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ALICE EMcal Recent Results

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					                ALICE EMcal Recent
                     Results
                         By
                 Bjørn S. Nilsen
                Creighton University
                       and the
                ALICE Collaboration




April 23 2010                                            1
                         Bjorn S. Nilsen, Creighton U.
                                         EMcal History
                        Original ALICE concept included a full barrel
                         electromagnetic calorimeter (1990), but
                         dropped due to lack of space.
     ALICE adopts a high resolution small coverage photon
      calorimeter PHOS.
     A new calorimeter, in addition to the existing PHOS, was put
      forward by a group of US collaborators looking to join the
      ALICE collaboration (2001).
     DOE approves the funding for the EMcal
     November 2009, ALICE takes first data with 2/9 of the EMcal
      installed.
     ALICE approves EMcal extension (JCAL)                          2
    April 23 2010             Bjorn S. Nilsen, Creighton U.
                    Start of Data Taking
  • Start of physics runs November 23 2009 at
    √s=0.9 TeV p-p.
       - All installed detectors operating.
       - First paper published on the first 284 events.
  • First accelerated beam December 14 2009 to
    √s=2.36 TeV p-p
  • Highest energy to date √s=7.0 TeV p-p April 30
    2010


April 23 2010                 Bjorn S. Nilsen, Creighton U.   3
April 23 2010                                   4
                Bjorn S. Nilsen, Creighton U.
                                       Jets Expected
                                     In ALICE EMcal




                                                       5
April 23 2010   Bjorn S. Nilsen, Creighton U.
          Most Recent Preliminary Results
                 p-p interactions

                ALICE-TPC-Di-jet




                                                            • angular distribution of
                                                              particles in TPC relative to
                                                              a high pt trigger particle
                                                              (single event!)




April 23 2010                      Bjorn S. Nilsen, Creighton U.                             6
                          PHOS Finds 0
                     PHOS (9 m2)


     Noise

                                                      m  2E 1 E 2  cos 1 2 
                                                                      1


                0       0  
                         1 < pt < 1.5 GeV
                                    

                                            Preliminary
April 23 2010                           Bjorn S. Nilsen, Creighton U.                  7
                      Still To Come
• 4 out of the original 18 super modules installed
     - Test beam planned starting August 2010 to calibrate the
       remaining super modules.
     - Installation planned shortly after late Summer 2011 LHC
       shutdown.
• JCal upgrade under way.
• EMcal detector performance better then expected
     - Calibrations still need to be performed and finalized
     - Trigger still needs work.
     - High luminosity/speed performance not optimal yet.
April 23 2010             Bjorn S. Nilsen, Creighton U.          8

				
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