Flavour Physics at LHC

Transcription

1 Flavour Physics at LHC ICFP2009, Hanoi, September 2009 Tatsuya Nakada LPHE/EPFL

2 Introduction (I) There exist solid observations for physics beyond the Standard Model T. Nakada ICFP2009 Hanoi September

3 Introduction (I) There exist solid observations for physics beyond the Standard Model Neutrino oscillations S-KAMIOKANDE T. Nakada ICFP2009 Hanoi September

4 Introduction (I) There exist solid observations for physics beyond the Standard Model Neutrino oscillations Dark matter S-KAMIOKANDE Bullet Galaxy Clusters T. Nakada ICFP2009 Hanoi September

5 Introduction (I) There exist solid observations for physics beyond the Standard Model Neutrino oscillations Dark matter N B / N =10 10 S-KAMIOKANDE Bullet Galaxy Clusters The Horn Antenna Bell Telephone Laboratory T. Nakada ICFP2009 Hanoi September

6 Introduction (I) There exist solid observations for physics beyond the Standard Model Neutrino oscillations Dark matter N B / N =10 10 S-KAMIOKANDE Bullet Galaxy Clusters The Horn Antenna Bell Telephone Laboratory also more philosophical/theoretical/esthetical arguments T. Nakada ICFP2009 Hanoi September

7 Introduction (II) There exists also strong anticipation that new physics is just around the corner, i.e. at the LHC energy scale. Once new particles were discovered at LHC, LC would be built to make detailed studies. T. Nakada ICFP2009 Hanoi September

8 Introduction (II) There exists also strong anticipation that new physics is just around the corner, i.e. at the LHC energy scale. Once new particles were discovered at LHC, LC would be built to make detailed studies. But there exists a complementary approach T. Nakada ICFP2009 Hanoi September

9 Introduction (III) Quark flavour physics, has been successfully uncovering physics at much higher scale than directly accessible, e.g. quark family structure and 3 rd generation of quark family. Using the quantum fluctuations in the loop diagram s b u, c, t, w V A d d, s T. Nakada EPS HEPC 2009 Cracow EPS Session

10 Some examples from the past m K and Br(K L μ + μ - ) m c Lee&Gaillard (1974) charm discovery Aubert et al., Augustin et al., 1974 (Niu et al. 1971?) CP: 1964, J.H. Christenson et al., Br(K 0 L + ) 0 Third family Kobayashi&Maskawa (1973) B 0 -B 0 oscillations ( m B ): ARGUS (1987 m t > 50 GeV/c 2 (NB: UA <m t <50 GeV/c 2 ) top discovery by CDF and D0 in 1995 (m t = 171.2±2.1 GeV/c 2 ) They were done before the direct discovery of c, b and t quarks Crucial contributions to establish SM May have already started to probe Beyond-SM T. Nakada ICFP2009 Hanoi September

11 Quark flavour physics, has been successfully uncovering physics at much higher scale than directly accessible, e.g. quark family structure and 3 rd generation of quark family. Using the quantum fluctuations in the loop diagram s b u, c, t, w V A Introduction (III) d d, s s b amplitude: A = A SM + A NP new particles S, P, d d, s A : rare decays, m arg A: CP violation Lorentz structure of A: photon polarization via final state angular distribution or mixing-decay CP violation T. Nakada EPS HEPC 2009 Cracow EPS Session

12 LHC Circumference of 27 km T. Nakada ICFP2009 Hanoi September

13 LHC and four large experiments Baseline pp Experiments also relevant for B physics LHCb ATLAS CMS ALICE Circumference of 27 km T. Nakada ICFP2009 Hanoi September

14 Three pp Experiments LHCb: (Not LHCB nor LHC-B) dedicated B physics experiment, locally adjusted luminosity of c.f. LHC design luminosity ATLAS/CMS: general purpose experiments, optimized for high-p T discovery physics at cm 2 s 1 B physics at the beginning of the LHC operation with T. Nakada ICFP2009 Hanoi September

15 Luminosities LHC machine, pp collisions at s = 14 TeV: design luminosity L = cm 2 s 1, bunch crossing rate = 40 MHz average non-empty bunch crossing rate f = MHz Pileup: n = number of inelastic pp interactions occurring in the same bunch crossing Poisson distribution with mean <n> = L inel /f, with inel = 80 mb <n> = 25 at cm 2 s 1 not good for B physics (except B s μμ?) T. Nakada ICFP2009 Hanoi September

