BESIII

The hyperon weak radiative decay $\Xi^0\to\gamma\Sigma^0$ is measured via the process $J/\psi\to\Xi^0\bar\Xi^0$. The absolute branching fraction of $\Xi^0\to\gamma\Sigma^0$ is determined to be $(3.69\pm 0.21_{\text{stat}}\pm0.12_{\text{syst}})\times 10^{-3}$, based on $(10.087\pm 0.044)\times 10^{9}$ $J/\psi$ events collected with the BESIII detector operating at the BEPCII collider. The decay asymmetry parameter is measured, with a complete angular analysis of the cascade decay chain, to be $\alpha_{\gamma} = -0.807\pm 0.095_{\text{stat}}\pm 0.011_{\text{syst}}$.

hep-ex↗

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.

hep-ex↗

arXiv2024

Observation of the Electromagnetic Dalitz Transition $h_c \rightarrow e^+e^-\eta_c$

Using $(27.12\pm 0.14)\times10^8$ $\psi(3686)$ decays and data samples of $e^+e^-$ collisions with $\sqrt{s}$ from 4.130 to 4.780~GeV collected with the BESIII detector, we report the first observation of the electromagnetic Dalitz transition $h_c\to e^+e^-\eta_c$ with a statistical significance of $5.4\sigma$. We measure the ratio of the branching fractions $\frac{\mathcal{B}(h_c\rightarrow e^+e^-\eta_c)}{\mathcal{B}(h_c\rightarrow \gamma \eta_c)}$ separately for the $h_c$ samples produced via $\psi(3686)\to\pi^0h_c$ and $e^+e^-\to\pi^+\pi^-h_c$. The average ratio is determined to be $(0.59\pm0.10(\text{stat.})\pm0.04(\text{syst.}))\%$, where the uncertainty includes both statistical and systematic components.

hep-ex↗

arXiv2024

Search for the leptonic decays $D^{+}\to e^+\nu_e$ and $D^{+}\to \mu^+\nu_\mu$

We present the first search for the leptonic decays $D^{*+}\to e^+\nu_e$ and $D^{*+}\to \mu^+\nu_\mu$ by analyzing a data sample of electron-positron collisions recorded with the BESIII detector at center-of-mass energies between 4.178 and 4.226 GeV, corresponding to an integrated luminosity of 6.32~fb$^{-1}$. No significant signal is observed. The upper limits on the branching fractions for $D^{*+}\to e^+\nu_e$ and $D^{*+}\to \mu^+\nu_\mu$ are set to be $1.1 \times 10^{-5}$ and $4.3 \times 10^{-6}$ at 90\% confidence level, respectively.

hep-ex↗

arXiv2024

Study of excited $Ξ$ states in $ψ(3686)\rightarrow{}K^{-}Λ\overlineΞ^{+}+c.c.$

Based on a sample of $(448.1\pm2.9)\times10^{6}$ $ψ(3686)$ events collected with the BESIII detector at BEPCII, the decays of $ψ(3686)\to{}K^{-}Λ\overlineΞ^{+} + c.c.$ with $\overlineΞ^+ \to \overlineΛ π^+$, $\overlineΛ\to \overline{p} π^+$ are studied.Two excited hyperons, $Ξ(1690)^-$ and $Ξ(1820)^-$, are observed with large significance ($ \gg 10 σ$) in the $K^{-}Λ$ invariant mass distributions. A partial wave analysis is performed, and the spin-parities of $Ξ(1690)^-$ and $Ξ(1820)^-$ are determined to be $\frac{1}{2}^{-}$ and $\frac{3}{2}^{-}$, respectively. The masses, widths, and product branching fractions of $Ξ(1690)^-$ and $Ξ(1820)^-$ are also measured.

hep-ex↗

arXiv2024

Observation of the semileptonic decays $D^0\rightarrow K_S^0\pi^-\pi^0 e^+ \nu_e$ and $D^+\rightarrow K_S^0\pi^+\pi^- e^+ \nu_e$

