Post on 24-Jan-2016
description
Review of Scalar Meson Production at = 7TeV in CMS, U(1)' Gauge Extensions of the
MSSMand
Calorimetry for Future Colliders
s
Thesis Defense
Burak Bilki
June 16, 2011
The Compact Muon Solenoid (CMS) Detector at the Large
Hadron Collider (LHC)
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CMS Subdetectors
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http://cms.web.cern.ch/cms/Detector/FullDetector/index.html
CMS Subdetectors – Transverse Slice
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CMS Data Taking
First collisions at =900 GeV started in 2009.
First =7 TeV collision was in March 2010.
In 2010, integrated luminosity reached ~50 pb-1. Two distinct run periods based on beam settings: Run2010A and Run2010B.
By the end of 2011, an integrated luminosity of 3-4 fb-1 is within reach.
The reasonable target by the end of 2012 is 10 fb-1.
s
s
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Scalar Meson Production at = 7TeV in CMS
s
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Reason of Interest
Whether the scalar mesons really exist or not is an important problem in hadron physics.
It is still a difficult yet interesting topic.
They have the same quantum numbers as the vacuum (JPC=0++) hence they can condense into the vacuum and break a symmetry such as a global chiral symmetry.
There are several theoretical models for their structures (diquark-antidiquark bound states, glueballs, molecules, etc.).KK
I=1/2 states: (or ), .
I=1 states: , .
I=0 states: (or ), , , , .
)800(*K )1430(*K
)980(0a )1450(0a
)600(0f )980(0f )1370(0f )1500(0f )1710(0f
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Search for Scalar Meson Production in
Process
/)2( JS
Datasets:
/MuOnia/Run2010A− Dec22ReReco_v1/RECO/MuOnia/Run2010B− Dec22ReReco_v1/RECO
MC Simulation (for acceptance):
/Psi2SToJpsiPiPi_2MuPEtaFilter_7TeV-pythia6/Fall10 - START38_V12-v1/GEN-SIM-RECO
Search Path:
• Reconstruct .
• Reconstruct .
• Look at mass spectrum.
/J /)2( JS
)2( S
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Search for Scalar Meson Production in
Process
/)2( JS
• Level 1 (hardware) muon trigger selection “L1_DoubleMuOpen OR L1_DoubleMu3”.
• Search for two oppositely charged muons with pt > 2 GeV/c (transverse momentum).
• Require at least 10 hits in the silicon strip tracker and 12 hits in the entire tracker system.
• Fit a vertex to the muon pair and retain if the fit is valid with a probability of at least 0.1% and the invariant mass of the muon pair is within 50 MeV/c2 of the PDG (Particle Data Group) value (3.096916 GeV/c2).
/J
2
9
Search for Scalar Meson Production in
Process
/)2( JS
Tracks
• No particle ID for tracks (assign pion mass to all tracks).
• Track pt > 0.4 GeV/c (transverse momentum).
• Require at least 1 hit in the pixel detector and at least 10 hits in the tracker.
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Search for Scalar Meson Production in
Process
/)2( JS
• Fit a vertex to all pions and muons with mass constraint on muons.
• Retain if vertex probability is more than 2% and ,
and the four tracks remain in < 1
/)2( JS
/J
2 /J )2( S22 R
11
/)2( JS
Unbinned maximum likelihood fit
2/1.09.3685))2(( cMeVSm
52424928))2(( SN
2/1.01.5))2(( cMeVS
708239938BackgroundN
Green: Selection )2( SMeVmm SJ
10)2(/
Red: Background
MeVmmMeV SJ4030 )2(/
12
13
Search for Scalar Meson Production in
Process
/)2( JS
)2( S
/J
)2( S
/J
T. Komada et.al., Phys. Lett. B 508, 31 (2001)13
Search for Scalar Meson Production in
Process
/)2( JS
• Fit the mass spectrum ( ) with a coherent sum of and production amplitudes.
222 )(
ii
erssism
reF
s
spg
8
)(12
21 4
)( ms
sp
s
2
2)2(
31
2/
22/
2)2(
32
)(
2
4)(F
M
sp
s
sMsMM
sd
d
S
JJS
: production coupling
: production phase
: coupling
r
g
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Search for Scalar Meson Production in
Process
/)2( JS
2741400r
152346382 r
22.012.32
0
2/5.68.568 cMeVm
20.034.2 g
2/6.288.166 cMeV
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Search for Scalar Meson Production in
Process
/)2( JS
)2( S
/J
gg
Describe the gluon emission by a multipole expansion of S (and possibly D) wave.
