Single muon highlights the M in CMS

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    CMS stands for "Compact Muon Solenoid". The solenoid is a powerful magnet system that bends the paths of muons, particles that penetrate from the collision at the center of the detector all the way out. The red track emerging at about 10 o'clock in the large image is a muon candidate. The reddish panes that it intersects are parts of the detector activating as the muon passes through. In the frame on the lower right the same track points upward. Note the curved path, the work of the solenoid magnet. This curvature gives us a very good read on the momentum of the muon. Where do you think all those other tracks (in yellow) come from?
    Copyright CERN for the benefit of the CMS Collaboration

    1. justinbischoff 59 months ago | reply

      Since the yellow lines are curved, they should be electrically charged. Some curve in opposite directions - could they be extra electrons and protons? What does the size of the red and blue bars indicate?

    2. carsten de 59 months ago | reply

      Since the radius of curvature is about the same, the particles should have similar charge/mass ratio. Electrons and positrons would be my guess.

    3. uslhc 59 months ago | reply

      As you've guessed, the tracks in yellow come from electrically charged particles such as electrons, muons, and charged hadrons (including protons). More information about decoding CMS event displays can be found in this article from particle physics news blog Symmetry Breaking: www.symmetrymagazine.org/breaking/2010/03/16/cms-event-di...

    4. carsten de 59 months ago | reply

      Hmm, last time I checked the muon was also charged, with a rest mass in between the electron and the hadrons. The path being almost straight would mean that the muon carries an enormous energy whereas all the other particles are fairly slow.
      What kind of decay process would have that signature? Some very heavy particle into muon plus muon neutrino (or antineutrino, I never remember which way 'round)? The naked muon itself is a rather boring particle...

    5. carsten de 59 months ago | reply

      Ooops, RTFM. ;-) Nice web site, but I lack the background for the finer details.

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