Preparations for CMS Heavy Ion Physics Program

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Directions of SINP MSU activity in CMS

• Preparations for CMS Heavy Ion Physics Program
• Development of software and reconstruction
  algorithms for pp and heavy ion collisions,
  calibration and monitoring
• Participation in design, testing and calibration
  of CMS HF calorimeter

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Main task of CMS Heavy Ion Program detection and
study of properties of superdense state of
nuclear matter quark-gluon plasma with ''hard
probes'' (jets, quarkonia and leading particles)

• 1993-1994 Participation in writting CMS Letter
  of Intend
• 1995-2000 Work on preparation of proposal for CMS
  Heavy Ion Program (published in CERN CMS Note
  2000/06)
• 2001-2002 Participation on behalf of CMS
  Collaboration in CERN Workshop Hard probes in
  heavy ion collisions at the LHC. Results are
  published in CERN Yellow Report
• 2003-2005 Work on CMS Physics Technical Design
  Report in the frame of CMS Heavy Ion Physics
  Group

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Jet reconstruction with calorimetry (window- and
cone-type finders)

• Jet reconstruction algorithm based on
  event-by-event ?-dependent background subtraction
  has been developed and included in CMS
  Reconstruction package ORCA

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• Photon reconstruction with ECAL
• Photon reconstruction algorithm based on
  event-by-event ?-dependent background subtraction
  is under development and to be included in CMS
  Reconstruction package ORCA

?/p0
p0 in jet
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Dimuon reconstruction (with tracker and muon
systems)

• Dimuon reconstruction algorithm based on primary
  Z-vertex finding and muon reconstruction seeded
  from Level 1 muon trigger has been developed and
  included in CMS Reconstruction package ORCA

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• Centrality reconstruction with calorimetry
• Centrality reconstruction algorithm based on
  correlation between (transverse) energy and
  impact parameter is under development and to be
  included in CMS Reconstruction package ORCA

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• Event plane reconstruction with calorimetry
• Event plane reconstruction algorithm based on
  event-by-event calculation of anisotropic energy
  flow has been developed and included in CMS
  Reconstruction package ORCA

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• Primary vertex reconstruction
• Primary vertex reconstruction algorithm based on
  reconstruction of hits belonging two barrel pixel
  layers?has been developed and included in CMS
  Reconstruction package ORCA

dN?/d? 2500
dN?/d? 8000
?x ?y 20 ?m, ?z 190 ?m
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• Creation of fast Monte-Carlo event generator
  (HYDJET)
• Fast Monte-Carlo event generator HYDJET including
  jet quenching (PYQUEN) and flow effects (HYDRO)
  has been developed and is applied for analysis
  in various channels in HI events on in CMS and
  ALICE Coll.

PT-distribution
Coefficient of azimuthal anizotropy v2(pT)
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• Physics simulations and analysis to study
  quark-gluon plasma with jet quenching
  (medium-induced partonic energy loss) in various
  channels
• high-pt QCD jets
  
  I.Lokhtin, A.Snigirev, EPJ C
  17 (2000) 527 Phys.At.Nucl. 64 (2001) 1487
• jets tagged by leading h,p0
  
  I.Lokhtin, A.Snigirev, PLB 567 (2003) 39
• B-jets tagged by leading µ
  
  I.Lokhtin, L.Sarycheva, A.Snigirev, K.Teplov,
  EPJ C 37 (2004) 465
• ?jet, ?/Z(?µµ-)jet
  
  I.Lokhtin, A.Sherstnev, A.Snigirev, PLB 599
  (2004) 260
• BB, DD ? µµ-
  
  
  
  I.Lokhtin, A.Snigirev, EPJ C 21 (2001) 155
  J.Phys. G 27 (2001) 2365
  Phys.At.Nucl. 65 (2002) 1733 NPA 702 (2002) 346
  
• energy-energy correlation
  
  I.Lokhtin, L.Sarycheva, A.Snigirev, EPJ C 36
  (2004) 375
• azimuthal anisotropy of energy flow
  
  I.Lokhtin, L.Sarycheva, A.Snigirev,
  S.Petrushanko, Pramana 60 (2003) 1045
  Phys.At.Nucl. 65 (2002) 943 CERN CMS Note
  2003/019

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Example of selected channel for full GEANT-based
CMS analysis medium-modified jet fragmentation
function (JFF), D(z), with leading p0

• JFF modified due to jet quenching can be
  observed with CMS

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Calibration and monitoring jet energy
correction using tracker (response subtraction
procedure)

• Improvement for Z-mass resolution 15
• Algorithm for jet energy correction using tracker
  responses has been developed and included in
  general CMS package for jet calibration

Single jets linearity
resolution Mass of Z' (120 GeV)
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Calibration and monitoring creation of library
of single particle responses for monitoring and
jet energy correction

With interaction in ECAL
W/o interaction in ECAL
P lt 10 GeV/c, purity 96.2
Algorithm to build library of particle responses
has been developed and included in general CMS
package
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Monitoring with minimum bias events

The algorithm for monitoring calorimeter towers
with flux of min bias events has been developed
(method of moments). It allows one to evaluate
the suppression factor with moments of readout
signal distribution (mean value in barrel and
endcap is affected by noise and thus is not
useful).
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Participation in CMS HF calorimeter tests at SpS
accelerator
Design and production of HF radiation monitoring
system (in cooperation with IHEP)
Neutron monitor
PMT
Ionizing radiation detector
HF shielding
HF wedge
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Development of HF calibration and
re-calibration Investigation of HF operation at
intensive irradiation
HF response at calibration using radioactive
source
Degradation of HF quartz fibers at irradiation
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• Work is performed by researchers of Hadronic
  Interactions Laboratory (Head - Ludmila
  Sarycheva, Professor of Chair of Physics
  Department) A.Ershov (PhD), A.Gribushin (PhD),
  O.Kodolova (PhD), I.Lokhtin (PhD), D.Okunev
  (student), S.Petrushanko (PhD), L.Sarycheva
  (Prof.), A.Snigirev (Dr.
  of Science), C.Teplov (student), I.Vardanyan
  (PhD)
• Results have been published in more than 40
  papers and reported during many international
  conferences, workshops and schools.
• At the moment two candidate dissertations and
  one doctor dissertation have been defended in
  addition, works on two candidate dissertations
  and one doctor dissertation are under progress.