2008 Vol. 32, No. 11

Particle and field theory
Search for exotic state 1-+π1(1400) at BESⅢ
ZHANG Zhen-Xia, LIU Hong-Bang, WU Ning, YU Guo-Wei, SHEN Xiao-Yan, ZHENG Han-Qing
2008, 32(11): 857-861. doi:10.1088/1674-1137/32/11/001
Abstract:

The J/ψ hadronic decays provide good laboratory to search for the hybrid states with exotic quantum numbers. A full Partial Wave Analysis (PWA) is performed to the generated Monte Carlo J/ψ→ρηπ data, based on the design of BESⅢ detector, to study the sensitivity of searching for a possible exotic state at BESⅢ.

A note on the mass splitting of K*(892)
GAO Dao-Neng, YAN Mu-Lin
2008, 32(11): 862-864. doi:10.1088/1674-1137/32/11/002
Abstract:

Belle Collaboration reported a new observed value of K*-(892) mass by studying τ→ K-ντdecay, which is significantly different from the current world average value given by Particle Data Group 2006. Motivated by this new data, we revisit the issue on the K*0(892)-K(892) mass splitting. Our theoretical estimation favors the new measurement by Belle Collaboration. Therefore further experimental efforts are urgently needed to improve our understanding of these issues.

Angular momentum of a brane-world model
JIA Bei, LI Xi-Guo, ZHANG Peng-Ming
2008, 32(11): 865-867. doi:10.1088/1674-1137/32/11/003
Abstract:
In this paper we discuss the properties of the general covariant angular momentum of a five-dimensional brane-world model. Through calculating the total angular momentum of this model, we are able to analyze the properties of the total angular momentum in the inflationary RS model. We show that the space-like components of the total angular momentum of the inflationary RS model are all zero while the others are non-zero, which agrees with the results from ordinary RS model.
particle and nuclear astrophysics and cosmology
An updated search of steady TeV γ-ray point sources in northern hemisphere using the Tibet air shower array
WANG Yue, BI Xiao-Jun, CUI Shu-Wang, DING Lin-Kai
2008, 32(11): 868-872. doi:10.1088/1674-1137/32/11/004
Abstract:

Using the data taken from Tibet II High Density (HD) Array (1997 February—1999 September) and Tibet-III array (1999 November—2005 November), our previous northern sky survey for TeV γ-ray point sources has now been updated by a factor of 2.8 improved statistics. From 0.0° to 60.0° in declination (Dec) range, no new TeV γ-ray point sources with sufficiently high significance were identified while the well-known Crab Nebula and Mrk421 remain to be the brightest TeV γ-ray sources within the field of view of the Tibet air shower array. Based on the currently available data and at the 90% confidence level (C.L.), the flux upper limits for different power law index assumption are re-derived, which are approximately improved by 1.7 times as compared with our previous reported limits.

Nuclear and ion Physics
A formula used to subtract the effect of gamma-ray of the others to that ofmeasured reaction in measurement of cross section of nuclear reaction andits application
ZHOU Feng-Qun, YANG Xing-Qiang, WANG Wei-Feng, LI Yong, ZHANG Fang, TUO Fei, KONG Xiang-Zhong
2008, 32(11): 873-876. doi:10.1088/1674-1137/32/11/005
Abstract:
According to the regulation of growing and decay of artificial radioactive nuclide, a formula used to subtract the effect of characteristic γ-ray of the others to that of measured reaction was deduced. And then the cross sections of120Te (n,2n)119mTe reaction induced by neutrons around 14~MeV were measured by activation relative to the93Nb (n, 2n)92mNb. In the process of the cross sections measured to be calculated, it was subtracted that the effect of characteristic γ-ray of126Te (n, p)126Sb to that of measured120Te (n, 2n)119mTe reaction using the formula deduced. The experimental results were (689±37) and (750±41) mb at the neutron energies of (13.5±0.3) and (14.6±0.3)MeV, respectively. Measurements were carried out by γ-detection using a coaxial HPGe detector. As samples, spectroscopically pure tellurium powder has been used. The fast neutrons were produced by the T(d, n)4He reaction. The neutron energies in these measurements were determined by the method of cross-section ratios between90Zr (n, 2n)89m+gZr and93Nb (n, 2n)92mNb reactions.
Analytical and statistical calculation of gamma dose rate for the accident of losing the shield for Tehran Research Reactor
Farshid Tabbakh, Azim Ahmadinyar
2008, 32(11): 877-881. doi:10.1088/1674-1137/32/11/006
Abstract:

In this paper we study the analytical and statistical results of estimating the gamma dose rate at pool access floor in TRR when the core shield accidentally decreases to some non-permitted levels. Due to the risk of experimental techniques, we use the analytical and statistical methods. In normal conditions (no risk), the discrepancies between experiment and two methods are justified and it is found that for such problems we have to normalize these methods to experimental results as follows: the analytical method by factor 0.13 and MCNP by 1.7.

Shell evolution at N=20 in the constrained relativistic mean field approach
SUN Bao-Hua, LI Jian
2008, 32(11): 882-885. doi:10.1088/1674-1137/32/11/007
Abstract:

The shell evolution at N=20, a disappearing neutron magic number observed experimentally in very neutron-rich nuclides, is investigated in the constrained relativistic mean field (RMF) theory. The trend of the shell closure observed experimentally towards the neutron drip-line can be reproduced. The predicted two-neutron separation energies, neutron shell gap energies and deformation parameters of ground states are shown as well. These results are compared with the recent Hartree-Fock-Bogliubov (HFB-14) model and the available experimental data. The perspective towards a better understanding of the shell evolution is discussed.

A systematic study of the superdeformation of Pb isotopes with relativistic mean field theory
GUO Jian-You, SHENG Zong-Qiang, FANG Xiang-Zheng
2008, 32(11): 886-891. doi:10.1088/1674-1137/32/11/008
Abstract:

The microscopically constrained relativistic mean field theory is used to investigate the superdeformation for Pb isotopes. The calculations have been performed with the four different interactions NL3, PK1, TM1 and NLSH, and show that there exists a clear superdeformed minimum in the potential energy surfaces. The excitation energy, deformation and depth of the well in the
superdeformed minimum are comparable for the four different interactions. Furthermore the trend for the change of the superdeformed excitation energy with neutron number is correctly reproduced. The calculated two-neutron separation energy in the ground state and superdeformed minimum together with their differences are in agreement with the available data. The larger energy difference appearing in the superdeformed minimum reflects a lower average level density at superdeformations for Pb isotopes.

Cold nuclear matter effects on J/ψ production in d-Au collisions
WANG Hong-Min, HOU Zhao-Yu, SUN Xian-Jing
2008, 32(11): 892-896. doi:10.1088/1674-1137/32/11/009
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