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Giovanni Carboni Università degli studi di Roma “Tor Vergata” and INFN

Status of LHCb and recent results. Giovanni Carboni Università degli studi di Roma “Tor Vergata” and INFN On behalf of the LHCb Collaboration. Symmetries and Spin Praha 2012. Charles University. Outline of this talk Introduction Detector performances Selected physics results

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Giovanni Carboni Università degli studi di Roma “Tor Vergata” and INFN

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  1. Status of LHCb and recent results Giovanni Carboni Università degli studi di Roma “Tor Vergata” and INFN On behalf of the LHCb Collaboration Symmetries and Spin Praha 2012 Charles University G. Carboni Spin 2012 Praha – Status of LHCb

  2. Outline of this talk • Introduction • Detector performances • Selectedphysicsresults • New states& decays • CP violation in b and c sectors • Rare decays • Electroweak • Summary and outlook Other LHCb Talks P. NaikAmplitudeanalysis for CP violationstudies in LHCb I. MachikhiliyanProduction and polarisationmeasurements in LHCb M. Ferro-LuzziLHCb upgrade A. Shires Rare decays in LHCb G. Carboni Spin 2012 Praha – Status of LHCb

  3. The LHCb experiment New results from LHCb

  4. > 800 members 59 institutes 16 countries G. Carboni Spin 2012 Praha – Status of LHCb

  5. Complementarity • In the search for New Physics Beyond the Standard Model • the LHCb approach is complementary to the direct one of ATLAS and CMS • If NP exists at the TeV scale its effects could be observed in decays • and CP asymmetries at much lower energies • This requires several high-precision tests of the SM and of the CKM • framework we use to describe CP violation • chart the known territory more accurately • explore new regions G. Carboni Spin 2012 Praha – Status of LHCb

  6. ms s New Physics ? ? ? ? ? ? Strengths of indirect approach • Can access higher scales and therefore see effect earlier: • K0 mixing and decay hints to c-quark prediction (GIM, 1973) • Third quark family inferred by Kobayashi and Maskawa (1973) to explain small CP violation measured in kaon mixing (1964), but only directly observed in 1977 (b) and 1995 (t) • Neutral currents (+N +N) discovered in 1973, but real Z discovered in 1983 • B0 mixing (1987) hints to large t-quaks mass • Can access the phases of the new couplings: • NP at TeV scale must have a “flavorstructure” to provide the suppression mechanism for already observed FCNC processes  once NP is discovered, it is important to measure this structure (including new phases) msSM |Vts2|, sSM= –arg(Vts2) = 2s Standard Model – Bsdecay: “Penguin” diagram Bs–Bsoscillations: “Box” diagram G. Carboni Spin 2012 Praha – Status of LHCb

  7. The LHCbExperiment The LHCb Forward spectrometer layout efficiently exploits the large production cross-section for b-anti b pairs in the forward direction (2 < h < 5) at moderate PT within acceptance doi:10.1007/JHEP04(2012)093 • unprecedented number • of reconstructableb-hadrons • created per year • democratic production: • mesons, baryons, charmed • particles G. Carboni Spin 2012 Praha – Status of LHCb

  8. Detector highlights • Excellent Impact Parameter (IP) and Vertex Resolution • Si Vertex Locator (VELO) inside LHC beam pipe (8 mm from beam) • Superior mass resolution • dipolar magnetic field (4 Tm) • high spatial accuracy of tracking • precise spatial alignment • Particle identification • hadrons • muons • electrons • powerful trigger • highly configurable • large rejection power G. Carboni Spin 2012 Praha – Status of LHCb

  9. 4 m 47 m K Bs K K Ds  d≈1 cm The LHCb Detector • Forward Spectrometer • Angular acceptance :15<θ<300 mrad • Nominal luminosity:L = 4 x 1032cm-2s-1 • (design 2 x 1032cm-2s-1) Example Primary vertex G. Carboni Spin 2012 Praha – Status of LHCb

  10. Vertexing in the VELO • Silicon strip detector • 21 stations • Each station measures R and Phi • Left-Right staggered in Z to allow for overlap p ~1m Retractable by ± 2.9 cm during injection • 4x45o sectors • 2048 strips • Pitch: 40 to 100 µm r-sensors -sensors • 10o-20o stereo angle • Inner and outer region • 2048 strips • Pitch: 35 to 100 µm p 42 mm Prompt J/y Bs J/y f 35 78 39 97 um pitch 8 mm [CONF-2012-002] Impact parameter resolution ~ 20 mmProper-time resolution: st = 45 fscfCDF: st = 87 fs[PRL97 242003] [PRL97 242003] G. Carboni Spin 2012 Praha – Status of LHCb

