| 1. |
- Ablikim, M., et al.
(author)
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Study of eta(1475) and X(1835) in radiative J/psi decays to gamma phi
- 2018
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In: Physical Review D. - : AMER PHYSICAL SOC. - 2470-0010 .- 2470-0029. ; 97:5
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Journal article (peer-reviewed)abstract
- The decay J/psi -> gamma gamma phi is studied using a sample of 1.31 x 10(9) J/psi events collected with the BESIII detector. Two structures around 1475 MeV/c(2) and 1835 MeV/c(2) are observed in the gamma phi invariant mass spectrum for the first time. With a fit on the gamma phi invariant mass, which takes into account the interference between the two structures, and a simple analysis of the angular distribution, the structure around 1475 MeV/c(2) is found to favor an assignment as the eta(1475) and the mass and width for the structure around 1835 MeV/c(2) are consistent with the X(1835). The statistical significances of the two structures are 13.5 sigma and 6.3 sigma, respectively. The results indicate that both eta(1475) and X(1835) contain a sizeable s (s) over bar component.
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| 2. |
- Zhang, S. -N, et al.
(author)
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Introduction to the high energy cosmic-radiation detection (HERD) facility onboard China's future space station
- 2017
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In: Proceedings of Science. - : Sissa Medialab Srl.
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Conference paper (peer-reviewed)abstract
- The High Energy cosmic-Radiation Detection (HERD) facility is one of several space astronomy payloads onboard China's Space Station, which is planned for operation starting around 2025 for about 10 years. The main scientific objectives of HERD are searching for signals of dark matter annihilation products, precise cosmic electron (plus positron) spectrum and anisotropy measurements up to 10 TeV, precise cosmic ray spectrum and composition measurements up to the knee energy, and high energy gamma-ray monitoring and survey. HERD is composed of a 3-D cubic calorimeter (CALO) surrounded by microstrip silicon trackers (STKs) from five sides except the bottom. CALO is made of about 7,500 cubes of LYSO crystals, corresponding to about 55 radiation lengths and 3 nuclear interaction lengths, respectively. The top STK microstrips of six X-Y layers are sandwiched with tungsten converters to make precise directional measurements of incoming electrons and gamma-rays. In the baseline design, each of the four side STKs is made of only three layers microstrips. All STKs will also be used for measuring the charge and incoming directions of cosmic rays, as well as identifying back scattered tracks. With this design, HERD can achieve the following performance: energy resolution of 1% for electrons and gamma-rays beyond 100 GeV and 20% for protons from 100 GeV to 1 PeV; electron/proton separation power better than 10-5; effective geometrical factors of >3 m2sr for electron and diffuse gamma-rays, >2 m2sr for cosmic ray nuclei. R&D is under way for reading out the LYSO signals with optical fiber coupled to image intensified IsCMOS and CALO prototype of 250 LYSO crystals.
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| 3. |
- Chen, X, et al.
(author)
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Bismuth Effects on Electronic Levels in GaSb(Bi)/AlGaSb Quantum Wells Probed by Infrared Photoreflectance
- 2015
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In: Chinese Physics Letters. - 0256-307X .- 1741-3540. ; 32:6
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Journal article (peer-reviewed)abstract
- GaSb(Bi)/Al0.2Ga0.8Sb single quantum wells are characterized by a Fourier transform infrared spectrometerbased photoreflectance method at 77 K. Spatially direct and indirect transitions between the electronic levels at and above the effective band gap are well resolved. The shifts of the electronic levels with Bi incorporation are identified quantitatively. The results show that the upshift of the valence band edge is clarified to be dominant, while the Bi-induced downshift of the conduction band edge does exist and contributes to the band gap reduction in the GaSbBi quantum-well layer by (29±6)%.
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| 4. |
- Li, Y., et al.
(author)
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Highly tensile-strained sub-monolayer Ge nanostructure on GaSb studied by scanning tunneling microscopy
- 2017
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In: Materials Research Express. - : IOP Publishing. - 2053-1591. ; 4:4, s. Article nr 045907 -
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Journal article (peer-reviewed)abstract
- Highly tensile-strained sub-monolayer Ge nanostructures on GaSb have been grown by molecular beam epitaxy and studied by ultrahigh-vacuum scanning tunneling microscopy. Four different coverage rates of Ge nanostructures on GaSb are achieved and investigated. It is found the growth of Ge on GaSb follows 2D growth mode. The crystal lattice of the sub-monolayer Ge nanostructures is coherent with that of the GaSb, inferring as large as 7.74% tensile strain in the Ge nanostructures.
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