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...     

Investigation of the tetraquark states ■ in the improved chromomagnetic interaction model

In the framework of the improved chromomagnetic interaction model, we complete a systematic study of the S-wave tetraquark states ■ ( Q = c, b, and q = u, d, s) with different quantum numbers: J^PC= 0⁽+(+)), 1⁽+(±)),and 2⁽+(+)). The mass spectra of tetraquark states are predicted, and the possible decay channels are analyzed by considering both the angular momentum and C-parity conservation. The recently observed hidden-charm tetraquark states with stra...     

Doubly heavy tetraquarks in an extended chromomagnetic model

Using an extended chromomagnetic model,we perform a systematic study of the masses of doubly heavy tetraquarks.We find that the ground states of the doubly heavy tetraquarks are dominated by the color-triplet ■configuration,which is opposite to that of fully heavy tetraquarks.The combined results suggest that the color-triplet configuration becomes more important when the mass difference between the quarks and antiquarks increases.We find three stable states that lie below the thresholds of two pseudoscalar mesons.They are the I^P=01⁺nnbb tetraquark,I^P=1⁺nncb tetraquark,and J^P=1⁺nsbb tetraquark.     

Estimation of radiative capture 13B(n,γ0+1)14B reaction rate in the modified potential cluster model

We discuss current attempts to employ the modified potential cluster model to describe the available experimental data on the ¹³B(n,γ₀₊₁)¹⁴B total cross-sections.The estimated results of the M1 and E1 transitions from the n¹³B scattering states to the ground and first excited states of ¹⁴B are presented.The 1^st resonance at E_x=1.275MeV(1⁺) is revealed in both the cross-section and reaction rate.Within the var...     

Analysis of the excited Ωc states as the 1/2± pentaquark states with QCD sum rules

We construct both the scalar-diquark-scalar-diquark-antiquark type and axialvector-diquark-axialvector-diquark-antiquark type interpolating currents to study the charmed pentaquark:states suscu with J^p=1/2^±.We employ the QCD sum rules to investigate the masses and pole residues of the charmed pentaquark states by taking into account the vacuum condensates up to dimension 13 in the operator product expansion.Our calculation results indicate that the scalar-diquark-scalar-diquark-antiquark type and axialvector-diquark-axialvector-diquark-antiquark type charmed pentaquark states suscu with J^p=1/2^- can be possible candidates of the excited states observed in the LHCb collaboration.     

Three-Body Recombination of Cold 3He–3He–T- System

The atom-atom-anion three-body recombination(TBR) and collision induced dissociation(CID) processes of the ³He–³He–T^- system at ultracold temperatures are investigated by solving the Schr¨odinger equation in the adiabatic hyperspherical representation. The variations of the TBR and CID rates with the collision energies in the ultracold temperatures are obtained. It is found that the J^Π= 1^- symmetry dominates the TBR and CID processes in most...     

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...     

QCD Axial Anomaly Enhances the ηη' Decay of the Hybrid Candidate η1（1855）

We study the hybrid mesons with the exotic quantum number I^GJ^PG=0⁺1^-+ and investigate their decays into the ηη’,a₁（1260）π,f₁（1285）η,f₁（1420）η,K^*（892）■,K₁（1270）■,and K₁（1400）■channels.It is found that the QCD axial anomaly enhances the decay width of the ηη’ channel although this mode is strongly suppressed by the small p-wave phase space.Our results support the interpretation of the η     

CALCULATION OF THE FINE STRUCTURE OF OXYGEN-LIKE IONS USING THE POLARIZATION POTENTIAL FUNCTION

We have calculated the forbidden transition energies and magnetic dipole transition probabilities of 2s²2p⁴(³P₁－³P₂) and 2s²2p⁴ (³P₀－³P₁) of oxygen-like isoelectronic sequences (Z=10－32) by a method of polarization potential correction. The transition energies show good agreement with experiment and are much better than the calculations in the literature. These results also illustrate that it is feasible to use the dipole expansion of the polarization potential to deal with some dynamic and non-dynamic effects in the central field approach. The relation of polarizability and cut-off radius with atomic number is discussed. We also give the fitted formula between the polarizability α₁ and atomic number Z as α₁=0.73429-9.56644×10^-4Z+7.43016×10^-5Z^{2-2.53298×10-6Z3+2.08306×10-8Z4.}     

Expected H →μ+μ-measurement precision with e+e-→Z(q■)H production at the CEPC

A search for the dimuon decay of the Standard Model Higgs boson is performed using Monte Carlo simulated events to mimic data corresponding to an integrated luminosity of 5.6 ab^-1 collected with the Circular Electron-Positron Collider detector in e⁺e^-collisions at■GeV.This study investigates thee⁺e^-→ZH,Z→q■,H→μ⁺μ^-process,and the expected significance considering only the statistical uncertainty in the data for a backgro...     

