LHCb Status and Physics

Transcription

1 LHCb Status and Physics Tatsuya Nakada CERN and EPFL SUSY in 2010 s , Sapporo 1

2 1) Introduction Contents 2) LHC(b) Experiments 3) Physics with 2008 data 4) Flavour Physics >2008 also ATLAS/CMS 5) Conclusions SUSY in 2010 s , Sapporo 2

3 1) Introduction With the recent big success by BABAR and BELLE, goal of heavy flavour physics is now shifting from understanding of CKM paradigm (SM) to search for physics Beyond the Standard Model (BSM) appearing in loops. Following the past successes: e.g. charm from m(k 0 ), Br(K L μμ), etc. top from CPV, m(b 0 ), etc. before the c and t discoveries, look for signs of BSM in rare processes with b-hadrons. SUSY in 2010 s , Sapporo 3

4 Flavour and New Physics energy scale L = L SM + O n d d > 4 c n d 4 effective new physics d > 4 operators new physics not far from the EW scale, i.e. = 1~10 TeV, to avoid fine tuning c n ~1 without introducing some symmetry SUSY in 2010 s , Sapporo 4

5 from the measured B d -B d oscillation frequency (V m d ~ c tb V td ) 2 y(m t2 ) SM + c N 16 2 m 2 W if c SM ~ c N ~ 1, > 10 3 TeV 1 from the various flavour changing processes F = 2 processes m d, m d, K, etc: > 10 2 ~10 4 TeV F = 1 processes Br(B d X s ), Br(B d X s l + l ), etc; > 20~50 TeV SUSY in 2010 s , Sapporo 5

6 either New Physics energy scale is >> EW energy scale or neither LHC nor LC will find New Physics New Physics has a special flavour properties e.g. flavour symmetry is broken at much higher energy scale than = 1~10 TeV Minimal Flavour Violation with multi Higgs model MSSM model, etc. SUSY in 2010 s , Sapporo 6

7 In case of MFV, little extra phase introduced, e.g. A b s V tb V ts, A b s V tb V ts A Bd Bd (V tb V td ) 2, A Bs Bs (V tb V ts ) 2 etc. i.e. sin 2 J/ KS = sin 2 SM, sin 2 J/ KS = sin 2 J/ m d m d SM, m s m s SM but m d / m s = m d SM / m s SM b l strong enhancement in B s μ + μ for large tan d, s H 0 A 0 l new Lorentz structure in b s current SUSY in 2010 s , Sapporo 7

8 ALICE ATLAS CMS LHCb LHCf MOEDAL TOTEM 2) LHC(b) Experiments Experiments being prepared now at LHC heavy ion and soft-pp experiment general purpose pp and heavy ion experiment general purpose pp and heavy ion experiment dedicated heavy flavour experiment forward 0 and production magnetic monopole search logs and diffraction physics ATLAS, CMS and LHCb are relevant for the flavour physics SUSY in 2010 s , Sapporo 8

9 LHC LHCb/MOEDAL CMS/TOTEM ATLAS/LHCf ALICE SUSY in 2010 s , Sapporo 9

10 pt of B-hadron ATLAS/CMS 100 μb LHCb 230 μb LHCb Spectrometer p p b b eta of B-hadron Shifted IP point Good mass and eigentime resolution: VELO + tracking system Hadron identification: RICH system L0 Lepton and Hadron p T trigger: Calorimeter and muon system SUSY in 2010 s , Sapporo 10

11 LHC tunnel radiation protection wall electronics huts with readout electronics and CPU farm LHC tunnel Muon Calo RICH-2 OT/IT Magnet TT RICH-1 VELO <L> ~ 2(-5) (L nominal = ), b = 500 μb ( inelastic = 80 mb), bb/10 7 sec B u,d,s,c, b, b, and other b-hadrons SUSY in 2010 s , Sapporo 11

