Isospin-conserving hadronic decay of the Ds1(2460) into Dsπ+π-

The internal structure of the charm-strange mesons D_s0^*(2317) and D_s1(2460) are the subject of intensive studies.Their widths are small because they decay dominantly through isospinbreaking hadronic channels D_s0^*(2317)⁺→D_s⁺π⁰ and D_s1(2460)⁺→D_s^*+π⁰.The D_s1(2460) can also decay into the hadronic final states D_s⁺ππ...     

Fine structure ofαdecay in222Pa

With the help of the gas-filled recoil spectrometer SHANS and a digital data acquisition system,the fine structure of the α decay for²²²Pa was studied.The nuclides were produced through the 1p3n evaporation channel via the heavy-ion induced fusion evaporation reaction ⁴⁰Ar+¹⁸⁶W.Based on the ER-α1-α2-α3 andα-γcorrelation measurement,three new α decays were observed in addition to the three branches known previously.The one with the largestαdecay energy was regarded as the ground state to ground state transition.The newly measuredαdecay properties of ²²²Pa were examined in a framework of reduced width.     

Multiple Auger Decay Following Xe+(4p3−1/2)Ionization

The Auger decay for the many-electron Xe+(4p3^?1/2)state is studied in detail,using multistep approaches.It is found that the single Auger decay channels are primarily Coster–Kronig processes,which is in accord with other theoretical and experimental results.The double and triple Auger decays result primarily from cascade processes,i.e.,the sequential two-step and three-step Auger decay,and as such,the contributions from direct processes can be neglected.Level-to-level rates for single,double,and triple decays are obtained,based on which comprehensive Auger electron spectra and ion yields are obtained.Our decay paths and Auger electron spectra are in agreement with the experimental analysis[Hikosaka et al.,Phys.Rev.A 76(2007)032708],and our ion yield ratios(Xe²⁺:Xe³⁺:Xe⁴⁺=4.6:87.0:8.4)are also in line with their values(5.0:86.0:9.0).However,with respect to the ion yield ratios,a discrepancy still remains among the experimental and theoretical results.Taking into account the complexity of Xe’s electronic structure,further,more detailed experiments are still required.     

Pure annihilation type decays B0→Ds- （K2*）+ and Bs →a2 in the perturbative QCD approach

We calculate the branching ratios of pure annihilation type decays B 0 →D_s^- （K₂^*）⁺ and Bs → a₂ using the perturbative QCD approach based on k T factorization. The branching ratios are predicted to be （60.6 +17.3+4.3+3.2 16.5 10.4 2.1 ）× 10^-6 for B⁰ →D_s^- （K₂^*）⁺ , （1.1 +0.4+0.1+0.1-0.4-0.2-0.1 ）×10-6 for Bs → ⁰a₂⁰ and （2.3 +0.8+0.2+0.1-0.8-0.4-0.1 ）×10-6 for Bs→D^-a₂⁺ . They are large enough to be measured in the ongoing experiment. Due to the shortage of contributions from penguin operators, there are no direct CP asymmetries for these decays in the Standard Model. We also derive simple relations among these decay channels to reduce theoretical uncertainties for the experiments, to test the accuracy of theory, and to search for a signal of new physics.     

Mixing of two-quasineutron and two-quasiproton Kπ=6+ configurations in the vicinity of 174Yb

In the framework of the projected shell model, we investigate the competition between the two-quasineutron and two-quasiproton K^π=6⁺ states in the ytterbium isotopes and N =104 isotones adjacent to ¹⁷⁴Yb. The ¹⁷⁴Yb results are compared with the experimental data.The K^π =6⁺ isomer observed in ¹⁷⁴ Yb is assigned as an admixture of the ν7/2^-[514] ν5/2^-[512] and π7/2⁺ [404]π5/2⁺ [402] intrinsic structure, which explains the experimental |g K-g R | value. Similar mixing would appear in ¹⁷⁴ Yb, ¹⁷⁶ Hf,and ¹⁷⁸ W. The low-lying K^π=6⁺ states are also predicted in ^170-178 Yb.     