Formalism by T. Yan, Phys. Rev. D 22, 7, 1652 (1980)
Implemented by CDF and BES collaborations.
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Search for Scalar Meson Production in
Process
/)2( JS
2
2
2
222222222 2
12423
2)(A
BO
m
mKmmmm
A
BmmPS
dm
d
)2(
2
)2(2
/22
)2(22
/24
)2(4
/422
4
24
S
SJSJSJ
M
MMmMmMmMMmmPS
)2(
2/
2)2(
2
2 S
JS
M
mMMK
4
44224
2
22222222
2
2
2
2
623
8
643
44
20
1
m
Kmmmm
m
Kmmmmmm
A
B
A
BO
:A
B
Higher Order terms
Free (shape) parameter
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Search for Scalar Meson Production in
Process
/)2( JS
13S Multipole expansion
13S Higher order multipole expansion
021.0260.0 A
B040.0377.0
A
B
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Systematic Effects
Binning: 5 MeV/c2 , 10 MeV/c2
Trigger: High Level Trigger Selection
Background Bias: MeVmmMeV SJ3525 )2(/
MeVmmMeV SJ4535 )2(/
Differences from the fit values are added in quadratures for
m
2r
rA
B)(HO
A
B19
Systematic Effects: Binning
2/2.61.569 cMeVm 2/7.282.168 cMeV
2/2.76.569 cMeVm 2/1.317.179 cMeV
12.032.02
r
r11.029.0
2
r
r
021.0256.0 A
B021.0259.0
A
B
040.0372.0)( HOA
B039.0369.0)( HO
A
B 20
Systematic Effects: Trigger Selection
2/4.70.565 cMeVm 2/6.383.194 cMeV
11.027.02
r
r
022.0268.0 A
B
042.0381.0)( HOA
B21
Systematic Effects: Background
2/4.54.569 cMeVm 2/4.210.146 cMeV
2/2.32.559 cMeVm 2/3.157.130 cMeV
14.036.02
r
r11.035.0
2
r
r
022.0242.0 A
B020.0268.0
A
B
042.0357.0)( HOA
B038.0381.0)( HO
A
B
MeVmmMeV SJ3525 )2(/ MeVmmMeV SJ
4535 )2(/
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Search for Scalar Meson Production in
Process: Summary
/)2( JS2/.)(4.10.)(5.68.568 cMeVsyststatm
2/.)(6.51.)(6.288.166 cMeVsyststat
.)(08.0.)(12.030.02
syststatr
r
.)(022.0.)(021.0260.0 syststatA
B
.)(023.0.)(040.0377.0)( syststatHOA
B
.)(028.0.)(004.0225.0 syststatA
B
.)(019.0.)(009.0336.0)( syststatHOA
B
022.0342.0)( HOA
B
BES
BES
CDF23
ReferencesT. Komada et. al., Phys. Lett. B 508, 31-36 (2001).M. Ishida et. al., Phys. Lett. B 518, 47-54 (2001).M. Ablikim et.al., Phys. Lett. B 598, 149-158 (2004).L. Hongbo (on behalf of BES Collaboration), Eur. Phys. J. A 31, 461-464 (2007).J. Z. Bai et al., Phys. Rev. D 62, 032002 (2000).M. Ablikim et.al., Phys.Lett.B 645, 19 (2007).D. Alde et.al., Phys. Lett. B 397, 350-356 (1997).E. M. Aitala et.al., Phys. Rev. Lett., 86, 5, 770 (2001).E. M. Aitala et.al., Phys. Rev. Lett., 86, 5, 765 (2001).H. Muramatsu et. al., Phys. Rev. Lett., 89, 25, 251801 (2002).A. Abulencia et. al., Phys. Rev. Lett. 96, 102002 (2006).T. Yan, Phys. Rev. D 22,1652 (1980).G. ’t Hooft et.al., Phys. Lett. B 662, 424-430 (2008).T. N. Pham, Phys. Lett. B 217, 165-168 (1989).L. Montanet, Nucl. Phys. (Proc. Suppl.) B 86, 381-388 (2000).N. N. Achasov, Phys. Part. Nucl. 36, 146-149 (2005) .N. N. Achasov et. al., Nucl. Phys. (Proc. Suppl.) B 162, 127-134 (2006).S. Ishida et. al., Phys. Lett. B 539, 249 (2002).G. Mennessier et. al., Phys. Lett. B 665, 205 (2008).T. Kojo et. al., Phys. Rev. D 78, 114005 (2008).CMS Collaboration, PAS MUO-10-002 (2010).K. Nakamura et. al. (Particle Data Group), J. Phys. G: Nucl. Part. Phys. 37 075021 (2010).