12 POINT 1 RB86 A RADIATION SHIELD B Mu-system HCAL ECAL RICH2 IT+OT MAG. C LHC CRYO RICH1 PX SHAFT VELO POINT 7 IP8 Brazil, China, France, Germany, Italy, Netherlands, Poland, Romania, Russia, Spain, Switzerland, UK, Ukraine, USA, 600 people, 75 MCHF SUSY in 2010 s , Sapporo 12

13 Beam pipe commissioned and ready for the beam Al exit window 1st and 2nd 10 mrad Be section 25 mrad Be section end of 25 mrad section Al bellow 10 mrad section stainless steel section SUSY in 2010 s , Sapporo 13

14 Magnet operational and field map measured BDL = 4 Tm, Power = 4.2 MW, Yoke = 1450 t - the field was measured with a precision of fulfils the requirement - good symmetry between the two polarities: B/<B>~ small fake P violation SUSY in 2010 s , Sapporo 14

15 VErtex LOcator 300 μm Si sensor as close as 8mm from the beam collision point ~ 1m r-sensors 4 45 o sectors beam axis -sensors 10 o -20 o stereo angle 84 mm Two RF boxes looking through from upstream SUSY in 2010 s , Sapporo 15

16 Outer Tracker and Silicon Tracker ~ m 2 Inner Tracker Outer Tracker Trigger Tracker Silicon Tracker SUSY in 2010 s , Sapporo 16

17 Outer Tracker Straw drift chambers Trigger Tracker ~ m μm Si 40μm Kapton XC Laminated Kapton-Al Inner Tracker ~ cm μm Si 320 μm Si SUSY in 2010 s , Sapporo 17

18 OT being commissioned, IT production in progress TT being installed OT stations (straw tubes) IT detector boxes (Si sensors) TT cable installation (Si sensors) SUSY in 2010 s , Sapporo 18

19 RICH Two RICH with three radiators Aerogel RICH1 ( mrad) C 4 F 10 CF 4 RICH2 ( mrad) SUSY in 2010 s , Sapporo 19

20 RICH-2 being commissioned, RICH-1 being installed RICH-1 gas enclosure shielding boxes bellow HPD photon detector RICH-2 RICH-1 RICH-1 four spherical mirrors SUSY in 2010 s , Sapporo 20

21 Calorimeter System Ecal Shashlik Hcal Fe-Scintillator tile SPD/PS Scintillator-Pb-Scintillator SUSY in 2010 s , Sapporo 21

22 Ecal and Hcal installed and being commissioned PS/SPD installed and being cabled SUSY in 2010 s , Sapporo 22

23 Muon System Fe shield Electronics tower MWPC support wall Projective readout based on MWPC s except 3-GEM at M1R1(high occupancy) SUSY in 2010 s , Sapporo 23

24 Foe one side, chambers all installed being cabled Installation of other side >50% completed (except M1) SUSY in 2010 s , Sapporo 24

25 Trigger and Online electronics boards in production, partially commissioned Calorimeter, Muon and Pile-up Level-0: medium p T trigger: 40 MHz 1 MHz All the detector data 1 30kB/event being installed, partially commissioned commercial components running HLT algorithms Switch CPU. CPU Readout Network Switch CPU. CPU Switch CPU. CPU data logging 2000 Hz storage device SUSY in 2010 s , Sapporo 25

26 In the past pp s = 14 TeV in 2005 pp s = 14 TeV in 2006 More recently End of 2007: pp s = 14 TeV Engineering s = 900 GeV Sector test (sec8-7) detector commissioning with particles; only with cosmics OK for ATLAS and CMS, not for LHCb SUSY in 2010 s , Sapporo 26

27 Middle of 2008:Start of s = 14 TeV alignment, calibration and trigger commissioning, increasing luminosity toward for ATLAS/CMS and ~ for LHCb for physics (Personally, I am certain that we will have some data in 08) From 2009: Stable physics s = 14 TeV ATLAS and CMS: clear interest to increase luminosities towards as quick as possible. B physics will become increasingly difficult. LHCb: collecting data with <10 33 for some years SUSY in 2010 s , Sapporo 27

