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The very recent claim on the discovery of ambient-pressure room-temperature superconductivity in modified lead-apatite has immediately excited sensational attention in the entire society, which is fabricated by sintering lanarkite (Pb2SO5) and copper(I) phosphide (Cu$_3$P). To verify this exciting claim, we have successfully synthesized Pb$_2$SO$_5$, Cu$_3$P, and finally the modified lead-apatite Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O. Detailed electrical transport and magnetic properties of these compounds were systematically analyzed. It turns out that Pb$_2$SO$_5$ is a highly insulating diamagnet with a room-temperature resistivity of ~7.18x10$^9$ Ohm.cm and Cu$_3$P is a paramagnetic metal with a room-temperature resistivity of ~5.22x10$^{-4}$ Ohm.cm. In contrast to the claimed superconductivity, the resulting Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O compound sintered from Pb$_2$SO$_5$ and Cu$_3$P exhibits semiconductor-like transport behavior with a large room-temperature resistivity of ~1.94x10$^4$ Ohm.cm although our compound shows greatly consistent x-ray diffraction spectrum with the previously reported structure data. In addition, when a pressed Pb$_{10-x}$Cu$_x$(PO$_4$)$_6$O pellet is located on top of a commercial Nd$_2$Fe$_{14}$B magnet at room temperature, no repulsion could be felt and no magnetic levitation was observed either. These results imply that the claim of a room-temperature superconductor in modified lead-apatite may need more careful re-examination, especially for the electrical transport properties., Comment: 12 pages, 13 figures

To avoid the impact from the background events directly from $e^+e^-$ annihilations or $J/\psi$ decays, we propose a novel approach to investigate $\eta$ decays, in particular for its rare or forbidden decays, by using $\eta^\prime\rightarrow\pi\pi\eta$ produced in $J/\psi$ decays at the $\tau-$charm factories. Based on the MC studies of a few typical decays, $\eta\rightarrow \pi\pi$, $\gamma l^+l^- (l= e, \mu)$, $l^+l^-$, as well as $l^+l^-\pi^0$, the sensitivities could be obviously improved by taking advantage of the extra constraint of $\eta^\prime$. Using one trillion $J/\psi$ events accumulated at the Super $\tau$-Charm facility, the precision on the investigation of $\eta$ decays could be improved significantly and the observation of the rare decay $\eta\rightarrow e^+e^-$ is even accessable., Comment: 7 pages, 6 figures

Topotactic transition is a structural phase change in a matrix crystal lattice mediated by the ordered loss/gain and rearrangement of atoms, leading to unusual coordination environments and metal atoms with rare valent states. As early as in 1990s, low temperature hydride reduction was utilized to realize the topotactic transition. Since then, topological transformations have been developed via multiple approaches. Especially, the recent discovery of the Ni-based superconductivity in infinite-layer nickelates has greatly boosted the topotactic transition mean to synthesizing new oxides for exploring exotic functional properties. In this review, we have provided a detailed and generalized introduction to oxygen-related topotactic transition. The main body of our review include four parts: the structure-facilitated effects, the mechanism of the topotactic transition, some examples of topotactic transition methods adopted in different metal oxides (V, Mn, Fe, Co, Ni) and the related applications. This work is to provide timely and thorough strategies to successfully realize topotactic transitions for researchers who are eager to create new oxide phases or new oxide materials with desired functions., Comment: 48 pages, 23 figures. A review paper in press at Advanced Functional Materials

Polarized hyperon-antihyperon pairs shed light on various unresolved puzzles in contemporary physics: How the strong interaction confines quarks into hadrons, how accurately the Standard Model describes microcosmos and even why our universe consists of so much more matter than antimatter. Thanks to their weak, parity violating decays, hyperons reveal their spin properties. This can be exploited e.g. the decomposition of the electromagnetic structure of hyperons, precision tests of flavour symmetry and searches for CP violation. At the BESIII experiment at BEPC-II, Beijing, China, hyperon-antihyperon pairs can be produced in abundance. Recently collected large data samples have triggered the development of new methods that provide unprecedented precision and a plethora of new results have emerged. When applied at future high-intensity facilities like PANDA and STCF, precision physics will be taken to a new level which can contribute to the solution to the aforementioned puzzles., Comment: 27 pages, 9 figures

