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JINR participation at Linear JINR participation at Linear Collider Collider

Physics and Detector R&DPhysics and Detector R&D

Dubna Dubna

A.Olchevski

5th Workshop on the Scientific Cooperation Between German Research

Centers and JINR

17-19 January 2005

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Subjects to coverSubjects to cover

• Beam Energy MeasurementBeam Energy Measurement• Forward CalorimeterForward Calorimeter• Forward TrackingForward Tracking• Hadron CalorimeterHadron Calorimeter• PhysicsPhysics

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The Energy SpectrometerThe Energy Spectrometerat the ILCat the ILC

DESY – Dubna - TU BerlinDESY – Dubna - TU BerlinCollaborationCollaboration

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Physics requirementsPhysics requirements

• Mass of top quark:Mass of top quark: (theor. uncertainty ~ 40 MeV) (theor. uncertainty ~ 40 MeV) →→ ΔΔEEbb/E/Ebb ≈≈1010-4-4..

• Mass of Higgs boson:Mass of Higgs boson: (theor. uncertainty ~ 40 MeV) (theor. uncertainty ~ 40 MeV) →→ ΔΔEEbb/E/Ebb ≈≈1010-4-4

• Mass of W-boson:Mass of W-boson: ((ΔΔMMWW ~~ 5 MeV) 5 MeV) →→ ΔΔEEbb/E/Ebb ≈ 5∙≈ 5∙1010-5-5

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Main idea of the spectrometerMain idea of the spectrometer

Concept:Concept:determination of the bending determination of the bending

angle angle θθof charged particles through a of charged particles through a

magnetmagnet

3 magnets (one analyzing, two 3 magnets (one analyzing, two ancillary) and a series of BPMs ancillary) and a series of BPMs (Beam Position Monitor)(Beam Position Monitor)

Measurements at different Measurements at different nominal LC energies are nominal LC energies are proposed to be performed at proposed to be performed at constant constant θθ by adjusting the by adjusting the current to the magnetscurrent to the magnets..

ΘΘ = bending angle = bending angle

→→B= magnetic fieldB= magnetic field

magnet

b dlBceE

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Responsibility of Dubna teamResponsibility of Dubna team

• Simulation of the magnetsSimulation of the magnets• Magnetic measurements on the prototype and Magnetic measurements on the prototype and

the design of the instrumentation for itthe design of the instrumentation for it• Slow control of spectrometerSlow control of spectrometer• Alignment and stabilizationAlignment and stabilization• Production of magnets (in case of acceptance of Production of magnets (in case of acceptance of

the project)the project)

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Simulation of the magnets was performedSimulation of the magnets was performed

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Main parts of magnetometers are Main parts of magnetometers are designeddesigned

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Dubna magnetometersS.Ivashkevitch

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AnalysisAnalysis of stability and alignment is in of stability and alignment is in progressprogress

Solutions and proposalsSolutions and proposals• construct the spectrometer on a construct the spectrometer on a single girder single girder (grounded (grounded

to the floor, ~25 m long, control its stabilityto the floor, ~25 m long, control its stability))• BPM-positioningBPM-positioning needed ~ 10 needed ~ 10 µmµm (laser interferometer (laser interferometer

resp. piezoelectrical devices or flexible bearings)resp. piezoelectrical devices or flexible bearings)• B-field stability and controlB-field stability and control →→ power and temperature controlpower and temperature control →→ permanent field measurements with two permanent field measurements with two

. complementary methods . complementary methods

Stability will be a key issueStability will be a key issue

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Cost estimate was performedCost estimate was performed

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Complementary methods for Complementary methods for beam energy determinationbeam energy determination

• SR produced in magnets of the spectrometer SR produced in magnets of the spectrometer (Dubna- Lomonosov MSU) – simulation, technical (Dubna- Lomonosov MSU) – simulation, technical evaluationevaluation

• resonance absorption of laser light (YerPhI, Armenia resonance absorption of laser light (YerPhI, Armenia - Dubna ) – theoretical estimation, simulation- Dubna ) – theoretical estimation, simulation

