Cos(Theta) between two correlated neutrons. Unpolarized case.

Below is the energy spectrum of two correlated neutrons in LAB frame. 10 million events. Sampled up to 10 MeV.

Below is [math]cos(\Theta)[/math] between two correlated neutron. No energy cut was made. Integrated over all energy spectrum.

And with energy cut.

The calculated asymmetry between correlated neutrons emitted [math]\leftleftarrows[/math] and [math]\leftrightarrows\lt math\gt is: :\lt math\gt \mbox{Asymmetry} = \frac{\leftrightarrows}{\leftleftarrows} = frac{209,578}{3,219} = 65.11[/math]

here:

• [math]\leftrightarrows[/math] are all events with angle between two neutron is [math]cos(\Theta_{nn}) \lt -0.9[/math] that is large enough angle [math]\Theta = (180\pm25)^o\lt math\gt *\lt math\gt \leftleftarrows[/math] are all events with angle between two neutron is [math]cos(\Theta_{nn}) \gt 0.9[/math] that is large enough angle [math]\Theta = (0\pm25)^o\lt math\gt :\lt math\gt \mbox{Energy}\ \mbox{Cut}\ \mbox{Yield} = \frac{counts\ with\ cut}{counts\ without\ cut} = \frac{1,227,505}{10,000,000} = 0.12277[/math]

[math]\mbox{Asymmetry}\ \mbox{Yield} = \frac{(counts\ anti-parallel) + (counts\ particle)}{event\ without\ cut} = \frac{209,578 + 3,219}{10,000,000} = 0.02128[/math]

Looks good, but we need big statistics!