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U(1)' Gauge Extensions of the MSSM
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U(1)' Model
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U(1)' Model
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U(1)' Model
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U(1)' Model
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U(1)' Model
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U(1)' Model
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U(1)' Model
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U(1)' Model
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U(1)' Model Search in CMS
Events of each signal type was produced by CalcHEP and hadronized by PYTHIA 6 with CTEQ6L parton distributions.
Signal 4A is not analyzed a it will be heavily suppressed compared to the others.
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U(1)' Model Search in CMS
Event Selection:
GeVET 100
cGeVp jetT /20
cGeVp leptonT /15
2(Missing transverse energy)(pseudorapidity)
Y
YY M
MR
~
'~
' Y
YYYY M
MR
~
'~~
'
'~~ ,YY
MM
'~~YY
M
YU )1( and ')1( YU gaugino masses
soft-breaking mass that mixes and gauginos.
YU )1( ')1( YU35
Analysis to compare MSSM and U(1)', no background study.
Two medium mixing cases are investigated in U(1)' model:
U(1)' Model Search in CMS
)0,0(),( '' YYY RR
)10,10(),( '' YYY RR
1fb=Ldt 100 TeV=s 14at scenario is considered.
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U(1)' Model Search in CMS - Signal 1
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U(1)' Model Search in CMS - Signal 1
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U(1)' Model Search in CMS - Signal 1
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U(1)' Model Search in CMS - Signal 2
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U(1)' Model Search in CMS - Signal 3A
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U(1)' Model Search in CMS - Signal 3A
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U(1)' Model Search in CMS - Signal 3B
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U(1)' Model Search in CMS - Signal 3B
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45454545
U(1)' Model Search in CMS - Signal 4B
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4646
U(1)' Model Search in CMS - Signal 4B
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References
S. Cecotti et.al., Phys. Lett. B 156, 318 (1985).
G. Cleaver et.al., Phys. Rev. D 57, 2701 (1998).
D. M. Ghilencea et.al., JHEP 0208, 16 (2002).
D. A. Demir et.al., Phys. Rev. D 59, 15002 (1999).
D. A. Demir et.al., Phys. Rev. Lett. 100, 91804 (2008).
A. Ali et.al., Phys. Rev. D 79, 95001 (2009).
V. Barger et.al., Phys. Lett. B 644, 361 (2007).
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Calorimetry for Future Colliders
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Upgrade for CMS Hadron Forward (HF) Calorimeters
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The Hadron Forward (HF) Calorimeter is a part of HCAL. One on each end of CMS, covering 3<η<5 (0.77°-5.7°). Composed of quartz fibers embedded in a 1.65 meter steel
absorber. Two lengths of fiber
Readout boxes containing PMTs sit behind it at 3< η<3.2.
Interaction point (~11m this way)
CMS Hadron Forward (HF) Calorimeters
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Motivation for An Upgrade R&D
Search for new PMTs to identify window hits and eliminate this effect keeping the abnormal signal at a low level and PMT performance at a better scale.
• Cerenkov radiation from particles directly hitting the PMT window create abnormally large signals.
• The glass window is plano-convex: ~ 2 mm thick at the center, ~ 6 mm thick at the edges.
S. Abdullin et. al.,Eur. Phys. J. C 53, 139, 2008
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PMT Information(Manufacturer Hamamatsu)
Window: ~2 mm thick at the center, ~6 mm thick at the edges.
Window: < 1 mm thick
Window: < 1 mm thick
Window: < 0.5 mm thick
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Beam Tests(CERN H2 Beamline – Summer09)
150 GeV/cMuon Beam
80 GeV/cElectron Beam
TriggerCoincidence of two
scintillation counters:4 cm x 4 cm
14 cm x 14 cm
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Muon Interactions with PMT WindowsFront Incidence Side Incidence
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Čerenkov Response of PMTs(Tests with The Fiber Bundle)
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Čerenkov Response of PMTs(Tests with The Quartz Fiber Calorimeter)
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PMT Window Event Selection andSignal Recovery with Four Anode PMT – 4CH
0. Identify PMT window events
1. Order signal magnitudes fromfour quadrants: S1>S2>S3>S4.
2. If S1/S2>20, then single quadrant hit:Signal=(4/3)*(S2+S3+S4)
3. Remaining <20% events are multiplequadrant hits:
3. a. If S2>0.8*(S2+S3+S4), thendouble quadrant hit:Signal=2*(S3+S4)
3. b. Remaining ~5% are triplequadrant hits:Signal=4*S4
3. c. Remaining ~2.5% is irreducible.
