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Highlights from the LHCb Experiment

Highlights from the LHCb Experiment. SILAFAE 2012 Kazu Akiba UFRJ-Brazil On Behalf of the LHCb Collaboration. UFRJ. Contents. B physics at the LHC. The LHCb Experiment. LHCb physics results Bs -> μ + μ γ from B->DK B-> hhh D mixing pA Run

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Highlights from the LHCb Experiment

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  1. Highlights from the LHCb Experiment SILAFAE 2012 KazuAkiba UFRJ-Brazil On Behalf of the LHCb Collaboration UFRJ

  2. Contents Kazu Akiba • B physics at the LHC. • The LHCb Experiment. • LHCb physics results • Bs->μ+μ • γfrom B->DK • B->hhh • D mixing • pA Run • TOO MANY!!!(82 papers submitted, over 100 conference notes ) • List: http://cdsweb.cern.ch/collection/LHCb%20Papers?ln=en • The Upgrade • Conclusion • Not Covered: Posters! • BJ/ΨKs decays -- Daniela Szilard Le CocqD'Oliveira • The LHCb’sJet Reconstruction -- Oscar A. A. Francisco • Electroweak studies at LHCb-- Valdir S. Guimaraes

  3. B Physics at the LHC • A hadron collider provides many B particles to study: High b and c production cross section at the TeV scales. • Also provides B and D particles with a high boost. Long lived particles can be distinguished from the prompt ones. • Production at low angles… • But also high background rate • Requirements: • Good vertex, IP resolution. • Good particle identification. • Highly selective trigger μ- PV Beam 1 Bs0 π+ Beam 2 IP Ds- _ bb production along the beam axis. σ(pp→bbX) = 75 ± 14 μb * * Phys. Lett. B 694 (2010) 209 KazuAkiba

  4. The LHCb Experiment Large HadronColliderbeauty Experiment for CP violation and Rare B Decays. KazuAkiba 4

  5. The LHCb Experiment RICH2 TT Si Outer Tracker straw Tubes ECAL HCAL Magnet VELO&PU Si Muon MWPCGEM Inner Tracker Si + Trigger Hard & Soft RICH1 Large HadronColliderbeauty Experiment for CP violation and Rare B Decays. KazuAkiba 5

  6. The LHCb Experiment RICH2 TT Si Outer Tracker straw Tubes ECAL HCAL Magnet Zoom in the vertex region VELO&PU Si Open during injection Closes for physics Muon MWPCGEM Inner Tracker Si + Trigger Hard & Soft RICH1 Large HadronColliderbeauty Experiment for CP violation and Rare B Decays. KazuAkiba 6

  7. The LHCbExperiment γ K, π pp e- μ n Large HadronColliderbeauty Experiment for CP violation and Rare B Decays. Kazu Akiba

  8. LHCb in Numbers Kazu Akiba Great Vertex Resolution! Primary/secondary separation, proper time resolution. Excellent momentum and mass resolution. Outstanding PID (K-π) and μ reconstruction. Dedicated Trigger system for B and C!

  9. Operations High Efficiency! Operating at 4x the design Luminosity / bunch Over 2/fb acquired this year! More than 3/fb integrated All to provide MANY physics results…(Most of results presented here with 2011 Data alone) Kazu Akiba

  10. Bs μ+μ- SM NP Kazu Akiba Very small branching ratio, but very well predicted in the Standard model: (3.54±0.30) x 10-9 But possibly enhanced by new physics:

  11. Bs μ+μ- Analysis Kazu Akiba A multivariate analysis strategy using a BDT method to discriminate signal/background. main background bb->μ+μ-X special care with Bhh’ (h(‘)μ) Peaking backgrounds well modelled.

  12. Bs μ+μ-Evidence Kazu Akiba BR(Bsμ+μ-) = (3.2-1.2+1.5 )x10-9 3.5 s excess Compatible with standard model 2011 + ½ 2012 (2.1/fb) 1/fb left to be analysed. LHCb-PAPER-2012-043

  13. Bs μ+μ- Candidate event @ >0.8 BDT Kazu Akiba

  14. Approaching γ Kazu Akiba The least precisely measured angle in the CKM unitarity triangles: B factories σ ~15-16o (see CKM2012 WG:V ) Direct measurements require the observation of very suppressed channels (Vub) It requires the delicate observation of interference LHCb has the capability ofmeasuring γin a wide varietyof channels with contributionsfrom tree diagrams or penguin.

  15. BDK → f → f • Where f can be: Kπ, KK, ππ, Kπππ, Ksππ, KsKK, Kππ0 … Kazu Akiba BDK family provides a theoretically clean lab to measure γ. Several different observables f provide independent measurements . The increasing statistics of LHCb will populate the suppressed decays required for an over constrained measurement of γ.