The process of $J/\psi \to \Lambda \bar{\Lambda}$ is studied using $1.0\times10^{12}$ $J/\psi$ Monte Carlo (MC) events at $\sqrt{s}$=3.097 GeV with a fast simulation software at future Super Tau Charm Facility (STCF). The statistical sensitivity for $CP$ violation is determined to be the order of $\mathcal{O} (10^{-4})$ by measuring the asymmetric parameters of the $\Lambda$ decay. Furthermore, the decay of $J/\psi \to \Lambda \bar{\Lambda}$ also serves as a benchmark process to optimize the detector responses using the interface provided by the fast simulation software.

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

Recent measurements of $CP$-related comparisons of the weak-interaction parameters that describe the decays of the $\Xi^-$ and the $\bar{\Xi}^+$ doubly strange hyperon and antihyperon are reviewed and their significance is discussed.

Antiferromagnetic spintronics is one of the leading candidates for next-generation electronics. Among abundant antiferromagnets, noncollinear antiferromagnets are promising for achieving practical applications due to coexisting ferromagnetic and antiferromagnetic merits. In this perspective, we briefly review the recent progress in the emerging noncollinear antiferromagnetic spintronics from fundamental physics to device applications. Current challenges and future research directions for this field are also discussed., Comment: 20 pages, 5 figures, A review article to be appearing at Materials Lab as part of the Virtual Special Issue - Beihang University at 70

Charged lepton flavor violation has long been recognized as unambiguous signature of New Physics. Here we describe the physics capabilities and discovery potential of New Physics models with charged lepton flavor violation in the tau sector as its experimental signature. Current experimental status from the B-Factory experiments BaBar, Belle and Belle II, and future prospects at Super Tau Charm Factory, LHC, EIC and FCC-ee experiments to discover New Physics via charged lepton flavor violation in the tau sector are discussed in detail. Submitted to the Proceedings of the US Community Study on the Future of Particle Physics (Snowmass 2021), Comment: 36 pages, 8 figures, Contribution to Snowmass 2021

The emergence of the infinite-layer superconducting nickelate thin films marks the Ni age of superconductivity, which has excited a huge surge of studies since the first report in August of 2019. Despite of the tremendous attention drawn from the entire material science community and a large body of theoretical studies, the experimental progress has been relatively slow due to the challenging sample fabrication, which may, in turn, be holding back the fast development of theoretical research. Therefore, a timely and comprehensive review on all the up-to-date experimental progress of the emergent infinite-layer Ni-based superconductors is urgently needed. In this review, we first introduce the history of more than 30-year-long Ni-based superconductivity exploration, then summarize the sample fabrication processes, later present the experimental electrical transport and magnetic properties, and finally come up with several key issues deserving intensive studies. This review is thus expected to be helpful for researchers with diverse research background to readily capture the major progress of this emerging field., Comment: 36 pages, 23 figures, a review article published online at Materials Today

We review status of $R$ measurement and QCD studies at low energy range, discuss prospects for a super $\tau-$charm factory in $2-7$ GeV. With a high-luminosity $e^+e^-$ collider, statistics are no longer problem for $R$ measurement and a precision of $2\%$ or even better is foreseen, that will lead to bring down the uncertainty of hadronic contribution to the QED running coupling constant $\Delta\alpha_{had}$ and the anomalous magnetic moment of the muon ($a_{\mu}$); measure the strong coupling constant $\alpha_s$ and the charm quark mass; improve the measurement of the resonance parameters of heavy charmonia. Huge data samples in $2-3$ GeV will make it possible to study excited states of $\rho$, $\omega$ and $\phi$, or exotic $Y(2175)$; measure electromagnetic form factor of mesons and baryons; and measure fragmentation functions of hadrons., Comment: 39 pages, 22 figures