28 A possible scenario 2008 most probably too optimistic physics run for a period of 1/4 of the nominal year (10 7 sec) <L>=10 33 for ATLAS and CMS (optimistic?) <L>= for LHCb (should be possible ) Ldt = 2.5 fb 1 each for ATLAS and CMS (if <L> is lower, trigger could be adjusted to have a similar number of b s) Ldt = 0.5 fb 1 for LHCb ATLAS and CMS accumulate Ldt = 30 fb 1 each end of B physics era and move to regime (except B s μμ) LHCb collect Ldt >~ 10 fb 1 LHCb should have 10 fb 1 data by the end of 2013±1 SUSY in 2010 s , Sapporo 28

29 3) Physics with 2008 data Very interesting results can be obtained for B s physics CP violation in B s J/ (i.e. s measurement) and Search for B s μμ decays where large, >O(1), BSM contribution not yet excluded Tevatron will run till 2009: CDF and D0, well understood detectors LHC can get b statistics fast, We need to organize ourselves for fast analysis SUSY in 2010 s , Sapporo 29

30 Time dependent CP asymmetries in B s, B s J/ decays Final states with leptons: lepton trigger very effective for ATLAS, CMS and LHCb Flavour tag necessary opposite side: lepton, jet-charge and kaon same side: slow kaon from the fragmentation eff = tag (1 2w wrong ) 2 [10 2 ] O.S. S.S. combined e μ K Jet K ATLAS =4.56 CMS under investigation LHCb N.N. = 7.08 SUSY in 2010 s , Sapporo 30

31 B s -B s oscillation has to be well resolved: good needed -good that m s is not too big -resolution function must be well understood measuring lifetimes, oscillation plot with D s etc. Proper time resolutions ATLAS CMS LHCb [fs] NB: worse resolution = more dilution in the CP asymmetries SUSY in 2010 s , Sapporo 31

32 Good mass and vertex resolutions to reduce background B s mass resolutions and Background/Signal ratios ATLAS CMS LHCb m [MeV/c 2 ] 16.5 ) 14 ) 14 +) B/S ) with J/ mass constraint +) without mass constraint SUSY in 2010 s , Sapporo 32

33 Event yields from the 2008 run Numbers of reconstructed J/ and those effectively flavour tagged ATLAS CMS LHCb N rec 23 k 27k 33 k N eff-tag rec 1.0 k? 2.3 k Full decay topology analysis is needed to determine J/ (CP = +1) / J/ (CP = 1) (L J/ - = 0, 2 vs L J/ - = 1) Total The background is assumed to be independent on tr. Should be measured from the side band data. CP-even CP-odd LHCb SUSY in 2010 s , Sapporo 33

34 B s -B s oscillation phase and decay width difference with 2008 data ATLAS CMS LHCb ( s ) 0.158? ( s )/ s NB CP s s 1 s2 /2 less sensitive to s Standard model expectation: s = 0.04 LHCb: BSM effect down to the level of SM can be excluded/discovered with the 2008 data LHCb: J/, c, D s+ D s can be added and ( s ) = 0.01with L dt = 10 fb 1 data ATLAS and CMS: ( s ) 0.04 with L dt = 30 fb 1 data By ~2013, SM prediction of s tested to a level of ~5 SUSY in 2010 s , Sapporo 34

35 Search for B s μ + μ decays Final states with leptons: lepton trigger very effective for ATLAS, CMS and LHCb Flavour tag not necessary, tough background PID: B, K, etc. vertex resolution: b μ X + b μ + X mass resolution: B μx, etc. + isolation, p T, etc. B s mass resolutions B s μ + μ ATLAS CMS LHCb m [MeV/c 2 ] SUSY in 2010 s , Sapporo 35