  16. B0D0K0* Kazu Akiba First observations of very suppressed channel! 2011 dataset (LHCB-CONF-2012-024) Shows already some CP violation. Asymmetry A (KK) = -0.47 +0.24-0.25 ±0.02 (sys)

  17. B+D0K+ B+DK+ , with Dhh [GLW/ADS*] PLB 712 (2012) 203 B+Dπ+ , with Dhh [GLW/ADS] PLB 712 (2012) 203 B+DK+ , with DKs hh [GGSZ] arXiv1209.5869 B+Dπ+ , with DKs hh [GGSZ] arXiv1209.5869 B+DK+ , with DπKππ [ADS*] LHCb-CONF-2012-30 B+Dπ+ , with DπKππ [ADS*] LHCb-CONF-2012-30 B+DK+ππ , with Dhh [GLW*/ADS] LHCb-CONF-2012-21 B0 (s)DK*0 , with Dhh [GLW/ADS] LHCb-CONF-2012-24 B0 (s) DKK with Dhh [GLW/ADS*] PRL 109 (2012) 131801 * First observations Kazu Akiba Combination of the ADS/GLW and GGSZ (Dalitz) give the LHCb’s constraint on γ= (71 +16-15 )o (CERN-LHCb-CONF-2012-032)

  18. Bhhh Kazu Akiba Disclaimer: Charged B and charged h… Access to t → s,d(Penguin) and the CKM phase γ b → u (Tree) interfering diagrams. CP violation expected from interference between tree and penguin diagrams. CP violation expected also from interferences between resonances in the phase space. A complete analysis of the CP asymmetries in the phase space is needed for a complete understanding.

  19. ACP in Bhhh Kazu Akiba • Measuring a a few combinations of final states:B+Kππ , B+KKK , B+πππ , B+KKπLHCb-CONF-2012-018, LHCb-CONF-2012-028 • Assymetries observed and well controlled using control channels (B J/Ψ K). • ACP(Kππ) = 0.034 ± 0.012 • ACP(KKK) = - 0.046 ± 0.012 • ACP(πππ) = 0.120 ± 0.028 • ACP(πKK) = - 0.153 ± 0.050

  20. BhhhDalitz Kazu Akiba Study of CPV across Dalitz plot (ACPvsm2hh): large CPV in specific resonance areas Typically at low m2 . More experimental work needed as well as on theory side

  21. Not only Beauty: Charm physics Kazu Akiba • More than just beauty in LHCb since the beginning! • Production cross section of charm at the LHC energy is very high. • Indeed it’s kind of a background for the B trigger • Charm trigger is limited by the trigger selection and bandwidth. • Small CP violation in the charm sector: any significant observation could be a sign for “new physics”. • Asymmetries in D0 decays seem to be a good place to look for it

  22. Time integrated ACP For a CP eigenstate final state (K-K+ or π+π-): pp collisions * *To first order A more robust measurement is given by Kazu Akiba

  23. ΔACP measurement 3.5 σ away from zero First evidence of CPV in the charm sector BUT: many other places to confirm it: D+hhh, D0->hhhh, Ds , … Kazu Akiba

  24. Brief reminder of mixing Kazu Akiba Time Evolution of Schödinger’s equation: Mass eigenstates can have different masses and decay widths than flavour states. Pure sample becomes mixed… If CP is conserved, q/p = 1, and q and p are real (no phase)

  25. Charm Mixing Very slow… Kazu Akiba • Mixing in D0 should be very small in SM and therefore could be a probe for NP… • Small contributions from box diagrams • b loop CKM suppressed (|VubV*cb|2≪1) • s, d loops GIM suppressed ( (m2s-m2d)/m2W~0) • Long-distance effects important (and difficult to calculate)

  26. Measuring mixing in charm Kazu Akiba Start with a D*+D0π+ tagged sample Fit first clean RS sample and determine signal shape Then fit WS sample with the signal shape fixed by RS sample Calculate WS/RS ratio R, fit the ratio of yields vs decay time flat?  no mixing not flat? mixing

  27. Tagged samples Kazu Akiba

  28. Results x = Δm/Γ, y=ΔΓ/2Γ ; x’ = x cosδ + y sin δ y'= y cosδ − x sin δ • No-mixing Hypothesis excluded at 9.1σarXiv:1211.1230 Kazu Akiba

  29. Results x = Δm/Γ, y=ΔΓ/2Γ ; x’ = x cosδ + y sin δ y'= y cosδ − x sin δ Kazu Akiba No-mixing Hypothesis excluded at 9.1σarXiv:1211.1230

  30. Mixing in BsJ/ψφ : ϕs 2011 data Kazu Akiba ϕsis the CP violating phase difference between oscillated and non-oscillated B0s decays. In the SM ϕsis equal to 2βs= 2arg(-VtsV*tb/VcsV*cb). ϕsexpected= 0.036 ±0.002 rad “New Physics” contributions to the box diagram could contribute a different value of ϕs… With this channel ΔΓs and Γscan be extractedfrom the Multi dimensional fit A good sample of BsJ/ψφ

  31. Angular analysis 2011 data J/ψ rest frame Φ rest frame Kazu Akiba • BsJ/ψφ is a mixture of CP-even and odd final states (V V) • Need an angular analysis to disentangle, but that also provides all the information we need. • We also need a good proper time resolution • And B tagging…

