Progress on accurate measurement of the Planck constant:Watt balance and counting atoms

The Planck constant h is one of the most significant constants in quantum physics.Recently,the precision measurement of the value of h has been a hot issue due to its important role for the establishment of both a new SI and a revised fundamental physical constant system.Up to date,two approaches,the watt balance and counting atoms,have been employed to determine the Planck constant at a level of several parts in 108.In this paper,the principle and progress on precision measurement of the Planck constant using watt balance and counting atoms at national metrology institutes are reviewed.Further improvement in determining the Planck constant and possible developments of a revised physical constant system in future are discussed.     

Phenomenological study of ■ decays

The measurement of decay parameters is one of the important goals of particle physics experiments, and the measurement serves as a probe to search for evidence of CP violation in baryonic decays. The experimental results will aid in advancing existing theoretical research and establishing new experimental objectives. In this study,we formulate the asymmetric parameters that characterize parity violation, and then derive formulas for the measurement of CP violation. The formulae for the joint ang...     

New physics searches with Higgs-photon associated production at the Higgs factory

A future Higgs factory is being designed for precise measurement of Higgs characteristics and to search for new physics. In this paper we propose that the Higgs-photon associated production process, e+e-→γh could be a useful channel for new physics. We express new physics model-independently in the effective Lagrangian approach,and find that the new physics effects of γh have only two degrees of freedom, much fewer than the Higgsstrahlung process. This point could be used to reduce the degeneracies of Wilson coefficients. We also calculate for the first time the 95% confidence level(CL) bounds of γh at the Higgs factory, and prove that γh is more sensitive to some dimension-6 operators than the current experimental data. In the optimistic scenario new physics effects may be observed at the CEPC or FCC-ee after the first couple of years of their run.     

高能物理的实验现状

本文简要介绍国内外高能物理发展的最新状况,概述了国外对顶夸克存在的证据、电弱相互作用的精密检验及重味物理与轻子物理的进展．另外,还介绍了在北京谱仪上,有关τ质量测量、Ｊ／ψ衰变性质、ψ衰变性质及Ｄｓ衰变性质方面的最新结果． The recent experiment status of high energy physics in the world are presented briefly.The evidence for the TOP quark,precision test of EW interaction, heavy flavor physics and lepton physics are summarized in the first part. The second part introduces the new results on τ mass measurement,ψ decay,Ds decay and J/ψ decay performance from BES.     

Extreme Ultraviolet Frequency Comb with More than 100μW Average Power below 100nm

Extreme ultraviolet(XUV) frequency comb is a powerful tool in precision measurement.It also brings many new opportunities to the field of strong field physics since high harmonic generation related phenomena can be studied with high repetition rate.We demonstrate the generation of an XUV frequency comb with the aid of intra-cavity high harmonic generation process.The setup is driven by a high power infrared frequency comb, and an average power of 4.5 kW is reached in the femtosecond enhancement ...     

Implications of the RK and R_(K*) anomalies

We discuss the implications of the recently reported R_K and R_(K*) anomalies, the lepton flavor nonuniversality in the B → Kl~+l~-and B → K~*l~+~l- decay channels. Using two sets of hadronic inputs of form factors, we perform a fit of new physics to the R_K and R_(K*) data, and significant new physics contributions are found. We suggest the study of lepton flavor universality in a number of related rare B,Bs,Bc and Λb decay channels, and in particular we give predictions for the μ-to-e ratios of decay widths with different polarizations of the final state particles, and of the b → dl~+l~- processes, which are presumably more sensitive to the structure of the underlying new physics. With the new physics contributions embedded in the Wilson coefficients, we present theoretical predictions for lepton flavor non-universality in these processes.     

Potential of octant degeneracy resolution in JUNO

This work extends the idea of using a cyclotron-based antineutrino source for purposes of neutrino physics.Long baseline experiments suffer from degeneracies and correlations between Θ_(23), δ_(CP) and the mass hierarchy.However, the combination of a superconducting cyclotron and a big liquid scintillator detector like JUNO in a medium baseline experiment, which does not depend on the mass hierarchy, may allow to determine whether the position of the mixing angle Θ_(23) is in the lower octant or the upper octant. Such an experiment would improve the precision of the Θ_(23) measurement to a degree which depends on the CP-phase.     

Classical-Noise-Free Sensing Based on Quantum Correlation Measurement

Quantum sensing,using quantum properties of sensors,can enhance resolution,precision,and sensitivity of imaging,spectroscopy,and detection.An intriguing question is:Can the quantum nature(quantumness)of sensors and targets be exploited to enable schemes that are not possible for classical probes or classical targets?Here we show that measurement of the quantum correlations of a quantum target indeed allows for sensing schemes that have no classical counterparts.As a concrete example,in the case that the second-order classical correlation of a quantum target could be totally concealed by non-stationary classical noise,the higher-order quantum correlations can single out a quantum target from the classical noise background,regardless of the spectrum,statistics,or intensity of the noise.Hence a classical-noise-free sensing scheme is proposed.This finding suggests that the quantumness of sensors and targets is still to be explored to realize the full potential of quantum sensing.New opportunities include sensitivity beyond classical approaches,non-classical correlations as a new approach to quantum many-body physics,loophole-free tests of the quantum foundation,et cetera.     