Despite that quantum chromodynamics, the theory of strong interaction, has colorful quarks and gluons as its basic degrees of freedom, all fundamental particles participating the strong interaction that can be directly detected in experiments are colorless or color-singlet hadrons. This phenomenon is called color confinement. Because of that, the study of hadron spectroscopy is essential in improving our understanding of the nonperturbative regime of QCD and to reveal the mechanism of color confinement. The high-luminosity electron-positron collision machine under discussion, Super tau-Charm Facility (STCF), can play an essential role in hadron spectroscopy by discovering new hadron resonances and measuring properties of known hadrons with an unprecedented precision. In the following, we will discuss briefly the topics on hadron spectroscopy that will be investigated at STCF., Comment: Contribution to Snowmass 2021 RF07

In this paper, a data-driven method to precisely simulate the detector response of the anti-neutron depositing in the Electromagnetic Calorimeter (EMC)at BESIII is introduced. A large anti-neutron data sample can be selected using the decay $J/\psi\to p\bar{n}\pi^{-}$ from the BESIII data sample of 10 billion $J/\psi$ events. The detection efficiency for and various observables of anti-neutrons interacting in the EMC detector are simulated, taking the correlations among the variables into consideration. The systematic uncertainty of this data-driven simulation method is determined to be less than 1\% on average. This method can be widely applied in physics processes that require precise simulation of the detector response of anti-neutrons in the EMC., Comment: 8 pages, 14 figures

Due to the lack of any magnetic order down to 1.7 K in the parent bulk compound NdNiO2, the recently discovered 9-15 K superconductivity in the infinite-layer Nd0.8Sr0.2NiO2 thin films has provided an exciting playground for unearthing new superconductivity mechanisms. In this letter, we report the successful synthesis of a series of superconducting Nd0.8Sr0.2NiO2 thin films ranging from 8 to 40 nm. We observe the large exchange bias effect between the superconducting Nd0.8Sr0.2NiO2 films and a thin ferromagnetic layer, which suggests the existence of the antiferromagnetic order. Furthermore, the existence of the antiferromagnetic order is evidenced by X-ray magnetic linear dichroism measurements. These experimental results are fundamentally critical for the current field., Comment: 25 pages, 22 figure, 1 table. The manuscript is in press at Advanced Materials

We report a sensitive study of $D_s^+ \to \tau^+ \nu_{\tau}$ decay via $\tau^+ \to e^+ \nu_e \bar{\nu}_{\tau}$ with an integrated luminosity of 1 ab$^{-1}$ at the center-of-mass energy of $4.009$ GeV at a future Super Tau Charm Facility (STCF). Under the help of the fast simulation software package, the statistical sensitivity for the absolute branching fraction of $D_s^+ \to \tau^+ \nu_{\tau}$ is determined to be $2\times10^{-4}$. Combining with our previous prospect of $D_s^+ \to \mu^+ \nu_{\mu}$, the ratio of the branching fractions for $D_s^+ \to \tau^+ \nu_{\tau}$ over $D_s^+ \to \mu^+ \nu_{\mu}$ can achieve a relative statistical precision of 0.5%, which will provide the most stringent test of the $\tau$-$\mu$ lepton flavor universality in heavy quark decays. Taking the decay constant $f_{D_s^+}$ from lattice QCD calculations or the CKM matrix element $|V_{cs}|$ from the CKMfitter group as an input, the relative statistical uncertainties for $|V_{cs}|$ and $f_{D_s^+}$ are estimated to be 0.3% and 0.2%, respectively., Comment: 9 pages, 3 figures