  11. T3 T2 Tracking System T1 IT Silicon + Straw Tubes TT + 3 stations (T1,T2,T3) each with 4 stereo planes (0o,+5o,-5o,0o) OT Outer Tracker Straw Tubes (56 k ch) Pitch 5.25 mm Length 2.4 ~ 4.9 m TT Similar sensors for TT & IT: Si µ-strip with pitch ~200 µm TT: 128 Modules (7 Si sensors) IT: ladders with 1 or 2 sensors Trigger Tracker ~1.41.2 m2 (144k ch) Inner Tracker ~0.5m2 around beam pipe (130k ch) dp/p = 0.4-0.6 % G. Carboni Spin 2012 Praha – Status of LHCb

  12. Excellent resolution + calibration of the mass scale (dp/p)scale = 0.02 % PLB 708 (2012) 241 Λb J/ψΛ Bs J/ψφ t > 0.3 ps σm = 9.0 ± 0.6 MeV/c2 σm = 7.0 ± 0.3 MeV/c2 G. Carboni Spin 2012 Praha – Status of LHCb

  13. Calorimeter and Muon Detectors Bs→ f g • ECAL: ShashlikPb-scintillators(E)/E = 10% /√E 1% • HCAL: Tile Fe-scintillatorallows triggering on hadronicfinal states • Muon system: 5 stations MWPCs+3-GEMFe filters 570 candidates y(2S) and X(3872) → mm pp RICH2 Lead and SPD MUON Preshower HCAL ECAL EPJC (2012) 72:1972 G. Carboni Spin 2012 Praha – Status of LHCb

  14. Unique to LHCb: 2 RICH Detectors – 3 Radiators New this year: gas-tight box for aerogelto avoid contamination by C4F10 gas 2 < p < 100 GeV/c coverage HPD Readout 83 mm 1024 Pixels RICH1 196 HPD RICH2 288 HPD G. Carboni HCP 2010 Toronto – Status of LHCb

  15. The LHCb Trigger 40 MHz Level-0 L0 m L0 had L0 e, g ‘High-pt’ signals in calorimeter & muon systems 1 MHz HLT1 ECAL Alley Had. Alley Muon Alley Associate L0 signals with tracks, especially those in VELO displaced from PV 30 kHz Global reconstruction HLT2 Inclusive selections: topological, m, m+track, mm, D→X, Φ Full detector information available. Global reconstruction similar to offline (nclusive and exclusive). Exclusive selections 4.5 kHz • Triggering is a challenge! • ~1/100 events contain b • interesting b branching fractions ~10-3 or less Farm with 19000 CPU cores HLT efficiency > 80% Overall typical L0xHLT efficiency: 30% (multibody hadron decays) to 90% (dimuons) O(1010) events/y storage G. Carboni Spin 2012 Praha – Status of LHCb

  16. Data taking in 2012 • runningconditions: L = 4 1032cm-2s-1 • L0 trigger 1 MHz saturating the bandwidth • deferredHLT trigger (10% gain) • magnetpolarityregularlyreversed (systematics!) • tiltedbeam-crossingplane (systematics!) G. Carboni Spin 2012 Praha – Status of LHCb

  17. G. Carboni Spin 2012 Praha – Status of LHCb

  18. Periodical magnetic field reversal crucial to keep systematic asymmetries under control PLB 713 (2012) 186 G. Carboni Spin 2012 Praha – Status of LHCb

  19. Flavor tagging Important for oscillations and CP violation measurements • same side, uses p or K emitted together with signal b-hadron • opposite side, detects flavor of partner b-hadron from decay ϵeff =ϵtag(1-2ω)2=ϵtag D2 G. Carboni Spin 2012 Praha – Status of LHCb

  20. Calibration performed using several self-taggingcontrol channels EPJC (2012) 72:2022 Example: Same-Side K vs. Opposite Side tagging in B0s  D-sp+ LHCB-CONF-2011-050 SSK only ϵeff =(1.3±0.4)% OS only ϵeff =(3.2±0.8)% G. Carboni Spin 2012 Praha – Status of LHCb

  21. Excellent data taking performance IntegratedL in 2011 @ 7 TeV, 2012 @ 8 TeV In 2012 larger physics yieldexpected (8 TeV vs. 7 TeV) 2012 1.5 fb-1 goal for 2012 G. Carboni Spin 2012 Praha – Status of LHCb

  22. Automatic luminosity leveling • stable beams VELO close: 4 min • stable beams  L = 4 1032 cm-2 s-1: 7 min Example  week 24 thisyear G. Carboni Spin 2012 Praha – Status of LHCb

