Institute Of High Energy Physics Research Articles

Analysis of the strong decays of SU(3) partners of the $\Omega(2012)$ baryon

Abstract We estimate the coupling constants and decay widths of the $SU(3)$ partners of the $\Omega(2012)$ hyperon, as discovered by the BELLE Collaboration, using the distribution amplitudes of the octet baryons within light cone sum rules method. Our study includes a comparison of the obtained results for the relevant decay widths with those derived within the framework of the flavor $SU(3)$ analysis. We observe a good agreement between the predictions of both approaches. Moreover, our results on the decay width of the $\Omega \to \Xi K$ is compatible with the existing experimental result within the uncertainties of the model predictions. These results can provide helpful insights for determining the nature of the $SU(3)$ partners of the $\Omega(2012)$ baryon. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Calibration of the Cryogenic Measurement System of a Resonant Haloscope Cavity

Abstract Possible light bosonic dark matter interactions with the Standard Model photon have been searched by microwave resonant cavities. In this paper, we demonstrate the cryogenic readout system calibration of a 7.138 GHz copper cavity with a loaded quality factor $Q_l=10^4$, operated at 22 mK temperature based on a dilution refrigerator. Our readout system consists of High Electron Mobility Transistors as cryogenic amplifiers at 4 K, plus room-temperature amplifiers and a spectrum analyzer for signal power detection. We test the system with a superconducting two-level system as a single-photon source in the microwave frequency regime and report an overall 95.6 dB system gain and -71.4 dB attenuation in the cavity's input channel. The effective noise temperature of the measurement system is 7.5 K. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

A 95 GeV light Higgs in the top-pair-associated diphoton channel at the LHC in the Minimal Dilaton Model

Abstract Motivated by experimental hints and theoretical frameworks indicating the existence of an extended Higgs sector, we undertake a study to explore the feasibility of detecting a 95 GeV light Higgs boson decaying into diphoton within the Minimal Dilaton Model (MDM) at the 14 TeV LHC. Initially, we identify the correlations between the production cross section, decay branching ratios, and model parameters, e.g., the scalar mixing angle $\sin\theta_S$. Subsequently, we utilize Monte Carlo simulations to generate the signal of the light Higgs boson via the process $pp \to t\bar{t}(s\to \gamma\gamma)$, along with the corresponding backgrounds. To effectively separate the signal from the dominant backgrounds $tt\gamma\gamma$, we employ a meticulous cut-based selection process. Ultimately, we find that with an integrated luminosity of $L = 3000 \fbm$, the regions of $|\sin\theta_S|>0.2$ can be covered at over a $3\sigma$ level. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Detecting Neutrinos from Supernova Bursts in PandaX-4T

Abstract Neutrinos from core-collapse supernovae are essential for the understanding of neutrino physics and stellar evolution. The dual-phase xenon dark matter detectors can provide a way to track explosions of galactic supernovae by detecting neutrinos through coherent elastic neutrino-nucleus scatterings. In this study, a variation of progenitor masses as well as explosion models are assumed to predict the neutrino fluxes and spectra, which result in the number of expected neutrino events ranging from 6.6 to 13.7 at a distance of 10 kpc over a 10-second duration with negligible backgrounds at PandaX-4T. Two specialized triggering alarms for monitoring supernova burst neutrinos are built. The efficiency of detecting supernova explosions at various distances in the Milky Way is estimated. These alarms will be implemented in the real-time supernova monitoring system at PandaX-4T in the near future, providing the astronomical communities with supernova early warnings. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Prospects to study hyperon-nucleon interactions at BESIII

Abstract 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. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Masses of the conjectured H-dibaryon at different temperatures

Abstract We present a lattice QCD determination of masses of the conjectured H-dibaryon $m_H$ at nine different temperatures
 $T/T_c =0.24, 0.63, 0.76, 0.84, 0.95, 1.09, 1.27, 1.52, 1.90$. In the meantime, the masses of baryon $N$, $\Sigma$, $\Xi$ and $\Lambda$ at different temperatures
 are also computed.
 The simulation is performed on anisotropic lattice with $N_f=2+1$ flavours of clover fermion at quark mass
 which corresponds to $m_\pi=384(4) {\rm MeV} $. The thermal ensembles were provided by the FASTSUM
 collaboration and the zero temperature ensembles by the Hadspec collaboration. We also calculate the spectral density of the correlation function of those particles.
 The spectral density distributions show rich peak structure at the lowest temperature, while at intermediate temperatures, the mass values of those particles obtained by extrapolation method reflect a two-peak structure.
 While the spectral density for octet baryon becomes smooth at $T/T_c = 1.27, 1.52, 1.90$, the spectral density for H-dibaryon becoms smooth at $T/T_c = 1.90$.
 At $T/T_c =0.24 $, the mass difference of H-dibaryon
 and
 $\Lambda$ pair $\Delta m = m_H - 2\,m_{\Lambda} $ is estimated to be $\Delta m = -14.6(6.2) {\rm MeV}$ which suggests there exists a bound H-dibaryon state. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Amplitude Analysis of the Decays D0→π+π-π+π- and π+π-π0π0

