Some material for Warren

Design and Testing of a Quartz Plate Cherenkov Calorimeter Prototype&Search for a Right Handed Majorana Mass Neutrino Using the CMS DetectorWarren ClaridaOutlineW. Clarida2High Energy Experimental Particle PhysicsIntroduction to the Large Hadron Collider (LHC) and Compact Muon Solenoid (CMS) DetectorDesign and Testing of the 1st Phase Quartz Plate Calorimeter (QPC) PrototypeMotivation of designTest Beam ResultsHeavy Majorana Mass Neutrino Search with the CMS Detector at the (LHC)IntroductionSignal StudiesBackgrounds2011 Data ResultsPlans for 2012 Data

High Energy Experimental Particle Physics (HEP)W. Clarida3Evolution of the last 100 years of physics.Begin with discovery of quantum mechanics in early 20th centuryThe natural extension of nuclear physicsStudy of fundamental particles and dynamics.Lead to the formulation of The Standard Model of physics.These studies are primarily done using the data coming from collisions of sub-atomic particles.Fixed target experiments: with particle beams hitting a stationary target.Particle collider: Accelerated particle beams colliding with each other.In both cases detectors a constructed around the collision points to observed post collision results.My work concerns the Compact Muon Solenoid (CMS) detector, a general purpose detector at the Large Hadron Collider (LHC).The Standard ModelW. Clarida4Current understanding of the fundamental nature of the universe.Very successful at explaining the fundamental forces of nature and its constituents.Still open questions, gravity, mass, dark matter.Future HEP studies will attempt to understand these questions.This is the goal of experiments such as the LHC.

W. Clarida5Large Hadron ColliderDiscovery Machine designed as the next step in HEP research.

Search for new physics, including the Higgs Boson, Supersymmetry, and more.

Designed for 7 times more energy than the Tevatron Collider.

Has already produced spectacular results including a new particle in the 2012 data that is probably the Higgs.

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LHC built in the old LEP tunnel.

4 detectors built for the LHCs collisions.CMS and ATLAS built as general purpose detectors.

There goal is the discovery of new physics.W. Clarida7

TrackerW. Clarida8

Innermost CMS subdetector.Purpose is to identify the momentum, and charge of particles.Output is the track of charged particles. These can be used in conjunction with other subdetectors to reconstruct electrons, photons, and muons.Calorimeters

Absorb and stop most of the particles coming from the collisions.Signal proportional to particle energy measured.Quark showers jets, electrons, and photons reconstructed from these energy deposits. W. Clarida9Muon System

Final layer of the detector.Similar to tracker observes the passage of particles. Almost no particles that are not muons make it to the muon system.Muon system tracks combined with tracker tracks to reconstruct muons.W. Clarida10Quartz Plate Calorimeter Prototype IW. Clarida11Why Quartz Cerenkov CalorimeterW. Clarida12Increasing beam energy and luminosities brings increased radiation levels in HEP detectors.Conventional calorimeters relying upon scintillating materials that are not sufficiently rad hard in these new types of environments.Proposed upgrades to the LHC will mean the CMS Hadronic Endcap Calorimeter will face this exact problem.This type of problem was solved for the forward region of the CMS detector by a Cerenkov based Hadronic Forward Calorimter (HF)This experience lead to the design of a sampling Cerenkov Quartz Calorimeter Prototype.

CMS CalorimeterHB Brass Absorber (5cm) + Scintillator Tiles (3.7mm)Photo Detector (HPD) |h| 0.0 ~ 1.4HE Brass Absorber (8cm) + Scintillator Tiles (3.7mm)Photo Detector (HPD) |h| 1.3 ~ 3.0HO Scintillator Tile (10mm) outside of solenoid Photo Detector (HPD) |h| 0.0 ~ 1.3HF Iron Absorber + Quartz Fibers Photo Detector (PMT) |h| 2.9 ~ 5.2CMS Calorimeter (ECAL+HCAL) - Very hermetic (>10 in all , no projective gap)HB+HB-HE+HE-HF+HF-HO0HO+1HO+2HO-1HO-2EB+EB-EE+EE-TrackerSuper conducting coilMuonchambersReturnyokeMotivation Coming From The (S)LHC Time-line~2021/222017 or 182013/142009Start of LHCRun 1: 7 TeV centre of mass energy, luminosity ramping up to few 1033 cm-2 s-1, few fb-1 delivered2030ILC, High energy LHC, ... ? Phase-II: High-luminosity LHC. New focussing magnets and CRAB cavities for very high luminosity with levellingInjector and LHC Phase-I upgrades to go to ultimate luminosity ~5x1034LHC shut-down to prepare machine for design energy and nominal luminosity Run 4: Collect data until > 3000 fb-1Run 3: Ramp up luminosity to 2.2 x nominal, reaching ~100 fb-1 / year accumulate few hundred fb-1 Run 2: Ramp up luminosity to nominal (1034 cm-2 s-1), ~50 to 100 fb-1