  23. Physics results • 58 physics publications to date, more in pipeline > 80 preliminary results submitted as Conference Papers Impossible to list all measurements I will try to give a panoramic view, withemphasis on the capabilities of the experiment For more details on quarkonia, CP violation in Bs and rare decays refer to dedicated talks. G. Carboni Spin 2012 Praha – Status of LHCb

  24. Precision measurements PLB 708 (2012) 241 • PDG Best measurements of B0s and Λ0b masses G. Carboni Spin 2012 Praha – Status of LHCb

  25. Penguins 0.42 fb-1 important to evaluate the penguin contribution to the measurement of sin2b in B0 J/ψ Ks from future CPV measurement in B0s J/ψ Ks  Most precise determination of the B0s J/ψ Ks branching fraction In agreement with SU(3) expectations arXiv:1205:0934 PLB (2012) in press G. Carboni Spin 2012 Praha – Status of LHCb

  26. Some firsts 0.8 fb-1 test of QCD predictions PRL 108, 251802 (2012) G. Carboni Spin 2012 Praha – Status of LHCb

  27. Two new excited b-baryons Ʌb*0 Ʌb0p+ p- predicted by quark model JP = 1/2- , 3/2- Ʌb0 Ʌc- p+ Talk by I. Machikhiliyan arXiv:1205.3452 4.9 σ 10.1 σ G. Carboni Spin 2012 Praha – Status of LHCb

  28. More penguins • Never seenbefore. B+ K++ (4.8 ± 0.4) 10-7PDG • BELLE limit B < 6.9 10-8 (90% CL) with 8 108 B-antiB pairs • SM prediction (1.96 ± 0.21) 10-8(*) • 1.0 fb-1 used • Analysis uses Boosted Decision Tree (BDT) • kinematics, vertex quality, track quality • trained on simulated signal sample and bkgd from data • PID selection applied separately • vetos on B+ J/ψ (ψ(2S)) K+ • (*) H.-Z.Song et al., Comm. Th. Phys. 50 (2008) G. Carboni Spin 2012 Praha – Status of LHCb

  29. Fitting • Use B+→ J/ψ K+ events to define signal shape and, under π+μ+μ- hypothesis, shape of mis-identified events • Components for partial reconstructed B decays and combinatorial bkgd • Validate by separating B+→J/ψK+ and B+→J/ψπ+ decays First transition ever observed LHCb-CONF-2012-006 Preliminary: B (B+ ++-)= (2.4±0.6(stat)±0.2(syst)) 10-8 G. Carboni Spin 2012 Praha – Status of LHCb

  30. still penguins: B0 K0*+– Talk by A. Shires 900 events @1 fb-1: larger than previous world total! Interference of the two diagrams Possible NP contributions LHCb-CONF-2012-008 crossing measured 1st time earlierhints at possible discrepancies not confirmed • PRELIMINARY consistent with SM prediction G. Carboni Spin 2012 Praha – Status of LHCb

  31. WHY THE HELL YOU CALL THEM PENGUIN DIAGRAMS? THEY DON’T LOOK LIKEPENGUINS I’VE NEVERSEEN A FEYNMANDIAGRAMTHATLOOKSLIKEYOU! G. Carboni Spin 2012 Praha – Status of LHCb

  32. Double charm production • Higher order QCD process? • Intrinsic charm? • Double Parton Scattering? Talk by I. Machikhiliyan A. SzczurekarXiv:1206.0274 J/ψ pairs previously seen in NA3 (FT) in 1982 G. Carboni Spin 2012 Praha – Status of LHCb

  33. J/ψ pairs • Standard simple selection of single J/y candidates in the m+m-decay mode. • Background from 2 J/yproduced in different pile-up collisions or in the decay of a B hadron removedrequiring the 2 J/y come from a common vertex. • Theoretical expectations • in LHCbacceptance • LO CSM with Single Parton Scattering (includingfeeddownfromy(2S)): • 4.1 ± 1.2 nb. [A. V. Berezhnoy et al., Phys. Rev. D84 (2011) 094023] • Contribution from Double Parton scattering: • 2 ± 1 nb [A. Novoselov, arXiv:1106.2184] PLB 707 (2012) 52 arXiv:1205.0975

  34. J/ψ + open charm open charm pairs arXiv:1205.0975 D0 D0 D0 D+ J/y D0 J/y D+ D0 Ds+ D0 Lc+ J/y Ds+ J/y Lc+ Combine hadron, with vertex requirement to remove contamination from pile-up and B hadron decays.

