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Overview of the LHCb experiment Status and Results Federico Alessio, CERN on behalf of the LHCb Collaboration Epiphany Conference, Krakow 09-01-2012.

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Presentation on theme: "Overview of the LHCb experiment Status and Results Federico Alessio, CERN on behalf of the LHCb Collaboration Epiphany Conference, Krakow 09-01-2012."— Presentation transcript:

1 Overview of the LHCb experiment Status and Results Federico Alessio, CERN on behalf of the LHCb Collaboration Epiphany Conference, Krakow

2 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 2 Outline 1.Introduction to LHCb The detector Physics scope 2.Detector operation Luminosity Leveling Trigger Detector performance 3.Selected physics results Direct CPV and CPV in charm physics CPV in B systems Rare decays Heavy flavour spectroscopy b and c cross sections Lifetime measurements ElectroWeak 4. The LHCb Upgrade

3 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 3 The LHCb experiment at the LHC LHCb is a collaboration of ~700 authors from 15 countries and 54 institutes

4 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 4 The LHCb experiment 4 Dedicated flavour physics experiment  forward precision spectrometer  optimised for beauty and charm decays Tracking Particle Identification Vertexing mrad

5 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN High B hadron production at the LHC  B decays in LHCb acceptance  D decays in LHCb acceptance  2x10 8 inclusive J/ψ triggers on tape Most B hadrons produced along beam axis  acceptance: 2 < η < 5 + planar detectors  vertex detector (VELO) close to beam (~8mm) with excellent resolution An optimised forward spectrometer 5

6 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN A typical LHCb event 6

7 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN LHCb physics scope 7

8 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN All measurements are coherent with CKM of SM BUT SM fails to explain matter-antimatter asymmetries  Present knowledge of CKM mostly thanks to B factories  LHCb will help reducing uncertainty on γ angle  NP is still expected in CP violation LHCb physics scope CP Violation and rare decays of beauty and charm are the main focus of LHCb CKM Fitter picture 8

9 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN Data taking at LHCb 1.1 fb -1 of data recorded out of 1.2 fb -1 of data delivered  efficiency > 90%, with > 98% of detector active channels  99% of recorded data is good for physics analyses  used about 30% or 50% of lumi for most analyses shown here 9 Thanks to LHC and its increasingly good performance!  # of bunches  Beam characteristics  Peak luminosities

10 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN Almost a nominal LHCb year Luminosity design value 2*10 32 cm -2 s -1  3*10 32 cm -2 s *10 32 cm -2 s -1 4*10 32 cm -2 s -1 : 2x designed value! Design values: L 7 TeV Pileup = 1  ( )  = 0.4  ( of visible pp interactions/ crossing) 10 L =  Running at higher  (higher lumi but same beam characteristics) means increasing number of interactions/crossing Not good for B physics ! keep this value low in a controlled way: luminosity leveling

11 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN Luminosity leveling LHCb ATLAS/CMS Luminosity leveling as real breakthrough: luminosity kept constant throughout entire fill  Fantastic operational stability Constant occupancies and trigger rates throughout fill Possibility of choosing the operational point: luminosity value is selected according to running conditions  Automatic procedure between LHCb and LHC Value of requested luminosity obtained by separating vertically the beams at the LHCb IP 11   = : ~3x designed value  Majority of data sample with similar  Similar occupancies, similar time to process events Operational stability: identical dataset for particular period of running Optimization of online trigger cuts!  per bunch distribution  RMS ~ 0.3

12 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 12 The LHCb trigger system Dedicated output trigger lines 3 kHz 630 TB of physics data, peak output of 920 MB/s, 11,157,775,209 physics events gathered

13 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN Detector performance I 13 Primary vertex resolution ~16  m Vertex resolution Accurate field map and alignment Momentum resolution: 0.2% - 0.4% Mass resolution: J/ψ = 13 MeV Y(1S) Y(2S) Y(3S) Momentum resolution

14 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 14 Detector performance II Resolution from prompt J/ψ: σ t = 50 fs [LHCb-CONF ] prompt J/ψ Lifetime resolution Particle ID with RICH: ~ 96% Kaon ID efficiency ~ 7% misID   K Particle IDentification

15 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 15 Offline processing and production Re-processed entire dataset (1.1fb -1 ) by end-November already!  Thanks to availability of computing groups  Thanks of usage of Tier-2 sites for re- processing  Allowed LHCb to write 3 kHz on tape 15