Molecular Nature of X(3872) in B0→ K0X (3872) and B+→ K+X (3872) Decays

We investigate the decays of B⁰→ K⁰X(3872) and B⁺→ K⁺X(3872) based on the picture where the X(3872) resonance is strongly coupled to the ■+ c.c. channel. In addition to the decay mechanism where the X(3872) resonance is formed from the ■ pair hadronization with the short-distance interaction, we have also considered the ■ rescattering diagrams in the long-distance scale, where D and ■ are formed from c and ■ separately. Because of the difference of the...     

X_0(2900) and X_1(2900):Hadronic Molecules or Compact Tetraquarks

Very recently the LHCb collaboration reported their observation of the first two fully open-flavor tetraquark states,the X₀(2900) of J^P=0⁺ and the X₁(2900) of J^P=1^-.We study their possible interpretations using the method of QCD sum rules,paying special attention to an interesting feature of this experiment that the higher resonance X₁(2900) has a width significantly larger than the lower one X₀(2900).Our res...     

Exotic ■_s~((*))D~((*)) molecular states and sc■ tetraquark states with J~P=0~+,1~+,2~+

We have calculated the mass spectra for the ■_s~((*))D~((*)) molecular states and sc■ tetraquark states with J~P=0~+,1~+,2~+.The masses of the axial-vector ■_sD~*,■_s~*D molecular states and ■ tetraquark states are predicted to be approximately 3.98 GeV,in good agreement with the mass of Z_(cs)(3985)~- from BESⅢ.In both the molecular and diquark-antidiquark scenarios,our results suggest that there may exist two almost degenerate states,as the strange partners of X(3872) and Z_c(3900).We propose to carefully examine Z_(cs)(3985) in future experiments to verify this.One may also search for more hidden-charm four-quark states with strangeness in not only the open-charm ■_s~((*))D~((*)) channels but also the hidden-charm channels η_cK/K~*,J/ψK/K~*.     

OPTICAL-OPTICAL DOUBLE-RESONANCE EXCITATION SPECTRA OF THE (6d)1Πg, (7d)1Πg HIGH-LYING RYDBERG STATES IN Na2

Two ¹Π_g states of Na₂ for v≤13 have been observed by using optical-optical double resonance (OODR) fluorescence excitation spectroscopy. The intermediate levels in B¹Π_u state are identified by the numerical calculations with the molec-ular constants for B¹Π_u←X¹Σ_g⁺ transitions and confirmed by the complemen-tary A¹Σ_g⁺←X¹Σ_g⁺ polarization spectra. Absolute vibrational numberings of the (6d)¹Π_g and (7d)¹Π_g states are determined by comparing the experimental OODR excitation intensities with the simulated Franck-Condon factors. The Dnnham coef-ficients and the Rydberg-Klein-Rees (RKR) potential energy curves of the (6d)¹Π_g, (7d)¹Π_g states are reported.     

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.     

Efficient production of ultracold polar molecules 23Na40K in their absolute ground state via intermediate state of the coupled complex B1Π |ν = 4〉～ c3Σ+|ν = 25〉

We report on the efficient creation of a sample of 2.2×10⁴ fermionic polar molecules ²³Na⁴⁰K in their rovibrational ground state X¹∑⁺|v=0,J=0>at 247 nK via an intermediate state of the spin-orbit coupled complex B¹Π|v=4〉～C³∑⁺|v=25〉.Compared with the intermediate state of the coupled complex B¹Π|v=12〉～c³∑⁺|v=35〉,this intermediate state has the larger Franck-Condon factors fo...     

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.     