By analyzing $e^+e^-$ annihilation data corresponding to an integrated luminosity of 2.93 $\rm fb^{-1}$ collected at a center-of-mass energy of 3.773 GeV with the \text{BESIII} detector, the first observation of the semileptonic decays $D^0\rightarrow K_S^0\pi^-\pi^0 e^+ \nu_e$ and $D^+\rightarrow K_S^0\pi^+\pi^- e^+ \nu_e$ is reported. With a dominant hadronic contribution from $K_1(1270)$, the branching fractions are measured to be $\mathcal{B}(D^0\rightarrow {K}_1(1270)^-(\to K^0_S\pi^-\pi^0)e^+\nu_e)=(1.69^{+0.53}_{-0.46}\pm0.15)\times10^{-4}$ and $\mathcal{B}(D^+\to \bar{K}_1(1270)^0(\to K^0_S\pi^+\pi^-)e^+\nu_e)=(1.47^{+0.45}_{-0.40}\pm0.20)\times10^{-4}$ with statistical significance of 5.4$\sigma$ and 5.6$\sigma$, respectively. When combined with measurements of the $K_1(1270)\to K^+\pi^-\pi$ decays, the absolute branching fractions are determined to be $\mathcal{B}(D^0\to K_1(1270)^-e^+\nu_e)=(1.05^{+0.33}_{-0.28}\pm0.12\pm0.12)\times10^{-3}$ and $\mathcal{B}(D^+\to \bar{K}_1(1270)^0e^+\nu_e)=(1.29^{+0.40}_{-0.35}\pm0.18\pm0.15)\times10^{-3}$. The first and second uncertainties are statistical and systematic, respectively, and the third uncertainties originate from the assumed branching fractions of the $K_1(1270)\to K\pi\pi$ decays.

hep-ex↗

arXiv2024

Measurement of $Λ$ transverse polarization in $e^{+}e^{-}$ collisions at $\sqrt{s}= 3.68-3.71$ GeV

With data samples collected with the BESIII detector at seven energy points at $\sqrt{s}= 3.68 - 3.71$ GeV, corresponding to an integrated luminosity of 333 pb$^{-1}$, we present a study of the $Λ$ transverse polarization in the $e^+e^-\toΛ\barΛ$ reaction. The significance of polarization by combining the seven energy points is found to be 2.6$σ$ including the systematic uncertainty, which implies a non-zero phase between the transition amplitudes of the $Λ\barΛ$ helicity states. The modulus ratio and the relative phase of EM-$psionic$ form factors combined with all energy points are measured to be $R^Ψ =$ 0.71$^{+0.10}_{-0.10}$ $\pm$ 0.03 and $ΔΦ^Ψ$ = (23$^{+8.8}_{-8.0}$ $\pm$ 1.6$)^\circ$, where the first uncertainties are statistical and the second systematic.

hep-ex↗

arXiv2024

Observation of $D^+_s\to η^\prime μ^+ν_μ$, Precision Test of Lepton Flavor Universality with $D^+_s\to η^{(\prime)} \ell^+ν_\ell$, and First Measurements of $D^+_s\to η^{(\prime)}μ^+ν_μ$ Decay Dynamics

By analyzing 7.33 fb$^{-1}$ of $e^+e^-$ annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of the semileptonic decay $D^+_s\to η^\prime μ^+ν_μ$, with a statistical significance larger than 10$σ$, and the measurements of the $D_s^+ \to ημ^+ν_μ$ and $D_s^+ \to η^\primeμ^+ν_μ$ decay dynamics for the first time. The branching fractions of $D_s^+ \to ημ^+ν_μ$ and $D_s^+ \to η^\primeμ^+ν_μ$ are determined to be $(2.235\pm0.051_{\rm stat}\pm0.052_{\rm syst})\%$ and $(0.801\pm0.055_{\rm stat}\pm0.028_{\rm syst})\%$, respectively, with precision improved by factors of 6.0 and 6.6 compared to the previous best measurements. Combined with the results for the decays $D_s^+ \to ηe^+ν_e$ and $D_s^+ \to η^\prime e^+ν_e$, the ratios of the decay widths are examined both inclusively and in several $\ell^+ν_\ell$ four-momentum transfer ranges. No evidence for lepton flavor universality violation is found within the current statistics. The products of the hadronic form factors $f_{+,0}^{η^{(\prime)}}(0)$ and the $c\to s$ Cabibbo-Kobayashi-Maskawa matrix element $|V_{cs}|$ are determined. The results based on the two-parameter series expansion are $f^η_{+,0}(0)|V_{cs}| = 0.452\pm0.010_{\rm stat}\pm0.007_{\rm syst}$ and $f^{η^{\prime}}_{+,0}(0)|V_{cs}| = 0.504\pm0.037_{\rm stat}\pm0.012_{\rm syst}$, which help to constrain present models on $f_{+,0}^{η^{(\prime)}}(0)$. The forward-backward asymmetries are determined to be $\langle A_{\rm FB}^η\rangle=-0.059\pm0.031_{\rm stat}\pm0.005_{\rm syst}$ and $\langle A_{\rm FB}^{η^\prime}\rangle=-0.064\pm0.079_{\rm stat}\pm0.006_{\rm syst}$ for the first time, which are consistent with the theoretical calculation.

