Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2017-03-26
Abstract：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.
Peer Review Status:
Awaiting Review
Subjects: Physics >> Condensed Matter: Structural, Mechanical and Thermal Properties submitted time 2017-03-26
Abstract：e+e− experiments at charmonium production threshold are reviewed, it is found that the contribution of the continuum process via virtual photon has been neglected in almost all the experiments and most channels analyzed. It is pointed out that the contribution of the continuum part may affect the final results significantly in ψ(2S) and ψ(3770) decays, while the interference between the continuum amplitude and the resonance amplitude may even affect the J/ψ decays as well as the ψ(2S) and ψ(3770). This leads to the revise of the analysis of strong and electromagnetic amplitude in ψ(2S) decays, including ψ(2S) → V P which is the long lasting puzzle between J/ψ and ψ(2S) decays. For ψ(3770) physics, a large constructive interference for light hadron modes and destructive interference for DD could be responsible for the discrepancy between the larger cross section of inclusive hadrons by direct measurement of e+e− → ψ(3770) → hadrons than the DD cross section measured using D single-tag and double-tag method.
Peer Review Status:Awaiting Review
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