arXiv subjects

Xiao-Rong Zhou

Publications and source records attributed to Xiao-Rong Zhou.

8 recordsLinked to original sources

arXiv2025

Probing the Core of Nuclear Structure through the $\pi N$ Scattering at an Electron-Positron Collider

Short-range correlation pairs (SRCs) -- core of nuclear structure, composed of highly off-shell nucleons -- are mostly studied via electron-nucleon scattering, leaving a gap in meson-based probes. We propose probing SRC off-shell nucleons via quasielastic $\pi^+$-bound proton scattering ($\pi^+ p \to \pi^+ p$) at electron-positron colliders, of which the beryllium-based ($^{9}$Be) beam pipe of the BESIII experiment operating at BEPCII, addresses a key gap and enables meson-beam investigations of SRCs. We point out that off-shellness of SRC nucleons yields measurable signatures: accumulated missing energy ($\sim0.1$\,GeV), shifted proton effective mass (0.7-0.8\,GeV), and cross-section differences from free scattering or with only Fermi motion. As an estimate, we find that BESIII's high luminosity and $\pi^+$ yield support $\sim10^4$ scattering events, while STCF ($50\times$ higher luminosity) will greatly enhance this number. This first meson-beam SRC study at an electron-positron collider fills $^{9}$Be research gaps and advances understanding of nuclear structure core and nonperturbative QCD.

hep-ph↗

arXiv2024

Bell nonlocality and entanglement in $e^{+}e^{-} \rightarrow Y\bar{Y}$ at BESIII

The Bell nonlocality and entanglement are two kinds of quantum correlations in quantum systems. Due to the recent upgrade in Beijing Spectrometer III (BESIII) experiment, it is possible to explore the nonlocality and entanglement in hyperon-antihyperon systems produced in electron-positron annihilation with high precision data. We provide a systematic method for studying quantum correlations in spin-1/2 hyperon-antihyperon systems through the measures for the nonlocality and entanglement. We find that with nonvanishing polarizations of the hyperon and its antihyperon, the kinematic region of nonlocality in the hyperon-antihyperon system is more restricted than the $\tau^{+}\tau^{-}$ system in which polarizations of $\tau$ leptons are vanishing. We also present an experimental proposal to probe the nonlocality and entanglement in hyperon-antihyperon systems at BSEIII.

hep-ph↗

arXiv2023

Phenomenological study of $J/\psi\to\Xi^0(\Lambda \pi^0) \bar{\Xi}^0(\bar{\Lambda} \gamma)$ decays

The measurement of decay parameters is one of the important goals of particle physics experiments, and the measurement serves as a probe to search for evidence of CP violation in baryonic decays. The experimental results will help advance existing theoretical research and establish new experimental objectives. In this paper, we formulate the asymmetric parameters that characterize parity violation, and then derive formulas for the measurement of CP violation. The formulae for the joint angular distribution of the full decay chain as well as the polarization observable of $\Xi ^ 0 $, $\bar { \Xi } ^ 0 $, $\Lambda $ and $\bar { \Lambda } $ are also provided for experiments. Lastly, we evaluated the sensitivity of two asymmetric parameters: $\alpha _ { \Xi ^ 0 \to \Lambda \pi ^ 0 } $ (abbreviated as $\alpha _ { \Xi ^ 0 } $) and $\alpha _ { \bar { \Xi } ^ 0 \to \bar { \Lambda } \gamma } $ (abbreviated as $\alpha_ {\bar{\Xi}^0 } $) for future experimental measurement.

hep-ph↗

arXiv2023

Sensitivity study of the charged lepton flavor violating process $\tau \to \gamma \mu$ at STCF

A sensitivity study for the search for the charged lepton flavor violating process $\tau \to \gamma\mu$ at the Super $\tau$-Charm Facility is performed with a fast simulation. With the expected performance of the current detector design and an integrated luminosity of \SI{1}{ab^{-1}} corresponding to one-year of data taking, the sensitivity on the branching fraction (BF) of $\tau \to \gamma\mu$ is estimated to be at the level of \num{e-8}. The sensitivity under different detector performances are also studied. With ideal performance, the BF could be probed to be \num{2.8e-8} at \SI{90}{\percent} confidence level. The sensitivity is expected to scale with the square root of the luminosity, therefore with a total luminosity of \SI{10}{ab^{-1}} corresponding to ten-year of data taking, the sensitivity could reach \num{8.8e-9}, which is about one order of magnitude improvement upon the current best upper limit.

hep-ex↗

arXiv2022

Measurement of $CP$ violation of neutral kaon system in $J/\psi$ decay at the Super Tau-Charm Facility

