1 / 9

End now?

End now?. Régis Lefèvre Masterclass – Thursday, March 27th 2014. What we will look for. Invariant mass. In special relativity (you certainly know E=mc 2 ), using energy and momentum conservation, a relativistic invariant, called the invariant mass appears.

calvine-jerom
Download Presentation

End now?

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. End now? Régis Lefèvre Masterclass– Thursday, March 27th 2014

  2. What we will look for

  3. Invariant mass • In special relativity (you certainly know E=mc2), using energy and momentum conservation, a relativistic invariant, called the invariant mass appears. • If a particle decays, the invariant mass of the decay products (calculated in any referential) is the mass of the initial particle. • We will calculate (the software will do it in fact) the e+e-, 𝜇+𝜇-, 𝛾𝛾, e+e-e+e-, e+e-𝜇+𝜇- or 𝜇+𝜇-𝜇+𝜇- invariant mass of our different candidates.

  4. Beyond E = mc2

  5. In the case of Z → e+e-

  6. About histograms • Numbers between 0 and 10 • Distribution of occurrences

  7. About histograms The table can be represented as a graph: Each bar represents the number of occurrences of a given value. This one tells you that the value 7 appeared 16 times. This type of graph is an histogram.

  8. Examples from ATLAS

  9. Cuts we will use • We will only considered tracks with sufficient transverse momentum: pT≥ 5 GeV/c • Selected tracks should come from the same primary vertex (same proton-proton interaction): check it zooming in on the side-view window • If you have difficulties on a given event, you may use Pixel Hits ≥ 2 (tracks more likely to come from a primary vertex)and/or SCT Hits ≥ 7 (good quality tracks); do no forget to remove those cuts moving to the next event

More Related