• Question: How many proton collisions are there per second in the LHCb experiment?

    Asked by MaxB on 12 Sep 2023.
    • Photo: Joel Goldstein

      Joel Goldstein answered on 12 Sep 2023:

      The LHC collides bunches of protons every 25 nanoseconds at each of the main detectors (CMS, ATLAS, LHCb). There are about 100 billion protons in each bunch.

      At CMS and ATLAS the beams are very tightly focused to provide the most collisions possible. This can give up to 100 or so high-energy collisions per bunch crossing (plus countless lower energy interactions where the protons just deflect each other out of the beam).

      At LHCb, they do not focus the beams so tightly so they only get a few high-energy collisions per bunch crossing. So probably about 100 million a second.