In this paper, we present a preliminary study of $CP$ violation effect of $K^{0}-\bar{K}^{0}$ system in $J/\psi$ decay. The $CP$ violation parameters $\eta_{+-}$ and $\eta_{00}$ as well as their corresponding phase $\phi_{+-}$ and $\phi_{00}$ can be determined by the difference of the time-dependent decay rates between $K^{0}$ and $\bar{K}^{0}$ produced from $J/\psi \rightarrow K^{-}\pi^{+}K^{0} + c.c.$ processes. We investigate the precisions of the measurements of the CP violation effect at the Super Tau-Charm facility(STCF), a $e^{+}e^{-}$ collider with a peak luminosity of $0.5\times10^{35}\ \rm{cm}^{-2}\rm{s}^{-1}$. The parameters $\eta_{+-}$ and its phase $\phi_{+-}$ can be measured at a relative precision of $1 \times 10^{-3}$, which the statistical accuracy will be several times better than that of the existing PDG average values.

hep-ex↗

arXiv2021

Feasibility study of measuring $b\to s\gamma$ photon polarisation in $D^0\rightarrow K_1(1270)^- e^+\nu_e$ at STCF

We report a sensitive study of measuring $b\to s\gamma$ photon polarisation in $D^{0}\to K_1(1270)^-e^+\nu_e$ with an integrated luminosity of $\mathcal L$ = 1 ab$^{-1}$ at a center-of-mass energy of 3.773 GeV at future Super Tau Charm Facility. More than 61,000 signals of $D^{0}\to K_1(1270)^-e^+\nu_e$ are expected. Based on a fast simulation software package, the statistical sensitivity for the ratio of up-down asymmetry is estimated to be $1.5\times 10^{-2}$ by performing a two-dimensional angular analysis in $D^{0}\to K_1(1270)^-e^+\nu_e$. Combining with measurements of up-down asymmetry in $B\to K_1\gamma$, the photon polarisation in $b\to s\gamma$ can be determined model-independently.

hep-ex↗

arXiv2020

A fast simulation package for STCF detector

A Super Tau Charm Facility (STCF) is one of the major options for the accelerator-based high energy project in China in the post-BEPCII era, and its R\&D program is underway. The proposed STCF will span center of mass energies ($\sqrt{s}$) ranging from 2 to 7 GeV with a peaking luminosity above $0.5\times 10^{35}$ cm$^{-2}$s$^{-1}$ at $\sqrt{s}=4.0$ GeV, and will provide a unique platform for tau-charm physics and hadron physics. In order to evaluate the physical potential capabilities and optimize the detector design, a fast simulation package has been developed. This package takes as inputs the response of physical objects in each sub-system of the detector including resolution, efficiency as well as related variables for the kinematic fit and the secondary vertex reconstruction algorithm. It can flexibly adjust the responses of each sub-detector system and is a critical tool for the STCF R\&D program.

physics.ins-det↗

arXiv2019

Absence of Superconductivity in Nd$_{0.8}$Sr$_{0.2}$NiO$_x$ Thin Films without Chemical Reduction

The recently reported superconductivity 9-15 K in Nd0.8Sr0.2NiO2/SrTiO3 heterostructures that were fabricated by a soft-chemical topotactic reduction approach based on precursor Nd0.8Sr0.2NiO3 thin films deposited on SrTiO3 substrates, has excited an immediate surge of research interest. To explore an alternative physical path instead of chemical reduction for realizing superconductivity in this compound, using pulsed laser deposition, we systematically fabricated 63 Nd0.8Sr0.2NiOx (NSNO) thin films at a wide range of oxygen partial pressures on various different oxide substrates. Transport measurements did not find any signature of superconductivity in all the 63 thin-film samples. With reducing the oxygen content in the NSNO films by lowering the deposition oxygen pressure, the NSNO films are getting more resistive and finally become insulating. Furthermore, we tried to cap a 20-nm-thick amorphous LaAlO3 layer on a Nd0.8Sr0.2NiO3 thin film deposited at a high oxygen pressure of 150 mTorr to create oxygen vacancies on its surface and did not succeed in higher conductivity either. Our experimental results together with the recent report on the absence of superconductivity in synthesized bulk Nd0.8Sr0.2NiO2 crystals suggest that the chemical reduction approach could be unique for yielding superconductivity in NSNO/SrTiO3 heterostructures. However, SrTiO3 substrates could be reduced to generate oxygen vacancies during the chemical reduction process as well, which may thus partially contribute to conductivity.

cond-mat.supr-con↗