Contribution of MSU in CMS project Contribution of

Contribution of MSU in CMS project

Contribution of MSU in CMS project 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

Contribution of MSU in CMS project 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

Contribution of MSU in CMS project 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

Contribution of MSU in CMS project Photon reconstruction with ECAL γ/π0 π0 in jet Photon reconstruction algorithm based on event-by-event dependent background subtraction is under development and to be included in CMS Reconstruction package ORCA

Contribution of MSU in CMS project 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

Contribution of MSU in CMS project 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

Contribution of MSU in CMS project 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

Contribution of MSU in CMS project Primary vertex reconstruction d. N /d = 2500 x = y = 20 m, d. N /d = 8000 z = 190 m Primary vertex reconstruction algorithm based on reconstruction of hits belonging two barrel pixel layers has been developed and included in CMS Reconstruction package ORCA

Contribution of MSU in CMS project Creation of fast Monte-Carlo event generator (HYDJET) PT-distribution Coefficient of azimuthal anizotropy v 2(p. T) 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.

Contribution of MSU in CMS project 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±, π0 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 ● 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

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

Contribution of MSU in CMS project Calibration and monitoring: jet energy correction using tracker (response subtraction procedure) Single jets: linearity resolution Mass of Z' (120 Ge. V) 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

Contribution of MSU in CMS project Calibration and monitoring: creation of library of single particle responses for monitoring and jet energy correction With interaction in ECAL P < 10 Ge. V/c, purity = 96. 2% W/o interaction in ECAL Algorithm to build library of particle responses has been developed and included in general CMS package

Contribution of MSU in CMS project 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).

Contribution of MSU in CMS project Participation in CMS HF calorimeter tests at Sp. S accelerator Design and production of HF radiation monitoring system (in cooperation with IHEP) Neutron monitor PMT HF wedge HF shielding Ionizing radiation detector

Contribution of MSU in CMS project 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

Contribution of MSU in CMS project Work is performed by researchers of Hadronic Interactions Laboratory (Head - Ludmila Sarycheva, Professor of Chair of Physics Department): A. Ershov (Ph. D), A. Gribushin (Ph. D), O. Kodolova (Ph. D), I. Lokhtin (Ph. D), D. Okunev (student), S. Petrushanko (Ph. D), L. Sarycheva (Prof. ), A. Snigirev (Dr. of Science), C. Teplov (student), I. Vardanyan (Ph. D) 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.