Window Event Selection Cut
μ
μSi ||
57
Pedestal
Front Muon Incidence on PMT WindowSide Muon Incidence on PMT Window
PMT Window Event Selection andSignal Recovery with Four Anode PMT – 4CH
58
Fiber Bundle PMTsAlgorithm should have no effect on the signal!!!
<2.5%misidentification
PMT Window Event Selection andSignal Recovery with Four Anode PMT – 4CH
4CH readout algorithms are >97% efficient. 59
Fiber Bundle PMTs with the PMTs in the Beamline!!!
Success!!!Large tail is gone!!!
PMT Window Event Selection andSignal Recovery with Four Anode PMT – 4CH
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Scheme 1 Scheme 3Scheme 2
The algorithms for 2CH readout are ~90% efficient.
PMT Window Event Selection andSignal Recovery with Four Anode PMT – 2CH
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References
CMS Detector Note (DN), CMS Note (NOTE) and CMS Conference Reports (CR): CMS DN-2009/005, CMS DN-2009/011, CMS DN-2009/012, CMS NOTE-2010/003, CMS CR-2010/083.
CMS HCAL Collaboration, “Study of various photomultiplier tubes with muon beams and Čerenkov light produced in electron showers”, JINST 5 P06002, 2010.
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Digital Hadron Calorimetry
63
Why Digital Calorimetry?
Idea emerged from the need of high segmentation calorimetry for the application of Particle Flow Algorithms (PFAs). An analog readout solution would result in unrealistic data sizes.
Simple digital readout with a threshold set well below the signal given by one minimum ionizing particle traversing the active medium.
A perfect calorimetry solution for the future lepton colliders providing high segmentation in a robust and sophisticated approach.
64
Tests With a Small-Size DHCAL Prototype
The calorimeter stack consisted of nine chambers interleaved with the combination of a steel (16 mm) and a copper (4 mm) absorber plates, corresponding to approximately 1.2 radiation length. Not all layers were usedfor all measurements.
The chambers measured 20 x 20 cm2. They were operated in avalanche mode with an average high voltage setting around 6.1 kV. The gas consisted of a mixture of three components: R134A (94.5%), isobutane (5.0%) and sulfur-hexafluoride (0.5%). 65
66
Electronic Readout System
Pad Board
Front-End Board
DCAL Chip
Data Concentrator
Data Collector
Trigger and Timing Module
The total number of readout channels was up to 2,304 for nine layers.66
Test Beam Setup and Data Collection
The stack containing nine layers within the blue hanging file structure
The gas distribution rack
67
Measurement of Positron Showers
Event display of a positron- induced shower. Average number of hits as a function of layer number for the
various beam energies. The lines represent the results of a GEANT4 simulation of the set-up together with the simulation of the response of RPCs with a standalone program (RPCSIM by J. Repond).
68
Simulating Larger Systems
Two different physics packages for 1 m3 simulations.Reasonable Gaussian fits for E > 2 GeVResolution ~ 58%/√E(GeV) (for E < 28 GeV)
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The Large-Size DHCAL Prototype
The large Digital Hadron Calorimeter (DHCAL) prototype was built:
The active medium is Resistive Plate Chambers (RPCs).
Sampling calorimeter with 52 layers (38 layers DHCAL, 14 layers tail catcher - TCMT).
Each layer has 96 x 96 readout channels (pads) of size 1 cm x 1 cm.
Total number of readout channels is ~480K.
Readout is digital: A pad registers a “1” (hit) if the signal it measures exceeds a predefined threshold, “0” otherwise.
The DHCAL was tested (is being tested):
At FNAL in October 2010 and January 2011, April – June 2011.
With a broad-band muon beam, pion and positron beams of various momenta between 2-60 GeV/c and primary proton beam (120 GeV/c).
70
Prompt Pion/Positron Analysis
Promptly investigate the calorimetric properties of the DHCAL with preliminary methods.
Initiate the development of DHCAL-specific algorithms in calorimetry.
Validation of the DHCAL concept.
