分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： τ lepton is one of three chareged leptons in nature, the measurements of its mass have been performed since its discovery. The present relative accuracy is already at the level of 10−4; more factors are still being studied in order to increase the accuracy. However, the available techniques for analysis and expectable luminosity from e+e− collider indicate that the precision upper limit of τ mass is almost reached, which means that brand new approaches should be looked for if the great improvement is yearned for.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： 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.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： The recent multiple solutions problem in high energy physics has been reviewed with a more mathematical viewpoint. Although previously these multiple solutions are found via fit process, in this letter we have proved that if a sum of two coherent simple Breit-Wigner functions is used to fit the measured distribution, there should be two and only two non-trivial solutions, which are related with each other by analytical formulae.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： The resonance parameters of the excited ψ-family resonances, namely the ψ(4040), ψ(4160), and ψ(4415), were determined by fitting the R-values measured by experiments. It is found that the previously reported leptonic partial widths of these states were merely one possible solutions among a four-fold ambiguity. By fitting the most precise experimental data on the R-values measured by the BES collaboration, this work presents all four sets of solutions. These results may affect the interpretation of the charmonium and charmonium-like states above 4 GeV/c2.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： Multiple solutions exist in many experimental situations when several interfering amplitudes are summed to fit experimentally measured distributions, such as cross sections, mass spectra, and/or the angular distributions. We show a few examples where multiple solutions are found, but only one solution is reported in the publications. Since there is no standard rule for choosing one among the solutions as the physics one, we propose a simple rule that agrees with what has been adopted in previous literatures: the solution corresponding to the minimal magnitudes of the amplitudes must be the physical solution. We suggest test this rule in the future analyses.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： 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.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： By fitting the R values between 3.7 and 5.0 GeV measured by the BES Collaboration, the upper limit of the electron width of the newly discovered resonance Y(4260) is determined to be 240 eV at 90% C.L. Together with the BaBar measurement on Γee• B(Y(4260) → π+π- J/ψ), this implies a large decay width of Y (4260) → π+π- J/ψ final states.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： 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.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： It is suggested that the newly observed Y(4260) by BaBar Collaboration is a molecular state composed of an ω and a χc1. Both the production and decay properties are discussed. A consequence for this molecular state, Y(4260), is that it decays copiously into π+π-π0χcl. It is also expected that Y(4260) →π0π0J/ψ is produced at half rate as Y(4260) →π0π0J/ψ. These decay modes should be searched for in the B factories using initial state radiative return data and B decay data as well.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： The baryon–antibaryon SU(3) nonets are proposed as a scheme to classify the increased number of experimentally observed enhancements near the baryon antibaryon mass threshold. The scheme is similar to the Fermi–Yang–Sakata model, which was put forth about fifty years ago in explaining the mesons observed at that time. According to the present scheme, many new baryon–antibaryon bound states are predicted, and their possible productions in quarkonium decays and B decays are suggested for experimental search.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： The branching fraction of the ψ" decays into charmless final states is estimated in the S- and D-wave charmonia mixing scheme. With the information of the hadronic decays of J/ψ and ψ', it is found that a large branching fraction, up to 13% of the total ψ" decays, may go to charmless final states. The experimental search for these decays is also discussed.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： Adding to the long standing “ρπ puzzle” in ψ′and J/ψ decays, recently BEijing Spectrometer (BES) reported B(ψ′→ K0SK0L) which is enhanced relative to the pQCD “12% rule” expectation from B(J/ψ → K0SK0L). If the enhancement is due to the mixing of the S- and D-wave charmonium states as in the ρπ case, the newly measured B(ψ′ → K0SK0L) gives a constraint on B(ψ″ → K0SK0L).It erves as a good test for the scenario of the S- and D-wave mixing in the ψ′and ψ″.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： In S- and D-wave mixing scheme, the branching ratio of ψ″→ρπ is estimated. Together with the continuum cross section of ρπ estimated by form factor, the observed cross section of ρπ production at ψ″ in e+e− experiment is calculated taking into account the interference effect between the resonance and continuum amplitudes and the initial state radiative correction. The behavior of the cross section reveals that the disappearance of ρπ signal just indicates the existence of the corresponding branching ratio Bψ″→ρπ at the order of 10−4.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： With the known branching ratios of ψ(2S)→π+π− and ψ(2S)→K+K−, the branching ratio of ψ(2S)→K0SK0L is calculated as a function of the relative phase between the strong and the electromagnetic amplitudes of the ψ(2S) decays. The study shows that the branching ratio of ψ(2S)→K0SK0L is sensitive to the relative phase and a measurement of the K0SK0L branching ratio will shed light on the relative phase determination in ψ(2S)→0−0− decays.
分类： 物理学 >> 凝聚态:结构、力学和热性能 提交时间： 2017-03-26
摘要： The measurements of ψ (2 S )→ ωπ 0 and ψ (2 S )→ π + π − in e + e − experiments are examined. It is found that the non-resonance virtual photon annihilation gives large contributions to the observed cross sections of these two processes. By including this contribution, the form factors and branching fractions of these two decay modes are revised.
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