16 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 16 Selected LHCb physics results See A. Ukleja, “Results on charm physics in LHCb” 17:35 on 9 January See A. Martens, “CPV violation in B systems in LHCb” 12:10 on 9 January See F. Soomro, “Search for rare decays in LHCb” 10:15 on 10 January See A.A. Alves Jr, “Heavy flavour spectroscopy in LHCb” 17:00 on 9 January See A. Dziurda, “The measurement of branching ratio of Bs->DsK and Bs->Dspi in the LHCb experiment” 10:50 on 11 January See P. Morawski, “The measurement of fs/fd from hadronic modes in LHCb experiment” 11:10 on 11 January

17 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 17 Direct CP Violation [LHCb-CONF ]

18 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 18 Direct CP Violation See more in A. Martens, “CPV violation in B systems in LHCb” 12:10 on 9 January [LHCb-CONF ]

19 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 19 [LHCb-CONF ] [LHCb-CONF ]

20 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 20

21 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 21 [LHCb-CONF ]

22 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 22 [LHCb-CONF ] Events yield in 340 pb -1 Most precise measurement

23 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 23 CPV in charm [LHCb-CONF ]  signficance of 3.5σ  First evidence of CP violation in charm sector! [LHCb-CONF ] See more in A. Ukleja, “Results on charm physics in LHCb” 17:35 on 9 January

24 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 24 SM expectations [A.J.Buras, arXiv: ] See more in F. Soomro, “Search for rare decays in LHCb” 10:15 on 10 January

25 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 25 Small excess in most sensitive bin, compatible with SM (event shown earlier) [LHCb-CONF ]

26 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 26 [arXiv: ] End of 2012…?Now…

27 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 27 Exotics, X(3872) and (non observation) of X(4140) [LHCb-CONF ] ψ(2S) See more in A.A. Alves Jr, “Heavy flavour spectroscopy in LHCb” 17:00 on 9 January X(3872)

28 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 28 Beauty and Charm cross-sections [Eur. Phys. J. C71 (2011) 1645] [PLB 694 (2010) ] [LHCb-CONF ] Analyses performed already in 2010 [Eur. Phys. J. C71 (2011) 1645] Differential LHCb J/ψ from b wrt to theorethical predictions

29 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 29 Lifetime measurements [arXiv: v2] [CDF note ] [Eur. Phys. J. C71:1532,2011] Analyses performed already in 2010 with 37 pb -1

30 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 30 EW measurements [LHCb-CONF ] [LHCb-CONF ]

31 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN LHCb is foreseeing to upgrade its detector in first LHC long shutdown (~2018?) To run at 10x design luminosity: L = To collect 10x more integrated luminosity: ~50fb -1 To improve trigger efficiencies  Removing hardware trigger and having all events available in the software trigger 31 LHCb Upgrade See C. Parkes, “Upgrade of the LHCb experiment” 15:20 on 10 January

32 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 32 LHCb Upgrade This can be achieved with a trigger-less readout architecture:  record all LHC events! require modification of readout system many Front-End electronics + detectors will be replaced readout electronics will be replace  To write to tape ~20kHz of triggered events!  Letter of Intent already submitted and approved by LHCC [LHCC-I-018]  Work is already progressing intensively with the aim of complete the upgrade in 2018! 3 kHz ~20 kHz

33 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 33 Conclusions Thanks to: -the outstanding performance of the LHC accelerator  Provided the LHC experiments with L > expectations -the outstanding work of the LHCb operation team  Reached the milestone of 1 fb -1 data recorded  Online efficiency above 90% and offline efficiency > 99% -the outstanding work of the LHCb analysis working groups  > 60 analysis have been published as conference proceedings  > 20 papers have been submitted to international journals LHCb set itself as the world leading experiment in flavor physics providing world class measurement for CP violation, charm physics, B hadrons physics, loop and penguin processes, exotics….  The dataset will be doubled, reaching a total of ~2.5 fb -1 by end of 2012  Many results will be finalized and an upgrade is envisaged for 2018 Stay tuned for the winter conference with the full 1.1 fb -1 dataset!

34 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 34 Backup

35 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 35 Another rare decay from related b  s diagram  Analysis of angular distribution allow extracting information about NP LHCb has largest sample in world, as clean as the B factories  A FB consistent with SM: data consistent with SM predictions  A FB changing sign as predicted by SM 303 signal events [LHCb-CONF ] [arXiv: ]

36 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 36 Study of quarkonia production provides important tests for Non-Relativistic QCD [LHCb-CONF ] [CMS-BPH ]

37 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 37 Heavy b barions [LHCb-CONF ]

38 Epiphany Conference, Krakow. 09/01/12 F. Alessio, CERN 38 Heavy b barions [LHCb-CONF ] 72.2 ± 9.4 events


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