hep-ex↗

arXiv2024

Measurement of the $e^{+}e^{-} \to K_{S}^{0} K_{L}^{0} π^{0}$ cross sections from $\sqrt{s}=$ 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 $e^{+}e^{-}\to K_{S}^{0} K_{L}^{0} π^{0}$. The results allow the Born cross sections of the process $e^{+}e^{-}\to K_{S}^{0} K_{L}^{0} π^{0}$, as well as its subprocesses $e^{+}e^{-}\to K^{*}(892)^{0}\bar{K}^{0}$ and $K^{*}_{2}(1430)^{0}\bar{K}^{0}$ to be measured. The Born cross sections for $e^{+}e^{-}\to K_{S}^{0}K_{L}^{0}π^{0}$ are consistent with previous measurements by BaBar, but with substantially improved precision. The Born cross section lineshape of the process $e^{+}e^{-}\to K^{*}(892)^{0}\bar{K}^{0}$ is consistent with a vector meson state around 2.2 GeV with a significance of 3.2$σ$. A Breit-Wigner fit determines its mass as $M_Y=(2164.7\pm9.1\pm3.1)~{\rm{MeV}}/c^{2}$ and its width as $Γ_{Y}=(32.4\pm21.0\pm1.8)~\rm{MeV}$.

hep-ex↗

arXiv2024

Study of light scalar mesons through $D_s^+ \to π^0 π^0 e^+ ν_e$ and $K_S^0 K_S^0 e^+ ν_e$ decays

Using 6.32~fb$^{-1}$ of $e^+e^-$ collision data recorded by the BESIII detector at center-of-mass energies between $4.178$ to $4.226$ GeV, we present the first measurement of the decay $D_s^+\to f_0(980)e^+ν_e,\,f_0(980)\to π^0π^0$. The product branching fraction of $D_s^+\to f_0(980)e^+ν_e,\,f_0(980)\to π^0π^0$ is measured to be $(7.9\pm1.4_{\rm stat} \pm0.3_{\rm syst})\times 10^{-4}$, with a statistical significance of $7.8σ$. Furthermore, the upper limits on the product branching fractions of $D_s^+\to f_0(500)e^+ν_e$ with $f_0(500)\to π^0π^0$ and the branching fraction of $D_s^+\to K_{S}^{0}K_{S}^{0}e^+ν_e$ are set to be $7.3\times 10^{-4}$ and $3.8\times 10^{-4}$ at 90\% confidence level, respectively. Our results provide valuable inputs to the understanding of the structures of light scalar mesons.

hep-ex↗

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 $e^+e^-\to ppπ^-\bar{d}+c.c.$ 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 $e^+e^-\to ppπ^-\bar{d}+c.c.$ cross section is determined to be from 9.0 to 145 fb depending on the center-of-mass energy at the $90\%$ confidence level.

hep-ex↗

arXiv2024

Precise Measurement of Born Cross Sections for $e^+e^-\to D\bar{D}$ at $\sqrt{s} = 3.80-4.95$ GeV

