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Welcome to the CDF Event Pictures page

This page is getting a little long, so here is what you will find below:

  • What's New -- a section of the latest, coolest events.
  • Generic CDF events -- look here to understand what the displays mean.
  • Events from Collider Run Ib ( 1994-95 ).
  • Events from Collider Run Ia ( 1992-93 ).
  • Events from the 1988-89 Collider Run.
  • Events from 1985 and 1987 (nothing here yet).

What's New ( as of March 8, 1995 ) :

The Latest, Greatest, Coolest Events Seen (and approved for public view by the CDF Collaboration)


Some "generic" CDF Events:
  • Example Z events Two events are shown, one Z --> two electrons and one Z --> two muons. Each event has a tracking view showing the charged tracks in the bend plane (we call this the r-phi view for radius-azimuth) of the the 1.4 Tesla CDF solenoid magnet. The diameter of the circle is about 3 meters. The "lego" plot is also shown for each event -- with "stacks" of electromagnetic (red) and hadronic (blue) energy seen in the calorimeter towers. Think of this "lego" plot as the surface of a cylinder around the solenoid unwrapped into a plane. Note in the Z--> two muon event the calorimeter energy scale is very small since the muons penetrate the calorimeter and leave only "minimum ionizing" pulse height. So we identify the muons from their charged tracks and hits in the Muon Chambers represented by the square box drawn outside of the 3 meter tracking circle. This box is not drawn to scale -- in the experiment the box is about 10 meters by 10 meters. Look closely to see the "hits", drawn as x's in line with nearly straight (therefore high momentum) tracks in the circle. In the lego plot we have drawn vertical lines to represent the energy of the muon tracks. Note the difference in the Z --> ee event where there are straight tracks pointing at clumps of red (electromagnetic) energy and no hits in the muon chambers.
    Two Z events
    Full page GIF picture of above
    Full page Postscript picture of above

  • Example W events Four events are shown, all examples of W --> electron + neutrino. As in the Z --> ee example above, the electrons are identified by straight tracks pointing at electromagnetic energy in red. The detector does not "see" the neutrino, so its existence is inferred by adding up all the visible energy in the detector and asking if there is an unbalanced vector sum -- the "missing energy" is the neutrino. In the Tevatraon Collider, some of the energy always escapes down the beampipe and we can only know the TRANSVERSE missing energy (acronymn is "MET"). So in the lego plot we show this MET as a solid red line. Ignore the yellow lines -- they are just crosshairs on the electron position. The four W events have different numbers of "jets"(clumps of electromagnetic and hadronic energy) as shown. Note when there are zero jets, the MET is just 180 degrees away from the electron.
    Four W events
    Full page GIF picture of above
    Full page Postscript picture of above

Events from Collider Run Ib ( 1994-95):
Events from Collider Run Ia ( 1992-93 ):
  • WZ Candidate from the 1992-93 Run This event has THREE electrons and missing energy (red vector in the upper right tracking picture). See how easy hadron collider physics can be ? Just Z --> ee, W --> e + neutrino, a few other low energy tracks, that's it. The electron at 2 o'clock ( 34 GeV transverse energy ) and the electron at 7 o'clock ( 56 GeV ) have a dielectron mass of about 82 GeV. The electron at 5 o'clock (short track exiting the solenoid ) is 22 GeV. The three pictures at the bottom are detailed blow-ups of each electron in its electromagnetic calorimeter. Lower left is the forward going (5 o'clock) electron with its longitudinal energy profile in the calorimeter. The other two pictures show the other two electrons, each scintillator tower viewed by two phototubes, each electron with a shower maximum profile.
    thumbnail GIF picture
    Full page Postscript picture
    Full page GIF picture

  • J/Psi K* Event (seen December 11,1992) This event has two secondary vertices identified by the CDF Silicon Vertex Detector. The tracks from one of the secondary vertices give an invariant mass equal to the B-meson, with daughters at the J/Psi and K* masses. Text and several pictures are available:
    Thumbnail GIF picture
    Full page Postscript picture
    Full page GIF picture
    Postscript text description
    MicroSoft Word version of the text

  • Dijet event with both jets b-tagged ! (seen October 28, 1992) This event has jets of 141 GeV and 111 GeV (Et), and BOTH jets have secondary vertex tags identified by the Silicon Vertex Detector. The event has a two jet invariant mass of 256 GeV and is the highest mass double b-tagged dijet event from Run Ia ( Run Ib hasn't been analyzed yet, so stay posted ).
    Dijet Event
    Full page GIF picture
    Full page Postscript picture

Events from the 1988-89 Collider Run:
  • The highest Et event seen in 1988-89 This event has two jets , one with transverse energy of 424 GeV and another with transverse energy of 371 GeV. The event was first seen on March 9, 1989. We have been here a long time, haven't we ? And the detector still "runs like a top".
    thumbnail GIF picture
    Full page GIF picture



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last modified 7/19/2001   email CDF
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