Table 1: Collider experiments at the energy frontier (DORIS, CESR, BES, Belle, Pep II not included

Transcription

1 3 Accelerator Location Process CM Energy Dates Some Expts. Major results SPEAR SLAC e e GeV Mark I, Crystal Ball Charm, τ, jets Petra DESY e e GeV JADE, Tasso, Argus... gluon jets, b mixing PEP SLAC e e + 29 GeV Mark II, TPC, MAC, ASP b-lifetime SppS CERN pp 540 GeV UA1, UA2, UA5 W/Z Tristan KEK e e GeV Amy, Topaz, Venus top has very high mass SLC SLAC e e + 91 GeV 90 s SLC polarized Z prod. (A LR ) LEP CERN e e + 91 GeV Aleph, Opal, L3, Delphi high statistics EW Hera DESY ep 30GeV on 900 GeV 92-now H1, Zeus, Hermes, HeraB Proton structure, diffraction Tevatron I Fermilab pp 900 GeV CDF, D0 top and W mass LEP II CERN e e GeV Aleph, Opal, L3, Delphi WW production, W mass Tevatron II Fermilab pp 980 GeV 01-09? CDF, D0 Higgs? Supersymmetry? LHC CERN pp 14 TeV late 00 s Atlas, CMS, LHCb Higgs? Supersymmetry? ILC?? e e GeV late 10 s?? Higgs? Supersymmetry? Table 1: Collider experiments at the energy frontier (DORIS, CESR, BES, Belle, Pep II not included

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4 a) e - Z 0 /γ f e + f e - e - b) Z 0 /γ e + e +

5 σ had [nb] ALEPH DELPHI L3 OPAL σ 0 20 Γ Z 10 measurements, error bars increased by factor 10 σ from fit QED unfolded M Z E cm [GeV]

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7 σ had [nb] ALEPH DELPHI L3 OPAL data 9.9 peak E cm [GeV] 30 peak data typical syst. exp. luminosity error theoretical errors: QED luminosity E cm [GeV] E cm [GeV] peak+2

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9 Prob. / 210 microns OPAL a) Prob. / 210 microns b) Right radius (cm) Left radius (cm)

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11 IP IP Copper RF Cavities Superconducting RF Cavities IP IP6

12 LEP IP4 IP5 IP6 Versoix River Lausanne IP3 IP7 IP2 SPS IP1 IP8 Railway CERN Meyrin airport Geneva lake 1 Bellegarde Zimeysa 1 km Geneva Cornavin Correlation versus IP

13 Voltage on rails [V] 0 Geneva TGV -7 RAIL Meyrin Zimeysa Voltage on beampipe [V] LEP beam pipe Bending B field [mt ] LEP NMR 16:50 16:55 Time

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15 Proton Anti-Proton

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19 Q 2 (GeV 2 ) DØ Central + Forward Jets CDF/DØ Central Jets ZEUS 95 BPC+BPT+SVTX & H1 95 SVTX + H1 96 ISR ZEUS & H prel E665 CHORUS CCFR JINR-IHEP JLAB E BCDMS NMC SLAC x

20 n a) d u u u d d u p b) d d d u u u d d s s u ) d d d u u u d d s K 0 s u K +

21 Spherical Coordinates p Collider Coordinates φ θ p T φ p θ φ η =ln tan θ/2 η p T η φ p T φ η Unroll in φ Lego Plot

22 p anti-p

23 p T 0 φ π 2π η

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28 6.0.1 Basics of electromagnetic calorimetery High energy photons and electrons interact two ways in high Z materials. Electrons can scatter from atomic electrons and ionize the material - we can detect this ionization but the electron energy does not change much. This is an incoherent process and scales as Z/atom or Z/A/gram of material. Both Electrons and photons can scatter off of the atomic nucleus. This a coherent scatter and scales as Z 2 /atom or Z 2 /A atom. The electron scatter is bremsstrahlung and the photon is pair-production of an e e + pair. The cross section for these interaction is approximately approximately independent of energy once the energy of the particles is m e c 2. The mean free path for both processes is 1 X 0 4αreZ 2 2 N A (21) A What happens when a high energy photon or electron hits some high Z material is illustrated in Figure After the first interaction 1 particle becomes 2, after the next, 2 particles become 4 etc. asymptotically there are slightly more electrons than photons. 27

