Search

We present a comprehensive review of purely leptonic and semileptonic decays of $D^{0(+)}$, $D_s^{+}$, and charmed baryons (including $\Lambda_c^{+}$, $\Xi_c$ and $\Omega_c$). The precise studies of these decays help deepen our understanding and knowledge of quantum chromodynamics via measuring decay constants and form factors, and test the Standard Model through examining the unitarity of Cabibbo-Kobayashi-Maskawa matrix and lepton flavor universality. We give an overview of the theoretical and experimental tools before discussing the recent progress. The data sets collected by BESIII near the production thresholds of $D\bar{D}$, $D_s^{(*)+}D_s^{(*)-}$ and $\Lambda_c^{+}\bar{\Lambda}_c^{-}$ offer important opportunities for studies of charm physics., Comment: 24 pages, 10 figures

The simulation of the instruments based on the cascade multiplication of electrons has always been an important and challenging subject in no matter high energy physics, astrophysics, radiography and other fields. In this work, a generic simulation toolkit is developed based on Geant4, ROOT and CADMesh toolkits for the electron multipliers based on the emission process of secondary electrons, especially for Microchannel Plate (MCP). Geometry of instruments can be directly imported by standard CAD files and multiple kinds of electromagnetic fields are supported. MCPSim is capable for simulating the general hadronic, weak and electromagnetic processes together with secondary electron emission, which provides a wider range of applications. Users are able to configure the simulation and define the output information by a simple textfile. By comparing with experimental measurements, good agreement is found. MCPSim is expected to guide the design and optimization of such electron multipliers and will be continuously developed and maintained to better satisfy the present and future requirements., Comment: 22 pages, 13 figures, 3 tables

The electric dipole moment (EDM) of elementary particles, arising from flavor-diagonal $CP$ violation, serves as a powerful probe for new physics beyond the Standard Model and holds the potential to provide novel insights in unraveling the puzzle of the matter-dominated Universe. Hyperon EDM is a largely unexplored territory. In this paper, we present a comprehensive angular analysis that focuses on entangled hyperon-antihyperon pairs in $J/\psi$ decays for the indirect extraction of hyperon EDM. The statistical sensitivities are investigated for BESIII and the proposed Super Tau-Charm Facility (STCF). Leveraging the statistics from the BESIII experiment, the estimated sensitivity for $\Lambda$ EDM can reach an impressive level of $10^{-19}$ $e$ cm, achieving a 3-orders-of-magnitude improvement over the only existing measurement in a fixed-target experiment at Fermilab with similar statistics. The estimated sensitivities for the $\Sigma^+$, $\Xi^-$, and $\Xi^0$ hyperons at the same level of $10^{-19}$ $e$ cm will mark the first-ever achievement and the latter two will be the first exploration of hyperons with two strange valence quarks. The EDM measurements for hyperons conducted at the BESIII experiment will be a significant milestone and serve as a litmus test for new physics such as supersymmetry and the left-right symmetrical model. Furthermore, at the STCF experiment, the sensitivity of hyperon EDM measurements can be further enhanced by 2 orders of magnitude. Additionally, this angular analysis enables the determination of $CP$ violation in hyperon decays, the effective weak mixing angle, and beam polarization.

This paper presents a comprehensive review of both the theory and experimental successes of Quantum Chromodynamics, starting with its emergence as a well defined theory in 1972-73 and following developments and results up to the present day. Topics include a review of the earliest theoretical and experimental foundations; the fundamental constants of QCD; an introductory discussion of lattice QCD, the only known method for obtaining exact predictions from QCD; methods for approximating QCD, with special focus on effective field theories; QCD under extreme conditions; measurements and predictions of meson and baryon states; a special discussion of the structure of the nucleon; techniques for study of QCD at high energy, including treatment of jets and showers; measurements at colliders; weak decays and quark mixing; and a section on the future, which discusses new experimental facilities or upgrades currently funded. The paper is intended to provide a broad background for Ph.D. students and postdocs starting their career. Some contributions include personal accounts of how the ideas or experiments were developed., Comment: Invited volume for the EJPC; 567 pages if text/figures and 4783 references occupying about 160 additional pages. arXiv abstract abridged, for the complete abstract please see the full text

The prospects to study hyperon-nuclei/nucleon interactions at BESIII and similar $e^+ e^-$ colliders are proposed in this work. Utilizing the large quantity of hyperons produced by the decay of 10 billion $J/\psi$ and 2.7 billion $\psi(3686)$ collected at BESIII, the cross sections of several specific elastic or inelastic hyperon-nuclei reactions can be measured via the scattering between the hyperons and the nucleus in the dense objects of BESIII detector. Subsequently, the cross sections of corresponding hyperon-nucleon interactions are able to be extracted with further phenomenological calculation. Furthermore, the interactions between antihyperon and nuclei/nucleon, including scattering and annihilation, can also be studied via the method proposed in this paper. The results will definitely benefit a lot the precise probe of the hyperon-nuclei/nucleon interactions and provide constraints for the studies of the potential of strong interaction, the origin of color confinement, the unified model for baryon-baryon interactions, and the internal structure of neutron stars. In addition, the desirable prospects of corresponding studies in the future Super Tau-Charm Factory (STCF) are discussed and estimated in this work.

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.

A generator of antiproton ($\bar{p}$) in Geant4 has been developed using a theoretical model with the consideration of near-threshold treatment and used preliminarily in COMET experiment. The precision of this generator has been verified by comparing with experimental results taken in CERN (1970) and ITEP (1994). By implementing this generator into official data analysis framework of COMET, the yield of $\bar{p}$ in COMET experiment can be evaluated properly. Background caused by $\bar{p}$ can also be estimated by this generator in future, which will instruct the design and optimization. Moreover, this generator can also be used in the simulation of other experiments involving near-threshold $\bar{p}$ generation., Comment: 14 pages, 5 figures, 5 tables

A new Goldstone particle named Majoron is introduced in order to explain the origin of neutrino mass by some new physics models assuming that neutrinos are Majorana particle. By expanding signal region and using likelihood analysis, it becomes possible to search for Majoron at experiments that is originally designed to search for $\mu-e$ conversion. For the COMET experiment, the sensitivity of process $\mu \rightarrow eJ$ is able to reach ${\mathcal{B}}(\mu \rightarrow eJ)=2.3\times 10^{-5}$ in Phase-I and $O(10^{-8})$ in Phase-II. Meanwhile, the sensitivities to search for Majoron at future experiments are also discussed in this article., Comment: 8 pages, 10 figures, 3 tables

The spontaneous muonium to antimuonium conversion is one of the interesting charged lepton flavor violation processes. It serves as a clear indication of new physics and plays an important role in constraining the parameter space beyond Standard Model. MACE is a proposed experiment to probe such a phenomenon and expected to enhance the sensitivity to the conversion probability by more than two orders of magnitude from the current best upper constraint obtained by the PSI experiment two decades ago. Recent developments in the theoretical and experimental aspects to search for such a rare process are summarized., Comment: 13 pages, 10 figures, 3 tables, contribution to Snowmass 2021