The CMS Experiment at CERN
- Permanent members -- Todd Adams, Andrew Askew, Sharon Hagopian (Emeritus), Vasken Hagopian (Emeritus), Kurtis Johnson, Harrison Prosper, and Horst Wahl
- Post Doctoral Fellows -- Jie Chen and Marc Weinberg
- Staff – M. Bertoldi (retired)
- Graduate students – Jordon Adams, Sam Bein, Joseph Bochenek, Brendan Diamond, Jeff Haas, Arka Santra, and Venkatesh Veeraraghaven
- Graduates – Sergei Gleyzer (Ph.D. 2011)
The Compact Muon Solenoid (CMS) is a detector that studies proton-proton
collisions at the Large Hadron Collider (LHC) at the European
particle physics laboratory (CERN) near Geneva, Switzerland.
This is the world's most energetic particle collider with a center of
mass energy of 8 TeV (a TeV is a trillion electron volts, more than
8000 times the energy of a proton at rest). In 2015 the LHC will increase
its energy to ~14 TeV. The two general-purpose detectors operating at the
LHC are CMS and ATLAS, both are designed to detect the Higgs particle,
measure the properties of the top quark, and search for new particles
such as dark matter and the supersymmetric partners of the standard family
of elementary particles. The LHC began high energy collisions in 2010
and has had three very successful years of operations.
On July 4, 2012, the CMS and ATLAS collaborations announced the
discovery of a new particle at a news conference watched around
the world. The particle was found as part of the search for the Higgs
boson.
FSU scientists
were part of the group who worked on this discovery.
The Florida State University is a member of the international collaboration
that designed, built, and operates the CMS detector.
CMS has a diameter of about 14 meters, a length of 20 meters and weighs 12,000
tons. If placed next to the Keen Building, the top of the detector would
reach the fifth floor. The magnet inside the detector has a 4-tesla field
inside a solenoidal volume of 6 meters diameter by 13 meters long.
The detector has 4 major subsystems: (1) the tracking sub-system made of
silicon; (2) the electromagnetic calorimeter (ECAL) made of lead tungstate
crystals; (3) the hadron calorimeter (HCAL) made of brass and scintillator;
and (4) the muon system composed of iron toroids. In addition the detector
has a state of the art data acquisition system, a trigger system, and
on-line and off-line computing.
The FSU CMS group's major detector responsibilities are associated
with the electromagnetic calorimeter (ECAL). We are engaged in algorithm
development, detector operations, data quality monitoring,
testbeam studies, and
studies of future detector options. The ECAL is a precision
calorimeter designed to provide high quality data for studying
decays of the Higgs boson to two photons. This analysis one of
the two important channels used to discover the new particle
announced in 2012.
We have also been involved in the hadron calorimeter (HCAL)
since the 1990's.
At FSU, we constructed and tested various components of the
detector and shipped them to CERN or Fermilab for further
testing/assembly. For HCAL one of our major responsibilities
is the calibration system that uses a pulsed nitrogen laser,
LEDs, and a radioactive wire source.
The parts of the calorimeters that are located close to the
LHC beamline are in a high radiation area where they can
be damaged. We have studied radiation damage of scintillators,
plastics, quartz fibers, silicon detectors,and lead tungstate
crystals over the past decade. The availability of 4 Tesla
magnets at the National High Magnetic Field Laboratory in
Tallahassee enabled us to measure the effect of magnetic
fields on various detector components.
Since 2010 the major focus of our group has been analysis of
the data for measurement of known reactions and searches for
new physics. We have been responsible for numerous papers
and results presented at conferences. Many of these have
revolved around our expertise with the electromagnetic
calorimeter. Some of our recent
interests include:
- Searches for the Higgs boson
- Searches for supersymmetry
- Gauge Mediated Supersymmetry Breaking (GMSB)
- Stealth SUSY
- Searches for dark matter
- Searches for new charged particles
- Searches for compositeness
- Searches for new extra dimensions
- Searches for a new symmetry
- Studies of double J/psi production
We have made a major commitment to this experiment and
will reap many more physics results with the data already
recorded and with the data that will be taken over the next
decade. If you like more information on FSU participation
in this experiment, contact us at
tadams@hep.fsu.edu.
You can visit the CMS home page at CMS home page .
Some diagrams and pictures from the CMS detector:
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