29 Figure 19: A photon showers in material. One can expect a hard interaction (bremsstrahlung or pair production) every X 0. 28

30 The number of particles/layer grows as 2 i where i is the number of X 0 you have traversed and the energy/particle drops by a factor of 2 each layer. At some point the energy/particle (E 0 /2 i ) becomes close to m e c 2 and the hard scatters stop. The critical energy is called E c and is actually more like 10 MeV. You can use this to solve for the maximum number of radiation lengths N. 2 N = E 0 /E c (22) What we detect is the ionization caused by the particles, which is proportional to the total path length. L = N i=1 (2i f e X 0 )=f e X 0 (2 N 1) f e X 0 E 0 /E c (23) where f e is the electron fraction in the shower 5/8. So the ionization observed is proportional to the incident energy. This is a nice linear detector.

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33 Sampling Calorimeter Uranium Liquid Argon V π+

34 `Typical' Event in the D0 Detector Missing ET 8.4 GeV ^s = 1187 GeV E T,GeV η φ x parton Jet Jet Energy, GeV 1< E <2 2< E <3 3< E <4 4< E <5 5<

35 EM E HAD E

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39 Proton antiproton collision z Produces W + recoil z W decays to e ν z Transverse view Can reconstruct p T of ν but not p

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41 LEP1, SLD Data LEP2, pp Data 68% CL m W [GeV] m H [GeV] Preliminary m t [GeV]

42 b jet q 1 b jet t t W - W + q 2 e or μ,τ ν

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44 τν+ X 21% W+W- decay signatures in top decays µµνν eeνν 1.2% 1.2% e µνν 2.5% 4 jets 44% e ν+2jet 15% µν+2jet 15%

45 0.8 Jet GeV CDF II Preliminary Secondary Vertex HT = 292 GeV 0.6 L xy = 2.1 mm Y (cm) I.P. L xy = 2.7 mm Jet GeV MET 42.2 GeV Electron 52.7 GeV 0 Jet GeV X (cm)

46 Dataflow of CDF "Deadtimeless" Trigger and DAQ Detector 2.5 MHz Crossing rate 396 ns clock cycle L1 Storage Pipeline: 42 Clock Cycles Deep L1 trigger Level1: 7.6 MHz Synchronous pipeline 5544ns latency <50 khz Accept rate L1 Accept 25,000 Hz L2 Buffers: 4 Events L2 trigger Level 2: Asynchronous 2 stage pipeline ~20µs latency 300 Hz Accept Rate L2 Accept 300 Hz L1+L2 rejection: 20,000:1 DAQ Buffers 100 Hz L3 Farm Mass Storage PJW 10/28/96

47 CDF Run 2 preliminary - L=333 pb 12000Selected events Background Z signal: 3394 ± 515 events 10000Fit result -1 Events per 5 GeV Dijet invariant mass (GeV)

48 16 CDF II Preliminary Data Wbb Wcc Wc QCD Mistags Top (6.7pb) L2d (cm)

49 CDF II preliminary Number of tagged events 160 mistags Wbb Wcc non-w Wc WW,WZ,Z ττ Single top Tot bkgd ± 1σ Data (162 pb require H T > 200 for 3 jets -1 ) Number of jets in W+jets

50 Lepton+jets: DØ Template Method Lepton + jets channel with b-tag using 'SVT' secondary vertex tagger similar selection one or more b-tagged jets 4 jets with p T >15 GeV No cut on low bias discriminant D LB - 60 tt candidates selected, S/B ~ 3/1 Systematic Δmtop Uncertainties (GeV/c2) Jet Energy Scale -5.3/+4.7 Gluon Radiation 2.4 Signal Model 2.3 Jet Energy Resolution 0.9 Calibration 0.5 Background Model 0.8 b-tagging 0.7 Trigger Bias 0.5 Limited MC Statistics 0.5 Total 6.0 NEW ~230 pb -1 best preliminary RunII top mass result M top =170.6±4.2 stat ±6.0 sys GeV /c 2 Moriond QCD, March 16, /17 Martijn Mulders, Fermilab

