arXiv subjects

Hai-Bo Li

Publications and source records attributed to Hai-Bo Li.

At least 19 recordsLinked to original sources

arXiv2026

Searches for new physics beyond the Standard Model in hyperon sector

Hyperon physics offers a distinctive laboratory for probing the intensity frontier and searching for physics beyond the Standard Model. This review summarizes recent results from the BESIII experiment, including pioneering studies of dark baryons, massless BSM particles, and invisible decay modes, together with investigations of baryon- and lepton-number violation. A central highlight is the determination of the $\Lambda$ electric dipole moment using quantum-entangled hyperon-antihyperon pairs, achieving a sensitivity three orders of magnitude beyond previous limits. These measurements provide world-leading constraints on new physics scenarios and establish a robust foundation for next-generation precision studies. By integrating experimental progress with theoretical developments and future facility prospects, this review emphasizes the critical role of hyperon probes in testing the fundamental laws of nature.

hep-ex↗

arXiv2025

Searching for Ultralight Dark Matter with M{\"o}ssbauer Resonance

We investigate the feasibility of probing the interactions between ultralight scalar dark matter and atomic nuclei using a stationary M\"ossbauer spectroscopy scheme. The exceptional energy resolution of the M\"ossbauer resonance enables searches for tiny nuclear energy shifts induced by the local dark matter field. The dark matter mass range considered in this work is $10^{-18}$--$10^{-8}~\mathrm{eV}$. We present projected constraints for two candidate M\"ossbauer isotopes, $^{109}\mathrm{Ag}$ and $^{45}\mathrm{Sc}$, with $^{109}\mathrm{Ag}$ providing the strongest sensitivity. For $^{109}\mathrm{Ag}$, projected sensitivities as low as approximately $10^{-19}$, $10^{-22}$, and $10^{-21}~\mathrm{GeV^{-1}}$ can be achieved for the scalar DM--photon, DM--gluon, and DM--quark couplings $f_{\gamma}^{-1}$, $f_{g}^{-1}$, and $f_{\hat{m}}^{-1}$, respectively. In the low-mass region, the projected sensitivity to the scalar DM--photon coupling approaches the current constraints from equivalence-principle (EP) tests. These results demonstrate that M\"ossbauer-based techniques provide a promising and competitive approach for probing ultralight dark matter interactions with Standard Model particles.

hep-ph↗

arXiv2025

Hyperon Physics at BESIII

This proceeding presents recent advances in the study of hyperon physics using data from the BESIII experiment. The BESIII detector has been in full operation at the BEPCII collider since 2008, providing excellent resolution, particle identification (PID), and large coverage for both neutral and charged particles. Leveraging the outstanding capability of the detector, the BESIII experiment has collected 10 billion $J/ψ$ and 2.7 billion $ψ(3686)$ events. In recent years, BESIII has conducted a series of analyses focusing on hyperon physics, utilizing the pair production of quantum-entangled hyperon-antihyperon pairs from these charmonium decays. The transverse polarizations of the $Λ$, $Σ^{+,0}$, and $Ξ^{-,0}$ hyperons have been observed in $J/ψ$ and $ψ(3686)$ decays, providing excellent opportunities to search for the CP violation in hyperon decays. Additionally, BESIII investigates weak radiative hyperon decays, semi-leptonic hyperon decays, and hyperon-nucleon interactions.

hep-ex↗

arXiv2025

A study to suppress a sneaking cosmic muon background in the COMET experiment

The COMET experiment, conducted at J-PARC, aims to search for muon-to-electron conversion with an unprecedentedly high sensitivity. One of the severest backgrounds in the Phase-I experiment originates from cosmic-ray muons. A cosmic muon sneaks into a detector solenoid magnet from a loophole, scattered and leaving a track in a cylindrical drift chamber. Among them, a positive muon track with reverse direction may mimic a signal electron of 105 MeV/$c$. In order to suppress the sneaking cosmic positive muon background, we developed a method to discriminate the track direction by using track-fitting quality. We demonstrated that the positive muon background can be reduced by an order of magnitude. In this paper, we will report the methodology, a Monte Carlo simulation and results with prospects.

hep-ex↗

arXiv2025

Remarks on strong phase shifts in weak nonleptonic baryon decays

A sizable strong-interaction phase shift in weak two-body nonleptonic baryon decay would enhance the possibility of discovering charge-conjugation parity ($CP$) violation in the baryon sector, which might help in the quest for understanding the matter-antimatter asymmetry in the universe. Over the past 60 years, empirical analyses involving different types of instruments, including fixed-target experiments and $e^+e^-$ colliders, have indicated that the phase shifts in nonleptonic hyperon decays are relatively small, below order ten degrees in size. A large phase shift, however, has been observed by BESIII in the decay of a charmed baryon into a hyperon and kaon, $Λ_c^+\to Ξ^0K^+$. In various experimental and theoretical studies on hyperon, charmed-baryon, and bottomed-baryon decays, different conventions have been adopted for defining the strong phases. It is important to be aware of this situation when obtaining global averages from different measurements and applying the results to future investigations on $CP$ violation among baryons. This paper gives an overview of the conventions employed in the literature for the strong phases and suggests a unified parameterization form applicable to the different alternatives. Numerical results under the unified parameterization form are also provided, which can serve as useful inputs to further pursuits of baryon $CP$ violation.

hep-ph↗

arXiv2025

How to determine nucleon polarization at existing collider experiments?

