Studies of hadronic B decays with early LHCb data

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Hadronic B decays @ LHCb - Kruger2010 2010-12-05 1 Studies of hadronic B decays with early LHCb data Aurélien MARTENS (LAL – Univ. Paris Sud 11 – Orsay) On behalf of the LHCb Collaboration
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Studies of hadronic B decays with early LHCb data. Aurélien MARTENS (LAL – Univ. Paris Sud 11 – Orsay) On behalf of the LHCb Collaboration. γ and the c urrent status of the CKM matrix. Full fit : CKMfitter : γ = (67.2 ± 3.9)° UTfit : γ = (65.6 ± 3.3)°. Loops. - PowerPoint PPT Presentation

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  • Studies of hadronic B decays with early LHCb dataAurlien MARTENS (LAL Univ. Paris Sud 11 Orsay)On behalf of the LHCb Collaboration

    Hadronic B decays @ LHCb - Kruger2010

  • and the current status of the CKM matrix

    CKMfitter Group (J. Charles et al.), EPJC41, 1-131(2005),Bona et al. (UTfit Collaboration), JHEP 0507 028(2005)LoopsTreesLoop constraints are more precise than tree ones.

    Good agreement with some small tensionDirect measurements :

    CKMfitter : = (71 23)

    UTfit : = (78 12)Full fit :

    CKMfitter : = (67.2 3.9)

    UTfit : = (65.6 3.3)Interest in more precise direct measurements

    Hadronic B decays @ LHCb - Kruger2010

  • Introduction : extraction at LHCbCurrent direct determination of is mainly dominated by Dalitz measurements in BDK, DKshh

    There are two direct ways to access the CKM angle In tree diagrams : B DX decaysTime integratedTime dependentIn loop diagrams : B hh or hhh charmless decaysAssumes U-spin to extract All of these accessible with unprecedented precision at LHCb

    Precise measurements of direct, mixing induced and interferences induced CPVMeasurements within Standard Model channels and new physics polluted onesuncover new physics contributions in loops by comparing it with treesBy comparing with global fitRoadmap for selected key measurements of LHCb, ariv:0912.4179v2

    Hadronic B decays @ LHCb - Kruger2010

  • Time integrated from treesAn ideal Standard Model candleTree diagrams no contribution from new physics in B decaysNeglect D mixing : dominant bias but still negligible (~1)Neglect CPV in D decays : negligible contributionAbsolute relative theoretical uncertainty (EW corrections) : / ~ 10-6

    ADS [PRL 78 3257(1997); PRD 63 036005(2001)], GLW [PLB 253 483(1991); PLB 265 172(1991)], GGSZ [PRD 68 054018(2003)]bu and bc transitions interfereD0s reco. in the same final state :CP eigenstate KK, [GLW]2 bodies & al. K, K0, K3 [ADS]Dalitz Kshh [GGSZ]ADS : CLEOc constraints on D decayExtentions : D0K Dalitz analysis with higher statisticsBsD integrated-untagged measurment

    BRrBB+D0K+(3.7 0.3) 10-40.1B0D0K*0(4.2 0.6) 10-5~0.3

    Hadronic B decays @ LHCb - Kruger2010

  • Time dependent from treesAn additional information from time dependent measurementsMeasure +M need an external model independent measurement of the mixing phaseBenefits from non vanishing lifetime differences [ for Bs, for Bd]Aleksan & al. [ZPC 54 653(1992)], Dunietz & al. [PRD 37 3186(1988) ; 39 3515E(1989)], Dunietz [PLB 427 179(1998)]MIXINGe-iSimultaneous U-spin based extraction :resolve 8-fold ambiguities (degenerated at low statistics) in BdD+-

    BRx [R]angleBsDs+K-(3.0 0.7) 10-40.4+sBdD+-(2.7 0.1) 10-30.02+2

    Hadronic B decays @ LHCb - Kruger2010

  • from loopsInclusive Bhh or hhh analysesbu involved in many (2,3)-bodies charmless B decaysLess particles in the final state more efficient trigger and reconstruction Examples of contributing and interfering diagrams(more in backup)BR 10-610-5Upper limits 10-6Fleischer [PLB 459(1999) 306 arXiv:9903456, EPJ C52(2007) 267 arXiv:0705.1121]

    Hadronic B decays @ LHCb - Kruger2010

  • LHCb in a nutshellThe Challenge: precise rare decays and time-dependent CP asymmetries in a high background environment.

