1 / 28

Intae Yu

Recent Physics Results at Hadron Colliders. Intae Yu. Sungkyunkwan University 핵입자물리워크샵 @ KSC2011 , Dec 2 nd , 2011. Reference: EPS2011 talks & Lepton Photon 2011 talks. Accelerator Operation. LHC delivered 5.74 fb -1 (2011) Inst. Lum = 3.55 ×10 33 cm -2 s -1 (2011.10)

libby-chambers
Download Presentation

Intae Yu

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Recent Physics Results at Hadron Colliders Intae Yu Sungkyunkwan University 핵입자물리워크샵 @ KSC2011 , Dec 2nd, 2011 Reference: EPS2011 talks & Lepton Photon 2011 talks

  2. Accelerator Operation • LHC delivered 5.74 fb-1 (2011) • Inst. Lum = 3.55 ×1033 cm-2 s-1 (2011.10) • Tevatron has delivered 12 fb-1 during Run II ( ended on Sep 30, 2011) • Inst. Lum = 4 ×1032 cm-2 s-1 (2011.7)

  3. New Central calorimeters Solenoid Central muon Old Front end Trigger DAQ Offline Partially new TOF Endplug calorimeter Silicon and drift chamber trackers Forward muon Particle Detectors at Tevatron CDF Detector D0 Detector • CDF with better tracking and particle Identification (PID) • D0 with better calorimetry and lepton coverage

  4. Particle Detectors at LHC CMS Detector ATLAS Detector • CMS with better tracking and electromagnetic calorimetry • ATLAS with better hadron calorimetry

  5. LHCb Detector at LHC LHCb Detector • LHCb optimized for flavor physics • Dedicated heavy flavor trigger, precise vertexing, excellent PID (RICH) • LHCb operating luminosity (3×1032cm-2s-1) << LHC design luminosity • Reduce multiple interactions → less combinatorial background

  6. Standard Model Higgs Search

  7. Higgs Production • gg→H is the dominant process at TeV scale proton collisions • The cross section at LHC is about ~10 times higher than at Tevatron 2TeV

  8. Higgs Decays • High Mass Higgs (MH>140 GeV/c2) • H → WW, ZZ • Low Mass Higgs (MH<140 GeV/c2) • H → bb, cc, ττ, γγ

  9. Higgs Search Strategy • High Mass Higgs (MH > 140 GeV/c2) • H → WW → lνlν: Relatively Low Background, No Mass Resonance • H → ZZ → l+l-l+l- : Low Background, Mass Resonances • Low Mass Higgs (MH < 140 GeV/c2) • gg → H → bb: Enormous QCD Background • (1) 2 TeV pp Collisions (V = W,Z) • qq → VH → Vbb : Lower Cross Section. Manageable Background • (2) 7 TeV pp Collisions • H → γγ : Small Branching Ratio, Controllable Background

  10. Status of Higgs Search at Tevatron Ben Kilminister ICHEP2010 • 100 < MH < 109 GeV/c2 &156 < MH < 177 GeV/c2 excluded at 95% CL

  11. Status of Higgs Search at LHC

  12. Status of Higgs Search at LHC • 141 GeV/c2 < MH < 446 GeV/c2 excluded at 95% CL

  13. Heavy Flavor Physics

  14. Bottom Baryons at Tevatron • Reconstruct Ξb-(0) through cascade decays • with , , and • Mass measurement of Ξb-(0) • M(Ξb0 ) = 5787.8±5.0(stat)±1.3(syst) MeV/c2 • M(Ξb0 ) - M(Ξb- ) = 3.1±5.6(stat)±1.3(syst) MeV/c2

  15. Bottom Baryons at LHCb • First observation of Λb →D0 p K- ( another mode for γ measurement) • Evidence of Ξb0 → D0 p K- ( consistent with CDF mass, ~2.6σexcess)

  16. Two-body Chamless B Decays at CDF • Two-body charmless B decays Sensitive to CKM angle γ significant contribution from penguin decays provides sensitivity to new physics (NP) • First evidence for Bs →π+π- • Br = (0.57±0.15(stat)±0.10(sys))×10-6 • Agree with pQCD estimates • First bounds for B →K+ K- • Br ∈ [0.05, 0.46] ×10-6 @ 90% CL