• radiative return using e.g. radiative return using e.g. ee++ee-- -> µ -> µ++µµ-- (Dubna) –(Dubna) – theoretical estimationstheoretical estimations

• polarization rotation measurementspolarization rotation measurements• Moller scatteringMoller scattering

CROSS-CHECKS neededCROSS-CHECKS needed Details are available on the Workshops Home PageDetails are available on the Workshops Home Page

http://www-zeuthen.desy.de/main/html/aktuelles/workshops.html http://www-zeuthen.desy.de/main/html/aktuelles/workshops.html

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Forward Forward CalorimetryCalorimetry

activitiesactivities1. CVD Diamond sensors. GPI-JINR-1. CVD Diamond sensors. GPI-JINR-

DESYDESY

2. Simulation. JINR-DESY2. Simulation. JINR-DESY

3. Physics. JINR-DESY3. Physics. JINR-DESY

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The complete system combines the microwave plasma reactor, vacuum and gas distribution system and instrumentation rack. The system is computer controlled. Microwave power source - 6 kW at 2.45 GHz, variable output Reaction gases: CH4, H2 (O2, Ar or CO2 optional) Gas is distributed with four mass flow controllers Gas process pressure: 20-120 Torr Substrate diameter: 76 mm (thick films), up to 100 mm (thin films) Substrate temperature control with a pyrometer Growth rate: 0.8 – 2.5 microns/hour (optical quality material) Diagnostic ports: 4 quartz windows Chamber: stainless steel, water cooled 

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Fig. 1. Responsivity (a.u.) vs photon energy for a diamond film of 0.28 thickness measured on the growth side (red squares)

and nucleation side (blue circles) of the sample. Bias voltage is 50 V. Open circles – the response on growth side at 10 V bias voltage. 25 microns were polished away from the nucleation

side to remove the most defective material.

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Fig.2. Alpha spectrum (241Am) for CVD-det. #5 at bias +500 V on rear contact. Test pulse is 14.4 fC (86400 e), 1ch. ADC=40 e.

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Shower from 50 GeV electron

Energy deposition in diamond

Simulation program

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Non radiative Bhabha (only e+ or e- in the final state)

All events with e+ and e- in the final state

Total Bhabha cross section

Cross section vs energy cut Events per bunch vs energy cut

Bhabha scattering simulation(in BeamCal angle range)

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BHLUMI TEEGGelectron angular distribution

for completely coincident events we have:Xsec_teegg = 31.655 0.483 nbXsec_bhlumi = 30.426 nb

TEEGGafter cut for minimum scattered

angle (0.5 mrad)

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FORWARD CHAMBERS OF THE LC DETECTOR

General layout of one quarter of the central tracking

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TRACK PERFORMANCE IN THE FCH (soft selection

rules 2/2/2) Soft selection rules (2/2/2 from 12)

have been applied for further studies of the FCH performance: minimum 2 hits are required for each of 3 projections of a track

In ideal case: no dead zones and wire noise, wire efficiency = 100%

tracking efficiency 87% for tracks originating from the e+e- - interaction point 82% for all tracks

Mean efficiency, ghost & clone rates vrs drift-tube space resolution: Wire efficiency = 100%Wire-noise probability = 0%-- only for tracks originating

from the e+e- - interaction point-- for all tracks

Small dependence on the drift-tube space resolution

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TRACK PERFORMANCE IN THE FCH (soft selection

rules 2/2/2) Mean efficiency, ghost & clone

rates for various wire efficiencies and wire noise level ( for all tracks in the FCH)

Mean efficiency, ghost & clone rates for various wire efficiencies and wire noise level ( for tracks originating from the e+e- - interaction point)

Drift-tube space resolution = 50 µm

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The First tests of pilot fast digitization unit

for the Tile HCAL

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-E10 kOhm

470 Ohm

SiPM

50v

100 Ohm

100 Ohm

12 kOhm

22 n

25

26

27

5:12

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Results for pilot TileCal electronics:

1.The 32ch unit was designed, built and successfully tested

2.Single photoelectron peaks can be measured3.The possibility of calibration in the self-trigger

mode is shown4.Dynamic range is estimated to be not less than

50 MIPs5.Time resolution at least 2 ns is obtained6.Cross-talk between neighbour channels is

measured at the level of about 0,25%7.More studies are needed (RC, stability, time

resolution)8.Many solutions for the DAQ system is reserved in

the design of the module and should be discussed

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PhysicsPhysics

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SUSY SUSY study at ILCstudy at ILC::Main task:Main task: STOP- STOP-squarks squarks pair productionpair production in in

polarized polarized PHOTON-PHOTONPHOTON-PHOTON collisionscollisions Authors/ParticipantsAuthors/Participants::

A.Skachkova, N.Skachkov A.Skachkova, N.Skachkov ( Dubna )( Dubna )

K.Moenig ( DESY, K.Moenig ( DESY, Zeuthen )Zeuthen )

A.Bartl, ( University, A.Bartl, ( University, Wien )Wien )

W.Majerotto ( HEPHY, Wien W.Majerotto ( HEPHY, Wien ))

April 2004-April 2004- talk given at LCWS2004 , talk given at LCWS2004 ,

ParisParis (to appear in (to appear in ProccedingsProccedings of of this Conference)this Conference)

In STANDARD MODEL:In STANDARD MODEL: TOPTOP-quark is the-quark is the heaviest heaviest oneone

In SUSY:In SUSY: STOPSTOP-squark -squark the the lightestlightest

oneone

i.e. i.e. STOPSTOPss have better chances have better chances to be to be discovereddiscovered !!

Studied processStudied process (at Etot = (at Etot = 1GeV1GeV) : ) :

gamma-gamma gamma-gamma STOP + STOP +

antiSTOPantiSTOP

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MSSMMSSM model was used with: M_gluino = M_squark = model was used with: M_gluino = M_squark = 370 GeV, it370 GeV, it corresponds to M_stop1 = 167 corresponds to M_stop1 = 167 GeV.GeV. Main background: Main background: Final states were defined by 2 decay channels:Final states were defined by 2 decay channels:

SIGNALSIGNAL::

qqneutralinobWneutralinob

charginobSTOP

lνlneutralino~b

Wneutralino~b

chargino~b

STOP

qqbWb

t

BACKGROUNDBACKGROUND::

lνlbWb

t

ttγγ ν1;2.Wqq1.W

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STOP/Top production processes have the STOP/Top production processes have the same observable same observable particlesparticles

in final statesin final states!!(differ only by neutralino pair presence in STOP case)(differ only by neutralino pair presence in STOP case)

The authors find out a The authors find out a set of physical observablesset of physical observables which which distibutions look very distibutions look very differentdifferent for for signalsignal and and backgroundbackground.. For example:For example:

• 1. Total energy, 1. Total energy, deposited in deposited in Calorimeter (fig.1, Calorimeter (fig.1,

red is STOP, green is red is STOP, green is top): top):

E_cal_tot. E_cal_tot. • 2. Invariant mass of 2. Invariant mass of

two b_jets (fig.2): two b_jets (fig.2): M_Bjet_BbarjetM_Bjet_Bbarjet

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Analogous effect was shown for two other invariant Analogous effect was shown for two other invariant masses.masses.

ImportantImportant: All figures 1-4 look much more better than : All figures 1-4 look much more better than in LHC case,in LHC case,

i.e. LC may be better suited for stop pair study than i.e. LC may be better suited for stop pair study than gluon-gluon channel at LHCgluon-gluon channel at LHC3. Distributions for 3. Distributions for

invariant mass of b-jet invariant mass of b-jet and of two quark jets and of two quark jets from W decay in from W decay in STOP/top cases (fig.3, STOP/top cases (fig.3, red is STOP, green is red is STOP, green is top):top):

M_Bjet1_Jet2.M_Bjet1_Jet2.4. Invariant mass of two b-4. Invariant mass of two b-

jets + two jets from one jets + two jets from one W decay and of muon W decay and of muon from another W decay from another W decay (fig.4):(fig.4):M_4jet_mu.M_4jet_mu.

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ConclusionConclusion

the work on the work on Instrumentation, Instrumentation,

Software, Simulation and Software, Simulation and Physics should be Physics should be

continuedcontinued