Observation of and Measurements of Decay Dynamics

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Manganese‐based materials are regarded as the most prospective cathode materials because of their high natural abundance, low toxicity, and high specific capacity. Nevertheless, the low conductivity, poor cycling performance, and controversial energy storage mechanisms hinder their practical application. Here, the MnS0.5Se0.5 microspheres are synthesized by a two‐step hydrothermal approach and employed as cathode materials for aqueous zinc‐ion batteries (AZIBs) for the first time. Interestingly, in‐depth ex situ tests and electrochemical kinetic analyses reveal that MnS0.5Se0.5 is first irreversibly converted into low‐crystallinity ZnMnO3 and MnOx by in situ electrooxidation (MnS0.5Se0.5‐EOP) during the first charging process, and then a reversible co‐insertion/extraction of H+/Zn2+ occurs in the as‐obtained MnS0.5Se0.5‐EOP electrode during the subsequent discharging and charging processes …

Physical Review Letters

We perform for the first time an amplitude analysis of the decay D+→ K S 0 π+ η and report the observation of the decay D+→ K S 0 a 0 (980)+ using 2.93 fb− 1 of e+ e− collision data taken at a center-of-mass energy of 3.773 GeV with the BESIII detector. As the only W-annihilation-free decay among D to a 0 (980) pseudoscalar, D+→ K S 0 a 0 (980)+ is the ideal decay in extracting the contributions of the W-emission amplitudes involving a 0 (980) and to study the final-state interactions. The absolute branching fraction of D+→ K S 0 π+ η is measured to be (1.27±0.0 4 stat±0.0 3 syst)%. The branching fractions of intermediate processes D+→ K S 0 a 0 (980)+ with a 0 (980)+→ π+ η and D+→ π+ K 0*(1430) 0 with K 0*(1430) 0→ K S 0 η are measured to be (1.33±0.0 5 stat±0.0 4 syst)% and (0.14±0.0 3 stat±0.0 1 syst)%, respectively.

The Circular Electron Positron Collider (CEPC) is a large scientific project initiated and hosted by China, fostered through extensive collaboration with international partners. The complex comprises four accelerators: a 30 GeV Linac, a 1.1 GeV Damping Ring, a Booster capable of achieving energies up to 180 GeV, and a Collider operating at varying energy modes (Z, W, H, and ttbar). The Linac and Damping Ring are situated on the surface, while the Booster and Collider are housed in a 100 km circumference underground tunnel, strategically accommodating future expansion with provisions for a Super Proton Proton Collider (SPPC). The CEPC primarily serves as a Higgs factory. In its baseline design with synchrotron radiation (SR) power of 30 MW per beam, it can achieve a luminosity of 5e34 /cm^2/s^1, resulting in an integrated luminosity of 13 /ab for two interaction points over a decade, producing 2.6 million Higgs bosons. Increasing the SR power to 50 MW per beam expands the CEPC's capability to generate 4.3 million Higgs bosons, facilitating precise measurements of Higgs coupling at sub-percent levels, exceeding the precision expected from the HL-LHC by an order of magnitude. This Technical Design Report (TDR) follows the Preliminary Conceptual Design Report (Pre-CDR, 2015) and the Conceptual Design Report (CDR, 2018), comprehensively detailing the machine's layout and performance, physical design and analysis, technical systems design, R&D and prototyping efforts, and associated civil engineering aspects. Additionally, it includes a cost estimate and a preliminary construction timeline, establishing a framework for …

Physical Review D

Using a data sample of 4.481× 10 8 ψ (3686) events collected with the BESIII detector, we report the first observation of the four-lepton-decays J/ψ→ e+ e− e+ e− and J/ψ→ e+ e− μ+ μ− utilizing the process ψ (3686)→ π+ π− J/ψ. The branching fractions are determined to be [5.48±0.31 (stat)±0.45 (syst)]× 10− 5 and [3.53±0.22 (stat)±0.13 (syst)]× 10− 5, respectively. The results are consistent with theoretical predictions. No significant signal is observed for J/ψ→ μ+ μ− μ+ μ−, and an upper limit on the branching fraction is set at 1.6× 10− 6 at the 90% confidence level. A C P asymmetry observable is constructed for the first two channels, which is measured to be (− 0.012±0.054±0.010) and (0.062±0.059±0.006), respectively. No evidence for C P violation is observed in this process.