Using data samples collected with the BESIII detector at the BEPCII collider at center-of-mass energies ranging from 3.80 to 4.95 GeV, corresponding to an integrated luminosity of 20 fb$^{-1}$, a measurement of Born cross sections for the $e^+e^-\to D^{0}\bar{D}^{0}$ and $D^{+}D^{-}$ processes is presented with unprecedented precision. Many clear peaks in the line shape of $e^+e^-\to D^{0}\bar{D}^{0}$ and $D^{+}D^{-}$ around the mass range of $G(3900)$, $\psi(4040)$, $\psi(4160)$, $Y(4260)$, and $\psi(4415)$, etc., are foreseen. These results offer crucial experimental insights into the nature of hadron production in the open-charm region.

hep-ex↗

arXiv2024

Observation of $D^+\to f_0(500)\mu^+\nu_\mu$ and study of $D^+\to \pi^+\pi^-\ell^+\nu_\ell$ decay dynamics

Using $2.93~\mathrm{fb}^{-1}$ of $e^+e^-$ collision data collected with the BESIII detector at the center-of-mass energy of 3.773 GeV,we investigate the semileptonic decays $D^+\to \pi^+\pi^- \ell^+\nu_\ell$ ($\ell=e$ and $\mu$). The $D^+\to f_0(500)\mu^+\nu_\mu$ decay is observed for the first time. By analyzing simultaneously the differential decay rates of $D^+\to f_0(500) \mu^+\nu_\mu$ and $D^+\to f_0(500) e^+\nu_e$ in different $\ell^+\nu_\ell$ four-momentum transfer intervals, the product of the relevant hadronic form factor $f^{f_0}_{+}(0)$ and the magnitude of the $c\to d$ Cabibbo-Kobayashi-Maskawa matrix element $|V_{cd}|$ is determined to be $f_{+}^{f_0} (0)|V_{cd}|=0.143\pm0.014_{\rm stat}\pm0.011_{\rm syst}$ for the first time. With the input of $|V_{cd}|$ from the global fit in the standard model, we determine $f_{+}^{f_0} (0)=0.63\pm0.06_{\rm stat}\pm0.05_{\rm syst}$. The absolute branching fractions of $D^+\to f_0(500)_{(\pi^+\pi^-)}\mu^+\nu_\mu$ and $D^+\to \rho^0_{(\pi^+\pi^-)} \mu^+\nu_\mu$ are determined as $(0.72\pm0.13_{\rm stat}\pm0.08_{\rm syst})\times10^{-3}$ and $(1.64\pm0.13_{\rm stat}\pm0.10_{\rm syst})\times 10^{-3}$. Combining these results with those of previous BESIII measurements on their semielectronic counterparts from the same data sample, we test lepton flavor universality by measuring the branching fraction ratios ${\mathcal B}_{D^+\to \rho^0 \mu^+\nu_\mu}/{\mathcal B}_{D^+\to \rho^0 e^+\nu_e}=0.88\pm0.10$ and ${\mathcal B}_{D^+\to f_0(500) \mu^+\nu_\mu}/{\mathcal B}_{D^+\to f_0(500) e^+\nu_e}=1.14\pm0.26$, which are compatible with the standard model expectation.

hep-ex↗

arXiv2024

Search for the light hadron decay $χ_{c1}(3872) \to π^{+}π^{-}η$

With a data sample corresponding to an integrated luminosity of 11.5~fb$^{-1}$ collected with the BESIII detector operating at the BEPCII storage ring, for the first time the light hadron decay $χ_{c1}(3872) \rightarrow π^{+}π^{-}η$ is searched for. While no significant signal is observed, the upper limits at the 90\% confidence level for $σ[e^{+}e^{-} \rightarrow γχ_{c1}(3872)] \mathcal{B}[χ_{c1}(3872) \rightarrow π^{+}π^{-}η]$ at center-of-mass energies from 4.13 to 4.34 GeV are determined. By normalizing to the $χ_{c1}(3872)\toπ^+π^- J/ψ$ decay channel, a 90\% confidence level upper limit for the branching fraction ratio $\mathcal{R}=\mathcal{B}[χ_{c1}(3872) \rightarrowπ^{+}π^{-}η]/\mathcal{B}[χ_{c1}(3872) \rightarrow π^{+}π^{-} J/ψ] < 0.12$ is given. These measurements provide important inputs for understanding the internal structure of the $χ_{c1}(3872)$ resonance.

