Caprini I, Colangelo G, Leutwyler H
National Institute of Physics and Nuclear Engineering, Bucharest, R-077125 Romania.
Phys Rev Lett. 2006 Apr 7;96(13):132001. doi: 10.1103/PhysRevLett.96.132001. Epub 2006 Apr 5.
We demonstrate that near the threshold, the pi pi scattering amplitude contains a pole with the quantum numbers of the vacuum--commonly referred to as the sigma--and determine its mass and width within small uncertainties. Our derivation does not involve models or parametrizations but relies on a straightforward calculation based on the Roy equation for the isoscalar S wave.
我们证明，在阈值附近，ππ散射振幅包含一个具有真空量子数的极点——通常称为σ——并在小的不确定性范围内确定其质量和宽度。我们的推导不涉及模型或参数化，而是基于同位旋标量S波的罗伊方程进行直接计算。