We report a feasibility study of pure leptonic decay $D_s^+\to\mu^+\nu_\mu$ by using a fast simulation software package at STCF. With an expected luminosity of $1~\mathrm{ab}^{-1}$ collected at STCF at a center-of-mass energy of 4.009 GeV, the statistical sensitivity of the branching fraction is determined to be 0.3\%. Combining this result with the $c\rightarrow s$ quark mixing matrix element $|V_{cs}|$ determined from the current global Standard Model fit, the statistical sensitivity of $D_s^+$ decay constant, $f_{D_s^+}$, is estimated to be 0.2\%. Alternatively, combining the current results of $f_{D_s^+}$ calculated by lattice QCD, the statistical sensitivity of $|V_{cs}|$ is determined to be 0.2\%, which helps probe possible new physics beyond. The unprecedented precision to be achieved at STCF will provide a precise calibration of QCD and rigorous test of Standard Model., Comment: 8pages, 7 figures

Ferrimagnets, which contain the advantages of both ferromagnets (detectable moments) and antiferromagnets (ultrafast spin dynamics), have recently attracted great attention. Here we report the optimization of epitaxial growth of a tetragonal perpendicularly magnetized ferrimagnet Mn2Ga on MgO. Electrical transport, magnetic properties and the anomalous Hall effect (AHE) were systematically studied. Furthermore, we successfully integrated high-quality epitaxial ferrimagnetic Mn2Ga thin films onto ferroelectric PMN-PT single crystals with a MgO buffer layer. It was found that the AHE of such a ferrimagnet can be effectively modulated by a small electric field over a large temperature range in a nonvolatile manner. This work thus demonstrates the great potential of ferrimagnets for developing high-density and low-power spintronic devices., Comment: 21 pages 9 figures

The relative significance of quantum conductivity correction and magnetic nature of electrons in understanding the intriguing low-temperature resistivity minimum and negative magnetoresistance of the two-dimensional electron gas at LaAlO3/SrTiO3 interfaces has been a long outstanding issue since its discovery. Here we report a comparative magnetotransport study on amorphous and oxygen-annealed crystalline LaAlO3/SrTiO3 heterostructures at a relatively high-temperature range, where the orbital scattering is largely suppressed by thermal fluctuations. Despite of a predominantly negative out-of-plane magnetoresistance effect for both, the magnetotransport is isotropic for amorphous LaAlO3/SrTiO3 while strongly anisotropic and well falls into a two-dimensional quantum correction frame for annealed crystalline LaAlO3/SrTiO3. These results clearly indicate that a large portion of electrons from oxygen vacancies are localized at low temperatures, serving as magnetic centers, while the electrons from the polar field are only weakly localized due to constructive interference between time-reversed electron paths in the clean limit and no signature of magnetic nature is visible., Comment: 9 pages, 4 figures. Accepted in Journal of Physics: Condensed Matter

One of the main bottleneck issues for room-temperature antiferromagnetic spintronic devices is the small signal read-out owing to the limited anisotropic magnetoresistance in antiferromagnets. However, this could be overcome by either utilizing the Berry-curvature-induced anomalous Hall resistance in noncollinear antiferromagnets or establishing tunnel junction devices based on effective manipulation of antiferromagnetic spins. In this work, we demonstrate the giant piezoelectric strain control of the spin structure and the anomalous Hall resistance in a noncollinear antiferromagnetic metal - D019 hexagonal Mn3Ga. Furthermore, we built tunnel junction devices with a diameter of 200 nm to amplify the maximum tunneling resistance ratio to more than 10% at room-temperature, which thus implies significant potential of noncollinear antiferromagnets for large signal-output and high-density antiferromagnetic spintronic device applications., Comment: 16 pages, 5 figures