Abstract Using e+e- annihilation data corresponding to an integrated luminosity of 2.93 fb-1 taken at the center-of-mass energy √s=3.773 GeV with the BESIII detector, a joint amplitude analysis is performed on the decays D0→π+π-π+π- and D0→π+π-π0π0(non-η). The fit fractions of individual components are obtained, and large interferences among the dominant components of the decays D0→a1(1260)π, D0→π(1300)π, D0→ρ(770)ρ(770) and D0→2(ππ)S are found in both channels. With the obtained amplitude model, the CP-even fractions of D0→π+π-π+π- and D0→π+π-π0π0(non-η) are determined to be (75.2 ± 1.1stat. ± 1.5syst.)% and (68.9 ± 1.5stat. ± 2.4syst.)%, respectively. The branching fractions of D0→π+π-π+π- and D0→π+π-π0π0(non-η) are measured to be (0.688 ± 0.010stat. ± 0.010syst.)% and (0.951 ± 0.025stat. ± 0.021syst.)%, respectively. The amplitude analysis provides an important model for binning strategy in the measurements of the strong phase parameters of D0→4π when used to determine the CKM angle γ(Φ3) via the B-→DK- decay. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Moving doubly heavy baryon in a strongly coupled plasma from holography

Abstract Gauge/gravity duality is used to study properties of the doubly heavy baryon $(\mathrm{QQq})$ at finite rapidity and temperature in the heavy-ion collision. We investigate the impact of rapidity on string breaking and screening of $\mathrm{QQq}$, and compare these effects with the results for $\rm Q\bar{Q}$ in detail. Computations reveal that the string-breaking distances of $\mathrm{QQq}$ and $\rm Q\bar{Q}$ are close in the confined state and the effects of rapidity and temperature on the string breaking are not significant. An interesting result shows that $\mathrm{QQq}$ cannot be found at high enough temperatures and rapidities; however, $\rm Q\bar{Q}$ can exist under any conditions as long as the separation distance is small enough. Besides, the screening distances of $\mathrm{QQq}$ and $\rm Q\bar{Q}$ are also compared at finite rapidity and temperature. Based on the above analysis, we infer that $\rm Q\bar{Q}$ is more stable than $\mathrm{QQq}$ at finite rapidity and temperature.Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

The $\mathbf{\bar{q}q\bar{s}Q}$ $\mathbf{(q=u,\,d;\,Q=c,\,b)}$ tetraquark system in a chiral quark model

Abstract The $S$-wave $\bar{q}q\bar{s}Q$ $(q=u,\,d;\,Q=c,\,b)$ tetraquarks, with spin-parity $J^P=0^+$, $1^+$ and $2^+$, in both isoscalar and isovector sectors are systematically studied in a chiral quark model. The meson-meson, diquark-antidiquark and K-type arrangements of quarks, along with all possible color wave functions, are comprehensively considered. The four-body system is solved by means of a highly efficient computational approach, the Gaussian expansion method, along with a complex-scaling formulation of the problem to disentangle bound, resonance and scattering states. This theoretical framework has already been successfully applied in various tetra- and penta-quark systems. In the complete coupled-channel case, and within the complex-range formulation, several narrow resonances of $\bar{q}q\bar{s}c$ and $\bar{q}q\bar{s}b$ systems are obtained, in each allowed $I(J^P)$-channels, within the energy regions $2.4-3.4$ GeV and $5.7-6.7$ GeV, respectively. The predicted exotic states, which are an indication of a richer color structure when going towards multiquark systems beyond mesons and baryons, are expected to be confirmed in future high-energy particle and nuclear experiments.Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Waveform Simulation in PandaX-4T

