1. Jun 2, 2015

### zhangyang

Pi-N scattering is useful for research on neucleon resonance.But pi meson is not stable,how could it be controled to collide with a neucleon?

While,virtual photon is also used to excite neucleon,it is internal line particle,which is determined by a reaction,so how hard could it be controled accurately?

2. Jun 2, 2015

### zhangyang

Sorry ,there is some error in my operation,I want to delate one of them.

3. Jun 2, 2015

### ChrisVer

Pi-N scattering in which experiment?
For example you can get pi-N scattering by placing some "target" near the creation of the pion.... (in fact a relativistic charged pion=momenta over some $m_\pi$'s, can travel for some meters before decaying. A momentum p~1GeV~10$m_\pi$ would bring the pion to travel for about L~80meters before decaying)

Last edited: Jun 2, 2015
4. Jun 2, 2015

5. Jun 2, 2015

### ChrisVer

I happened to ask for a confirmation (which I got) yesterday about the formula I had deduced for a similar scenario:
in that formula you could solve for $l_{lab}$ instead of momentum (you can try different momenta $p$) and $m$ the mass of the pion. The lifetime is given in Vanshee's post above.