36 With 2008 data ) assuming the SM Br = ~ ATLAS CMS LHCb uses distributions N ) signal ~2 ~2 for signal and background Limit at 90% CL N background ~5 ~ <~ (90%CL) LHCb; BSM contribution down to the level of SM can be excluded/discovered. SM prediction Expected CDF+D0 Limit Uncertainty in bkg prediction Integrated Luminosity (fb 1 ) LHCb: L dt = 10 fb 1, >5 observation for SM Br ATLAS and CMS: L dt = 30 fb 1, <~ (90%CL) (They plan to continue this programme at L=10 34, 4 in one year) SUSY in 2010 s , Sapporo 36

37 4) Flavour physics >2008 Subjects which require very high statistics good control of systematics, detector and physics. Here are some examples Search for a BSM Lorentz structure in b s current using polarization of in b s+, for real or virtual B d K 0 μ + μ detailed studies of the event structure A FB : forward-backward asymmetry of μ + μ other angular distributions SUSY in 2010 s , Sapporo 37

38 Final states with leptons: lepton trigger very effective for ATLAS, CMS and LHCb Flavour tag not necessary for one canonical year 10 fb (CMS study not yet available) 1 (ATLAS) and 2fb 1 (LHCb) ATLAS LHCb (m) [MeV/c 2 ] N signal ATLAS B/S <4.8 ~0.5 LHCb [MeV/c 2 ] m( 0 μμ) [MeV/c 2 ] m( 0 μμ) SUSY in 2010 s , Sapporo 38

39 A FB performance ATLAS 30 fb 1 forward-backward asymmetry three canonical years LHCb 2 fb -1 one canonical year + ATLAS 30 fb -1 + Belle 2006 SM model SM extensions m μμ 2 [GeV 2 ] By ~2013, LHCb zero crossing point with 10 fb 1 (s 0 ) = 0.28 (GeV/c 2 ) 2 [36K events] SUSY in 2010 s , Sapporo 39

40 There is more information in K 0 μ + μ K 0 polarisation can be measured SUSY in 2010 s , Sapporo 40

41 Examples for K 0 polarisation with 2fb 1 data NB: Theoretical complication: K *0 is a wide resonance Effect of non-resonant K to be better understood LHCb will look for other radiative decays, e.g. B s 47k events with 10 fb 1 SUSY in 2010 s , Sapporo 41

42 An interesting quantity: R K With 10 fb 1 data K ± e + e 10 k K ± μ + μ 19 k LHCb by 2013 (R K ) = SUSY in 2010 s , Sapporo 42

43 Extraction of Different ways to extract are considered by LHCb 1) Interfering b c+w ( us) and b u+w ( cs) a) via B s -B s oscillation time dependent decay asymmetries b) via DCS decays of D relative decay rates c) via D-D state mixing relative decay rates d) K 0 -K 0 state mixing Dalitz plot study 2) Interfering b u-tree+b d-penguins and B-B oscillations + U-spin time dependent decay asymmetries L0 hadron p T trigger, K/ identification: essential SUSY in 2010 s , Sapporo 43

44 1-a) B s D s± K m and B s D m s K ± flavour tag, K/ identification (D s background), 1-b) B + DK + and B DK or B 0 DK 0 and B 0 DK 0 with D K ± m 1-c) B 0 DK 0 and B 0 DK 0 with D K ± mand D K + K, + 1-d) B + DK + and B DK or B 0 DK 0 and B 0 DK 0 with D K S + K/ identification and mass and vertex resolution to reduce combinatorial background Detector acceptance for charge asymmetry, kinematics, Description of D decays: strong phases between DCS and CA decay amplitudes, Dalitz plot distribution, Normalization of some background channels SUSY in 2010 s , Sapporo 44