Spectroscopic parameters and molecular constants of HI(X~1Σ~+),DI(X~1Σ~+) and TI(X~1Σ~+) isotope molecules

The potential energy curve (PEC) of HI(X¹Σ⁺) molecule is studied using the complete active space self-consistent field method followed by the highly accurate valence internally contracted multireference configuration interaction approach at the correlation-consistent basis sets, aug-cc-pV6Z for H and aug-cc-pV5Z-pp for I atom. Using the PEC of HI(X¹Σ⁺), the spectroscopic parameters of three isotopes, HI(X¹Σ⁺), DI(X¹Σ⁺) and TI(X¹Σ⁺), are determined in the present work. For the HI(X¹Σ⁺), the values of D₀, D_e, R_e, ω_e, ω_eχ_e, α_e and B_e are 3.1551 eV, 3.2958 eV, 0.16183 nm, 2290.60 cm^-1, 40.0703 cm^-1, 0.1699 cm^-1 and 6.4373 cm^-1, respectively; for the DI (X¹Σ⁺), the values of D₀, D_e, R_e, ω_e, ω_eχ_e, α_e and B_e are 3.1965 eV, 3.2967 eV, 0.16183 nm, 1626.8 cm^-1, 20.8581 cm^-1, 0.0611 cm^-1 and 3.2468 cm^-1, respectively; for the TI (X¹Σ⁺), the values of D₀, D_e, R_e, ω_e, ω_eχ_e, α_e and B_e are of 3.2144 eV, 3.2967 eV, 0.16183 nm, 1334.43 cm^-1, 14.0765 cm^-1, 0.0338 cm^-1 and 2.1850 cm^-1, respectively. These results accord well with the available experimental results. With the PEC of HI(X¹Σ⁺) molecule obtained at present, a total of 19 vibrational states are predicted for the HI, 26 for the DI, and 32 for the TI, when the rotational quantum number J is equal to zero (J = 0). For each vibrational state, vibrational level G(?), inertial rotation constant B_? and centrifugal distortion constant D_? are determined when J = 0 for the first time, which are in excellent agreement with the experimental results.     

Double-heavy tetraquark states with heavy diquark-antiquark symmetry

We calculate the masses of the QQqq(Q=c,b:q=u,d,s)tetraquark states with the aid of heavy diquark-antiquark symmetry(HDAS)and the chromomagnetic interaction(CMI)model.The masses of the highestspin(J=2)tetraquarks that have only the(QQ)(3):(qq)₃.color structure are related with those of conventional hadrons using HDAS.Thereafter,the masses of their partner states are determined with the mass splittings in the CMI model.Our numerical results reveal that(i)the lightest ccnn(n=u,d)is an I(J^P)=0(1⁺)state around 3929 MeV(53 MeV above the DD^* threshold),and none of the double-charm tetraquarks are stable;(ii)the stable double-bottom tetraquarks are the lowest 0(1⁺)bbin around 10488 MeV(≈116 MeV below the BB^*threshold)and the lowest 1/2(1⁺)bbns around 10671 MeV(≈20 MeV below the BB_s^*/B_sB^*threshold);and(iii)the two lowest bcnn tetraquarks,namely the lowest 0(0⁺)around 7167 MeV and the lowest 0(1)around 7223 MeV,are in the nearthreshold states.Moreover,we discuss the constraints on the masses of double-heavy hadrons.Specifically,for the lowest nonstrange tetraquarks,we obtain T_cc<3965 MeV,T_bb<10627 MeV,and T_bc<7199 MeV.     

Infrared studies of oxygen-related complexes in electron-irradiated Cz-Si

This paper investigates the infrared absorption spectra of oxygen-related complexes in silicon crystals irradiated with electron (1.5~MeV) at 360~K. Two groups of samples with low [O_i]=6.9× 10¹⁷~cm^-3 and high [ O_i]=1.06× 10¹⁸~cm^-3 were used. We found that the concentration of the VO pairs have different behaviour to the annealing temperature in different concentration of oxygen specimen, it is hardly changed in the higher concentration of oxygen specimen. It was also found that the concentration of VO₂ in lower concentration of oxygen specimen gets to maximum at 450~℃ and then dissapears at 500~℃, accompanied with the appearing of VO₃. For both kinds of specimens, the concentration of VO₃ reachs to maximum at 550~℃ and does not disappear completely at 600~℃.