Interference effects on Higgs mass measurement in e~+e~-→H(γγ)Z at CEPC

A high luminosity Circular Electron Positron Collider(CEPC) as a Higgs Factory will be helpful for precision measurements of the Higgs mass. The signal-background interference effect is carefully studied for the Higgs diphoton decay mode in associated Z boson production at future e~+e~-colliders at energy 246 GeV. The mass shifts go up from about 20 MeV to 50 MeV for the experimental mass resolution ranging from 0.8 GeV to 2 GeV.     

Doublet bands at borders of A ≈ 130 island of chiral candidates: Case study of ~(120)I

Positive-parity doublet bands were reported in ~(120)I. Based on these, we discuss the corresponding experimental characteristics, including rotational alignment, and re-examine the corresponding configuration assignment.The self-consistent tilted axis cranking relativistic mean-field calculations indicate that the doublet bands are built on the configuration πh_(11/2)■νh_(11/2)~(-1). By adopting the two quasiparticles coupled with a triaxial rotor model, the excitation energies, energy staggering parameter S(I), B(M1)/B(E2), effective angles, and K plots are discussed and compared with available data. The obtained results support the interpretation of chiral doublet bands for the positive-parity doublet bands in ~(120)I, and hence identify this nucleus as the border of the A ≈ 130 island of chiral candidates.     

(EC+β+) decay of 130Pm and 128Pr

¹³⁰Pm and ¹²⁸Pr were produced by irradiation of ⁹⁶Ru with ³⁶Ar, and studied using a He-jet recoil tape transport system. Based on X-% and %-% coincidence measurements, the (EC+ # ⁺) decay scheme of ¹³⁰Pm was proposed for the first time and the (EC+ # ⁺) decay scheme of ¹²⁸Pr was revised.     

The (EC+β+) decay of153Er

¹⁵³Er has been produced by irradiation of¹⁴²Nd with¹⁶O,and studied using a He-jet recoil tape transport system.A decay scheme is proposed for the first time,based on X- and - coincidence measurements, which takes account of 12 observed -rays.This work was supported by Academia Sinica     

Zero-fieldμSR in a spin glass CuMn (1.1 at.%): precise measurement of static and dynamic effects belowT g

Zero-field muon spin relaxation is observed in a spin glassCuMn (1.1 at.%) using surface muon beam. The static amplitude of random local field on ⁺ is obtained belowT _g, and the static spin polarization of Mn moments is found to set on belowT _g.We would like to thank Dr. H. Miyajima for preparing the specimen, Dr. S. Chikazawa and Dr. Y. Miyako for measuring the ac-susceptibility, stuff of TRIUMF for the excellent hosptality, the Japan Society for the Promotion of Science and NSERC of Canada for the financial support. EAGLE spectrometer was built by U.C. BerkeleySR group and Prof. K.M. Crowe, and we are grateful that they kindly provided a chance for us to use the spectrometer.     

Final state photon bremsstrahlung ine + e −→Z 0→hadrons as a tool for a precise measurement of the weak quark couplings

We discuss for the processe ⁺ e ^?→Z ⁰→q \(\bar q\) how final state photons can be used to disentangle the weak couplings of up and down type quarks. Since the flavour composition of multihadronic events with final state photons is different from that of all multihadrons, a combination of observables from the two samples allows the couplings to be determined. Both theZ ⁰ width and the forward-backward charge asymmetry at centre-of-mass energies aroundM _Z0 can be used to constrain the weak couplings. Taking into account the theoretical uncertainties a precision for the sum of the square axial and vector couplings of δ(v ²+a ²)～4% for up and down type quarks separately seems feasible for 10⁶ Z ⁰'s. The precision from asymmetry measurements will be less significant.     

The Ame2020 atomic mass evaluation (Ⅰ). Evaluation of input data,and adjustment procedures

This is the first of two articles(Part I and Part II) that presents the results of the new atomic mass evaluation, Ame2020. It includes complete information on the experimental input data that were used to derive the tables of recommended values which are given in Part II. This article describes the evaluation philosophy and procedures that were implemented in the selection of specific nuclear reaction, decay and mass-spectrometric data which were used in a least-squares fit adjustment in order to determine the recommended mass values and their uncertainties. All input data, including both the accepted and rejected ones, are tabulated and compared with the adjusted values obtained from the least-squares fit analysis. Differences with the previous Ame2016 evaluation are discussed and specific examples are presented for several nuclides that may be of interest to Ame users.     

The AME2016 atomic mass evaluation (Ⅰ).Evaluation of input data;and adjustment procedures

This paper is the first of two articles(Part Ⅰ and Part Ⅱ) that presents the results of the new atomic mass evaluation,AME2016.It includes complete information on the experimental input data(also including unused and rejected ones),as well as details on the evaluation procedures used to derive the tables of recommended values given in the second part.This article describes the evaluation philosophy and procedures that were implemented in the selection of specific nuclear reaction,decay and mass-spectrometric results.These input values were entered in the least-squares adjustment for determining the best values for the atomic masses and their uncertainties.Details of the calculation and particularities of the AME are then described.All accepted and rejected data,including outweighted ones,are presented in a tabular format and compared with the adjusted values obtained using the least-squares fit analysis.Differences with the previous AME2012 evaluation are discussed and specific information is presented for several cases that may be of interest to AME users.The second AME2016 article gives a table with the recommended values of atomic masses,as well as tables and graphs of derived quantities,along with the list of references used in both the AME2016 and the NUBASE2016 evaluations(the first paper in this issue).     

