Transcript Towards Physics at LHC with CMS detector

High Energy Physics at TIFR
Started with Bhabha
and ……….
Tariq Aziz
TIFR, Mumbai
May 27-28, 09
Department of High Energy Physics
14 Faculty + 14 Students + 4 PostDoc
44 Eng + 25 Techs +15 Services + 4 Admin
Accelerator Based
CMS at CERN, Belle at KEK, D0 at Fermilab
D0n
Non-Accelerator based
Gravitation (Gauribidanur), Cold-atoms (Mumbai)
Neutrino physics (PUSHEP)
Cosmic rays(Ooty), Gamma-ray astronomy (Pachmarhi & Hanle)
India at LHC
First Large Scale Indian Participation in an International
Experiment
Indian accelerator research labs, led by RRCAT, Indore, and
BARC, Mumbai, have contributed substantially, in kind, towards
the LHC machine
Indian scientists/software personnel are contributing in-kind
to the development of GRID software
Two groups:
India-CMS
&
India-ALICE
Indian Participation in CMS Collaboration
TIFR and Panjab University
Hardware responsibilities:
- Outer hadron calorimeter
Ensure more hermetic calorimeter for missing energy
BARC and Delhi University
- Silicon Pre-shower Detector.
Discriminate between π0/ to detect Higgs  2γ mode
(for light Higgs favored by existing data)
2 mm strip width sensor
Outer Hadron Calorimeter of CMS
Extend HCAL outside the solenoid magnet and make additional shower sampling
CMS Detector ¼ Logitudinal view
HO
HB
HF
TIFR Colloquium
HE
Relevant for the late development of showers
Lowering of YB-1 and YB-2
TIFR Colloquium
HO basic design
• Detector element is a plastic scintillator tile which
produces light when charged particles pass through it
• This light is collected by embedded WLS fibers
• Light is transported to HPD detector via clear optical
fibers spliced to WLS fibers
• Size and placement of the tiles is matched to geometric
towers in the Barrel calorimeter
• Tiles are grouped together and packed in “trays” for ease
of handling, and 6 trays in each phi sector are in turn
inserted inside aluminum honeycomb housings.
Physics potentials of CMS Detector at LHC
Test the Standard (model) first and ensure
no surprises from the detector before the
real surprises from new physics
A.K.Nayak, T.Aziz, A. Nikitenko
b-Tagging Crucial
Purity of b-tagging: IP3D
Significance of 3rd track
B-discriminator
B-discriminator
> 2.5>2.5
Efficiency < 40%
IP3D Significance
of 3rd track
Efficiency< 40%
Expected measurement for 100 pb-11
Evaluation of b-jet energy correction from data
A.K.Nayak, T.Aziz,
A.Nikitenko
Needed for Higgs, SUSY bbA; A and CPV Higgs Search
Resolution is
improved by 25 %
Jets from Calo Towers
Mass peak restored after b-jet corrections
From 10 fb-1 of data
Measurement of Z  e
S.Bansal +K.Mazumdar
Visible mass in 100 pb-1
Benchmark process for Higgs searches
in H  emode.
e + channel is clean and will be free from
severe systematics inherent for jets, specially
during initial phase of LHC.
signal 520 event, bkg=20
Will be used for normalising   l +jet rates.
e +  combination reduces Drell-Yan
background and increases signal rate.
invariant mass: assume collinear s  poor statistics
since e,  should not be back-to-back  affects mass resolution.
Trileptons from Chargino-Neutralino pair (
•
K.Mazumdar+ others
Very low rate, but clean signal in exclusive mode: 3 isolated leptons with 2
OSSF + no hadronic activity in central region of detector  extended
coverage of calorimeter needed. Need to resort to mSUGRA model
•
2 possibilities for signal signatures, depending on parameter values:
3-body decay:
Minvmax= m20-m10
2-body decay:
M2invmax= (m220-m2~l)(m2~l-m210)/m2~l
Accuracy of kinematical end
point (~m1/2) about 10
GeV
Trileptons from pair can be seen with
significance >5 , for m1/2 <250 GeV, with Lint >=30 fb-1
Cosmic rays at CMS
TTtttt at Very high momentum – Never done before
Muon Charge Ratio
A.Nayak, T.Aziz, P.G.Abia
Charge ratio
Zenith Angle in Radian
Indian Participation in BELLE Experiment at KEKB
BELLE Experiment:
A worldwide Collaboration of 400 participants from 55 Institutions
Study the difference between particle and its anti-particle using
huge number of B and anti-B mesons And search for Rare B decays
Indian groups:
Tata Institute, Mumbai,
IMSC & IIT Chennai,
Panjab University,
IIT, Guwahati (recent)
Participation: modest
Data Taking, Detector Monitoring and Calibration,
Reconstruction Algorithms, Physics Analysis
R&D for next Detector phase
Determination of RD
DCSD/CFD
N.Joshi, T.Aziz, K.Trabelsi
Estimate internal
W-exchange
Ds from , K*K, KsK
and Ds* from Ds 
Silicon Microstrip Detector Development R&D
For BELLE Detector Upgrade in the High Luminosity Phase
Also Develop inhouse capabilities for future participation where
High Resolution Tracking is Involved -- SLHC, FAIR , ILC….