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Topological Particle ID - Summary
Muons: All active layers have aligned clusters with no more than two consecutive layers with non-isolated clusters.
Pions: At least one track segment in the interaction region that spans at least four layers. If such a track segment is not found, at least one pair of track segments that span three layers with at least 20o angle in between. rrms > 5.
Positrons: rrms < 5.
Hits
irms N
r=r 2
where ri is the distance of each hit to the x-y center of all the hits in the corresponding layer and NHits is the total number of hits.
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Particle ID Results in Oct '10 DataCALICE PreliminaryCALICE Preliminary CALICE PreliminaryCALICE Preliminary
CALICE PreliminaryCALICE Preliminary CALICE PreliminaryCALICE Preliminary
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Particle ID Results in Oct '10 DataCALICE PreliminaryCALICE Preliminary CALICE PreliminaryCALICE Preliminary
CALICE PreliminaryCALICE PreliminaryCALICE PreliminaryCALICE Preliminary
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DHCAL Response To Hadrons (Oct '10 Data – Pion ID)
No SelectionNo Hits in last two layers
32 GeV data point is not included in the fit.
N=aE
CALICE CALICE PreliminaryPreliminary
CALICE CALICE PreliminaryPreliminary
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No SelectionNo Hits in last two layers
32 GeV data point is not included in the fit.
CALICE PreliminaryCALICE Preliminary
DHCAL Response To Hadrons (Oct '10 Data – Pion ID)
C E
α=
E
σ⊕
B. Bilki et.al. JINST4 B. Bilki et.al. JINST4 P10008, 2009.P10008, 2009.
MC predictions for a large-size DHCAL based on the small-size prototype results.
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DHCAL Response To Positrons (Oct '10 Data – Positron ID)
CALICE PreliminaryCALICE Preliminary
Reconstruct the positron energies using this fit function on an event by event basis.
N=a+bEm
B. Bilki et.al. JINST4 B. Bilki et.al. JINST4 P04006, 2009.P04006, 2009.
Data (points) and MC (red line) for the small-size prototype and the MC predictions for a large-size DHCAL (green, dashed line).
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DHCAL Response To Positrons (Oct '10 Data – Positron ID)CALICE CALICE
PreliminaryPreliminary
CALICE CALICE PreliminaryPreliminary
CALICE CALICE PreliminaryPreliminary
CALICE CALICE PreliminaryPreliminary
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No processingCorrected for non-linearity
DHCAL Response To Positrons (Oct '10 Data – Positron ID)
CALICE PreliminaryCALICE Preliminary
C E
α=
E
σ⊕
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Summary
With the successful test beam campaigns, the digital hadron calorimeter concept is being validated under extensive physics and technical tests. Here, we present a first look analysis on the October 2010 secondary beam data to obtain the digital hadron calorimeter properties. More sophisticated analyses will be forthcoming in the near future.
The particle identification algorithms defined here provide sufficiently well discrimination at high energies. However, the complications in the event topologies at low energies require further studies to integrate these energies into the calorimetric measurements. These new algorithms are expected to improve the current measurements as well. With the present algorithms, a hadronic
energy resolution of , and an electromagnetic energy
resolution between 24% and 14% in the energy range of 2 – 25 GeV are obtained.
Further methods are being developed to obtain unbiased samples of pure beam particles and to obtain the DHCAL response not only as an energy measuring calorimeter, but also as a unique source of information of detailed hadronic interactions with unprecedented spatial resolution.
7.5%⊕55%
E=
E
σ
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60 GeV/c pions in DHCAL
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120 GeV/c protons in DHCAL
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Combined System (SiW ECAL+DHCAL) in 3D
http://polywww.in2p3.fr/~jeans/autoDisplays_stereo/show.html 83
References
Q. Zhang et.al., “Environmental dependence of the performance of resistive plate chambers”, JINST 5 P02007, 2010.
B. Bilki et.al., “Hadron showers in a digital hadron calorimeter”, JINST 4 P10008, 2009.
B. Bilki et.al., “Measurement of the rate capability of Resistive Plate Chambers”, JINST 4 P06003, 2009.
B. Bilki et.al., “Measurement of positron showers with a digital hadron calorimeter”, JINST 4 P04006, 2009.
B. Bilki et.al., “Calibration of a digital hadron calorimeter with muons”, JINST 3 P05001, 2008.
G. Drake et al., NIM A578, 88 (2007)
CAN-030, CAN-031, CAN-032.
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