From T1.00002: The LHC and Beyond April 2011 APSRadiation IncreaseSLHC -> CMS Calorimeter UpgradeW. Clarida, DPF 200915Quartz plates will not be affected by high radiation. Quartz in the form of fiber was irradiated in Argonne IPNS for 313 hours.The fibers were tested for optical degradation before and after 17.6 Mrad of neutron and 73.5 Mrad of gamma radiation.Quartz plates could be used to replace plastic scintillators.

Current HE not sufficiently radiation hardPlastic scintillator tiles and wavelength shifting fiber is only moderatly radiation resistant up to 25 kGy while at SLHC, expect up to 30kGy in some areas of HE. R&D new scintillators and waveshifters in liquids, paints, and solids, and Cerenkov radiation emitting materials e.g. Quartz

Quartz Plate Prototype IW. ClaridaA single tower calorimeter prototype was simulated and developed for testing.Quartz plates with imbedded fiberswere layered between iron blocks.

162006 Test BeamW. Clarida17The QPC1 was test at both Fermilabs meson test beam facility and CERNs H2 beam line facility.Energy scans and surface scans were done at both locations.Both electromagnetic and hadronic responses were tested. The calorimeter was also simulated using GEANT4.

The uniformity of response by QPC1 for 100 GeV electrons.Hadronic Calorimeter SetupHadronic setup mimicked HE with 5cm steel absorber between each layer.A 20 layer single tower was measured at with 7 differing energy pion beams.The red shows the GEANT4 simulations, while the black is the data.Fitting the data to the standard response function, the stochastic term (A) is 235 4% negligible noise and a constant of 10.9 0.4% (C).

W. Clarida18Hadronic ResolutionHadronic Response Linearity within 0.1%

Electromagnetic SetupWith the absorber depth reduced to 2cm the QPC1 can act as an Ecal.A Cerenkov calorimeter is a radiation hard option for future calorimeters at high energy needing high radiation detectors.4 different energy electron beams where tested again using a 20 layer tower.The electromagnetic resolution gave fit values: A = 312 %, B = 7.50.5%, and C = 6.70.2%.W. Clarida19Electromagnetic ResolutionElectromagnetic Response Linearity within 1%Future of the QPCW. Clarida20This initial design served to show that a sampling Cerenkov calorimeter would work for HEP studies.As Cernkov light yield is much lower than scintillation the efficiency of collection must be higher, or more light must be produced. The fiber layout used in this study increased efficiency, but required the use of WLS fibers that are not radiation hard.Work is being done here at Iowa to develop radiation hard WLS fiber options.Other studies have been done to increase the light production by depositing radiation hard scintillators on the quartz plate.The subsequent versions of the QPC have used these deposited plates, and have shown significant improvements.Majorana Neutrino SearchW. Clarida21Why Search For Heavy Majorana NeutrinosWe know that neutrinos must be massive particles.1.9 103 eV2 < m2atm < 3.0 103 eV27 105 eV2 < m2sol < 9 105 eV2Adding a standard Dirac mass term in the SM requires right handed neutrinos, which havent been observed.The leading theoretical candidate for accommodating neutrino masses is the so-called seesaw mechanismNew right hand neutrinos and a very large mass scale (N) are introduced.This leads to terms that look like my2 v2/mN, where y2 is the yukawa coupling of to the higgs field.The lightest new heavy Majorana mass neutrinos would have an approximate mass mN.This study follows a model independent phenomenological approach allowing the new massive neutrino states mass (mN) and the mixing between the heavy Majorana neutrino and the SM neutrino (VlN) to be free parameters.W. Clarida22SignatureOwing to the heavy neutrinos Majorana nature, it is its own antiparticle, which allows for processes that violate lepton-number conservation by two units.Minimizing the extension to the Standard Model only decays into SM gauge bosons are considered.The primary signature is then 2 same sign leptons, no missing energy (energy unmeasured by the detector), and 2 jets from the W decay.Dimuons signatures where the first signal studied.non-observation of neutrinoless double- decay puts a very low bound on the mixing element for electrons:

Also this takes advantage of the excellent muon detection of CMS.W. Clarida23

23CMS Muon Reconstruction24

Muon are reconstructed combining information from the central tracker and the muon system. Achieving a momentum resolution of ~3% for muon pT < 300 GeV.Charge mis-ID for this range is ~ 10-5The acceptance region is:

