Instantaneous Lumi and Integrated Lumi

  • Context: Undergrad 
  • Thread starter Thread starter ChrisVer
  • Start date Start date
Join the discussion
Registration is free. Ask a follow-up in this thread, or start your own.
4 replies · 1K views
Messages
3,372
Reaction score
465
I have a pretty basic question...
How can you convert the Instantaneous Luminosity [itex]L_t[/itex] to the integrated Luminosity [itex]L[/itex]?
I know that the relation is the following:
[itex]L = \int L_t dt[/itex]
but if the time is [itex]\sim 25~ns[/itex] and [itex]L_t = 1.7 \times 10^{34} ~cm^{-2} s^{-1}[/itex], then I get an integrated luminosity of:
[itex]L=42.5 \times 10^{25} ~cm^{-2} = 4.25 \times 10^{-13} fb^{-1}[/itex]
which doesn't make sense as a number... dividing with the time gives a more sensible result but right now I don't see why.
 
Physics news on Phys.org
You calculated the integrated luminosity from a single LHC bunch-crossing.
If you want the integrated luminosity collected within a day, you have to take a day as time.

Dividing luminosity by time gives wrong units, how can that be more sensible?
 
  • Like
Likes   Reactions: ChrisVer
So in general it's impossible without knowing the time-span of your data-collection to translate your integrated luminosity to the instantaneous one? (the reverse of the above)

As for the units, true... I got to use sleepnessless as an excuse.
 
ChrisVer said:
So in general it's impossible without knowing the time-span of your data-collection to translate your integrated luminosity to the instantaneous one? (the reverse of the above)
Can you tell how fast I went in my car, traveling 30 km, if I don't tell you how long I was traveling?
 
  • Like
Likes   Reactions: vanhees71 and ChrisVer
mfb said:
Can you tell how fast I went in my car, traveling 30 km, if I don't tell you how long I was traveling?

Officer, I can't have been going 80 miles per hour! I've only been driving ten minutes!
 
  • Like
Likes   Reactions: ChrisVer and vanhees71