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. Clarida2Introduction 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)IntroductionMonte Carlo StudiesBackgrounds2010 Data ResultsStill To Be Done

W. Clarida3IP1- ATLAS (general purpose)IP5-CMS (general purpose)IP2-ALICE (Heavy Ion, p-ion)IP8-LHCb (pp B-Physics)Design: 2808x2 bunches protons, 1011 protons/bunch, 14 TeV center of mass energy2011: 7 TeV center of mass energy, 930/1400 bunches > 1033cm-2s-1 Expect more than 1 fb-1

Large Hadron ColliderW. Clarida4

Why Quartz Cerenkov CalorimeterW. Clarida5Increasing 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.This problem was solved for the forward region of the CMS detector by a Cerenkov detection based Hadronic Forward Calorimter (HF)This experience lead to the design of a sampling Cerenkov Quartz Calorimeter Prototype.

Motivation 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 Increase

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 coilMuonchambersReturnyokeSLHC -> CMS Calorimeter UpgradeW. Clarida, DPF 20098Quartz 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 radiation hard up to 2.5 MRad while at SLHC, expect 25MRad in 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.

92006 Test BeamW. Clarida10The 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 uniformity of response by QPC1 for 100 GeV electrons.Hadronic Calorimeter SetupHadronic setup mimicked HE with 5cm steel absorber between each layer.20 layers were read out.Proof of concept but light yield not sufficient for HE needs.W. Clarida11

Hadronic ResolutionHadronic Response LinearityElectromagnetic SetupWith the absorber depth reduced to 2cm the QPC1 can act as an Ecal.We wee a Cerenkov calorimeter is a radiation hard option for future calorimeters at high energy high radiation detectors.Light yield probably needs to be increased.Future QPC prototypes with the use of scintillating coatings on plates.W. Clarida12

Electromagnetic ResolutionMajorana Neutrino SearchW. Clarida13Introduction To Majorana NeutrinosWe know that neutrinos must be massive particles.1.9 103 eV2 < m2atm < 3.0 103 eV27 105 eV2 < m2sol < 9 105 eV2The simplest method of adding a Dirac mass term in the SM requires right handed neutrinos, which havent been observed.With the addition of Majorana mass terms1 the left handed nature of the 3 known neutrinos can be preserved. They would have a mass scale given so called seesaw relationship: mMm ~ mD2 where the Majorana mass and neutrino mass must balance each other and the dirac mass is on the order of a standard quark or lepton mass.There would be an addition of new heavy Majorana mass neutrinos with a mass mN ~ mM We are searching for such a massive neutrino at the LHC.There have been two recent papers which discuss the potential of finding a heavy Neutrino between the masses of 100 and 200 GeV at the LHCThe Search for Heavy Majorana Neutrinos1The Little Review on Leptongenesis2W. Clarida141) A. Atre, T. Han, S. Pascoli, B. Shang, 0901.3589 [hep-ph]2) A. Pilaftsis, 0904.1182 [hep-ph]SignatureThe Majorana nature of the heavy neutrino allows for lepton number violating final states.In order to still be within the SM, we only look at decays with SM gauge bosons.Our primary signature is chosen to be two same sign muons with no ETmiss and 2 jets from a W.We will look first for decay into muons 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. Clarida15

15CMS Muon Reconstruction16

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:

16Current Limits & CMS ContributionW. Clarida17

In 2009, the mass range of 100 GeV 200 GeV was studied, there are no current limits set from direct searches.The full mass range was expected to be excluded with 100 pb-1 at 10 TeV. (S=1 & SVN).For our search we use a parameterization of the cross section. The equation relating the S value and the cross section is below[1].The other parameter, 0(N4), is the bare cross section depending only upon the neutrino mass and the collision energy.

1) arXiv:0901.3589v2W. Clarida187TeV Signal GenerationA program based upon matrix element calculation is used to generate weighted Majorana neutrino events with pp collision properties. (written by T. Han U. Wisconsin)The output from the 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 datasets for the masses: 50, 60, 70, 80, 90, 100, 110, and 120 GeV.

Mass304050607080901001101200(N4) (pb)98.4122.1135.0114.869.620.06.03.01.30.8

W. Clarida19Muon 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

W. Clarida21

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.

W. Clarida22

Selection CutsMuonsMu pt > 20, 10 (1st muon, 2nd muon)Eta < 2.4Ecal Isolation < 4 GeVHcal Isolation < 6 GeVRelative Isolation < 0.1Normalized Chi2 < 10D0 < 0.2 mm11 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 > 20 GeV, eta < 3.0

W. Clarida23Quality CutsIsolation CutsPt CutsZ vetoBackgroundsW. Clarida24Real 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.Real BackgroundsFor the 2010 date the contributions from the real backgrounds are insignificant.