45 2) B d + and B s K + K flavour tag, K/ identification (K background), validity of U-spin symmetry (C) (S) CP asymmetries fit results corresponding to 2fb 1 B d + B s K + K B d K + B s + K (0.07*) (A CP ) (0.015*) (0.09*) LHCb performance in determination with 10 fb 1 D s K DK /KK ADS GLW+D Dalitz ( ) ) ~2013 LHCb tree determination of = 2.4, unaffected by BSM ) With a weak assumption on U-spin symmetry Could be affected by BSM SUSY in 2010 s , Sapporo 45

46 Extraction of For LHCb, a promising method is time dependent Dalitz plot analysis for B d + 0 and B d + 0 : i.e. mode ( modes are marginal except 0 0 channel) LHCb B d fb 1 N signal B/S (m ) B d ( ) tag eff 14 k 1 60 MeV/c 2 50 fs 5.8% LHCb B d fb 1 N signal B/S (m ) B d ( ) 1200 <5 16 MeV/c 2 32 fs SUSY in 2010 s , Sapporo 46

47 generated LHCb determination with mode with 2fb 1 data m 2 ( + 0 ) reconstructed m 2 ( 0 ) together with 0 0 mode, ~2013 LHCb determination of a with 10fb 1 ( ) = 4.6, could be affected by BSM SUSY in 2010 s , Sapporo 47

48 BSM Phase of b s penguin Analogous to B d K S, time dependent CP asymmetry for B s can measure the BSM phase in b s penguin (for B s, with only t contribution, SM makes 0 CP asymmetry) LHCb B s performance with 2 fb 1 data (m B s ) B/S N sig ) ( ) ( s-eff ) 12 MeV/c fs 0.1 ) Br = angular analysis needed to resolve CP=1 and = 1 states ~2013 with 10 fb 1 data: ( s-eff ) = 0.04 (B d K s for LHCb, ( d-eff ) = 0.14) currently ( d-eff ) = 0.18 SUSY in 2010 s , Sapporo 48

49 BSM in the D system LHCb will collect a large D tagged D 0 sample (also used for PID calibration) D 0 K + K + K + K + N signal [10 6 ] Combined with slow + to make D + Use B D + ± X to determine D + vertex 45k K + decays/2 fb 1, B/S~2.6, ( D )=45 fs ~2013 LHCb performance with 10 fb 1 data (x' 2 ) = , (y') = ±0.37 ± CP performance under study (KK and ) BABAR BELLE SUSY in 2010 s , Sapporo 49

50 Other topics Lepton favour violating decays 3μ, μee? Lepton flavour violating B decays B eμ Lepton flavour violating D decays D eμ being or will be looked at. (we cannot do everything now) SUSY in 2010 s , Sapporo 50

51 5) Conclusions i) LHC is a b-factory coming online soon, experiments are busy to be ready. LHCb will be ready! ii) Physics with s = 14 TeV will start in data could allow us to exclude/discover BSM effect in the B s sector down to the SM level e.g. for B s J/ and B s μμ. iii) By 2013, wide range of flavour physics in B and D will be explored by LHCb extending further the results obtained by BABAR, BELLE, CDF and D0. iv) We need help from theory. With a much better theoretical understanding for the form factors and decay constants, we might already see a deviation from CKM with, V ub, m d, and sin2. SUSY in 2010 s , Sapporo 51

52 LHC experiments will soon face the reality. There will be some bad surprises; background level is higher than expected, resolution is worse, etc But with real data, we can learn how to cope with them. SUSY in 2010 s , Sapporo 52

53 LHC experiments will soon face the reality. There will be some bad surprises; background level is higher than expected, resolution is worse, etc But with real data, we can learn how to cope with them. CESAR, DORIS, LEP, Tevatron, PEP-II and KEKB, all produced flavour physics results beyond the original expectations. There must be good surprises at LHC too! SUSY in 2010 s , Sapporo 53

54 My scenario matrix for 2014 at LHC ATLAS CMS high p T physics BSM Only SM BSM LHCb flavour physics Only SM BSM BSM Particle Physics Exciting moment is ahead! SUSY in 2010 s , Sapporo 54