51 Lepton+jets: CDF Template Method Lepton +jets selection: Kinematic Fit; lowest χ 2 One e or μ with p T >20 GeV/c solution 3 jets with E T >15 GeV, 4 th jet E T >8 GeV compatible with missing E T >20 GeV b-tags 0 tag sample: 4 th jet E T > 21 GeV S/B~2/3 1 tag sample: One jet with SVX tag S/B~3/2 2 tag sample: Use more efficient Jet Probability algorithm for 2 nd b-tag S/B~40/1 0 tag 40 evts 1 tag 17 evts 0,1, 2-tag combined 2 tags 11 evts M top = stat ±6.6 sys GeV /c 2 Reconstructed Top Mass (GeV/c 2 ) Moriond QCD, March 16, /17 Martijn Mulders, Fermilab

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61 Fig. 1. A simulated 130-GeV Higgs signal, reconstructed by using an electromagnetic calorimeter with energy resolution of, for channel with integrated luminosity of 100 before (left) and after (right) background subtraction. Fig. 2. A 3-D cut-away view of the CMS PWO ECAL.

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63 Supersymmetry and R-hadrons R-parity conserved, stable hadronizes to R hadrons R-mesons: R-baryons: R-gluinoballs:, ( Gluino R-hadron production at LHC: NB1: heavy hadrons also predicted in theories with leptoquarks, extra dimenstions, GUT... NB2: Stable gluinos at LHC mass ranges not excluded by accelerator experiments or cosmology Aafke Kraan, March 2005, La Thuile p.5/22

64 Interactions of R-hadrons in ATLAS Muon chambers Hadronic calorimeter RPC3 RPC2 RPC1 Tiles Tiles ++ + S n S p S p S n + S p S + p 10 m 7.5 m 7 m 5 m 4 m Tiles S o p S + n π o 3 m Electro magnetic calorimeter Tracking LiAr LiAr LiAr Presampler Magnet TRT S o n R p p o R R p π + + R n S o n o S n R o p 2 m 1 m Nr of interactions: Si strips Pixels 0 m Aafke Kraan, March 2005, La Thuile p.11/22

65 How does electron cooling work? The velocity of the electrons is made equal to the average velocity of the ions. The ions undergo Coulomb scattering in the electron gas and lose energy, which is transferred from the ions to the co-streaming electrons until some thermal equilibrium is attained. Electron Gun Electron Collector Electron beam Storage ring Ion beam 1-5% of the ring circumference Sergei Nagaitsev (Fermilab/AD) 2

66 First e-cooling e demonstration 07/15/05 Dist. function (arb. units) Pbar beam: 63.5e10 Barrier-bucket bunched. Bunch length 1.7-us Tr. emittance (95%,n) kept at 4-pi mm-mrad Electron beam current: 200 ma Traces are 15 min apart Fract. momentum spread Sergei Nagaitsev (Fermilab/AD) 15

67 All data, with old world-average M top All data, with new world-average M top Theory uncertainty Region excluded by direct searches Higgs Boson Mass [GeV/c 2 ]

68 t t t H

69 q q W* W* q' H q' q q Z * Z * q H q

70 10 2 σ(pp _ H+X) [pb] 10 s = 2 TeV M t = 175 GeV σ(pp H+X) [pb] _ qq Hqq gg H CTEQ4M qq _ HW qq _ HZ 10-3 gg,qq _ Htt _ gg,qq _ Hbb _ M H [GeV]

71 Higgs Branching Fractions from HDECAY branching ratio 10-1 bb gluons WW ZZ 10-2 ττ γγ Zγ Higgs boson mass (GeV/c 2 )

72 CDF PRELIMINARY Events per 10 GeV/c Events per 10 GeV/c Observed events Predicted bgr Dijet Mass (GeV/c 2 ) Excess over background Expected MC shape (PYTHIA) Dijet Invariant Mass (GeV/c 2 )

73 Events 10 1 DØ L = 174 pb -1 W + 2 b-tagged jets Data W + jets QCD tt Wbb other WH Dijet Mass (GeV)