Preparations for CMS Heavy Ion Physics Program

2. 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 Directions of SINP MSU activity in CMS

3. 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 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)

4. Jet reconstruction algorithm based on event-by-event -dependent background subtraction has been developed and included in CMS Reconstruction package ORCA Jet reconstruction with calorimetry (window- and cone-type finders)

5. 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 γ/π0 π0 in jet

6. 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 Dimuon reconstruction (with tracker and muon systems)

7. 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

8. 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

9. 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

10. 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)

11. Physics simulations and analysis to study quark-gluon plasma with jet quenching (medium-induced partonic energy loss) in various channels: high-pt QCD jetsI.Lokhtin, A.Snigirev, EPJ C 17 (2000) 527; Phys.At.Nucl. 64 (2001) 1487 jets tagged by leading h±,π0I.Lokhtin, A.Snigirev, PLB 567 (2003) 39 B-jets tagged by leadingμI.Lokhtin, L.Sarycheva, A.Snigirev, K.Teplov, EPJ C 37 (2004) 465 γ+jet, γ*/Z(→μ+μ-)+jet I.Lokhtin, A.Sherstnev, A.Snigirev, PLB 599 (2004) 260 BB, DD →μ+μ-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

12. JFF modified due to jet quenching can be observed with CMS Example of selected channel for full GEANT-based CMS analysis: medium-modified jet fragmentation function (JFF), D(z), with leading π0

13. 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 Calibration and monitoring: jet energy correction using tracker (response subtraction procedure) Single jets: linearity resolution Mass of Z' (120 GeV)

14. 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 < 10 GeV/c, purity = 96.2% Algorithm to build library of particle responses has been developed and included in general CMS package

15. 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).

16. 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

17. 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

18. 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.