  32. Results BsJ/ψφ(LHCb-CONF-2012-002) Kazu Akiba

  33. Results BsJ/ψφ New delta gamma from atlas Kazu Akiba

  34. Proton-Ion Kazu Akiba Sept 13th– pA run (also) in LHCb~4 hour data taking at L ~ 5 1025 cm-2s-1 Very good and stable conditions No problem of multiplicities in the detector Use of the System for Measuring Overlap with Gas KS ,Λ, f, Dpeaks reconstructed offline Good expectations for January (pA, Ap) run

  35. Proton-Ion • Sept 13th – pA run (also) in LHCb ~4 hour data taking at L ~ 5 1025 cm-2s-1 • Very good and stable conditions • No problem of multiplicities in the detector • Use of the System for Measuring Overlap with Gas • KS ,Λ, f, D peaks reconstructed offline • Good expectations for January (pA, Ap) run h Kazu Akiba

  36. Proton-Ion Kazu Akiba Sept 13th– pA run (also) in LHCb~4 hour data taking at L ~ 5 1025 cm-2s-1 Very good and stable conditions No problem of multiplicities in the detector Use od the System for Measuring Overlap with Gas KS ,Λ, f, Dpeaks reconstructed offline Good expectations for January (pA, Ap) run

  37. Ks , L PRELIMINARY R =1.745 ± 0.014(stat) R =1.818 ± 0.043(stat) Kazu Akiba l

  38. f, D0 PRELIMINARY R =2.163 ± 0.071(stat) R =1.820± 0.307 (stat) Kazu Akiba l

  39. Upgrade Kazu Akiba

  40. Motivation Plan to go to 20 x 1032 cm-2s-1 ATLAS/CMS LHCb Kazu Akiba • Currently LHCb design can cope with Lumi./bunch L > 4Ldesign • LHC still provides more than what we can handle: • Current detector is limited due to 1 MHz readout. • Higher Luminosities do not translate to higher yields for hadronic modes. • The upgrade is planned as a major Trigger/Readout upgrade: • From 1 to 40 MHz full readout  Every collision read out to a computing farm • Higher instantaneous Luminosity  Higher occupancies • Full tracking in the trigger

  41. In Fact Kazu Akiba 2

  42. Detector Upgrade Silicon Trackers Si Strips (replace all) Outer Trackers Straw tubes (replace R/O) Option: Scint. Fibres Calo PMTs (Reduce PMTs gain+ replace R/O) VELO Si Strips (replace all) Muon MWPC (almost compatible) RICH HPDs (replace HPDs + R/O) Design a common Read Out Board : Tell 40. Kazu Akiba

  43. Schedule Kazu Akiba March 2011, “Letter of Intent for the LHCb Upgrade” submitted to LHCC June 2011, LHCC endorses the LOI, green light for TDR preparation June 2012, Submission of “Framework TDR for the LHCb Upgrade” to LHCC, endorsed in September/2012. 2013, R&D, technological choices, preparation of subsystems TDRs Mid/end 2013, Submission of LHCb subsystems TDRs to LHCC 2014-2015, R&D of the choices and production of new detectors/ test of 40MHz prototypes. 2017-2018 Long Shutd. 2 / LHCb upgrade installation

  44. Conclusions Kazu Akiba • The LHCb has an outstanding performance! • Just a few of the achievements of the experiment. Mostly with 2011 dataset: 1/fb . Now:>3/fb! • First evidence of Bsμμ. • First measurements of the CKM γphase. Observation ofvery suppressed channels • Large CP asymmetry in B3 h; More analysis & theory needed! • First evidence found CPV in D0 decays • LHCbobserved D0 mixing. No mixing excluded with 9.1σ. • ϕs= -0.001 ±0.101(stat)±0.027(sys); no indications of NP. • Nice data taking and analysis capability and in the pA run. • The results from the current experiment motivate for a complete Upgrade of the detector • All the front end to be upgraded. • Vertex/Tracking improvement. • R&D effort coordinated up until 2016, installation in 2017.

  45. The LHCb Detector and Collaboration Thanks! Kazu Akiba

  46. Rare Decays summary Kazu Akiba D0  μ+μ- BR < 1.3 x 10-8new world best limit K0Sμ+μ- BR < 11 x 10-9new world best limit B0(s) μ+μ-μ+μ-BR < 1.3 (5.4)x10-8 first limits B0μ+μ- BR < 9.4x10-10 new world best limit B0s μ+μ- BR = (3.2+1.5-1.2)x10-9 first evidence!

  47. Bdμ+μ- BR(B0→ μ+μ-) < 9.4 x 10-10 @95% CL Kazu Akiba

  48. Bs μ+μ- Kazu Akiba Long awaited measurement: Still 1/fb to be analysed!

  49. Combination of AΓ and ΔACP CL for no CPV : 2x10-5 Mod. Phys. Lett. A, Vol. 27, No. 26 (2012) 1230026 • Plenty of theoretical papers since the evidence for ΔACP≠0 • Values of the order of 10-2 seem possible due to enhanced penguin amplitudes • Still , no clear picture on whether SM (enhanced penguins) or NPmore measurements Kazu Akiba

  50. Physics of the Future Kazu Akiba ;

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