All Results

Discussion on upper limit of the precision for τ mass measurement

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

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. |

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. |

A Mathematical Review on the Multiple Solublem Problem

K. Zhu; X. H. Mo; C. Z. Yuan; P. WangSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

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. |

On the leptonic partial widths of the excited ψ states

X. H. Mo; C. Z. Yuan; P. WangSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

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. |

Multiple solutions in extracting physics information from experimental data

C. Z. Yuan; X. H. Mo; P. WangSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

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. |

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. |

Determining the upper limit of Γee for the Y(4260)

X. H. Mo; G. Li; C. Z. Yuan; K. L. He; H. M. Hu; Hu J. H.; P. Wang; Z. Y. WangSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

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. |

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. |

The Y(4260) as an ω χc1 molecular state

C. Z. Yuan; P. Wang; X. H. MoSubjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties

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. |

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

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. |