Using the data samples collected at and around the center-of-mass energies of 3.097 GeV and 3. 773 GeV with the BES-Ⅱ detector at the BEPC collider, we select the pure particle samples of muon, electron, kaon and pio...Using the data samples collected at and around the center-of-mass energies of 3.097 GeV and 3. 773 GeV with the BES-Ⅱ detector at the BEPC collider, we select the pure particle samples of muon, electron, kaon and pion, and their mutual （mis）identification rates are also obtained.展开更多
Using a data sample of about 33pb^-1 collected at and around √s = 3.773 GeV with the BES-Ⅱ detector at the BEPC, we have directly measured the branching fraction for inclusive semimuonic decay of neutral D mesons to...Using a data sample of about 33pb^-1 collected at and around √s = 3.773 GeV with the BES-Ⅱ detector at the BEPC, we have directly measured the branching fraction for inclusive semimuonic decay of neutral D mesons to be BF（D^0 → μ^＋X） = （7.2 ± 1.5 ± 0.8）%.展开更多
Using the Monte Carlo samples of about 800 pb^-1 and 500 pb^-1 generated at and around 3.773 GeV with BOSS （BESⅢ Offtine Software System） 6.0.2 and BOSS 6.1.0, we have studied the branching fractions for D^0 → K^...Using the Monte Carlo samples of about 800 pb^-1 and 500 pb^-1 generated at and around 3.773 GeV with BOSS （BESⅢ Offtine Software System） 6.0.2 and BOSS 6.1.0, we have studied the branching fractions for D^0 → K^-l^＋vl and D^0 →π^- l^＋ vl （l=e, μ）. According to the simulation results, the expected precision of these measurements for 20fb^-1 ψ（3770） data which will be collected on BESⅢ are well estimated.展开更多
We construct dark energy models which have high derivative terms. In the framework of a single scalar field model with a higher derivative, the equation of state （EOS） ω might have some special character in the evo...We construct dark energy models which have high derivative terms. In the framework of a single scalar field model with a higher derivative, the equation of state （EOS） ω might have some special character in the evolvement, which states that the universe will evolve in some interesting ways. We study the different kinds of dark energy models, and classify them into several genera by their character in the evolvement.展开更多
Up to now,at least 806 carbon allotropes have been proposed theoretically.Three interesting carbon allotropes(named Pbam-32,P6/mmm,and I43d)were recently uncovered based on a random sampling strategy combined with spa...Up to now,at least 806 carbon allotropes have been proposed theoretically.Three interesting carbon allotropes(named Pbam-32,P6/mmm,and I43d)were recently uncovered based on a random sampling strategy combined with space group and graph theory.The calculation results show that they are superhard and remarkably stable compared with previously proposed metastable phases.This indicates that they are likely to be synthesized in experiment.We use the factor group analysis method to analyze theirΓ-point vibrational modes.Owing to their large number of atoms in primitive unit cells(32 atoms in Pbam-32,36 atoms in P6/mmm,and 94 atoms in I43d),they have many Raman-and infrared-active modes.There are 48 Raman-active modes and 37 infrared-active modes in Pbam-32,24 Raman-active modes and 14 infrared-active modes in P6/mmm,and 34 Raman-active modes and 35 Raman-and infrared-active modes in I43d.Their calculated Raman spectra can be divided into middle frequency range from 600 cm-1 to 1150 cm-1 and high frequency range above 1150 cm-1.Their largest infrared intensities are 0.82,0.77,and 0.70(D/Å)2/amu for Pbam,P6/mmm,and I43d,respectively.Our calculated results provide an insight into the lattice vibrational spectra of these sp3 carbon allotropes and suggest that the middle frequency Raman shift and infrared spectrum may play a key role in identifying newly proposed carbon allotropes.展开更多
基金Supported by the National Natural Science Foundation of China under Grant Nos 10491300, 10225524, 10225525, 10425523, 10625524 and 10521003, the Knowledge Innovation Project of Chinese Academy Sciences （KJ95T-03）, the One-Hundred Talents Program of Chinese Academy Sciences （U-11, U-24, U-25, U-602, U-34）.
文摘Using the data samples collected at and around the center-of-mass energies of 3.097 GeV and 3. 773 GeV with the BES-Ⅱ detector at the BEPC collider, we select the pure particle samples of muon, electron, kaon and pion, and their mutual （mis）identification rates are also obtained.
基金Supported by National Natural Science Foundation of China of China under Grant Nos 10491300, 10225524, 10225525, 10425523, 10625524 and 10521003, the Knowledge Innovation Project of Chinese Academy Sciences under Grant No KJ95T- 03, 100 Talents Program of Chinese Academy Sciences （U-11, U-24, U-25）, the Knowledge Innovation Project of Chinese Academy Sciences （U-602, U-34）.
文摘Using a data sample of about 33pb^-1 collected at and around √s = 3.773 GeV with the BES-Ⅱ detector at the BEPC, we have directly measured the branching fraction for inclusive semimuonic decay of neutral D mesons to be BF（D^0 → μ^＋X） = （7.2 ± 1.5 ± 0.8）%.
基金Supported by the National Science Foundation of China under Grant Nos 10491300, 10521003, and 10625524.
文摘Using the Monte Carlo samples of about 800 pb^-1 and 500 pb^-1 generated at and around 3.773 GeV with BOSS （BESⅢ Offtine Software System） 6.0.2 and BOSS 6.1.0, we have studied the branching fractions for D^0 → K^-l^＋vl and D^0 →π^- l^＋ vl （l=e, μ）. According to the simulation results, the expected precision of these measurements for 20fb^-1 ψ（3770） data which will be collected on BESⅢ are well estimated.
文摘We construct dark energy models which have high derivative terms. In the framework of a single scalar field model with a higher derivative, the equation of state （EOS） ω might have some special character in the evolvement, which states that the universe will evolve in some interesting ways. We study the different kinds of dark energy models, and classify them into several genera by their character in the evolvement.
基金Project supported by the National Natural Science Foundation of China(Grant Nos.U1404111,11504089,61874160,61675064,and 11404098)the Fund for Young Key Teacher of Henan Province,China(Grant No.2016GGJS-059)the Henan Provincial Major Scientific and Technological Projects,China(Grant No.182102210289).
文摘Up to now,at least 806 carbon allotropes have been proposed theoretically.Three interesting carbon allotropes(named Pbam-32,P6/mmm,and I43d)were recently uncovered based on a random sampling strategy combined with space group and graph theory.The calculation results show that they are superhard and remarkably stable compared with previously proposed metastable phases.This indicates that they are likely to be synthesized in experiment.We use the factor group analysis method to analyze theirΓ-point vibrational modes.Owing to their large number of atoms in primitive unit cells(32 atoms in Pbam-32,36 atoms in P6/mmm,and 94 atoms in I43d),they have many Raman-and infrared-active modes.There are 48 Raman-active modes and 37 infrared-active modes in Pbam-32,24 Raman-active modes and 14 infrared-active modes in P6/mmm,and 34 Raman-active modes and 35 Raman-and infrared-active modes in I43d.Their calculated Raman spectra can be divided into middle frequency range from 600 cm-1 to 1150 cm-1 and high frequency range above 1150 cm-1.Their largest infrared intensities are 0.82,0.77,and 0.70(D/Å)2/amu for Pbam,P6/mmm,and I43d,respectively.Our calculated results provide an insight into the lattice vibrational spectra of these sp3 carbon allotropes and suggest that the middle frequency Raman shift and infrared spectrum may play a key role in identifying newly proposed carbon allotropes.