European Physical Journal C

This paper presents a study of Z→ llγ decays with the ATLAS detector at the Large Hadron Collider. The analysis uses a proton–proton data sample corresponding to an integrated luminosity of 20.2 fb− 1 collected at a centre-ofmass energy

Zinc‐ion batteries (ZIBs) have become a global research hotspot in recent years due to their eco‐friendliness, safety, abundant resources, and low cost. However, some significant challenges seriously affect their overall performance, thus hindering their further development and practical applications. Recently, multifunctional and adjustable 2D carbides and nitrides (MXenes) are extensively used for the modification of ZIBs, and fruitful achievements are achieved. In order to make a systematic understanding of these studies, it is highly desirable to provide an overview of MXenes based on their modification methods and action mechanisms. In this review, a basic introduction to ZIBs and MXenes is presented and the main modification approaches of MXenes in solving the issues of ZIBs are discussed in detail, including activation and composite strategies of the cathode, interface engineering, structural optimization …

Journal of High Energy Physics

Based on e+ e− collision data collected at center-of-mass energies from 2.000 to 3.080 GeV by the BESIII detector at the BEPCII collider, a partial wave analysis is performed for the process e+ e−→ π 0. The results allow the Born cross sections of the process e+ e−→ π 0, as well as its subprocesses e+ e−→ K∗(892) 0 0 and(1430) 0 0 to be measured. The Born cross sections for e+ e−→ π 0 are consistent with previous measurements by BaBar, but with substantially improved precision. The Born cross section lineshape of the process e+ e− K∗(892) 0 0 is consistent with a vector meson state around 2.2 GeV with a significance of 3.2σ. A Breit-Wigner fit determines its mass as M Y=(2164. 7±9. 1±3. 1) MeV/c 2 and its width as Γ Y=(32. 4±21. 0±1. 8) MeV.

arXiv preprint arXiv:2310.09489

Particle Identification (PID) plays a central role in associating the energy depositions in calorimeter cells with the type of primary particle in a particle flow oriented detector system. In this paper, we propose a novel PID method based on the Residual Neural Network (ResNet) architecture which enables the training of very deep networks and bypasses the need to reconstruct feature variables to classify electromagnetic showers and hadronic showers in high-granularity calorimeters. Using Geant4 simulation samples with energy ranging from 5 GeV to 120 GeV, it is compared with Boosted Decision Trees (BDT) approaches. In shower classification, we observe an improvement in background rejection by a factor of at least 3.5, over a wide range of high signal efficiency (). These findings highlight the prospects of ANN with residual blocks for imaging detectors in the PID task of particle physics experiments.

Chinese Chemical Letters

The design and development of energy storage device with high energy/power density has become a research hotspot. Zinc-ion hybrid capacitors (ZHCs) are considered as one of the most promising candidates. However, the application of ZHCs is hindered by their low energy density at high power density due to the unsatisfactory cathode material. In this study, a novel 3D phosphorus-doped carbon nanotube/reduced graphene oxide (P-CNT/rGO) aerogel cathode is synthesized through a synergistic modification strategy of CNT insertion and P doping modification combined with 3D porous design. The as-obtained P-CNT/rGO aerogel cathode manifests significantly increased surface aera, expanded interlayer spacing, and enhanced pseudocapacitance behavior, thus leading to significantly enhanced specific capacitance and superb ions transport performance. The as-assembled ZHC based on P-CNT/rGO …

Nano Energy

As a new type cathode material for aqueous zinc-ion batteries (ZIBs), manganese-based sulfides have gradually received researchers’ concern in recent years due to their lower electronegativity, higher electronic conductivity and better electrochemical activity compared with the corresponding manganese-based oxides. However, the revelation of energy storage mechanism for manganese-based sulfides is full of great challenges, which largely restricts their application. Herein, inspired by density functional theory calculations, we design and synthesize the γ-MnS and α-MnS hollow microspheres with different crystallographic types for the first time, delivering significantly different energy storage mechanisms of the two MnS electrodes. Impressively, the γ-MnS electrode can stably exist and store energy during the whole charging/discharging processes, while the α-MnS electrode first undergoes irreversible in situ …

Physical Review D

Using a data sample of 4.481× 10 8 ψ (3686) events collected with the BESIII detector, we report the first observation of the four-lepton-decays J/ψ→ e+ e− e+ e− and J/ψ→ e+ e− μ+ μ− utilizing the process ψ (3686)→ π+ π− J/ψ. The branching fractions are determined to be [5.48±0.31 (stat)±0.45 (syst)]× 10− 5 and [3.53±0.22 (stat)±0.13 (syst)]× 10− 5, respectively. The results are consistent with theoretical predictions. No significant signal is observed for J/ψ→ μ+ μ− μ+ μ−, and an upper limit on the branching fraction is set at 1.6× 10− 6 at the 90% confidence level. A C P asymmetry observable is constructed for the first two channels, which is measured to be (− 0.012±0.054±0.010) and (0.062±0.059±0.006), respectively. No evidence for C P violation is observed in this process.