We also considered Z/+Jets. The contribution from this background was negligible.W. Clarida25(pb)Yield (34 pb-1)Error (stat)# MC eventsWZ10.50.0420.003254WW280.0010.0012ZZ4.30.0090.001124tW10.560.0150.00320Total0.0670.00426Muon Selection Criteria EfficienciesDataSet (N4 Mass)# Events (MC)Track QualityPTIsolationAll Muon301460060.19%29.90%67.69%25.13%401460061.25%32.71%69.14%28.48%501455062.66%38.71%70.03%33.99%601455061.38%37.95%69.44%33.24%701445060.45%27.71%68.42%23.81%801410059.52%15.83%67.77%13.30%901420058.40%29.80%63.76%24.82%1001020055.79%22.57%58.18%16.75%1101015058.73%51.41%62.91%42.41%120765059.29%56.04%64.07%47.10%WZ incl.21947521.782e-31.97%3.16%4.441e-4ZZ incl.21133683.527e-33.62%4.79%1.835e-3W. Clarida27Selection Cut EfficienciesDataSet (N4 Mass)# EventsMuonJetZ VetoAll CutsError (stat.)301460025.13%11.49%99.99%4.46%1.75e-3401460028.48%11.78%99.97%5.12%1.87e-3501455033.99%12.25%99.99%6.23%2.07e-3601455033.24%14.18%99.99%7.33%2.25e-3701445023.81%17.46%99.65%6.37%2.10e-3801410013.30%21.78%100%4.66%1.82e-3901420024.82%32.32%99.94%13.84%3.12e-31001020016.75%43.96%99.91%12.93%3.56e-31101015042.41%43.63%99.81%32.85%5.69e-3120765047.10%45.41%99.76%37.46%7.00e-3WZ incl.21947524.441e-420.03%96.89%1.599e-47.26e-6ZZ incl.21133681.835e-339.52%92.14%1.808e-45.52e-6Muon Fake Rate DeterminationW. Clarida28To 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. Events with a fakeable object are weighted by a factor determined by the fake rate (f) of f/(1-f)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 criteriaCurrently there is no correction for signal contamination as we see no excess.The f is a function of muon pT and .Muon Fake Rate CutsW. Clarida29We look for events with a well separated opposite side jet. R>1.0 from the muon.Fake rate dependence on jet pT.Prediction from 40 GeV cut compared to actual results for 20,40,60 GeV cuts in QCD MC. There is an over prediction for events with high pT jetsAccounted for in our final systematics.Muons:pT > 10 GeV < 2.4RelIso < 0.1 (0.4 for loose)2/ndof < 10Transvers IP < 0.2 mmJets:pT > 40 GeV < 3.0TriggerHLT_Mu9

T/L RatioW. Clarida30||/PT10-1515-2020-2530-350.0-1.00.19620.00520.13310.00920.13270.01470.11070.01341.0-1.4790.22920.0087 0.1590 0.0146 0.0976 0.0172 0.0903 0.01691.479-2.00.23640.0089 0.1431 0.0138 0.1266 0.0189 0.1223 0.01812.0-2.50.25870.0157 0.1689 0.0250 0.0842 0.0285 0.0783 0.0250Single Fake Prediction:3.089 0.247 events (Ns)Double Fake Prediction:2.082 0.323 events (ND)Total Fake Prediction1.007 0.735 (NF)Wait 3+1 1The single prediction over counts by including double fake events where one muon passed the tight criteria.NF = NS - NDClosure Test & Systematic ErrorW. Clarida31Predict the dimuon rate in ttbar with FR obtained from QCD MCIn the ttbar sample we find 63 fake muons.The FR prediction is 104.79 3.79This gives us a ratio of predicted/observed 1.66The over prediction seems to come from a high jet PT tail present in ttbar, not in QCD.This leads us to assign a 50% systematic error on our fake rate result.

95% Preliminary Exclusion 2010W. Clarida32

This is preliminary. It does not contain all systematic errors. Much of the 2011 sensitive mass region has not been studied. 2010 results above 100 GeV are not competitive with precision electroweak measurements. Already 7 times more data in 2011.

To Be DoneW. Clarida33Redo Analysis with 2011 DataUnderstand pile upUnderstand Trigger efficiencies for signalNot in current MCInclude systematics in exclusion resultJES and muon reconstruction not expected to have significant affect must confirm.Use Alpgen (another generator) to understand systematics from signal MCInclude pile up systematicsSystematic on expected real backgroundsExtend search up to ~200 GeVInvestigate use of MET significance cut.BackupW. Clarida34Fake Rate Calc. DetailsW. Clarida35Define some variables:f: ratio of muons passing tight cuts to those passing loose cuts NL: Events with 2 muons passing loose cutsNmu: Events with 2 real muonsNS: Events with 1 real and 1 fake muonND: Events with 2 fake muonsN2t,1t,0t: Events where 2, 1, or 0 muons pass tight cutsNL can be written in terms of measurable N2t,1t,0t or in terms of truth Nmu,S,DNL = Nmu + NS + ND = N2t + N1t + N0tThe measurable can be written in terms of the truthN0t = (1-f)2NDN1t = (1-f)NS + 2f(1-f)NDN2t = Nmu + fNS + f2NDWork out the algebra and get:N2t = Nmu + f/(1-f)N1t 2f2/(1-f)2N0t + f2/(1-f)2N0t