    Needs excellent vertexing, p reconstruction, particle-IDVErtexLOcator,PileUpTrigger TrackerTracking StationsRICHES:PID: K, separationMuon SystemCalorimetersThe LHCb Detector at the LHC [JINST 3 S08005]See Plenary by O. Steimkampf

    Hadronic B decays @ LHCb - Kruger2010

  • TriggerHLT2 :Inclusive Topological Trigger : Build a B using 2,3,4 tracks Compensate for missing pTHLT1 :- Build a good track from any L0 Recover some efficiency for hadronic triggersThe bottleneck : Bandwidth and rate limitations Already high (3.6 GeV) ET hadronic triggers

    Hadronic B decays @ LHCb - Kruger2010

  • Analysis requirements : PID

    Hadronic B decays intensive use of PID in any analysisPerformance is close to MC expectationsLifetime and Tagging performance studies also under progressSee talk by A. Contu

    Hadronic B decays @ LHCb - Kruger2010

  • Observations : time integrated treesClean hadronic B signals observed reasonably in agreement with expectationsFirst observation of pure colour suppressed hadronic B decays in a hadron collider (?)Wait for full 2010 run reprocessing to observe BDK with DKKExpect 15 to 50 BsD0K*0 in the full 2010 reprocessingBD(K)74 11BD(K)K444 30~35pb-1

    Hadronic B decays @ LHCb - Kruger2010

  • Prospects : time integrated treesAriv:1007.0504, PRD 81, 031105(R)(2010)+ preliminary results @ CKM 2010Current status on the measurement of asymmetriesLHCb 1fb-1 @ s=7TeV :Competitive measurements with current dominating measurementspossible first results from LHCb @ Winter 2011 conferences : ACP+ and RCP+ competing with CDF ratios of BR(BDK)/BR(BD) First observation of BsD0K*0 and BR(BsD0K*0)/BR(BdD00)~15 LHCb combined sensitivity on time integrated in 2011ADS

    DKACP+BaBar0.25 0.06 0.02 CDF0.39 0.17 0.04DKAADSBelle0.39 0.26 +0.06 0.04CDF0.63 0.40 0.23

    Hadronic B decays @ LHCb - Kruger2010

  • Observations : time dependent trees

    B+D0 & B0D+ BsDs also seenSix body final states observed !BsDs()

    Hadronic B decays @ LHCb - Kruger2010

  • Prospects : time dependent trees

    B factories legacypossible first results from LHCb @ Winter 2011 conferences : Measurements of ratio of BR(B0DK)/BR(B0D) Upper limits on BsD(K,) First observations of D(s)(K) and best measurements of D(s) () fd/fs from N(B0DK)/N(BsDs)~15 statistical sensitivity on time dependent in 2011Fleischer, Serra, Tuning [Ariv:1004.3982v3]http://www.slac.stanford.edu/xorg/hfag/

    Hadronic B decays @ LHCb - Kruger2010

  • Observations : loops

    MC expectationsRaw asymmetries already visible by eye ! work ongoing on proper estimatesBdBs

    Hadronic B decays @ LHCb - Kruger2010

  • Prospects : loops

    possible first results from LHCb @ Moriond 2011 : Measurement of BR(BsK)/BR(BdK) ACP measurements competitive with CDF results~15 sensitivity on loops for LHCb by fall 2011CDF, [N PB (Proc. Suppl.) 170 (2007) 3945]http://www.slac.stanford.edu/xorg/hfag/

    B0KPDG10Aver.0.098 0.013CDF0.086 0.023 0.009BsKCDF0.39 0.15 0.08

    Hadronic B decays @ LHCb - Kruger2010

  • SummaryLHCb is performing well and is already able to observe hadronic B decays10-5 and 10-6 hadronic decays are observed or about to be soDiscoveries of new expected Bs decay modes hopefully for Winter conf.Raw asymmetries observed in some channelsHopefully calibrated by Winter conf. to produce first CPV results

    Wait for even more exciting data taking periods in 2011 sensitivity is going to be of the order of 15 in loops AND trees sensitivity of 15 both in time independent AND time dependent treesCompetitive with existing measurementsLHCb will be competitive with CDF resultsLHCb will improve our knowledge on by the end of 2011

    Hadronic B decays @ LHCb - Kruger2010

  • Thank youHave fun : find the 4 PVs !

    Hadronic B decays @ LHCb - Kruger2010

  • Additional requirements : Lifetime & taggingLifetime and Tagging are key ingredients for time dependent and Bhh Lifetime resolution of 77fs (worse than expected)Recent improvements obtainedTagging performance studies under progress

    Hadronic B decays @ LHCb - Kruger2010

  • Charmless diagrams

    Hadronic B decays @ LHCb - Kruger2010

  • Hadronic B decays @ LHCb - Kruger2010