All Results

Subjects: Physics >> General Physics: Statistical and Quantum Mechanics, Quantum Information, etc.

There is a puzzle in the +c family, i.e., one member with JP = 3/2+ is missing in a L = 2 multiplet which the heavy quark effective theory predicts, and JP’s of c(2765)+ and c(2940)+ are unknown. Using a light diquark picture to calculate baryon masses, we study possible assignments of two c’s with unknown JP and the missing +c with 3/2+ for L = 2, and we find the most probable possibility that the peak corresponding to c(2880)+ actually includes a missing member with spin 3/2+ for L = 2 and that quantum numbers of c(2765)+ and c(2940)+ are 2S (1/2+) and 2P(1/2−), respectively. |

On uncertainty of the beam energy measurement in e+e− collision using Compton Backscattering.

X. H. MoSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

The beam energy is measured in e+e- collision by using Compton Backscattering. The uncertainty of this measurement process is studied by virtue of analytical formulas, and the special effects of variant energy spread and energy drift on the systematic uncertainty estimation are also studied with Monte Carlo sampling technique. These quantitative conclusions are especially important for understanding the uncertainty of beam energy measurement system. |

On two cryogenic systems of high purity germanium detector

Zhang Jian-Yong; Cai Xiao; MO Xiao-HuSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

Two cryogenic systems of high purity germanium detector, liquid nitrogen and mechanical coolers, are expound, together with explanations of merits and demerits for each kind of cooling methods. The resolutions of detector to the characteristic lines of 152Eu under different cooling conditions are studied. The laboratory results indicate that the mechanical cooler (X-Cooler II) is an ideal replacement candidate for the liquid nitrogen cooler that is being utilized by BEMS at BEPC-II. |

Study of the data taking strategy for a high precision τ mass measurement

Y.K.Wang; J.Y.Zhang; X.H.Mo; C.Z.YuanSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

To achieve a high precision τ mass measurement at BESIII, two free para-meters (mτ and ε) and three parameters (mτε and σBG)fittings are simulated using sampling technique. For two parameters fitting, two points should be taken, the one is near the threshold of τ+τ- production to determine mτ , the other point is at 3.595 GeV to determine e±ciency. The ratio of luminosity at the two points is 3 to 1. For three parameters fitting, one point should be added at the low energy region with about 10% of the total luminosity. The optimal ratio of luminosity at the other two points is still 3 to 1. |

Measurement of radiation dose at the north interaction point of BEPCII

Mo Xiaohu; Zhang Jianyong; Zhang Tianbao; Zhang Qinjiang; Achasov Mikhail; Fu Chengdong; Muchnoi Nikolay; Qin Qing; Qu Huamin; Wang Yifang; Wu Jingming; Xu Jinqiang; Yu BoxiangSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

The technique details for measuring radiation dose are expounded. The results of radiation levels of gamma and neutron are presented and the corresponding radiation shielding is discussed based on the simplified estimation. In addition, the radiation level of photon as background for the future experiment is measured by NaI(Tl) detector. |

Significance of Energy Scale for Physics at BESIII

C. D. Fu; X. H. MoSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

The effects of absolute energy calibration on BESIII physics are discussed in detail, which mainly involve the effects on τ mass measurement, cross section scan measurement, and generic error determination in other measurements. |

Experimental Searches for the Non-D(D) Decays of ψ(3770) in e+e- Collider

K. L. He; X. H. Mo; P. Wang; C. Z. YuanSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

The previous experiments which provide information on the ψ(3770) to non-DD decays are reviewed. Three approaches of searching for the non-D(D) decays are discussed in detail. It is also pointed out that the search for the non-D(D) decays of the ψ(3770) is very important for the understanding of the dynamics of charmonium decays. |

Further corroboration of equivalence of two X2 forms

X.H. MoSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

The equivalence of two χ2 forms for linear function fit is proved by mathematical. The simplified R-value measurement are quoted to test the conclusion equivalence. |

Correlation in estimation of the Q value

X.H. MoSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

Q value, the ratio of charmless hadronic decays between ψ'and J/ψ, is evaluated to be (26.0 +/- 3.5)%. The dependence in evaluation is taken into account carefullyu, and several approaches are adopted to find out the correlation coefficient or covariance between different measurements. |

Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

Here, we investigated the irradiation defect in reduced activation ferritic/martensitic steels by slow positron beam. Three ion-irradiation experiments were carried out: (i) He2+ irradiation, (ii) H+ irradiation and (iii) He2+ irradiation followed by H+ irradiation, at temperature 450 oC. The presents of vacancy defects, represented by ∆SHe+H parameter, induced by sequential irradiations was larger than the sum of defects, ∆SHe parameter + ∆SH parameter, caused by single He ions and single H ions. The synergistic effect of He and H was confirmed clearly from the perspective of positron annihilation spectroscopy. |