Answer:


Explanation:
m = Mass of proton = 
v = Speed of proton = 0.5c = 
Circumference of the colider is 7 km


Centripetal acceleration is 

Force on protons is 
Both have positive charge. In fact, an alpha particle IS a nucleus of a Helium atom.
E, 63% of the value. I forget the rationale behind it but I learnt that in engineering. 90% confident for that answer.