24Current Limits & CMS ContributionW. Clarida25

The L3 and DELPHI collaboration have searched for Z->lN decays.They have set limits on S (~|VN|2) up to a mN of 90 GeV2009 MC studies indicated that the the 2011 CMS data should be able to extend these limits to above 200 GeV.There are additional indirect limits from precision electroweak measurement. (90% CL of |VN|2 < 0.0060)

W. Clarida267TeV Signal GenerationThe heavy Majorana neutrino production and decay process is simulated using an event generator implemented in ALPGEN.The output from this first step is is in unweighted Les Houches format.These events are interfaced with CMSSW to include parton showering with pythia. Full detector simulation, digitization and reconstruction are then performed.We produced 50k datasets for the masses: 50, 70, 75, 80, 85, 90, 95, 100, 105, 110, 130, 150, 170, 190, and 210 GeV.A similar process was used to create Monte Carlo simulations of the various backgrounds to the signal.

Generated Data SetsW. Clarida27

Selection CutsMuonsMu pt > 20, 10 (1st muon, 2nd muon)Eta < 2.4Ecal Isolation < 4 GeVHcal Isolation < 6 GeVRelative Isolation < 0.1Normalized Chi2 < 10D0 < 0.1 mm, Dz < 0.1 cm11 hits in tracker, at least one muon system hitGlobal and tracker MuonDimuon mass > 5 GeVNo event with 3rd muon in Z mass windowJets2 Jets with pt > 30 GeV, eta < 2.5MET < 50 GeV

W. Clarida28Quality CutsIsolation CutsPt CutsZ vetoTag and Probe MethodW. Clarida29The muons in simulation and data may be compared using the tag and probe method.Z bosons (or any other strong resonance) are reconstructed using two muons, one called the tag and the other the probe.The tag muon is a high quality muon passing stringent tests.The probe muons passes lest stringent tests.Tag probe pairs within whose invariant mass is within a Z mass window are be kept. The probe muon can then be tested to pass the tighter selection cuts.An efficiency for real muons to pass these cuts can then be established. Eff = TP/(TP + TF)TP is the number of passing pairsTF is the number of failing pairsThese values can be found in the simplest case by simply countingAlternatively a fit of the invariant mass can be made, and in data a background can be then considered.

MC/Data ScalingCriteriapT range (GeV/c)DataMC Data/MCIso10-200.7360.000.7530.000.9780.00> 200.8930.000.9030.000.9900.00ID10-200.9870.000.9890.000.9980.00> 200.9970.000.9900.000.9930.00Total10-200.9750.00> 200.9830.00To correct for difference between the detector simulation and the actual detector performance in muon reconstruction simulated events where scaled.The scaling factors where found for isolation and ID cuts for 2 different transverse momentum ranges.W. Clarida3031Muon Selection Criteria EfficienciesData Set mN# Events (MC)Track QualityPT & EtaIsolationAll Muon504999750.2%25.8%44.5%16.8%704999950.1%8.90%39.5%5.15%804999445.2%13.1%36.1%6.02%854999748.1%14.1%37.5%7.46%904819257.1%20.8%42.8%10.3%954999350.6%33.0%46.8%18.2%1104969465.4%56.1%56.1%36.2%1304819769.5%66.8%63.2%46.7%1504999772.5%71.8%67.1%51.4%1704819675.4%75.7%69.7%54.7%1904999977.3%78.4%71.4%56.7%2104730079.2%81.0%73.3%58.4%W. Clarida32Selection Cut EfficienciesData Set (mN)# EventsMuonJetAll Cuts# of Events for 4.96 fb-1504999716.86.200.432 0.0261834070499995.159.800.323 0.022270980499946.0220.11.07 0.05079885499977.4630.71.20 0.046 483904819210.334.72.60 0.071714954999318.236.9 5.40 0.1010361104969436.242.411.9 0.159261304819746.746.917.0 0.185761504999751.451.320.7 0.193591704819654.755.223.3 0.212331904999956.759.226.3 0.221632104730058.462.228.8 0.24117(% Events Passing Cuts)BackgroundsW. Clarida33Real backgrounds WW, WZ, ZZ, tWThese are backgrounds than can produce 2 same sign muons.Take contribution from Monte Carlo.Fake backgrounds QCD, tt, W+jetsProcesses where one or both muons are faked from jets.Used loose/tight method to get muon fake rate from dataClosure check with ttbar and QCD MC. Assign systematic.Muon Fake Rate DeterminationW. Clarida34To estimate the number of events we should expect from fake muons we determine the fake rate using a loose/tight method.The rate is a ratio of the number of muons passing a set of tight and loose cuts. Essentially events with a fakeable object are weighted by a factor determined by the fake rate (FR) of fFR/(1-FR)Nexp = Nw/ttbar + NQCDNw/ttbar is obtained from the number events with one loose muon not passing the tight cutsNQCD is obtained from the number of events with two loose muons not passing the tight cuts.Nw/ttbar must be corrected for double counting events where there are two fakes but one pass the full selection criteriaThe FR is a function of muon pT and .

