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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.
- 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.
- 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.
- 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:
- 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 ).
- 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".
- Full page GIF picture
Return to CDF Run I Experiment main page
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