Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 1/42 Vienna Central European Seminar Particle Physics and the LHC Jeroen van Tilburg Physikalisches Institut Heidelberg On behalf of the LHCb collaboration Status and physics at LHCb Outline LHCb experiment and detector performance LHCb experiment and detector performance Selected physics results Selected physics results Outlook and summary Outlook and summary

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 2/42 New physics effects in B and D decays New particles can appear as virtual particles in loop and penguin diagrams. Indirect searches have a high sensitivity to effects from new particles. Can see NP effects before the direct searches. Indirect measurements can access higher scales. Possible to measure the phases of the new couplings New physics at TeV scale must have a flavour structure to provide suppression of FCNC. b s s b b s b s bs → Complementary to direct searches. Strength of indirect approach

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 3/42 CKM picture Incredible success of CKM paradigm in last decades. All measurements coherent with CKM of SM. Accuracy of angles determined by experiment Accuracy of sides determined by theoretical uncertainties But, SM fails to explain matter-antimatter asymmetry in the Universe New physics must hold additional sources of CP violation Effects are small but there is still room for NP effects. Precision measurement of CKM elements. Comparison between tree and penguin decays. Not all CKM angles well constrained (e.g. γ and β s ). → CP violation and rare decays of B hadrons and charm are the main focus of LHCb Large amounts of clean data available Precision tests: allow to look for small effects beyond SM → CP violation and rare decays of B hadrons and charm are the main focus of LHCb Large amounts of clean data available Precision tests: allow to look for small effects beyond SM From CKMFitter Current fit results:

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 4/42 Tracking stations Velo RICH1+2 Muon Calo LHCb detector Good vertex resolution Time-dependent measurements. Suppress background from prompt decays. Good particle identification Important for trigger, flavour tagging Suppress background. Good momentum resolution Mass resolution of heavy flavours. Suppress background. Good vertex resolution Time-dependent measurements. Suppress background from prompt decays. Good particle identification Important for trigger, flavour tagging Suppress background. Good momentum resolution Mass resolution of heavy flavours. Suppress background. LHCb made for Heavy Flavour physics

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 5/42 LHCb detector Angular coverage optimised for B-physics. High B hadron production at LHC  bb = 284 ± 53  b (√s = 7 TeV) [PLB ] Forward spectrometer Most B hadrons produced along beam axis. Acceptance: 2 < η < 5. Complementary to GPD’s. Vertex detector close to beam. Easy access to planar subdetectors. High B hadron production at LHC  bb = 284 ± 53  b (√s = 7 TeV) [PLB ] Forward spectrometer Most B hadrons produced along beam axis. Acceptance: 2 < η < 5. Complementary to GPD’s. Vertex detector close to beam. Easy access to planar subdetectors. L~1 cm

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 6/42 Collaboration 760 members 15 countries 54 institutes

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 7/42 Detector performance: Luminosity Luminosity leveling LHCb already running above design lumi Average L~3×10 32 cm −2 s −1 (nominal 2×10 32 ) Need to cope with higher occupancies More pile-up: average  ~1.5 (nominal 0.5) Continuous, automatic adjustment of offset of colliding beams. Allows optimal conditions throughout a fill. Luminosity leveling LHCb already running above design lumi Average L~3×10 32 cm −2 s −1 (nominal 2×10 32 ) Need to cope with higher occupancies More pile-up: average  ~1.5 (nominal 0.5) Continuous, automatic adjustment of offset of colliding beams. Allows optimal conditions throughout a fill. LHCb recorded 1.1 fb −1 in 2011 Data taking ended on 30 Oct. Only ~340 pb −1 used for most results shown here. Data taken with high efficiency ~90% Offline data quality rejects < 1% Sub-detectors all with > 98% active channels. LHCb recorded 1.1 fb −1 in 2011 Data taking ended on 30 Oct. Only ~340 pb −1 used for most results shown here. Data taken with high efficiency ~90% Offline data quality rejects < 1% Sub-detectors all with > 98% active channels.