hep-ex↗

arXiv2024

Investigation of the $ΔI = 1/2$ rule and test of CP violation through the measurement of decay asymmetry parameters in $Ξ^-$ decays

Using $(10087\pm44)\times 10^{6}$ $J/ψ$ events collected with the BESIII detector, numerous $Ξ^-$ and $Λ$ decay asymmetry parameters are simultaneously determined from the process $J/ψ\to Ξ^- \barΞ^+ \to Λ(pπ^-) π^- \barΛ(\bar{n} π^0) π^+$ and its charge-conjugate channel. The precisions of $α_0$ for $Λ\to nπ^0$ and $\barα_0$ for $\barΛ \to \bar{n}π^0$ compared to world averages are improved by factors of 4 and 1.7, respectively. The ratio of decay asymmetry parameters of $Λ\to nπ^0$ to that of $Λ\to pπ^-$, $\langle α_0 \rangle/ \langle α_{Λ-} \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 more than $5σ$, which signifies the existence of the $ΔI = 3/2$ transition in $Λ$ for the first time. Beside, we test for CP violation in $Ξ^- \to Λπ^-$ and in $Λ\to n π^{0}$ with the best precision to date.

hep-ex↗

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.

hep-ex↗

arXiv2023

$\mathcal R(3780)$ Resonance Interpreted as the $1^3D_1$-Wave Dominant State of Charmonium from Precise Measurements of the Cross Section of $e^+e^-\rightarrow$ Hadrons

We report the precise measurements of the cross section of $e^+e^-\rightarrow$ hadrons at center-of-mass energies from 3.645 to 3.871 GeV. We thereby perform the most precise study of the cross sections and find a complex system composed of three resonances of $\mathcal R(3760)$, $\mathcal R(3780)$, and $\mathcal R(3810)$. For the first time, we measure the $\mathcal R(3810)$ electronic width to be $(19.4 \pm 7.4 \pm 12.1)$ eV. For the $\mathcal R(3760)$ resonance, we measure the mass to be $(3751.9\pm 3.8\pm 2.8)$ MeV/$c^2$, the total width to be $(32.8 \pm 5.8 \pm 8.7)$ MeV, and the electronic width to be $(184\pm 75\pm 86)$ eV. For the $\mathcal R(3780)$ resonance, we measure its mass to be $(3778.7\pm 0.5\pm 0.3)$ MeV/$c^2$, total width to be $(20.3 \pm 0.8 \pm 1.7)$ MeV, and electronic width to be $(265\pm 67\pm 83)$ eV. Forty-seven years ago, the $\psi(3770)$ resonance was discovered, and was subsequently interpreted as the $1^3D_1$-wave dominant state of charmonium. However, our analysis of the total-hadron cross sections indicates that the $\psi(3770)$ is not a single state, but a complex system composed of the $\mathcal R(3760)$, $\mathcal R(3780)$, and $\mathcal R(3810)$ resonances. Among these, we interpret the $\mathcal R(3780)$ is a resonance dominated by the $1^3D_1$ charmonium state.

hep-ex↗

arXiv2023

Precise measurement of the branching fractions of $J/ψ\rightarrow\barΛπ^{+}Σ^{-}+c.c.$ and $J/ψ\rightarrow\barΛπ^{-}Σ^{+}+c.c.$

Based on a data sample of $(10087\pm44)\times10^6$ $J/ψ$ events collected with the BESIII detector, the branching fraction of $J/ψ\rightarrow\barΛπ^{+}Σ^{-}+c.c.$ is measured to be $(1.221\pm 0.002\pm 0.038)\times10^{-3}$, and the branching fraction of its isospin partner mode $J/ψ\rightarrow\barΛπ^{-}Σ^{+}+c.c.$ is measured to be $(1.244\pm 0.002\pm 0.045)\times10^{-3}$ with improved precision. Here the first uncertainties are statistical and the second ones systematic. The isospin symmetry of the $Σ$ baryon in charmonium hadronic decay and the "$12\%$ rule" are tested, and no violation is found. The potential of using these channels as $Σ$ baryon sources for nuclear physics research is studied, and the momentum and angular distributions of these sources are provided.

hep-ex↗