arXiv subjects

L. P. An

Publications and source records attributed to L. P. An.

3 recordsLinked to original sources

arXiv2026

Search for the doubly Cabibbo-suppressed decays $D^0\to K^+\pi^-\eta^\prime$ and $D^+\to K^+\pi^0\eta^\prime$

We present the first search for the doubly Cabibbo-suppressed decays $D^0\to K^+\pi^-\eta^\prime$ and $D^+\to K^+\pi^0\eta^\prime$ using an $e^+e^-$ collision data sample corresponding to an integrated luminosity of 20.3 fb$^{-1}$, collected at a center-of-mass energy of 3.773 GeV with the Beijing Spectrometer III (BESIII) detector at the Beijing Electron-Positron Collider II (BEPCII). No significant signals are observed, and the upper limits on their decay branching fractions are set to be $3.0\times 10^{-5}$ and $2.1\times 10^{-5}$ at the 90% confidence level, respectively. By combining these results with the world-average branching fractions of the corresponding Cabibbo-favored decays, upper limits at the 90% confidence level are obtained on the ratios of doubly Cabibbo-suppressed to Cabibbo-favored branching fractions. The limits are determined to be $1.6\times \tan^4\theta_C$ and $3.7\times \tan^4\theta_C$ for $D^0\to K^+\pi^-\eta^\prime$ and $D^+\to K^+\pi^0\eta^\prime$, respectively, where $\theta_C$ denotes the Cabibbo mixing angle.

hep-ex↗

arXiv2026

Measurement of CP Asymmetry Parameters and Polarization Correlations in $\Omega^{-}\bar{\Omega}^{+}$ Pairs

Using $(2.71 \pm 0.01) \times 10^9$ $\psi(3686)$ events collected with the BESIII detector, a joint full angular distribution analysis is carried out for the process $\psi(3686) \to \Omega^-(\to\Lambda K^-) \, \bar{\Omega}^{+}(\to \bar{\Lambda}K^+)$. The first simultaneous measurement of the weak decay parameters $\phi_{\Omega^{-}}$ and $\phi_{\bar{\Omega}^{+}}$ for $\Omega^- \to K^-\Lambda$ and $\bar{\Omega}^+ \to K^+\bar{\Lambda}$ is performed, yielding the first result for the CP-sensitive observable, $\phi_{\rm CP} = (-0.004 \pm 0.055 \pm 0.017)~\text{rad}$, where the first and second uncertainties are statistical and systematic, respectively. This further enables the extraction of the weak and strong phase differences between the $P$- and $D$-wave amplitudes: $(\xi_D - \xi_P) = (-0.15 \pm 2.25 \pm 0.69)~\text{rad}$ and $(\delta_D - \delta_P) = (-0.97 \pm 0.88 \pm 0.34)~\text{rad}$. Additionally, the polarization correlations between $\Omega^{-}$ and $\bar{\Omega}^{+}$ are measured.

hep-ex↗

arXiv2023

STCF Conceptual Design Report: Volume 1 -- Physics & Detector

The Super $τ$-Charm facility (STCF) is an electron-positron collider proposed by the Chinese particle physics community. It is designed to operate in a center-of-mass energy range from 2 to 7 GeV with a peak luminosity of $0.5\times 10^{35}{\rm cm}^{-2}{\rm s}^{-1}$ or higher. The STCF will produce a data sample about a factor of 100 larger than that by the present $τ$-Charm factory -- the BEPCII, providing a unique platform for exploring the asymmetry of matter-antimatter (charge-parity violation), in-depth studies of the internal structure of hadrons and the nature of non-perturbative strong interactions, as well as searching for exotic hadrons and physics beyond the Standard Model. The STCF project in China is under development with an extensive R\&D program. This document presents the physics opportunities at the STCF, describes conceptual designs of the STCF detector system, and discusses future plans for detector R\&D and physics case studies.

hep-ex↗