Measurement of 59Co(ai,x)reaction cross sections with the fast neutrons based on the 9Be(p,n)reaction

The cross sections of the ⁵⁹Co(n,x)reaction in the average energy range of 15.2-37.2 MeV were meas-ured using activation and an off-line γ-ray spectrometric technique.The neutrons were generated from the ⁹Be(p,n)reaction with proton beam energies of 25-45 MeV at the MC-50 Cyclotron facility of the Korean Institute of Radi-ological and Medical Sciences(KIRAMS).Theoretical cal lculations of neutron-induced reactions on ⁵⁹Co were per-formed using the nuclear model code TALYS-1.9.The results for the ⁵⁹Co(n,x)reactions were compared with the theoretical values obtained using TALYS-1.9 and the literature data provided in EXFOR and the TENDL 2019 nuc-lear data library.The theoretical values obtained using TALYS-1.9 with adjusted parameters are comparable to the experimental data.The measured reaction cross sections of a few radionuclides are new,and the others are compar-able to the literature data,and thus,they can strengthen the database.The present study on cross sections leads to useful insight into the mechanisms of ⁵⁹Co(n,x)reactions.     

Probes of axial and nonaxial hexadecapole deformation effects in nuclei around 230U

The structure properties for even–even nuclei around ²³⁰U, located on the hexadecapoledeformation island, are investigated using the potential-energy-surface calculation within the framework of the macroscopic-microscopic model. The impact of different deformation degrees of freedom(including axial and nonaxial quadrupole and hexadecapole deformations) on total energy,shell, and pairing contributions is analyzed, based on the projected energy maps and curves. The single-particle struc...     

Measurement of(n,α)and(n,2n)reaction cross sections at a neutron energy of 14.92±0.02 MeV for potassium and copper with uncertainty propagation

Experimentally measured neutron activation cross sections are presented for the ⁶⁵Cu(n,0)^62mCu,⁴¹ K(n,a)^38Cl,and ⁶⁵Cu(n.2n)⁶⁴Cu reactions with detailed uncertainty propagation.The neutron cross secions were measured at an incident energy of 14.92±0.02 MeV,and the neutrons were based on the(d,n)a fusion reaction.The ²⁷ Al(n,a)²⁴Na reaction was used as a reference reaction for the normalization of the neutron flux.The pre-calib-rated lead-shielded HPGe detector was used to detect the residues'γ-ray spetra.The data from the measured cross sections are compared to the previously measured cross sections from the EXFOR database,theoretically calculated cross sections using the TALYS and EMPIRE codes,and evaluated nuclear data.     

Zcs(4000)+ and Zcs(4220)+ in a Multiquark Color Flux-Tube Model

We systematically investigate the mass spectrum, spatial configuration and magnetic moment of the ground and p-wave states ■ with various color-spin configurations in a multiquark color flux-tube model. Numerical results indicate that the state Z_cs(4000)⁺ can be described as the compact state ■ with 1³S₁. Its main colorspin configuration is ■ and its magnetic moment is 0.73μN. The state Z_cs(4220)⁺can be depicted as the compact sta...     

Weak decays of doubly heavy baryons:Bcc→BD*

The discovery of Ξ_cc⁺⁺has inspired new interest in studying doubly heavy baryons.In this study,the weak decays of a doubly charmed baryon B_ccto a light baryon B and a charm meson D^*(either a pseudoscalar or a vector one)are calculated.Following our previous work,we calculate the short distance contributions under the factorization hypothesis,whereas the long distance contributions are modeled as the final state interactions,which are calculated with the one particle exchange model.We find that the B_cc→BD^*decays'branching ratios are obviously larger,as they receive contributions of more polarization states.Among the decays that we investigate,the following have the largest branching fractions:BR(Ξ_cc⁺⁺→∑⁺D^*+)∈[0.46%,3.33%]estimated with τΞ_cc⁺⁺=256 fs;BR(Ξ_cc⁺→AD^*+)∈[0.38%,2.63%]and BR(Ξ_cc⁺→∑⁰D^*+)∈[0.45%,3.16%]with τΞ_cc⁺⁺=45 fs;and BR(Ω_cc⁺→Ξ⁰D⁺)∈[0.27%,1.03%),BR(Ω_cc⁺→∑⁰D^*+)∈[0.07%,0.44%],and BR(Ω_cc⁺→∑⁰D^*+)∈[0.06%,0.45%] with τ_(Ω_cc)⁺=75 fs.By comparing the decay widths of pure color commensurate channels with those of pure bow-tie ones we find that the bow-tie mechanism plays an important role in charm decays.     

