In an effective Lagrangian model we find that the N*(1535) resonance contribution might be important to the interpretation of the present data of the pp → ppη′ and pn → dφ reactions. The strong coupling strength of N*(1535) to η′ and φ are indicated, and the possible implication to the intrinsic component of N*(1535) is explored. These results may provide hints to the real origin of the OZI rule violation. It is stressed that further measurements could be performed at the Cooling Storage Ring (CSR) at Lanzhou of China.
研究了BESⅢ漂移室(MDC)时间测量道的性能,包括空间分辨、动量分辨、击中效率、噪声率和Bhabha事例重建效率等。并用2011年的Bhabha事例样本对MDC性能作了run by run监测,研究了引起数据质量变化的各种因素。另外还研究了工作高压丢失(trip)对MDC性能的影响,此外,为了提高数据质量开发了相应软件包以去掉受高压丢失影响的事例。
Decays of both η and η' provide very useful information in our understanding of low-energy QCD, and experimental signatures for these decays would be extremely helpful at BES-Ⅲ. The rare decays of the η and η' mesons could serve as a low-energy test of the Standard Model and its beyond. The sensitivities of the measurements of η and η' decays are discussed at BES-Ⅲ, in which the η and η' mesons are produced in the ψ decays.
The calibration algorithm for RPC-based muon detector at BESⅢ has been developed. The calibration method, calibration error and algorithm performance are studied. The primary results of efficiency and noise at layer, module and strip levels have been calibrated with cosmic ray data. The calibration constants are available for simulation and reconstruction tuning. The results of Monte Carlo and data are also compared to check the validation and reliability of the algorithm.
DJpsiFDC is an event generator package for the process gg → J/ψJ/ψ. It generates events for primary leading-order 2 → 2 processes. The package could generate a Les Houches Event (LHE) document and this could easily be embedded into detector simulation software frameworks. The package is produced in Fortran code.
We study the J/ψ pair production issue at the Fermilab Tevatron Run II with a center-of-mass energy of s^(1/2)=1.96TeV. Both the color-singlet and color-octet production mechanisms are considered. Our results show that the transverse momentum (pT) scaling behaviors of the double J/ψ differential cross-sections in the color-singlets and color-octets deviate distinctively from each other while pT is larger than 8GeV, and with a luminosity of 5fb^-1 , the J/ψ pair events from the color-singlet scheme are substantially measurable in the Tevatron experiments, even with a certain lower transverse momentum cut. Hence the Tevatron is still a possible platform to check the heavy quarkonium production mechanism.
The strong decays of the N*(1535) resonance are investigated in an extended chiral quark model by including the low-lying qqqqq components in addition to the qqq component.The results show that these five-quark components in N*(1535) contribute significantly to the N*(1535)→ Nπ and N*(1535) → Nη decays.The contributions to the Nη decay come from both the lowest energy and the next-to-lowest energy five-quarks components,while the contributions to the Nπ decay come from only the latter one.Taking these contributions into account,the description for the strong decays of N*(1535) is improved,especially for the puzzling large ratio of the decays to Nη and Nπ.
AN ChunSheng1,2,3 & ZOU BingSong1,2,3 1 Institute of High Energy Physics,Chinese Academy of Sciences,Beijing 100049,China
The number of ψ' events accumulated by the BESⅢ experiment from March 3 through April 14, 2009, is determined by counting inclusive hadronic events. The result is 106.41×(1.00±0.81%)×106 . The error is systematic dominant; the statistical error is negligible.
We present in the work two intriguing results in the entanglement classification of a pure and true tripartite entangled state of 2 × M × N under stochastic local operation and classical communication: (i) the internal symmetric properties of the nonlocal parameters in the continuous entangled class; (ii) the analytic expression for the total numbers of the true and pure entangled class 2 × M × N states. These properties help better understand the nature of the 2 × M × N entangled system.