Abstract Signal reconstruction through software processing is a crucial component of the background and signal models in the PandaX-4T experiment, which is a multi-tonne dark matter direct search experiment. The accuracy of signal reconstruction is influenced by various detector artifacts, including noise, dark count of photomultiplier, photoionization of impurities in the detector, and other relevant considerations.
In this study, we present a detailed description of a semi-data-driven approach designed to simulate the signal waveform. 
This work provides a reliable model for the efficiency and bias of the signal reconstruction in the data analysis of PandaX-4T. 
By comparing critical variables which relate to the temporal shape and hit pattern of the signals, we demonstrate a good agreement between the simulation and data. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

Analysis of b → cτ ¯ ν τ anomalies using weak effective Hamiltonian with complex couplings and their impact on various physical observables

Abstract B Meson anomalies triggered an interest as experimental measurements of the branching ratios and different polarization asymmetries by BABAR, Belle and LHCb have shown differences in the Standard Model (SM) predictions. In this work we address the complex WCs coupling by adding the dimension-six vector, (pseudo-)scalar, and tensor operators using model-independent weak effective Hamiltonian (WEH) with the assumption of left-handed neutrinos and with constraints coming from the leptonic branching ratio of charmed-meson. We analyze the parameter space of the new physics (NP) WCs that can explain the anomalies for the most recent data from HFLAV summer 2023. We find that the allowed parametric region of left-handed scalar couplings heavily depends on the constraints of the Bc branching ratio, and the maximum pull from the SM predictions comes for its 60 percent limit. And parametric region changes if we add LHCb data and extend our analysis. Furthermore, we derive the sum rules that correlate these observables with the LFU ratio of D and D* mesons and due the large errors in the experimental measurements of considered experimental observables, we predict these observables in terms of the LFU ratio of D and D* mesons. We find that the most significant impact of NP arises from the WC CSL= 4CT. Finally, we investigate the impact of these NP couplings on various angular and CP-triple product asymmetries. Content from this work may be used under the terms of the Creative Commons Attribution 3.0 licence. Any further distribution of this work must maintain attribution to the author(s) and the title of the work, journal citation and DOI. Article funded by SCOAP3 and published under licence by Chinese Physical Society and the Institute of High Energy Physics of the Chinese Academy of Science and the Institute of Modern Physics of the Chinese Academy of Sciences and IOP Publishing Ltd.

The performance of AC-coupled Strip LGAD developed by IHEP

The AC-coupled Strip LGAD (Strip AC-LGAD) is a novel LGAD design that diminishes the density of readout electronics through the use of strip electrodes, enabling the simultaneous measurement of time and spatial information. The Institute of High Energy Physics has designed a long Strip AC-LGAD prototype with a strip electrode length of 5.7 mm and pitches of 150 μm, 200 μm, and 250 μm. Spatial and timing resolutions of the long Strip AC-LGAD are studied by pico-second laser test and beta source tests. The laser test demonstrates that spatial resolution improves as the pitch size decreases, with an optimal resolution achieved at 8.3μm. Furthermore, the Beta source test yields a timing resolution of 37.6 ps.

B meson rare decays in the TNMSSM* *Supported by the National Natural Science Foundation of China (12075074, 12235008, 11535002, 11705045), the Natural Science Foundation for Distinguished Young Scholars of Hebei Province, China (A2022201017), the Natural Science Foundation of Guangxi Autonomous Region (2022GXNSFDA035068), and the Youth Top-Notch Talent Support Program of the Hebei Province, China.

We investigate the two loop electroweak corrections to B meson rare decays and in the minimal supersymmetry standard model (MSSM) extension with two triplets and one singlet (TNMSSM). The new particle contents and interactions in the TNMSSM can affect the theoretical predictions of the branching ratios and , and the corrections from two loop diagrams to the process can reach around . Considering the latest experimental measurements, the numerical results of and in the TNMSSM are presented and analyzed. The findings indicate that the results in the TNMSSM can fit the updated experimental data well, and the new parameters , clearly affect the theoretical predictions of and .

Strong decays of the P c(4312) and its isospin cousin via the QCD sum rules* *Supported by the National Natural Science Foundation (12175068) and the Fundamental Research Funds for the Central Universities of China

In this study, considering the conservation of isospin in the strong decays, we investigate the strong decays of the pentaquark molecule candidate and its possible higher isospin cousin in the framework of the QCD sum rules. Further, the pole residue of the Δ baryon with isospin eigenstate is obtained. If the possible pentaquark molecule candidate could be determined, it would shed light on the interpretations of the states in future experiments.

