Compute the average number of interactions per bunch crossing for a luminosity L=2.5E31 cms-1,if the total cross section is sigma =20mb and bunch crossing occur every T=4.What is the probability of having zero interactions in a bunch?

2 answers

What is a bunch crossing? Bunch of what?

What are mb units? Millbarnes?

cm/s is not a unit of luminosity

What is T? What are its units?

this is jibberish
Trying to sort out the units.

20 mb = 20 millibarns (mbarn)?

the luminosity is presumably cm2 s^-1

because by definition

event rate = luminosity * cross section

Not sure of units of T ns?