In recent years, the field of antiferromagnetic spintronics has been substantially advanced. Electric-field control is a promising approach to achieving ultra-low power spintronic devices via suppressing Joule heating. In this article, cutting-edge research, including electric-field modulation of antiferromagnetic spintronic devices using strain, ionic liquids, dielectric materials, and electrochemical ionic migration, are comprehensively reviewed. Various emergent topics such as the Neel spin-orbit torque, chiral spintronics, topological antiferromagnetic spintronics, anisotropic magnetoresistance, memory devices, two-dimensional magnetism, and magneto-ionic modulation with respect to antiferromagnets are examined. In conclusion, we envision the possibility of realizing high-quality room-temperature antiferromagnetic tunnel junctions, antiferromagnetic spin logic devices, and artificial antiferromagnetic neurons. It is expected that this work provides an appropriate and forward-looking perspective that will promote the rapid development of this field., Comment: 47 pages, 21 figures. Review

Thick-section plates made from a recently developed Al-Cu-Mg-Li alloy have been evaluated to understand the influence of microstructure on the anisotropy of tensile strengths after natural and artificial ageing treatment. Pancake-shaped grains with a coarse substructure and strong crystallographic texture with a beta-fibre orientation at the mid-thickness position are observed. In addition, an inhomogeneous distribution of T1 precipitates through the plate thickness has been revealed with the volume fraction of intragranular precipitates ~ 40% higher at the plate centre than the thickness position. Altogether these microstructural features contribute to the in-plane anisotropy of tensile strengths that is ~ 5% higher at the mid-thickness position than the 1/4 thickness position. The variation of ageing-induced T1 precipitates through the plate thickness further contributes to the through-thickness anisotropy that is ~ 3% higher in T8 temper as compared to T3 temper.

The emerging Ni-based superconducting oxide thin films are rather intriguing to the entire condensed matter physics. Here we report some brief experimental results on transport measurements for a 14-nm-thick superconducting Nd0.8Sr0.2NiO2/SrTiO3 thin-film heterostructure with an onset transition temperature of ~9.5 K. Photoluminescence measurements reveal that there is negligible oxygen vacancy creation in the SrTiO3 substrate during thin-film deposition and post chemical reduction for the Nd0.8Sr0.2NiO2/SrTiO3 heterostructure. It was found that the critical current density of the Nd0.8Sr0.2NiO2/SrTiO3 thin-film heterostructure is relatively small, ~4x10^3 A/cm2. Although the surface steps of SrTiO3 substrates lead to an anisotropy for in-plane resistivity, the superconducting transition temperatures are almost the same. The out-of-plane magnetotransport measurements yield an upper critical field of ~11.4 T and an estimated in-plane Ginzburg-Landau coherence length of ~5.4 nm. High-field magnetotransport measurements up to 50 T reveal anisotropic critical fields at 1.8 K for three different measurement geometries and a complicated Hall effect. An electric field applied via the SrTiO3 substrate slightly varies the superconducting transition temperature. These experimental results could be useful for this rapidly developing field., Comment: 14 pages, 8 figures. Some typos are corrected and new references are included

The damage mechanisms and load redistribution of high strength TC17 titanium alloy/unidirectional SiC fibre composite (fibre diameter = 100 $\mu$m) under high temperature (350 {\deg}C) fatigue cycling have been investigated in situ using synchrotron X-ray computed tomography (CT) and X-ray diffraction (XRD) for high cycle fatigue (HCF) under different stress amplitudes. The three-dimensional morphology of the crack and fibre fractures has been mapped by CT. During stable growth, matrix cracking dominates with the crack deflecting (by 50-100 $\mu$m in height) when bypassing bridging fibres. A small number of bridging fibres have fractured close to the matrix crack plane especially under relatively high stress amplitude cycling. Loading to the peak stress led to rapid crack growth accompanied by a burst of fibre fractures. Many of the fibre fractures occurred 50-300 $\mu$m from the matrix crack plane during rapid growth, in contrast to that in the stable growth stage, leading to extensive fibre pull-out on the fracture surface. The changes in fibre loading, interfacial stress, and the extent of fibre-matrix debonding in the vicinity of the crack have been mapped for the fatigue cycle and after the rapid growth by high spatial resolution XRD. The fibre/matrix interfacial sliding extends up to 600 $\mu$m (in the stable growth zone) or 700 $\mu$m (in the rapid growth zone) either side of the crack plane. The direction of interfacial shear stress reverses with the loading cycle, with the maximum frictional sliding stress reaching ~55 MPa in both the stable growth and rapid growth regimes.

