Invisible decay

Idea

B(inivisible)/B(normalization)={N(upper limit)/efficiency(invisible)}/{N(normalization)/efficiency(normalization)} * {1/(1-sigma)}

• B(inivisible): branching ratio of the invisible decay
• B(normalization): branching ratio of the reference channel
• N(upper limit): upper limit of the yield of the invisible decay
• N(normalization): yield of the reference channel
• efficiency(invisible): acceptance of the invisible decay
• efficiency(normalization): acceptance of the reference channel
• sigma: systematic uncertainty

What applies here:

The channel we are using is : gamma p -> p eta_prime -> p pi+ pi－ （eta)