Reconstructing parton distribution function based on maximum entropy method* *Supported by Key Project for Undergraduate Teaching Reform and Quality Enhancement Research Plan in Ordinary Colleges and Universities in Tianjin (A231005505)

A new method based on the maximum entropy principle for reconstructing the parton distribution function (PDF) from moments is proposed. Unlike traditional methods, the new method does not require any artificial assumptions. For the case of moments with errors, we introduce Gaussian functions to soften the constraints of moments. Through a series of tests, the effectiveness and reconstruction efficiency of this new method are evaluated comprehensively, demonstrating that this method is reasonable and can achieve high-quality reconstruction with at least the first six moments as input. Finally, we select a set of lattice quantum chromodynamics (QCD) results regarding moments as input and provide reasonable reconstruction results for the pion.

Fully-light vector tetraquark states with explicit P-wave via QCD sum rules*

Abstract In this study, we apply the QCD sum rules to investigate the vector fully-light tetraquark states with an explicit P-wave between the diquark and antidiquark pairs. We observed that the (or ) type current with fully-strange quarks couples potentially to a tetraquark state with a mass , which supports assigning as the diquark-antidiquark type tetraquark state with . The and vector tetraquark states with the structure (or ) are consistent with and , respectively, which lie in the region from to . The central values of the masses of the fully-strange vector tetraquark states with an explicit P-wave are approximately (or ). Predictions for other fully-light vector tetraquark states with and without hidden-strange are also presented.

Time-reversal asymmetries in * *Supported in part by the National Key Research and Development Program of China (2020YFC2201501) and the National Natural Science Foundation of China (NSFC) (12147103)

We study the decays of with . We examine the full angular distributions with polarized , where the T-odd observables are identified. We discuss the possible effects of new physics (NP) and find that the T-odd observables are sensitive to them as they vanish in the standard model. Special attention is given to the interference of (pseudo)scalar operators with (axial)vector operators in polarized , which are studied for the first time. Their effects are proportional to the lepton masses and therefore may evade the constraint from at the LHCb naturally. As is uncontaminated by the charmonia resonance, it provides a clean background to probe NP. In addition, we show that the experimental central value of in at the LHCb can be explained by the NP case, which couples to the right-handed quarks and leptons. The polarization fraction of at the LHCb is found to be consistent with zero regardless of the NP scenarios.

Observability of parameter space for charged Higgs boson in its bosonic decays in two Higgs doublet model Type-1

This study explores the possibility of discovering through its bosonic decays, i.e., (where ϕ = h or A), within the Type-I two Higgs doublet model (2HDM). The main objective is to demonstrate the available parameter space after applying recent experimental and theoretical exclusion limits. We suggest that = 150 GeV is the most probable mass for the decay channel in collisions at = 8, 13, and 14 TeV. We also report on the application of a modern machine learning approach to a multivariate technique for heavy charged Higgs production in association with a single top quark through weak interaction to demonstrate its observability in comparison with the most relevant Standard Model backgrounds using the neural networks of boosted decision Tree (BDT), likelihood (LH), and multilayer perceptron (MLP).

R&D of glass scintillator for nuclear radiation detection

In 2021, the Institute of High Energy Physics proposed a design of glass scintillator coupled with SiPM as a new solution for the next generation calorimeter, to explore the application of glass scintillators in high energy physics and nuclear radiation detection. The Large Area Glass Scintillator Collaboration Group was established to research and develop a glass scintillator with high density, high light yields and fast decay time. Through continuous optimization, the glasses have excellent scintillation performance with a light yield of 1000 ph/MeV and a density of 6 g/cm3. Moreover, the neutron response of the glasses was investigated, and different high-energy particles can be distinguished by signal amplitude. In addition, the radiation resistance of different glasses was tested under proton beam. All the glasses appeared opaque and produced a high radioactive background, because Gd element interacts with proton to produce radionuclides with high activity and long half-life.

Solving the strong CP problem via a -characterized mirror symmetry* *Supported in part by the National Natural Science Foundation of China (12175038) and in part by the Fundamental Research Funds for the Central Universities

In the standard model QCD Lagrangian, a term of CP violating gluon density is theoretically expected to have a physical coefficient , which is typically on the order of unity. However, the upper bound on the electric dipole moment of the neutron enforces the value of to be extremely small. The significant discrepancy between theoretical expectations and experimental results in this context is widely recognized as the strong CP problem. To solve this puzzle in an appealing context of two Higgs doublets, we propose a -characterized mirror symmetry between two Higgs singlets with respective discrete symmetries. In our scenario, the parameter can completely disappear from the full Lagrangian after the standard model fermions take a proper phase rotation as well as the Higgs doublets and singlets. Moreover, all of new physics for solving the strong CP problem can be allowed near the TeV scale.