论文标题
共振和连续振幅之间的干扰对矢量Quarkonia衰减分支分支的影响
Impact of the interference between the resonance and continuum amplitudes on vector quarkonia decay branching fraction measurements
论文作者
论文摘要
重新审视了重质量Quarkonium腐烂到$ e^+E^ - $ calliders的浅甘表示最终状态的分支部分的测量。在$ e^+e^ - $ nihihitation实验中，连续幅度的背景贡献及其对共振振幅的干扰是不可估的。随着实验测量的精确度提高，这些效果变得越来越重要。虽然前者可以通过从共振峰上取出的数据轻松减去，但后者取决于共振和连续幅度之间的相对大小和相位。定义了两个比率来估计这些效果的大小，$ r_ {r}^{f} $对于干扰项与共振项的贡献的比率和$ r_ {c}^{f} $对于连续术语。我们发现$ r_ {r}^{f} $对于狭窄的共振而言，$ r_ {r_ {r_ {r}^{f} $和$ r_ {c}^{f} $都可能很大。这表明干扰效应对于瞄准百分比或更高精度的分支分数的测量至关重要，需要正确测量或估计。
The measurement of the branching fraction of a heavy quarkonium decaying into light hadronic final state at $e^+e^-$ colliders is revisited. In $e^+e^-$ annihilation experiments, background contributions from the continuum amplitude and its interference with the resonance amplitude are irreducible. These effects become more and more significant as the precision of experimental measurements improves. While the former can be easily subtracted with data taken off the resonance peak, the latter depends on the relative size and phase between the resonance and continuum amplitudes. Two ratios are defined to estimate the size of these effects, $r_{R}^{f}$ for the ratio of the contribution of the interference term to the resonance term and $r_{c}^{f}$ for that to the continuum term. We find that $r_{R}^{f}$ could be as large as a few percent for narrow resonances, and both $r_{R}^{f}$ and $r_{c}^{f}$ could be large for broad resonances. This indicates that the interference effect is crucial for the measurements of the branching fractions aiming at the percent level or better precision and needs to be measured or estimated properly.
