15.1 Mass

$$E_1(\vec p=0)=M_{\infty}+P[1]\frac{e^{-M_{\infty} L}}{\sqrt{M_{\infty}L}}$$ $P[0]=M_{\infty}$

$$\begin{gather} \chi^2/d.o.f.=0.31478 \\ P[0]=0.271806\pm (2.1e-05) \\ P[1]=0.694019\pm (0.058) \\ \end{gather}$$ { $$\begin{gather} C=\begin{pmatrix} 4.55e-10& -0.65\\ -0.65& 0.00339\\ \end{pmatrix} \end{gather}$$ }