  17. Two-body Chamless B Decays at LHCb • Excellent PID using RICH at LHCb • Acp(B0 → Kπ) = -0.088±0.011±0.008 Consistent with world average -0.098±0.011 • Acp(Bs0 → Kπ) = 0.27±0.08±0.02 (0.39±0.17 @ CDF)

  18. B0 →K*μ+μ- Decays • Probe helicity structure in B0 →K*μ+μ- and search for NP especially forward-backward asymmetry (AFB) as a function of lepton invariant mass (q2) ~300 K*ll events • AFB consistent with SM @ LHCb can determine cross point sensitive to NP

  19. Bs Mixing Phase • CPV phase φs in Bs → J/ψφ probes NP Earlier CDF results show some deviation (~ 2σ) from SM 0.8σfrom SM 1σfrom SM • Analysis is under progress using ~ 350 pb-1 @ LHCb Sensitivity to be improved by including CP-eigenstate Bs → J/ψf0(980)

  20. Dimuon Charge Asymmetry at D0 • D0 reported the anomalous like-sign charge asymmetry using 6.1fb-1 • , • Absl= (-0.957±0.251(stat)±0.146(syst)) × 10-2 3.2σfrom SM 3.9σfrom SM • Updated results from D0 (impact parameter dependent analysis) • Absl= (-0.787±0.172(stat)±0.093(syst)) × 10-2

  21. Search for New Physics in Bs System • Absland CPV phase φs in Bs → J/ψφ have interesting connections. • , , • Absland φs measurements are consistent

  22. Bs/Bd → μ+μ- at CDF • SM rate is small and well understood. NP can enhance the rate. • Updated CDF analysis : improved Neural Network (NN) and more data • Br(Bd → μ+μ-) < 6×10-9 @ 95% CL (SM prediction 1.1×10-10 ) • Br(Bs → μ+μ-) ∈ [0.46,3.9]×10-8 @ 90% CL (SM prediction 3.2×10-9 ) • Assuming signals, Br(Bs → μ+μ-) = 1.8+1.1-0.9×10-8 (~ 2.8σ)

  23. Bs/Bd → μ+μ- at CMS • Cut-based Analysis • 1.14 fb-1 • No excess observed • Br(Bd → μ+μ-) < 4.6×10-9 @ 95% CL • Br(Bs → μ+μ-) < 1.9 ×10-8 @ 95% CL ( CDF 1.8×10-8 )

  24. Bs/Bd → μ+μ- at LHCb • Boost Decision Tree (BDT) out of 9 kinematical and topological variables • Train BDT on MC, Calibrate on data (sidebands, B→hh) • Br(Bd → μ+μ-) < 5.2×10-9 @ 95% CL • Br(Bs → μ+μ-) < 1.5 ×10-8 @ 95% CL (CMS/LHCb Combined: 1.1×10-8 , CDF: 1.8×10-8 )

  25. Top-AntiTop Charge Asymmetry • NLO QCD predicts an asymmetry for produced via annihilation Top quark is emitted along the direction of incoming quark Exchange of new particles can modify the asymmetry forward-backward asymmetry center - forward asymmetry

  26. Top-AntiTop Charge Asymmetry at Tevatron • CDF measured the and Δy dependence of the asymmetry Larger asymmetry observed in high mass and large rapidity difference • No clear mass dependence in D0 data

  27. Top-AntiTop Charge Asymmetry at LHC • LHC results are consistent with SM prediction • Different variables : ATLAS (Δy), CMS (Δη)

  28. Summary • Standard model Higgs boson is excluded at 95% CL in the mass range 141-476 GeV/c2 by the combined search of CMS and ATLAS at LHC. • LHC experiments, especially, begin to produce physics results comparable to or better than Tevatron results on heavy flavor frontier • During the Tevatron run II (2002~2011), CDF and D0 contributes significantly to understanding of standard model. • LHC accelerator has delivered 5.7/5.7/1.2 fb-1 to CMS/ATLAS/ LHCb experiments respectively. • Some anomalies in dilepton charge asymmetry and top pair charge asymmetry are observed although their significances are not large yet • More interesting results will be expected from LHC by 2012 when the size of data is increased by several times.

More Related