High-spatial-resolution secondary ion mass spectrometry offers a method for mapping lithium at nanoscale lateral resolution. Practical implementation of this technique offers significant potential for revealing the distribution of Li in many materials with exceptional lateral resolution and elemental sensitivity. Here, two state-of-the-art methods are demonstrated on an aluminium-lithium alloy to visualise nanoscale Li-rich phases by mapping the 7Li+ secondary ion. NanoSIMS 50L analysis with a radio frequency O- plasma ion source enabled visualisation of needle-shaped T1 (Al2CuLi) phases as small as 75 nm in width. A compact time-of-flight secondary ion mass spectrometry detector added to a focused ion beam scanning electron microscope facilitated mapping of the T1 phases down to 45 nm in width using a Ga+ ion beam. Correlation with high resolution electron microscopy confirms the identification of T1 precipitates, their sizes and distribution observed during SIMS mapping.

Lepton scattering is an established ideal tool for studying inner structure of small particles such as nucleons as well as nuclei. As a future high energy nuclear physics project, an Electron-ion collider in China (EicC) has been proposed. It will be constructed based on an upgraded heavy-ion accelerator, High Intensity heavy-ion Accelerator Facility (HIAF) which is currently under construction, together with a new electron ring. The proposed collider will provide highly polarized electrons (with a polarization of $\sim$80%) and protons (with a polarization of $\sim$70%) with variable center of mass energies from 15 to 20 GeV and the luminosity of (2-3) $\times$ 10$^{33}$ cm$^{-2}$ s$^{-1}$. Polarized deuterons and Helium-3, as well as unpolarized ion beams from Carbon to Uranium, will be also available at the EicC. The main foci of the EicC will be precision measurements of the structure of the nucleon in the sea quark region, including 3D tomography of nucleon; the partonic structure of nuclei and the parton interaction with the nuclear environment; the exotic states, especially those with heavy flavor quark contents. In addition, issues fundamental to understanding the origin of mass could be addressed by measurements of heavy quarkonia near-threshold production at the EicC. In order to achieve the above-mentioned physics goals, a hermetical detector system will be constructed with cutting-edge technologies. This document is the result of collective contributions and valuable inputs from experts across the globe. The EicC physics program complements the ongoing scientific programs at the Jefferson Laboratory and the future EIC project in the United States. The success of this project will also advance both nuclear and particle physics as well as accelerator and detector technology in China., Comment: EicC white paper, written by the whole EicC working group

We report a feasibility study of $CP$ violation of $\tau^{-}\rightarrow K_{S}\pi^{-} \nu_{\tau}$ decay at a Super Tau Charm Facility~(STCF).With an expected luminosity of 1~ab$^{-1}$ collected by STCF per year at a center-of-mass energy of 4.26 GeV, the statistical sensitivity for the $CP$ violation is determined to be of order $9.7\times10^{-4}$ by measuring the decay-rate difference between $\tau^{+}\rightarrow K_{S}\pi^{+}\bar{\nu}_{\tau}$ and $\tau^{-}\rightarrow K_{S}\pi^{-} \nu_{\tau}$. The analysis is performed using a reliable fast simulation software package, which can describe the detector responses properly and vary the responses flexibly for further optimization. Moreover, the energy-dependent efficiencies for reconstructing $\tau^{-}\rightarrow K_{S}\pi^{-} \nu_{\tau}$ are presented and the expected $CP$ sensitivity is proportional to $1/\sqrt{\mathcal{L}}$ in the energy region from 4.0 to 5.0 GeV. The sensitivity of $CP$ violation is of order $3.1\times10^{-4}$ with 10~ab$^{-1}$ integrated luminosity, which is equivalent to ten years data taking in this energy region at STCF.