JINR%20participation%20at%20Linear%20Collider%20Physics%20and%20Detector%20R

1
JINR participation at Linear Collider Physics
and Detector RD
A.Olchevski
5th Workshop on the Scientific Cooperation
Between German Research Centers and JINR 17-19
January 2005

• Dubna

2
Subjects to cover

• Beam Energy Measurement
• Forward Calorimeter
• Forward Tracking
• Hadron Calorimeter
• Physics

3
The Energy Spectrometerat the ILC

• DESY Dubna - TU Berlin
• Collaboration

4
Physics requirements

• Mass of top quark
• (theor. uncertainty 40 MeV) ? ?Eb/Eb
  10-4.
• Mass of Higgs boson
• (theor. uncertainty 40 MeV) ? ?Eb/Eb
  10-4
• Mass of W-boson
• (?MW 5 MeV) ?
  ?Eb/Eb 510-5

5
Main idea of the spectrometer

• Concept
• determination of the bending angle ?
• of charged particles through a magnet
• 3 magnets (one analyzing, two ancillary) and a
  series of BPMs (Beam Position Monitor)
• Measurements at different nominal LC energies are
  proposed to be performed at constant ? by
  adjusting the current to the magnets.
• T bending angle ?
• B magnetic field

6
Responsibility of Dubna team

• Simulation of the magnets
• Magnetic measurements on the prototype and the
  design of the instrumentation for it
• Slow control of spectrometer
• Alignment and stabilization
• Production of magnets (in case of acceptance of
  the project)

7
Simulation of the magnets was performed
8
Main parts of magnetometers are designed
9
Dubna magnetometers S.Ivashkevitch
10
Analysis of stability and alignment is in progress

• Solutions and proposals
• construct the spectrometer on a single girder
  (grounded to the floor, 25 m long, control its
  stability)
• BPM-positioning needed 10 µm (laser
  interferometer resp. piezoelectrical devices or
  flexible bearings)
• B-field stability and control
• ? power and temperature control
• ? permanent field measurements with two
  .
  complementary methods
• Stability will be a key issue

11
Cost estimate was performed
12
Complementary methods for beam energy
determination

• SR produced in magnets of the spectrometer
  (Dubna- Lomonosov MSU) simulation, technical
  evaluation
• resonance absorption of laser light (YerPhI,
  Armenia - Dubna ) theoretical estimation,
  simulation
• radiative return using e.g. ee- -gt µµ- (Dubna)
  theoretical estimations
• polarization rotation measurements
• Moller scattering
• CROSS-CHECKS needed
• Details are available on the Workshops Home Page
• http//www-zeuthen.desy.de/main/html/aktuelles/wor
  kshops.html

13
Forward Calorimetryactivities

• 1. CVD Diamond sensors. GPI-JINR-DESY
• 2. Simulation. JINR-DESY
• 3. Physics. JINR-DESY

14
(No Transcript)
15
(No Transcript)
16
(No Transcript)
17
Simulation program
Shower from 50 GeV electron
Energy deposition in diamond
18
Bhabha scattering simulation (in BeamCal angle
range)
Cross section vs energy cut
Events per bunch vs energy cut
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
19
electron angular distribution
TEEGG
BHLUMI
for completely coincident events we
have Xsec_teegg 31.655 0.483
nb Xsec_bhlumi 30.426 0.321 nb
TEEGG after cut for minimum scattered angle (0.5
mrad)
20
FORWARD CHAMBERS OF THE LC DETECTOR

• General layout of one quarter of the central
  tracking

21
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 ee- -
  interaction point
• ? 82 for all tracks

• Mean efficiency, ghost clone rates vrs
  drift-tube space resolution
• Wire efficiency 100Wire-noise
  probability 0
• -- only for tracks originating from the
  ee- - interaction point
• -- for all tracks

Small dependence on the drift-tube space
resolution
22
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 ee- - interaction
  point)

Drift-tube space resolution 50 µm
23
The First tests of pilot fast digitization unit
for the Tile HCAL
24
50v
25
(No Transcript)
26
(No Transcript)
27
(No Transcript)
28

• Results for pilot TileCal electronics
• The 32ch unit was designed, built and
  successfully tested
• Single photoelectron peaks can be measured
• The possibility of calibration in the
  self-trigger mode is shown
• Dynamic range is estimated to be not less than 50
  MIPs
• Time resolution at least 2 ns is obtained
• Cross-talk between neighbour channels is measured
  at the level of about 0,25
• More studies are needed (RC, stability, time
  resolution)
• Many solutions for the DAQ system is reserved in
  the design of the module and should be discussed

29
Physics
30
(No Transcript)
31
(No Transcript)
32
SUSY study at ILCMain task
STOP-squarks pair production in
polarized PHOTON-PHOTON collisions

• Authors/Participants
• A.Skachkova, N.Skachkov ( Dubna )
• K.Moenig ( DESY, Zeuthen )
• A.Bartl, ( University, Wien )
• W.Majerotto ( HEPHY, Wien )
• April 2004-?
• talk given at LCWS2004 , Paris
• (to appear in Proccedings of
• this Conference)

• In STANDARD MODEL
• TOP-quark is the heaviest one
• In SUSY
• STOP-squark ? the lightest one
• i.e. STOPs have better chances
• to be discovered !
• Studied process (at Etot 1GeV)
• gamma-gamma ?
• ?STOP antiSTOP

33
MSSM model was used with M_gluino M_squark
370 GeV, it
corresponds to M_stop1 167 GeV.
Main background Final states were defined
by 2 decay channels

• SIGNAL

BACKGROUND
34
STOP/Top production processes have the same
observable particles in final states!(differ
only by neutralino pair presence in STOP
case)The authors find out a set of physical
observables which distibutions look very
different for signal and background.

• For example
• 1. Total energy, deposited in Calorimeter (fig.1,
  
• red is STOP, green is top)
• E_cal_tot.
• 2. Invariant mass of two b_jets (fig.2)
  M_Bjet_Bbarjet

35
Analogous effect was shown for two other
invariant masses.Important All figures 1-4 look
much more better than in LHC case,i.e. LC may be
better suited for stop pair study than
gluon-gluon channel at LHC

• 3. Distributions for invariant mass of b-jet and
  of two quark jets from W decay in STOP/top cases
  (fig.3, red is STOP, green is top)
• M_Bjet1_Jet2.
• 4. Invariant mass of two b-jets two jets from
  one W decay and of muon from another W decay
  (fig.4)
• M_4jet_mu.

36
Conclusionthe work on Instrumentation,
Software, Simulation and Physics should be
continued