Doubly excited 2s2p 1,3P1 resonances in photoionization of helium

The multi-configuration Dirac-Fock（MCDF） method is implemented to study doubly excited 2s2p ^1,3P₁ resonances of the helium atom and the interference between photoionization and photoexcitation autoionization processes.In order to reproduce the total photoionization sprectra,the excited energies from the ground 1s^{2 1}S₀ state to the doubly excited 2s2p ^1,3P₁ states and the relevant Auger decay rates and widths are calculated in detail.Furthermore,the interference profile determined by the so-called Fano parameters q and ρ² is also reproduced.Good agreement is found between the present results and other available theoretical and experimental results.This indeed shows a promising way to investigate the Fano resonances in photoionization of atoms within the MCDF scheme,although there are some discrepancies in the present calculations of the 2s2p ³P₁ state.     

Non-factorizable contributions in D0→π+π- decay

We have analyzed the D^0→π^+π^- decay with α_s corrections in quantum chromodynamic (QCD) factorization and with the soft-gluon corrections in the light cone QCD sum rules. The soft-gluon effects are firstly calculated in the decay channel. The results show that once the factorization contributions, the α_s corrections, and the soft-gluon effects are all considered, we can satisfactorily explain the experimental data in the decay channel.     

Reconciliation of Theoretical Lifetimes of the 5s5p3P2o Metastable State for 88Sr with Measurement: The Role of the Blackbody-Radiation-Induced Decay

We conducted measurement and calculation to resolve the long-standing large discrepancy in the metastable state lifetime for the ⁸⁸Sr atom between theoretical and experimental results. The present lifetime τ = 830_-240⁺⁶⁰⁰s,measured using the magneto-optical trap as a photon amplifier to detect the weak decay events, is approximately60% larger than the previous experimental value τ = 520_-140⁺³¹⁰s. By considering the electron correlation effec...     

57Fe Mössbauer spectrometry: A powerful technique to analyze the magnetic and phase characteristics in RE–Fe–B permanent magnets

This review summarizes the recent advances on the application of ⁵⁷Fe M?ssbauer spectrometry to study the magnetic and phase characteristics of Nd–Fe–B-based permanent magnets. First of all, the hyperfine structures of the Ce₂Fe₁₄B,(Ce,Nd)₂Fe₁₄B and MM₂Fe₁₄B phases are well-defined by using the model based on the Wigner-Seitz analysis of the crystal structure. The results show that the isomer shift δ and the quadrupole splitting ?EQ of those 2:14:1 phases show minor changes with the Nd content, while the hyperfine field Bhfincreases monotonically with increasing Nd content and its value is influenced by the element segregation and phase separation in the 2:14:1 phase. Then, the hyperfine structures of the low fraction secondary phases are determined by the ⁵⁷Fe M?ssbauer spectrometry due to its high sensitivity. On this basis,the content, magnetic behavior, and magnetization of the REFe₂ phase, the amorphous grain boundary(GB) phase, and the amorphous worm-like phase, as well as their effects on the magnetic properties, are systematically studied.     

The effects of Er3+ ion concentration on 2.0-μm emission performance in Ho3+/Tm3+ co-doped Na5Y9F32 single crystal under 800-nm excitation

Na₅Y₉F₃₂ single crystals doped with ~0.8-mol% Ho³⁺,~1-mol% Tm³⁺,and various Er³⁺ ion concentrations were prepared by a modified Bridgman method.The effects of Er³⁺ion concentration on 2.0-μm emission excited by an800-nm laser diode were investigated with the help of their spectroscopic properties.The intensity of 2.0-μm emission reached to maximum when the Er³⁺ ion concentration was ~1 mol%.The energy transfer mechanisms between Er³⁺,Ho³⁺,and Tm³⁺ ions were identified from the change of the absorption spectra,the emission spectra,and the measured decay curves.The maximum 2.0-μm emission cross section of the Er³⁺/Ho³⁺/Tm³⁺tri-doped Na₅Y₉F₃₂ single crystal reached 5.26 × 10^-21 cm².The gain cross section spectra were calculated according to the absorption and emission cross section spectra.The cross section for ~2.0-μm emission became a positive gain once the inversion level of population was reached 30%.The energy transfer efficiency was further increased by 11.81% through the incorporation of Er³⁺ ion into Ho³⁺/Tm³⁺ system estimated from the measured lifetimes of Ho³⁺/Tm³⁺-and Er³⁺/Ho³⁺/Tm³⁺-doped Na₅Y₉F₃₂single crystals.The present results illustrated that the Er³⁺/Ho³⁺/Tm³⁺tri-doped Na₅Y₉F₃₂ single crystals can be used as promising candidate for 2.0-μm laser.     