We propose a novel approach to measure spin polarization of nucleons produced in electron--positron collisions. Using existing tracking devices and supporting structure material, general-purpose spectrometers can be utilized as a large-acceptance polarimeter without hardware upgrade. With the proposed approach, the spin polarization of nucleons can be revealed, providing a complementary and accurate description of the final-state particles. This could have far-reaching implications, such as enabling the complete determination of the time-like electromagnetic form factors of nucleons.

hep-ph↗

arXiv2024

Creating true muonium via charmonium radiative decay

True muonium, the bound state of a muon and an antimuon ($μ^+μ^-$), has long been theoretically predicted but remains experimentally elusive. We investigate the production of true para-muonium in the radiative decay of $J/ψ$ meson,and analyze the prospects for detecting true muonium in current and future high-energy $e^+e^-$ experiments, particularly focusing on the BESIII experiment and the proposed Super Tau-Charm Facility. Although the events are rare at the super tau-charm facility, the detection of true para-muonium via $J/ψ$ radiative decays could become feasible at its future updates.

hep-ph↗

arXiv2024

Conceptual Design of the Muonium-to-Antimuonium Conversion Experiment (MACE)

The spontaneous conversion of muonium to antimuonium is one of the interesting charged lepton flavor violation phenomena offering a sensitive probe of potential new physics and serving as a tool to constrain the parameter space beyond the Standard Model. The Muonium-to-Antimuonium Conversion Experiment (MACE) is designed to utilize a high-intensity muon beam, a Michel electron magnetic spectrometer, a positron transport system, and a positron detection system, to either discover or constrain this rare process with a conversion probability of $\mathcal{O}(10^{-13})$. This article presents an overview of the theoretical framework as well as a detailed description of the experimental design for the search for muonium-to-antimuonium conversion.

hep-ex↗

arXiv2024

Prospects to study hyperon-nucleon interactions at BESIII

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 $J/ψ$ and 2.7 billion $ψ(3686)$ 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.

hep-ex↗

arXiv2023

Search for Majoron at the COMET Experiment

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 $μ-e$ conversion. For the COMET experiment, the sensitivity of process $μ\rightarrow eJ$ is able to reach ${\mathcal{B}}(μ\rightarrow eJ)=2.3\times 10^{-5}$ 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.

hep-ex↗

arXiv2023

Probing hyperon electric dipole moments with a full angular analysis

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 $J/ψ$ 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 $Λ$ 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 $Σ^+$, $Ξ^-$, and $Ξ^0$ 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.

hep-ex↗

arXiv2023

MCPSim: A Geant4-based generic simulation toolkit for electron multipliers represented by Microchannel Plate

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.

physics.ins-det↗

arXiv2023

Recent Progress in Leptonic and Semileptonic Decays of Charmed Hadrons

We present a comprehensive review of purely leptonic and semileptonic decays of $D^{0(+)}$, $D_s^{+}$, and charmed baryons (including $Λ_c^{+}$, $Ξ_c$ and $Ω_c$). 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 $Λ_c^{+}\barΛ_c^{-}$ offer important opportunities for studies of charm physics.

hep-ex↗

arXiv2022

50 Years of Quantum Chromodynamics

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.

hep-ph↗

arXiv2022

Measurement of $CP$ violation of neutral kaon system in $J/ψ$ 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 $J/ψ$ decay. The $CP$ violation parameters $η_{+-}$ and $η_{00}$ as well as their corresponding phase $ϕ_{+-}$ and $ϕ_{00}$ can be determined by the difference of the time-dependent decay rates between $K^{0}$ and $\bar{K}^{0}$ produced from $J/ψ\rightarrow K^{-}π^{+}K^{0} + c.c.$ 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 $η_{+-}$ and its phase $ϕ_{+-}$ 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↗

arXiv2022

Implementation of antiproton generator in Geant4

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.

hep-ex↗

arXiv2022

Snowmass2021 Whitepaper: Muonium to antimuonium conversion

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.

hep-ph↗

arXiv2021

Study of the Standard Model with weak decays of charmed hadrons at BESIII

A comprehensive review of weak decays of charmed hadrons ($D^{0/+}$, $D^+_s$ and $Λ^+_c$) based on analyses of the threshold data from $e^+e^-$ annihilation in the BESIII experiment is presented. Current experimental challenges and successes in understanding decays of the charmed hadrons are discussed. Precise calibrations of QCD and tests of the Standard Model are provided by measurements of purely leptonic and semi-leptonic decays of charmed hadrons, and lepton universality is probed in purely leptonic decays of charmed mesons to three generations of leptons. Quantum correlations in threshold data samples provide access to strong phases in the neutral $D$ meson decays and probe the decay dynamics of the charmed $Λ_c$ baryon. Charm physics studies with near-threshold production of charmed particle pairs are unique to BESIII, and provide many important opportunities and challenges.

hep-ex↗