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 8/42 Detector performance: vertex resolution VELO sensors only 8 mm from beam. Impact parameter resolution = 12  m for high p T tracks. Good primary and secondary vertex resolution. Suppress background from prompt decays. Good proper-time resolution Important for time-dependent measurements. VELO sensors only 8 mm from beam. Impact parameter resolution = 12  m for high p T tracks. Good primary and secondary vertex resolution. Suppress background from prompt decays. Good proper-time resolution Important for time-dependent measurements. Sensors RF foil Beam axis 8 mm [LHCb-CONF ] B s  J/  Prompt J/  Resolution from prompt J/ψ :  t = 50 fs …in good agreement with simulation Primary vertex resolution Decay time in B s → J/ψ  VELO tomography with hadronic vertices

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 9/42 Detector performance: PID Particle ID with RICH detectors Kaon ID efficiency ≈ 96%, misID π→K ≈ 7% Particle ID with Muon detector Muon ID efficiency 97.3±1.2% (p>4 GeV/c) misID π→μ ≈ 2.4%, p→μ ≈ 0.18% Particle ID with RICH detectors Kaon ID efficiency ≈ 96%, misID π→K ≈ 7% Particle ID with Muon detector Muon ID efficiency 97.3±1.2% (p>4 GeV/c) misID π→μ ≈ 2.4%, p→μ ≈ 0.18% Flavour tagging Tagging of production flavour (B or B) Important for mixing & CP analyses. Performance calibrated using control channels such as B + → J/ψ K + Tagging power: ε(1-2ω) 2 = (3.2 ± 0.8) % (opposite side) (1.3 ± 0.4) % (same side) from B s →D s  mixing analysis preliminary [LHCb-CONF ] Flavour tagging Tagging of production flavour (B or B) Important for mixing & CP analyses. Performance calibrated using control channels such as B + → J/ψ K + Tagging power: ε(1-2ω) 2 = (3.2 ± 0.8) % (opposite side) (1.3 ± 0.4) % (same side) from B s →D s  mixing analysis preliminary [LHCb-CONF ]

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 10/42 Detector performance: mass resolution Integrated Bdl ~ 4 Tm Accurate field map and alignment Momentum resolution 0.4–0.6 % Mass resolution J/  : 13 MeV MC: 10 MeV → Accurate mass measurements. Integrated Bdl ~ 4 Tm Accurate field map and alignment Momentum resolution 0.4–0.6 % Mass resolution J/  : 13 MeV MC: 10 MeV → Accurate mass measurements. Measured B masses [MeV/c 2 ] ± ± ± ± 6 PDG World-best mass measurements! (2010 data only) Dimuon mass spectrum LHCb-CONF Preliminary ± 0.29

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 11/42 Selected physics results

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 12/42 Measurement of Δm s [LHCb-CONF ] ∆m s : B s -B s mixing frequency using B s →D s  Flavour specific final state High branching ratio (~0.3%) Important to resolve the fast B s oscillations. Average decay time resolution ~45 fs Event selection based on kaon ID, track IP and vertex χ 2 ∆m s extracted from unbinned ML fit to B s →D s  candidates Uses mass, decay time and flavour tagging Method includes now same side tagging (cf 2010 fit) ∆m s : B s -B s mixing frequency using B s →D s  Flavour specific final state High branching ratio (~0.3%) Important to resolve the fast B s oscillations. Average decay time resolution ~45 fs Event selection based on kaon ID, track IP and vertex χ 2 ∆m s extracted from unbinned ML fit to B s →D s  candidates Uses mass, decay time and flavour tagging Method includes now same side tagging (cf 2010 fit) Event yield in 340 pb −1

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 13/42 Measurement of Δm s Δm s = ± 0.041(stat) ± (sys) ps −1 B s oscillations Dominant systematics uncertainty: z-scale and momentum scale Dilution of mixing amplitude from tagging and proper time Most precise measurement of Δm s [LHCb-CONF ] Preliminary