60Co gamma radiation effect on AlGaN/AlN/GaN HEMT devices

The testing techniques and experimental methods of the ⁶⁰Co gamma irradiation effect on AlGaN/AlN/ GaN high electron mobility transistors （HEMTs） are established. The degradation of the electrical properties of the device under the actual radiation environment are analyzed theoretically, and studies of the total dose effects of gamma radiation on AlGaN/AlN/GaN HEMTs at three different radiation bias conditions are carried out. The degradation patterns of the main parameters of the AlGaN/AlN/GaN HEMTs at different doses are then investigated, and the device parameters that were sensitive to the gamma radiation induced damage and the total dose level induced device damage are obtained.     

Magnetic and quadrupole moments of the Zc(4020)+,Zc(4050)+,and Zc(4600)+ states in the diquark-antidiquark picture

The magnetic and quadrupole moments of the Z_c(4020)⁺,Z_c(4050)⁺,and Z_c(4600)⁺ states are calculated within the QCD light-cone sum rules.The compact diquark-antidiquark interpolating currents and the distribution amplitudes of the on-shell photon are used to extract the magnetic and quadrupole moments of these states.The magnetic moments are acquired as μ_Zc=0.50_-0.22^+0.22μ_N,μ     

Study of singlet-triplet mixing via semileptonic decays

The singlet-triplet mixing of ¹P₁-3P1 is studied via calculating the branching ratios of semileptonic decay Bs→D_s1lν and B→D₁ lν by means of the instantaneous Bethe-Salpeter method. Special attention is paid to the relativistic corrections, since they are large for the P -wave states. Using the Mandelstam Formalism, we compute the transition form factors not only in the high-energy lepton end-point region but also in the full Q2 region. In addition, the non-perturbative QCD effects are taken care of in the overlapping integral over the relativistic wave functions of the initial and final states.     

Coexistence and fluctuations phenomena with Davidson-like potentials in quadrupole-octupole deformed nuclei

The energy spectra of three types of two-dimensional potentials(we will call them‘Davidson-like potentials’(DLPs)),characterized by four minima separated by barriers,are investigated.The predictions for spectra and wave functions are obtained by using the nine-point finite-difference method.For these potentials,with the existence of a single configuration,a transition of spectra,as a function of barrier height,is covered from tunneling splitting modes to fluctuations phenomena,with equal peaks wave functions,crossing to the spectra of purely anharmonic oscillator potentials(AOPs).A different type of phase transition occurs when two(or more)configurations coexist.With the change of the parameters,a transition of spectra is covered from coexistence phenomena of two distinct quantum tunneling modes to fluctuations phenomena,with unequal peaks wave functions,crossing to the spectra of purely AOPs.Using DLPs,a particular application of the coherent quadropole-octupole model to describe energy bands with alternating parity of the nuclei¹⁰⁰Mo,^146,148Nd,^148,150Sm,²²⁰Ra,^220,222Rn,and^220,222Th is presented.The global parametrization of the model for the selected nuclei is achieved.     

Experimental Evidence of Two-Proton Emissions from 18Ne Excited State

Experiment ^18Ne＋^197 Au was performed in Heavy Ion Research Facility Radioactive Ion Beam Line at Lanzhou （RIBLL）. The nuclear energy levels of ^18Ne were built by complete kinematical reconstruction of the decay products and diproton decay were observed from ^18Ne excited states. At 6.15 MeV, the experimental relative momentum and angular correlations of the emitted protons are given. The obvious enhancement at ｜qrol｜= 23 MeV/c and θc.m. = 40° shows the experimental criterion of ^2He cluster decay from ^18Ne^q.