Closure TestsW. Clarida35As the fake rate is the dominate background some time was taken to study the fake rate prediction.1) Compare MC prediction to MC truth.2) Observe the fake rate sensitivity prediction to changes in definition.3) Compare high met prediction to data1) Fake rate obtained from QCD sample. Prediction made on QCD, W+jets, ttbar. The values agreed within 35%2) Vary the loose cut value for the muon relIso: 23%. Vary the jet pt cut: 18% Based upon 1 and 2 a 35% systematic is applied.3) Compare the observed events in high MET to the prediction. 48 observed 55 2.03 (stat) 15.80 (syst) predicted. Backgrounds And Observed DataW. Clarida36Source# EventsIrreducible SM Backgrounds: WZ3.20.30.2 ZZ1.00.10.1 Wgamma0.750.270.07 ttW1.060.050.53 W+W+qq0.760.060.38 W-W-qq0.450.060.34 Double-parton WW0.070.020.04Total Irreducible SM Background7.30.40.7Misidentified Lepton Background63.14.222.1Total Background70422Data65After the full selection is applied 65 events are observed.

70 events were predicted. 8% difference is well within the 35% systematic.

Typical Event in Data

W. Clarida37Rho-ZRho-PhiLego3D TowerSystematic ErrorW. Clarida38Integrated luminosity: 2.2%PDF and Q2 Scale: 1% eachMuon Trigger and Selection: 2% per muon each for trigger and selection efficiency.Jet Energy Scale: 3.3-14% depending on mNJet Energy Resolution: 0.1%-1% depending on mNPile Up model: 1% from varying the number of interactions by 0.6.Background Estimate: dominated by fake rate 35%Muon resolution: The error on the muon momentum is between 1.3-6%, this had a negligible affect on the overall signal efficiency.95% Exclusion 2011W. Clarida39As no excess is observed an exclusion on the mixing can be made.

The 95% C.L. upper limit on the cross section is obtained.

From this a limit on the mixing element squared can be obtained using the bare cross section (defined as the cross section where the mixing is 1.0)95% CL upper limits on the cross section time acceptance times efficiency can also be calculated. (A)obs=5.39fb and (A)exp = 5.26fbPlans For 2012 DataW. Clarida40Redo Analysis with 2012 DataHigher luminosity -> higher trigger thresholdsSome evidence in 2011 data that higher pt cuts would reduce our background.More data in 2012 already.The studied mass range will be extended to 700 GeV.Possibly include additional channels (trilepton channels, emu channel, tau channels).Use mass distribution to improve signal sensitivity.May improve upon the precision electroweak limits in the 100-200 GeV range.

Thank you!W. Clarida41BackupW. Clarida42

W. Clarida43Muon Distribution

At low mass the muon pt distribution is split. As the neutrino mass increases the muon pt distributions converges and then begins to increase.The eta and phi distributions are all flat across the mass range.Muon Isolation

The Ecal and Hcal isolation is the sum of deposits within an dR cone of 0.3.

The relative isolation is the sum of the deposits/max(20, mu pt)

All three of the isolations distributions we use dont change as the neutrino mass increases. JetMET

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MET, Jet Multiplicity and Jet Pt all increase with Majorana Mass2nd Jet/Muon Pt Cuts

Our event signature is 2 jets + 2 muons, however at the lower masses the 2nd objects can be difficult to identify.Our efficiency when requiring two jets is very low for the much of the studied mass range.We use asymmetrical cuts for the muon pt so this effect isnt as significant.

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Fake RateW. Clarida47

Closure TestsW. Clarida48

Bare Cross SectionW. Clarida49

Majorana Neutrino Gauge InteractionsW. Clarida50

From F. del Aguila, J. A. Aguilar-Saavedra, R. Pittau hep-ph/0703261

qq'

N

W + +

+

W q'q

(GeV)Nm60 80 100 120 140 160 180 200

2 | N|V

-510

-410

-310

-210

-110

1

10

ExpectedsCL1 Expected sCL2 Expected sCL

ObservedsCLL3 LimitsDELPHI Limits

CMSs = 7 TeV, L = 4.98 fb1

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