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 14/42 Measurement of  s from B s → J/   /f 0  s : interference phase between B s mixing and b→ccs decay. Small penguin pollution. B s counterpart of B d → J/  K 0. Small in SM:  s = −0.036±0.002 Prediction from CKMfitter 2011 New particles in box diagrams can modify measured phase  s =  s SM +  s NP  s : interference phase between B s mixing and b→ccs decay. Small penguin pollution. B s counterpart of B d → J/  K 0. Small in SM:  s = −0.036±0.002 Prediction from CKMfitter 2011 New particles in box diagrams can modify measured phase  s =  s SM +  s NP

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 15/42 Measurement of  s Narrow  resonance (clean)  Vector-vector final state (requires angular analysis) CP odd final state (no angular analysis)  BR about 20% of B s → J/   LHCb-CONF-051 LHCb-CONF-049 → First seen by LHCb last winter Two decay modes B s → J/   B s → J/  f 0 (980)

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 16/42 Measurement of  s B s → J/   has vector-vector final state: Mixture of CP-odd and CP-even decay amplitudes Even and odd amplitudes can be disentangled using decay angles. Angular analysis of B s → J/   Transversity angles Decay amplitudes used in fit: P wave → S wave (non resonant K + K - )

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 17/42 Measurement of  s Angular analysis of B s → J/   PDF of unbinned ML fit described as: Complicated PDF: 3 independent implementations in LHCb

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 18/42 Measurement of  s Angular analysis of B s → J/   Main systematic errors from uncertainties in the description of angular and decay time acceptance and background angular distribution. Time and angular distributions

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 19/42 Measurement of  s CL contours obtained using Γ s from J/ψφ. CP-odd final state, cannot determine Γ s and ΔΓ s simultaneously. When using both Γ s and ΔΓ s from B s →J/ψφ:  s =-0.44±0.44(stat)±0.02(syst) Two solutions: PDF insensitive to B s → J/   B s → J/  f 0 (980) Result of the two fits

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 20/42 Measurement of  s Next steps: Resolve ambiguity by fitting S-wave phase in bins of M(KK) Y. Xie et al., JHEP 0909:074 (2009) Included more data (2.5 times more data recorded) Include same-side tagging (~1.5x more tagging power) → Expect ~2x smaller statistical error. LHCb-CONF Combined fit  s =-0.03 ± 0.16(stat) ± 0.07 (sys) Comparison with Tevatron Preliminary

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 21/42 Direct CP in B d,s →K  Tree-penguin interference in B d,s →K  decays allows to look for direct CP violation. LHCb has a very good particle identification capability. Isolate decays contributing to B->hh’ (K, ,p) Charmless charged two-body B decays Tree Penguin

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 22/42 Direct CP in B d,s →K  B 0 → K    B 0 → K    B d,s →     : Clear asymmetry in raw distributions B s →   K  B s →   K  [LHCb-CONF ]

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 23/42 Direct CP in B d,s →K  Raw asymmetry has to be corrected for detector and production asymmetry. Detector asymmetry → measured using charm control samples: D *+ →D 0 (K  )  +, D *+ →D 0 (KK)  + and D 0 →K . Production asymmetry κ: dilution of A prod due to B mixing, lifetime and acceptance κ(B 0 )~0.3, κ(B s )~-0.03 A prod measured using B 0 →J/  K * (K  ) Interaction asymmetry L/R detector asymmetry Final correction factors: [LHCb-CONF ]

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 24/42 Direct CP in B d,s →K  → Most precise, and first 5  observation of CP violation in hadronic machine. → first 3  evidence of CP violation in B s 0 →πK Eventual goal to measure time-dependent asymmetries in e.g. B (s) →  +  -, K + K - → determine CKM angle γ from loop decays Compare to γ measurements from tree decays, e.g. B +/0 →D 0 K +/* : ADS+GLW and Dalitz method. B s →D s K : Time-dependent, tagged analysis. → determine any contribution from new physics → First observation of B s →  Also measured BRs for CP eigenmodes Preliminary [LHCb-CONF ] A CP for K  modes WA:

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 25/42 Search for B d,s   +  − Very rare decay (FCNC and helicity suppressed) BR(B s   +  − ) SM = (3.2 ± 0.2)x10 −9 BR(B d   +  − ) SM = (1.1 ± 0.1)x10 −10 Sensitive to New Physics: E.g. branching ratio in MSSM enhanced by sixth power of tan  : A.J.Buras, arXiv: [EPJ C64 391] Exclusion regions in MSSM (NUHM) Recent excitement from CDF measurement: BR(B s   +  − ) = (1.8 )x10 −8 (7 fb -1 ) arXiv: − 0.9 The decay B d,s →  +  − provides sensitive probe for New Physics. Blue: Allowed regions for given BR measurement

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 26/42 Search for B d,s   +  − Loose selection to reduce data set Evaluate signal/background in a 2D-space of Invariant mass m  MVA classifier BDT combining kinematic and geometrical variables Data driven calibration through control channels and mass sidebands Normalize to channels with known BR Loose selection to reduce data set Evaluate signal/background in a 2D-space of Invariant mass m  MVA classifier BDT combining kinematic and geometrical variables Data driven calibration through control channels and mass sidebands Normalize to channels with known BR Selection & analysis strategy

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 27/42 Search for B d,s   +  − [LHCb-CONF ] M  for signal region in 4 bins of BDT Mass distribution studied in 4 bins of BDT Expect ~ 1 event in each bin from SM. Main background from bb→  X and misidentified B→h + h − Mass distribution studied in 4 bins of BDT Expect ~ 1 event in each bin from SM. Main background from bb→  X and misidentified B→h + h − Small excess (2 events) in most sensitive bin, compatible with SM. Expected mass resolution obtained from interpolation of dimuon resonances (from J/  to  ’s) → Verified with B → hh events

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 28/42 Search for B d,s   +  −

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 29/42 Search for B d,s   +  − The final branching ratio can be calculated as: Normalization Production ratio f s /f d taken from LHCb’s measurements using semileptonic and hadronic decays. → Smaller error than HFAG average. → Dominant systematic error. LHCb-CONF-034 Three complementary normalization channels with very different systematics: Values for α very compatible

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 30/42 Search for B d,s   +  − No significant excess observed in 0.3 fb -1 Upper limits (preliminary): BR(B s   +  − ) < 1.5 x 10 −8 (95% CL) BR(B d   +  − ) < 5.2 x 10 −9 (95% CL) CMS also set a limit this Summer with 1.1 fb -1 BR(B s   +  − ) < 1.9 x 10 −8 (95% CL) arXiv: LHCb + CMS analyses combined (preliminary) BR(B s   +  − ) < 1.1 x 10 −8 (95% CL) This is ~ 3.4 × SM value Most probable value ~ 4 × Excess over SM not confirmed. LHCb-CONF arXiv: Future prospects [LHCb-CONF ]

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 31/42 B d   +  − K * rare decay in the SM. BR (B d  l + l − K * ) ~ 1.0 x 10 −6 SM diagrams can be easily modified in presence of NP Angular distributions contain a lot of information. Many observables probe helicity structure of NP Zero crossing point of A FB (q 2 ) well predicted in SM Hadronic uncertainties are minimized Measures ratio Wilson coefficients C 9 /C 7. Sensitive to SUSY, graviton exchanges, extra dimensions… Angular distributions in B d   +  − K * Flipping the b→s diagram…

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 32/42 Angular distributions in B d   +  − K * Results from CDF & B-factories show intriguing behaviour at low q 2 : → however, precision is limited. SM C 7 =-C 7 SM [arXiv: ]

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 33/42 Angular distributions in B d   +  − K * J/  veto  (2S) veto B d mass window 302 signal events Event selection [LHCb-CONF ] 309 pb -1 in signal candidates B/S ~ 0.3 Selection using BDT BDT variables chosen to minimize acceptance effects Angular acceptance from MC Trained on B d  J/  K * for signal and mass sidebands for background Selection using BDT BDT variables chosen to minimize acceptance effects Angular acceptance from MC Trained on B d  J/  K * for signal and mass sidebands for background

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 34/42 Angular distributions in B d   +  − K * Angular fit Not enough data yet to perform full angular analysis. → Measure in 6 q 2 bins: A FB Longitudinal polarisation, F L Differential branching fraction d Г /dq 2 → Fit A FB and F L using the 1D projections of θ l and θ K Used B d  J/  K * to validate fitting procedure and angular acceptance