  35. CP Violation G. Carboni Spin 2012 Praha – Status of LHCb

  36. First evidence (3.3s) of CP violation in Bs Bs →p+ K- Bs →p- K+ PRL 108, 201601 (2012) byproduct Most precise single measurement G. Carboni Spin 2012 Praha – Status of LHCb

  37. CP violation in Bs mixing More in talk by P. Naik Small SM phase, good place to look for NP effects Phys. Rev. D84 (2011) 033005, G. Carboni Spin 2012 Praha – Status of LHCb

  38. PRL 108, 101803 (2012) Two-fold ambiguity ΔΓs  -ΔΓs resolved by measuring ΔΓs 0.37 fb-1 8500 candidates G. Carboni Spin 2012 Praha – Status of LHCb

  39. Latest combined measurements of LHCb-CONF-2012-002 • ϕs from Bs J/ψφ 21200 evs. • ϕs fromBs  J/ψ f0(980) and J/ψ f0(1370) 7400 evs • ΔΓs= ΓL-ΓH = 0.116 ± 0.018 ± 0.006 ps-1 arXiv:1204.5675 Preliminarycombined result using 1 fb-1 ϕs = -0.002 ± 0.083 ± 0.027 rad still statistics dominated room for improvement CDFfindsconsistentresultwith 11000 decays (CDF Note 10778) Details in Talk by P. Naik G. Carboni Spin 2012 Praha – Status of LHCb

  40. Towards the  measurement CP mode ADS mode [Phys. Rev. D, 63 (2001), p. 036005] 5.8 σ CP asymmetry observed 1 fb-1 B-[-K+]DK- B+[+K-]DK+ PLB 712, (2012), 203 B-[-K+]Dπ- B+[+K-]Dπ+ More in Talk by P. Naik G. Carboni Spin 2012 Praha – Status of LHCb

  41. CP in charm sector • D0 mixing now established at % level • CP Violation expected to be small in SM since relevant • diagrams are dominated by the two first generations • Indirect CP Violation (in mixing) expected to be universal • and of O(10-4) • Direct CPV expected to be • negligible in Cabibbo-allowed decays • up to O(10-3) in Single-Cabibbo-suppressed decays LHCb-PAPER-2012-006 G. Carboni Spin 2012 Praha – Status of LHCb

  42. Huge statistics available use pscharge to tag  D0/D0 Detector and production asymmetries cancel in the difference G. Carboni Spin 2012 Praha – Status of LHCb

  43. zero CPV excluded at 3.5 σ level 0.62 fb-1 PRL 108, 111602 (2012) world averageresult ΔaCPdir = (−0.656 ± 0.154 )% • Lots of recent theory papers on the subject motivated by the DACP measurement. • However new calculations suggest that large hadronic enhancements in the SM could account for the result (e.gJ. Brod et al., arXiv:1111.5000). • Stay tuned for more data… G. Carboni Spin 2012 Praha – Status of LHCb

  44. Bs +– PRL 108, 231801 (2012) • Bsm+m-strongly suppressed in SMPredicted BR = (3.2 ± 0.2)  10-9* very sensitive to new physics • Analysis based on multivariate estimator (BDT, combining vertex and geometrical information) & dimuon mass Mmm •  At the moment not enough candidates to provide significant measurement of BR • World-best limit set:BR < 4.5 × 10-9 (at 95% CL)cf< 7.7 × 10-9(CMS arXiv:1203.3976)< 22 × 10-9(ATLAS CONF-2012-010) • Large enhancement of BR relative to SM expectation is ruled out (arXiv:1005.5310) Talk by A. Shires G. Carboni Spin 2012 Praha – Status of LHCb

  45. Impact of LHCb measurements • LHCb results provide strong constraints on possible models for new physicsComplementary to the direct searches at ATLAS/CMS • Recent examples: limit on Bsm+m-constraining SUSY at high tan band combination of Bsm+m-and fs restricting various models: [N. Mahmoudi, Moriond QCD] [D. Straub, arXiv:1107.0266 Bsm+m-(LHCb1fb-1) Direct exclusion(CMS 4.4 fb-1) (fs) G. Carboni Spin 2012 Praha – Status of LHCb

  46. W & Z G. Carboni Spin 2012 Praha – Status of LHCb

  47. 2.7 TeV/c Z0: probably the fastest ever made (by man) G. Carboni Spin 2012 Praha – Status of LHCb

  48. W and Z physics in the forward region has unique characteristics • one parton at high, one at low Bjorken-x • LHCb uniquely probes PDF down to x ~ 810-6 • Q2 defined by +- mass G. Carboni Spin 2012 Praha – Status of LHCb

  49. arXiv:1204.620 acceptedbyJHEP 37 pb-1 Z  μ+μ- W  μν G. Carboni Spin 2012 Praha – Status of LHCb

  50. Cross-section measurements LHCb-CONF-2012-011 G. Carboni Spin 2012 Praha – Status of LHCb

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