The ratios among condensates from e+e− (I=1) data

We calculate the ratios among condensates from the ρ channel (I=1) e⁺e⁻ data in a systematic way. We use quotients of SVZ sum rules for different moments of the correlation functions. The results turn out to be very accurate. A factor of 1.6 for the ratio of the four quark condensate over the gluon condensate compared with the standard value is predicted.     

A preliminary quadrupole asymmetry study of a Iβ=0.12 superconducting single spoke cavity

An Accelerator Driven System (ADS) has been launched in China for nuclear waste transmutation. For the application of high intensity proton beam acceleration, the quadrupole asymmetry effect needs to be carefully evaluated for cavities. Single spoke cavities are the main accelerating structures in the low energy front-end. The single spoke cavity has small transverse electromagnetic field asymmetry, which may lead to transverse RF defocusing asymmetry and beam envelope asymmetry. A superconducting single spoke resonator (PKU-2 Spoke) of β =0.12 and f=325 MHz with a racetrack-shaped inner conductor has been designed at Peking university. The study of its RF field quadrupole asymmetry and its effect on transverse momentum change has been performed. The quadrupole asymmetry study has also been performed on a β =0.12 and f=325 MHz ring-shaped single spoke cavity. Our results show that the quadrupole asymmetry is very small for both the racetrack-shaped and the ring-shaped single spoke cavity.     

A measurement of the spin correlation parameter CNN (θ) in n-p scattering at 181 MeV

The spin correlation parameter C_NN has been measured for n-p elastic scattering at 181 MeV. A comparison with predictions from various phase shift sets and potential models reveals sizeable deviations from the for the data Paris potential and Saclay phase shifts. For the Paris potential the deviations are directly related to an overprediction of the ³D₂ phase shift parameter.     

A C>1 Completion of the Kerr Space–Time at Spacelike Infinity Including I+ and I−

It is well known that, for asymptotically flat spacetimes, one cannot in general have a smooth differentiable structure at spacelike infinity, i ⁰. Normally, one uses direction dependent structures, whose regularity has to match the regularity of the (rescaled) metric. The standard C ^>1-structure at i ⁰ ensures sufficient regularity in spacelike directions, but examples show very low regularity on I ⁺ and I ^–. The alternative C ¹⁺-structure shows that both null and spacelike directions may be treated on an equal footing, at the expense of some manageable logarithmic singularities at i ⁰. In this paper, we show that the Kerr spacetime may be rescaled and given a structure which is C ^>1 in both null and spacelike directions from i ⁰.     

Angular distribution measurement of 14N(γ, π+) 14Cgs at Eγ=320 MeV

Differential cross sections for ¹⁴N(γ, π⁺)¹⁴C_gs at a photon energy of 320 MeV, near the peak of the free nucleon delta resonance, have been measured at six angles ranging from 35° to 120°. Momentum-space calculations based on the distorted wave impulse approximation yield results which are lower than experiment by a factor of three.     

(ΩΩ)0+ Dibaryon Productions in Central Au+Au Collisions at RHIC Energy (sNN)1/2 =130 GeV

Based on the measured transverse mass spectra of π^-, K^-, and p at the RHIC energy (s_NN)^1/2=130 GeV, di-omega productions from baryon-baryon reactions in hadronic matter are studied. Results about the >(ΩΩ)_0⁺ number show that the deeply bound state >(ΩΩ)_0⁺ can be observed at RHIC energies.     

Precise measurement of the magnetic moment of doubly closed shell + 1 nucleon nucleus17F(I π=5/2+,T 1/2=64.5 s)

Hyperfine interactions of -emitting¹⁷F implanted in single crystals of NaF and CaF₂ were studied. The nuclear magnetic moment of theI =5/2⁺ state was determined with improved precision to be |(¹⁷F;I =5/2⁺,T _1/2=64.5s)|=4.72130±0.00025 µ_N.     

Two-dimensional quenching lifetime measurement of OH:A 2 Σ +(υ′ = 1) and NO:A 2 Σ(υ′ = 0) in atmospheric-pressure flames

Planar laser-induced fluorescence is currently widely applied to research on combustion. However, conventional approaches for semi-quantitative measurement could not provide the satisfactory solution and the problem due to collisional quenching remains to be solved. This paper describes the two-dimensional (2D) quenching-time-constant measurement of OH:A ^{2 +}( = 1) and NO:A ² ( = 0) in flame cross sections at atmospheric pressure. These measurements involve 1–2 ns decay time of the excited state using a high-speed image intensifier and a tunable laser with a pulse duration of 3 ns at FWHM. The correlation factors of the exponential fits for the fluorescence decays after the laser pulse were larger than 0.999 in all experiments presented in this study. Furthermore, the measured Stern-Volmer plots of the quenching rate at 1.0, 1/2, 1/3, and 1/4 atm pressure using the same experimental apparatus was confirmed to have a linear relationship for both OH and NO, showing that the 2D decay-time measurements of 1–2 ns have been successful. For NO:A ² ( = 0), the obtained quenching rates inside the inner cone and in the outer flame in the NO-seeded methane-air Bunsen flame were 8.7 × 10⁸ and 7.8 × 10⁸ s^–1, respectively, and for OH:A ² ( = 1), the obtained quenching rate mapping in the outer flame was around 5.6 × 10⁸ s^–1 in the methane-air flame.