Physical Review D

With a data sample corresponding to an integrated luminosity of 11.5 fb− 1 collected with the BESIII detector operating at the BEPCII storage ring, for the first time the light hadron decay χ c 1 (3872)→ π+ π− η is searched for. While no significant signal is observed, the upper limits at the 90% confidence level for σ [e+ e−→ γ χ c 1 (3872)] B [χ c 1 (3872)→ π+ π− η] at center of mass energies from 4.13 GeV to 4.34 GeV are determined. By normalizing to the χ c 1 (3872)→ π+ π− J/ψ decay channel, a 90% confidence level upper limit for the branching fraction ratio R= B [χ c 1 (3872)→ π+ π− η]/B [χ c 1 (3872)→ π+ π− J/ψ]< 0.12 is given. These measurements provide important inputs for understanding the internal structure of the χ c 1 (3872) resonance.

arXiv preprint arXiv:2401.08252

Using events collected with the BESIII detector at BEPCII, the decay of is observed for the first time. The branching fraction of this decay is measured to be $\mathcal{B}_{\psi(3686) \to \Omega^- K^+ \bar{\Xi}^0 +c.c.}=(2.78 \pm 0.40 \pm 0.18 ) \times 10^{-6}$, where the first uncertainty is statistical and the second is systematic. Possible baryon excited states are searched for in this decay, but no evident intermediate state is observed with the current sample size.

Chinese Chemical Letters

In the face of multiple challenges brought by the changes of global climate and environment, developing clean energy and updating green energy storage equipment are important ways to achieve carbon peak and carbon neutrality. Aqueous batteries have become a research hotspot due to their advantages of using the multivalent charge carrier, high ionic conductivity, environmental friendliness and cost effectiveness. In this work, the Cu2Se@C (Cu2Se coated on carbon clothes) thin film with a three-dimensional braided structure is fabricated by a simple electrochemical deposition method for Cu2+ storage for the first time. Compared with the commercial Cu2Se powder, the well-designed Cu2Se@C film shows enhanced specific capacity (640 mAh/g at 0.5 A/g) and rate performance (542 mAh/g at 5 A/g) as well as superior cycling stability (82.7% capacity retention after 1000 cycles at 1 A/g). The Cu2+ storage …

arXiv preprint arXiv:2312.02524

Using annihilation data corresponding to an integrated luminosity of 2.93 taken at the center-of-mass energy ~GeV with the BESIII detector, a joint amplitude analysis is performed on the decays and (non-). The fit fractions of individual components are obtained, and large interferences among the dominant components of , , and are found in both channels. With the obtained amplitude model, the -even fractions of and (non-) are determined to be and , respectively. The branching fractions of and (non-) are measured to be and , respectively. The amplitude analysis provides an important model for binning strategy in the measurements of the strong phase parameters of when used to determine the CKM angle via the decay.

Physical review letters

This Letter reports the observation of τ-lepton-pair production in ultraperipheral lead-lead collisions Pb+ Pb→ Pb (γ γ→ τ τ) Pb and constraints on the τ-lepton anomalous magnetic moment a τ. The dataset corresponds to an integrated luminosity of 1.44 nb− 1 of LHC Pb+ Pb collisions at s NN= 5.02 TeV recorded by the ATLAS experiment in 2018. Selected events contain one muon from a τ-lepton decay, an electron or charged-particle track (s) from the other τ-lepton decay, little additional central-detector activity, and no forward neutrons. The γ γ→ τ τ process is observed in Pb+ Pb collisions with a significance exceeding 5 standard deviations and a signal strength of μ τ τ= 1.0 3− 0.05+ 0.06 assuming the standard model value for a τ. To measure a τ, a template fit to the muon transverse-momentum distribution from τ-lepton candidates is performed, using a dimuon (γ γ→ μ μ) control sample to constrain systematic uncertainties. The observed 95% confidence-level interval for a τ is− 0.057< a τ< 0.024.