Shape measurement of aspheric plastic lens with large angle

In this paper, according to the features of easy distortion and scratch for aspheric plastic lens, a noncontact measuring method is raised to test error in shape of the lens. Namely, the distance between a template and its image reflected with tested lens can be measured in nearly the vertical direction of the lens axis when the two-dimensional (2D) template is put near the measured surface. Then, the outline of the central cross-section could be obtained by calculating and curve fitting. Furthermore, three-dimensional (3D) surface can be imitated through rotating the component. A new fitting method of drift measurement is presented to prevent reducing precision when the lens and the template are fixed. The template is adjusted according to the position of the lens. The measurement precision is in the order of magnitued of sub-microns. Rotationally symmetric convex aspheric surface with any angle can be measured by this method.     

Relativistic heavy-ion physics: Experimental overview

The field of relativistic heavy-ion physics is reviewed with emphasis on new results and highlights from the first run of the relativistic heavy-ion collider at BNL and the 15 year research programme at the super proton synchrotron (SPS) at CERN and the AGS at BNL.     

Heavy ions at the LHC: Physics perspectives and experimental program

Ultrarelativisitc heavy ion physics is entering the new era of collider experiments with the start-up of RHIC at BNL and construction for detectors at LHC well under way. At this cross-roads, the article will give a summary of the experimental program and our current view of heavy ion physics at the LHC, concentrating in particular on physics topics that are different or unique compared to current facilities.     

Constraints on leptophobic gauge bosons with polarized neutrons and protons at RHIC

We explore the sensitivity and the physical interest of the measurement of parity-violating spin asymmetries in one-jet production in the presence of a new leptophobic neutral gauge boson, , within polarized hadronic collisions at the BNL RHIC. We focus on polarized neutron collisions which could be achieved in a realistic upgrade of the RHIC-spin program. We show that, in the case of a discovery, a compilation of the information coming from both polarized and collisions should constrain the number of Higgs doublets and the presence or absence of trilinear fermion mass terms in the underlying model of new physics. Received: 20 November 2001 / Published online: 5 April 2002     

The Muon <Emphasis Type="Italic">g</Emphasis> − 2 experiment at Fermilab

Precision measurements of the anomalous magnetic moment of the muon a_μ are a stringent test of the Standard Model. The last measurement of a_μ at Brookhaven National Laboratory (BNL) differs from the Standard Model prediction by 3-4σ: a possible indication of new physics. A successor to that experiment has been constructed at Fermilab, with the aim of reducing the experimental uncertainty by a factor of four to 140 ppb. The measurement technique continues to use the storage ring concept from BNL, with muons circulating in a highly uniform magnetic dipole field. The spin precession frequency is extracted by analysing the modulation of the rate of higher-energy positrons from muon decays, which are detected by 24 calorimeters around the inside of the ring. Compared to the previous experiment, significant improvements have been made in the areas of muon beam preparation, storage ring hardware, field measuring equipment, and detector and electronics systems. In these proceedings, I report on the status of the experiment as of June 2018, presenting an overview of the experiment’s progress, some initial data from the first run, and the anticipated timeline for a new result.     

Spin physics at RHIC: Present and future

In 2001–2002 the relativistic heavy-ion collider (RHIC) at the Brookhaven National Laboratory (BNL) was first commissioned for polarized proton collisions. Polarized protons were injected into the RHIC, accelerated to 100 GeV, stored and the two beams were made to collide in four interaction regions. I will review the progress made by the RHIC spin program, followed by the physics goals for the next few years. After that I will present a brief overview of a proposal to build a high intensity polarized electron/positron beam facility at BNL which would enable deep inelastic scattering (DIS) experiments to be pursued at BNL by its collisions with the RHIC hadron beams.     

EDM of the muon, deuteron, and proton in storage rings

I discuss the progression of ideas over the last decade that has led to extremely sensitive dedicated electric dipole moment (edm) storage ring designs. These ideas grew out of our experience in BNL E821: a precision measurement of the anomalous magnetic moment of the muon (Bennett et al. Phys Rev D73:072003, 2006).     

启动物理试验分析系统

启动物理试验是压水堆核电机组装料后实施的一系列堆芯物理性能试验项目。传统物理试验设备体积庞大,测量范围较小,测量精度不能满足物理试验方法要求。自主研发的启动物理试验分析系统（PSAS）针对物理试验中反应性测量方法、设备软硬件设计、微电流测量量程切换、数据处理、数据传输方式等问题进行了优化研究,以提高设备的测量能力与适用性,并减小了设备的体积。通过研究堆及阳江核电站3号机物理试验检验,PSAS可以获得准确的测量结果,适用于压水堆物理试验。     

超高能诱发核反应的国际合作实验研究进展

综述超高能诱发核反应的国际合作实验进展及相关的重离子物理研究现状.内容包括:1.有关夸克物质(夸克胶子等离子体QGP)的理论预言.2.超高能重离子碰撞的实验:(1)BNL/AGS能区的固定靶实验回顾;(2)CERN/SPS能区的固定靶实验回顾;(3)BNL/RHIC能区的对撞实验现状;(4)CERN/LHC能区的对撞实验现状.     

Prospects for atom interferometry

Atom interferometers were first realized ten years ago, and since then have evolved from beautiful demonstrations of quantum physics into instruments at the leading edge of precision measurement. In this article we trace the development of atom interferometry, looking at how the physical principles have been put into practice to achieve ground-breaking experiments. We also discuss new atom optical techniques that are becoming available and anticipate the ways in which the consequent improvements will provide new opportunities in metrology and the study of fundamental physics.