Light hadron, charmonium(-like) and bottomonium(-like) states

Hadron physics represents the study of strongly interacting matter in all its manifestations and understanding its properties and interactions. The interest in this field has been revitalized by the discovery of new light hadrons, charmonium- and bottomonium-like states. In this paper, the most recent experimental results from different experiments are reviewed.     

Thermal QCD sum rules study of vector charmonium and bottomonium states

We calculate the masses and leptonic decay constants of the heavy vector quarkonia, J/ψ and ϒ mesons at finite temperature. In particular, considering the thermal spectral density as well as additional operators coming up at finite temperature, the thermal QCD sum rules are acquired. Our numerical calculations demonstrate that the masses and decay constants are insensitive to the variation of temperature up to T ≅ 100 MeV, however after this point, they start to fall altering the temperature. At deconfinement temperature, the decay constants attain roughly to 45% of their vacuum values, while the masses are diminished about 12%, and 2.5% for J/ψ and ϒ states, respectively. The obtained results at zero temperature are in good consistency with the existing experimental data as well as predictions of the other nonperturbative models.     

Observation and characterization of the fluorescence decay of the 2s2p(6)np 1P(o) excited states of Ne

Fluorescence decay of the 2s2p(6)np (1)P(o) excited states of neon has been observed directly for the first time. This process has also been observed indirectly by threshold photoelectron spectroscopy and in electron/photon coincidences. The measurements have allowed this weak decay channel to be characterized and branching ratios derived. The fluorescence excitation spectrum is well described by a simple Rydberg model that highlights the interplay and competition between the decay channels of autoionization and fluorescence.     

Strong decays of P-wave mixing heavy-light 1~+ states

Many P-wave mixing heavy-light 1~+ states have not yet been discovered by experiment, while others have been discovered but without width information, or with large uncertainties on the widths. In this paper, the strong decays of the P-wave mixing heavy-light 1~+ states D0, D~±, D~±s, B0, B~±and Bs are studied by the improved BetheSalpeter(B-S) method with two conditions of mixing angle θ: one is θ = 35.3?; the other is considering a correction to the mixing angle θ =35.3?~+θ_1. Valuable predictions for the strong decay widths are obtained: Γ(D′01)=232 MeV,Γ(D01)=21.5 MeV, Γ(D′_1~±.)=232 MeV, Γ(D_1~±)=215 MeV, Γ(D′_(s1)~±)=0.0101 MeV, Γ(D~±s1)=0.950 MeV, Γ(B′_1~±)=263 MeV, Γ(B~±1) = 16.8 MeV, Γ(B′s1) = 0.01987 MeV and Γ(B_(s1)) = 0.412 MeV. It is found that the decay widths of D~±s1 and Bs1 are very sensitive to the mixing angle. The results will provide theoretical assistance to future experiments.     

First observation of high spin states in90Tc

High spin states in⁹⁰Tc have been studied via the⁵⁸Ni (³⁵Cl, 2pn) ⁹⁰Tc reaction at beam energy of 124 MeV. Twenty-six newγ-rays were observed, a new level scheme was established and spins were assigned. Two band-like structures were established up to about 20? with an excitation energy of 6–7 MeV. The band (B) shows collective characteristic at high spin. We suggest it to be of a quasi-particle configurationπg_9/2?vf _5/2.     

First observation of excited states in the neutron-rich nucleus 138Te

The very neutron-rich nucleus ¹³⁸Te produced in the spontaneous fission of ²⁴⁸Cm has been investigated using the EUROGAM II %-ray multidetector array. The excited states of ¹³⁸Te observed for the first time indicate that the region of ground state deformation beyond the doubly magic nucleus ¹³²Sn has yet not been reached.     

First observation of trapped high-field seeking ultracold neutron spin states

Ultracold neutrons were stored in a volume, using a magnetic dipole field shutter. Radial confinement was provided by material walls. Low-field seeking neutrons were axially confined above the magnetic field. High-field seeking neutrons are trapped inside the magnetic field. They can systematically shift the measured neutron lifetime to lower values in experiments with magnetic confinement.     

Impurity band states in SI(P)

A comparison is made between calculated impurity band densities of state in Si(P) for donor concentrations below that of the semiconductor-to-metal transition and experimental results obtained from photoluminescence spectra after subtracting an electron-hole droplet line. The theoretical results were obtained within the large interaction limit of the Hubbard model, assuming the impurities to be randomly distributed. The density of states was computed from cumulants appropriate to the low and high impurity density limit.     

LiⅠ等电子序列[(1s2p)3P,4d]2P0及 [(1s2s)1S,5p]2P0自电离态的计算

利用鞍点复转动及全实加关联的方法,计算了LiⅠ等电子序列[(1s2p)3P,4d]2P0及[(1s2s)1S,5p]2P0自电离态的能量和宽度.计算结果中包括相对论修正和质量极化修正.文中讨论了自电离宽度随核电荷数Z的变化关系,同时也讨论了精细结构分裂值及相对论修正随核电荷数Z的变化关系.     

Measurements of theg J -factors of12C in the3 P 1 and3 P 2 states

Using the atomic beam magnetic resonance method the Zeeman interactions of¹²C in the³ P ₁ and³ P ₂ states at magnetic fields of about 3.4 kOe have been measured. The measured quantities areg _J (³ P ₁)?g_J(³ P ₂)=15.4(1.0)·10^?6 g _J (³ P ₂)=1.5010616 (50), from which the following value for g_J(³P₁) can be calculated:g _J (³ P ₁)=1.5010770 (50). The experimental results are in moderate agreement with theoretical calculations.     

Surface states in Si(111)2×1 and Ge(111)2×1 by optical reflectivity

Surface states in Si(111)2×1 and Ge(111)2×1 are detected by the method of the change of external reflectivity, both at energies below and above the gap. Optical transitions at 2.6 eV in Si and at 1.8 eV and 3.1 eV in Ge, as well as the already known transitions below the gap are observed.     

Experimental determination of the helium 2(3)P(1)-1(1)S0 transition rate

We present the first experimental determination of the 2(3)P(1)-1(1)S0 transition rate in helium and compare this measurement with theoretical quantum-electrodynamic predictions. The experiment exploits the very long (approximately 1 minute) confinement times obtained for atoms magneto-optically trapped in an apparatus used to create a Bose-Einstein condensate of metastable (2(3)S1) helium. The 2(3)P(1)-1(1)S0 transition rate is measured directly from the decay rate of the cold atomic cloud following 1083 nm laser excitation from the 2(3)S1 to the 2(3)P1 state, and from accurate knowledge of the 2(3)P1 population. The value obtained is 177+/-8 s(-1), which agrees very well with theoretical predictions, and has an accuracy that compares favorably with measurements for the same transition in heliumlike ions higher in the isoelectronic sequence.     

Symmetry-resolved vibrational spectroscopy for the C 1s(-1)2 pi(u) Renner-Teller pair states in CO(2)

Symmetry-resolved excitation spectra have been measured for the Renner-Teller pair states A(1) and B(1) split from the core-excited C 1s(-1)2 pi(u) state in CO(2). A vibrational progression with the spacings of approximately 145 meV is found in both the A(1) and B(1) spectra at different energies and assigned to the symmetric stretching mode caused in the B(1) linear state, with the help of ab initio calculations. Appearance of the vibrations in the A(1) spectrum is interpreted as due to non-adiabatic coupling between the A(1) and B(1) states via the bending motion.