Contribution of MSU in CMS project

Contribution of MSU in CMS project

• 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

Contribution of MSU in CMS project

• 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)

Contribution of MSU in CMS project

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)

Contribution of MSU in CMS project

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

Contribution of MSU in CMS project

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)

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

Primary vertex reconstruction algorithm based on reconstruction of hits belonging two barrel pixel layershas been developed and

included in CMS Reconstruction package ORCA

dN/d = 2500 dN/d = 8000

x =

y = 20 m,

z = 190 m

Contribution of MSU in CMS project

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 v

2(p

T)

Contribution of MSU in CMS projectPhysics 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

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

Contribution of MSU in CMS project

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)

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 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

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 SpS accelerator

Design and production of HF radiation monitoring system (in cooperation with IHEP)

Neutron monitor

Ionizing radiation detector

PMTHF wedge HF shielding

Contribution of MSU in CMS project

Development of HF calibration and re-calibrationInvestigation 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 (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.