Challenging High Tech Area
High Spatial Resolution Tracking Detector
Never Built Earlier in India
Industry Participation – Very Important
Phase I -- Single Sided
Phase II -- Double Sided
Indian Effort: Mask Design at TIFR, Processing at BEL
Single Sided - 11 Sets of 32 strips with different
strip width and pitch
Single Sided – 1024 strips with fixed strip width and pitch
Double-Sided with single metal contact
Double-Sided with double metal contact
Wafers with different crystal orientations
All on 4-inch n-type bulk wafer
TIFR Effort on
Silicon Microstrip Detector
Design, Simulation and Testing in Institute Lab
Fabrication at Bharat Electronics, Bangalore
On 300 m thin n-type silicon wafer
of 4-inch diameter
Developed Single Sided Detector
Small Corner Under High Magnification
11 Sets of 32 strips each
Strip width
Strip pitch
Strip length
12 m to 48 m
65 m to 120 m
7.5cm
Strip p-type implant
AC coupled via Aluminum
Overhang - isolated by SiO2
For the first time truly Microstrip
Detector developed in India
Polyresistors 3-4 M
For Common bias
DC pad and AC pad on
each strip
I – V Characteristics
I - V Characteristics of Silicon Microstrip Detector
Current ( nano amps )
600
Set 1
Set 2
400
Set 3
Set 4
Set 5
Set 6
Set 7
Set 8
Set 9
200
Set 10
Set 11
0
0
50
100
150
200
250
Voltage ( -ve )
All 11 sets pass
acceptance test
300
350
400
450
C – V Characteristics
C - V Characteristics
250
Capacitance ( pf )
200
Set 1
Set 2
Set 3
Set 4
150
Set 5
Set 6
Set 7
Set 8
100
Set 9
Set 10
Set 11
50
0
0
20
40
60
Voltage ( -ve )
80
100
120
Double sided silicon detector
Specifications continued
Wafer crystal orientation : < 100 >,Type: FZ
Wafer thickness : 300 µm , Size
: 4 inch
Resistivity : > 5 Kohm-cm
Breakdown voltage : > 300V
Polysilicon resistor value : > 4 Megaohms
Total Dark current : <= 2 microamps @ 100V
Number of Dead Strips < 1%
Area
: 79600 x 28400
Effective Area : 76800 x 25600
Nex Step:
1024 strips
I - V characteristics of Single Sided Detector
Current ( nano amps )
5000
4000
3000
8004-5*
8018-1*
8018-2*
8018-3
8004-7
8004-8
2000
1000
0
0
100
200
300
400
Reverse voltage ( volts )
500
< 1 nam per strip at 100 volts
1024 Strips
C - V characteristics of Single Sided Detector
120
8004-5*
8018-3
capacitance ( pf )
110
8018-1*
8004-7
8018-2*
8004-8
100
90
80
70
60
50
40
0
50
100
Reverse voltage (volts)
We had difficulty with pin-holes. That problem is solved
Number of bad strips < 0.5%
Similar to Hammatsu
CMS acceptance < 1% bad strip
150
DSSD- N-type strips
DC pad
N-strip
P-stop
Silicon Microstrip Detector design and development,
1024 strips on one plane, 512 on the other plane of
300m thin silicon wafer, strip width 12m, length
7600m, common bias via polyresistors, required
for high resolution tracking
Non-Accelerator based Particle Physics
Important Cosmic Ray Research Areas
• Study of the elemental and isotopic composition of
cosmic rays at GeV-TeV energies using balloon or
satellite-borne detectors.
• Gamma ray astronomy over the GeV-TeV-PeV-EeV
energies.
• Energy spectrum and composition around the knee (E
~ 3 x 1015 eV).
• Energy spectrum and composition around the ankle (E
~ 3 x 1018 eV).
• Energy spectrum and composition at energies ~ 1020
eV and observation of the Greisen-Zatsepin-Kuzmin
cutoff.
Air Cherenkov Telescope – 1st of 6
Hanle, Ladakh , 4250 m Altitude
GRAPES-3 Air Shower Array at Ooty )
Most of the Detector Components produced in-house
High quality Scintillators produced at CRL Ooty
Four muon halls, each housing a 4-module block
CRL Ooty
Forbush Decrease associated with the large Solar flare
of 2003 Oct 28, observed with the GR-3 muon detector
October-November, 2003
Thank You