We report the highest-energy observation of entanglement, in topantitop quark events produced at the Large Hadron Collider, using a protonproton collision data set with a center-of-mass energy of TeV and an integrated luminosity of 140 fb recorded with the ATLAS experiment. Spin entanglement is detected from the measurement of a single observable , inferred from the angle between the charged leptons in their parent top- and antitop-quark rest frames. The observable is measured in a narrow interval around the topantitop quark production threshold, where the entanglement detection is expected to be significant. It is reported in a fiducial phase space defined with stable particles to minimize the uncertainties that stem from limitations of the Monte Carlo event generators and the parton shower model in modelling top-quark pair production. The entanglement marker is measured to be for GeV. The observed result is more than five standard deviations from a scenario without entanglement and hence constitutes both the first observation of entanglement in a pair of quarks and the highest-energy observation of entanglement to date.

arXiv preprint arXiv:2310.00720

Using an collision data sample of events taken at the center-of-mass energy of by the BESIII detector at the BEPCII collider, the process is studied for the first time employing a novel method. The hyperons are produced by the collisions of hyperons from decays with nuclei in the material of the BESIII detector. The total cross section of is measured to be at beam momenta within , where the uncertainties are statistical and systematic, respectively. This analysis is the first study of -nucleon interactions at an collider, providing information and constraints relevant for the strong-interaction potential, the origin of color confinement, the unified model for baryon-baryon interactions, and the internal structure of neutron stars.

Physical review letters

A combined amplitude analysis is performed for the decays B 0→ DD 0 s+ π− and B+→ D− D s+ π+, which are related by isospin symmetry. The analysis is based on data collected by the LHCb detector in proton-proton collisions at center-of-mass energies of 7, 8, and 13 TeV. The full data sample corresponds to an integrated luminosity of 9 fb− 1. Two new resonant states with masses of 2.908±0.011±0.020 GeV and widths of 0.136±0.023±0.013 GeV are observed, which decay to D s+ π+ and D s+ π− respectively. The former state indicates the first observation of a doubly charged open-charm tetraquark state with minimal quark content [c s u d], and the latter state is a neutral tetraquark composed of [c s u d] quarks. Both states are found to have spin-parity of 0+, and their resonant parameters are consistent with each other, which suggests that they belong to an isospin triplet.

arXiv e-prints

The decay is studied based on 7.33 fb of collision data collected with the BESIII detector at center-of-mass energies in the range from 4.128 to 4.226 GeV. The absolute branching fraction is measured as , the most precise measurement to date. Combining with the world average of , the ratio of the branching fractions obtained is , in agreement with lepton universality. By performing a partial wave analysis, the hadronic form factor ratios at are extracted, finding and , where the first uncertainties are statistical and the second are systematic. No significant -wave contribution from is found. The upper limit $\mathcal {B}(D_s^+\to f_0 (980)\mu^{+}{\nu} _ {\mu})\cdot {\mathcal B}(f_0 (980)\to K^+ K^-)< 5.45\times 10^{-4} $ is set at 90\% confidence level.

arXiv preprint arXiv:2307.12852

By analyzing 7.33 fb of annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of the semileptonic decay and studies of the and decay dynamics for the first time. The branching fractions of and are determined to be and , respectively, with precision improved by factors of 5.9 and 6.5 compared to the previous best measurements. Combined with the results for the decays and , the ratios of the decay widths are examined, both inclusively and in several four-momentum transfer ranges. No evidence for lepton flavor universality violation is found within the current statistics. The products of the hadronic form factors and the Cabibbo-Kobayashi-Maskawa matrix element are determined. The results based on the two-parameter series expansion are and , which constrain present models on . The mixing angle in the quark flavor basis is determined to be .

arXiv preprint arXiv:2307.12852

By analyzing 7.33 fb of annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of the semileptonic decay and studies of the and decay dynamics for the first time. The branching fractions of and are determined to be and , respectively, with precision improved by factors of 5.9 and 6.5 compared to the previous best measurements. Combined with the results for the decays and , the ratios of the decay widths are examined, both inclusively and in several four-momentum transfer ranges. No evidence for lepton flavor universality violation is found within the current statistics. The products of the hadronic form factors and the Cabibbo-Kobayashi-Maskawa matrix element are determined. The results based on the two-parameter series expansion are and , which constrain present models on . The mixing angle in the quark flavor basis is determined to be .

arXiv preprint arXiv:2307.12852

By analyzing 7.33 fb of annihilation data collected at center-of-mass energies between 4.128 and 4.226 GeV with the BESIII detector, we report the observation of the semileptonic decay and studies of the and decay dynamics for the first time. The branching fractions of and are determined to be and , respectively, with precision improved by factors of 5.9 and 6.5 compared to the previous best measurements. Combined with the results for the decays and , the ratios of the decay widths are examined, both inclusively and in several four-momentum transfer ranges. No evidence for lepton flavor universality violation is found within the current statistics. The products of the hadronic form factors and the Cabibbo-Kobayashi-Maskawa matrix element are determined. The results based on the two-parameter series expansion are and , which constrain present models on . The mixing angle in the quark flavor basis is determined to be .