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 35/42 Angular distributions in B d   +  − K * LHCb-CONF In bin LHCb Theory

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 36/42 Angular distributions in B d   +  − K * Next steps Determine zero-crossing point in A FB (q 2 ) Add phi angle and A T (2) Include full 2011 data set. With > 2 fb -1 do full angular analysis Next steps Determine zero-crossing point in A FB (q 2 ) Add phi angle and A T (2) Include full 2011 data set. With > 2 fb -1 do full angular analysis Data consistent with SM predictions at present sensitivity and indicate that A FB is changing sign as predicted by the SM (most recent CDF result also has negative first bin: arXiv: ) Data consistent with SM predictions at present sensitivity and indicate that A FB is changing sign as predicted by the SM (most recent CDF result also has negative first bin: arXiv: ) Already effective in constraining NP arXiv:

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 37/42 Charm physics Dedicated trigger lines for charm decays Yield of O(10 8 ) events per fb −1 Flavour tag from charge of slow pion. Large statistics available > 10 6 D 0  K + K  from D *+  D 0  + Many opportunities for charm physics at LHCb [LHCb-CONF ] D 0  K + K  Mixing established in the charm sector. Next step: look for CP violation Mixing established in the charm sector. Next step: look for CP violation No mixing excluded at 10.2  Presence of mixing allows to search for indirect CPV CP violation expected to be very small in SM Good place to look for new physics effects. HFAG averages x=(0.63±0.19)% y=(0.75±0.12)%

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 38/42 Charm physics A Г in D 0 →K + K - (CPV in mixing) [LHCb-CONF ] Measurement (2010 only; 28 pb -1 ): y CP in D 0 →K + K - (CPV in mixing) LHCb is currently updating with more statistics Combined with measurement of y gives access to CPV. Measurement (2010 only; 28 pb -1 ): [LHCb-CONF ]

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 39/42 Charm physics ΔA CP in D 0 →h + h - (CPV in decay) Production and detector asymmetry cancel. Measurement (2011 only; 580 pb -1 ): [LHCb-CONF ] New result ! Only presented last week at HCP Signifance 3.5  First evidence of CP violation in charm sector! 1.4 M events 0.4 M events Preliminary

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 40/42 LHCb Upgrade Main limitation that prevents exploiting higher luminosity is the Level-0 (hardware) trigger To keep output rate < 1 MHz requires raising thresholds  hadronic yields reach plateau Proposed upgrade is to remove hardware trigger read out detector at 40 MHz (bunch crossing rate) Trigger fully in software in CPU farm. Will allow to increase luminosity by factor ~ 5 to 1–2 × cm -2 s -1 Requires replacing front-end electronics and part of tracking system. Planned for the long shutdown in Running for 10 years will then give ~ 50 fb -1 Letter of Intent recently submitted to the LHCC Physics case endorsed, detector R&D underway (e.g. scintillating-fibre tracking, TOF, …)

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 41/42 LHCb Upgrade LHCb Upgrade LoI: CERN-LHCC Integrated luminosity of order 50 fb -1 allows to measure NP effects below the % level.

Vienna Seminar, Particle physics and the LHC, Status and physics at LHCb, Jeroen van Tilburg 42/42 Conclusion No time to mention: B s    and other radiative B decays. Semileptonic B decays Electroweak physics. Higgs and exotica. LFV tau decays And much, much more… No time to mention: B s    and other radiative B decays. Semileptonic B decays Electroweak physics. Higgs and exotica. LFV tau decays And much, much more… LHCb will have huge contribution to flavour physics in the years to come. LHCb will perform the precision measurements needed to see effects from new physics. The future will bring an even better understanding of our detector and much more statistics! Hope to see first hints from new physics soon. Expect more interesting results this Winter. LHCb will have huge contribution to flavour physics in the years to come. LHCb will perform the precision measurements needed to see effects from new physics. The future will bring an even better understanding of our detector and much more statistics! Hope to see first hints from new physics soon. Expect more interesting results this Winter.