16 Luminosities LHC machine, pp collisions at s = 14 TeV: design luminosity L = cm 2 s 1, bunch crossing rate = 40 MHz average non-empty bunch crossing rate f = MHz Pileup: n = number of inelastic pp interactions occurring in the same bunch crossing Poisson distribution with mean <n> = L inel /f, with inel = 80 mb <n> = 25 at cm 2 s 1 not good for B physics (except B s μμ?) ATLAS and CMS B physics in the early stage of the LHC operation ~3 years with L = cm 2 s 1 At LHCb: L tuneable by adjusting final beam focusing Choose to <L> ~ cm 2 s 1 (max. ~ ) Clean environment: <n> = 0.5 Less radiation damage Will be available from first physics run Probability pp interactions/crossing Luminosity [cm s ] T. Nakada ICFP2009 Hanoi September

17 Luminosities LHC machine, pp collisions at s = 14 TeV: design luminosity L = cm 2 s 1, bunch crossing rate = 40 MHz average non-empty bunch crossing rate f = MHz Pileup: n = number of inelastic pp interactions occurring in the same bunch crossing Poisson distribution with mean <n> = L inel /f, with inel = 80 mb <n> = 25 at cm 2 s 1 not good for B physics (except B s μμ?) ATLAS and CMS B physics in the early stage of the LHC operation ~3 years with L = cm 2 s 1 At LHCb: L tuneable by adjusting final beam focusing Choose to <L> ~ cm 2 s 1 (max. ~ ) Clean environment: <n> = 0.5 Less radiation damage Will be available from first physics run A standard year In one nominal year = 10 7 s: At LHCb 2 fb 1 of data, bb pairs produced At ATLAS/CMS 10 fb 1 of data T. Nakada ICFP2009 Hanoi September Probability pp interactions/crossing Luminosity [cm s ] 2 3 4

18 B physics at LHC + and LHC is a b factory! ( b not B ) e + e (4S) BB PEPII, KEKB pp bbx ( s = 14 TeV, t bunch =25 ns) LHC (LHCb, ATLAS, CMS) T. Nakada ICFP2009 Hanoi September

19 B physics at LHC + and LHC is a b factory! ( b not B ) e + e (4S) BB PEPII, KEKB pp bbx ( s = 14 TeV, t bunch =25 ns) LHC (LHCb, ATLAS, CMS) Production bb 1 nb ~500 μb Typical bb rate 10 Hz khz T. Nakada ICFP2009 Hanoi September

20 B physics at LHC + and LHC is a b factory! ( b not B ) e + e (4S) BB PEPII, KEKB pp bbx ( s = 14 TeV, t bunch =25 ns) LHC (LHCb, ATLAS, CMS) Production bb 1 nb ~500 μb Typical bb rate 10 Hz khz bb purity ~1/4 bb / inel = 0.6% Trigger is a major issue! Pileup T. Nakada ICFP2009 Hanoi September

21 B physics at LHC + and LHC is a b factory! ( b not B ) e + e (4S) BB PEPII, KEKB pp bbx ( s = 14 TeV, t bunch =25 ns) LHC (LHCb, ATLAS, CMS) Production bb 1 nb ~500 μb Typical bb rate 10 Hz khz bb purity ~1/4 bb / inel = 0.6% Trigger is a major issue! Pileup b-hadron types B + B - (50%) B 0 B 0 (50%) B + (40%), B 0 (40%), B s (10%) B c (< 0.1%), b-baryons (10%) b-hadron boost Small Large (decay vertexes well separated) Production vertex Not reconstructed Reconstructed (many tracks) T. Nakada ICFP2009 Hanoi September

22 B physics at LHC + and LHC is a b factory! ( b not B ) e + e (4S) BB PEPII, KEKB pp bbx ( s = 14 TeV, t bunch =25 ns) LHC (LHCb, ATLAS, CMS) Production bb 1 nb ~500 μb Typical bb rate 10 Hz khz bb purity ~1/4 bb / inel = 0.6% Trigger is a major issue! Pileup b-hadron types B + B - (50%) B 0 B 0 (50%) B + (40%), B 0 (40%), B s (10%) B c (< 0.1%), b-baryons (10%) b-hadron boost Small Large (decay vertexes well separated) Production vertex Not reconstructed Reconstructed (many tracks) Neutral B mixing Coherent B0 B 0 pair mixing Incoherent B 0 and B s mixing (extra flavour-tagging dilution) Event structure BB pair alone Many particles not associated with the two b hadrons T. Nakada ICFP2009 Hanoi September

23 ATLAS and CMS ATLAS and CMS Some flavour physics during the low luminosity period with final states containing muons (triggered by the high p T muon trigger) Rare decays in b s B = 2: B s μ + μ CP violation in b s B = 2: B s J/ Lorentz structure b s in B = 1: B d K 0 μ + μ CDF and D0 have shown that good B physics can be done with the high p T detectors! T. Nakada ICFP2009 Hanoi September

24 LHCb LHCb: A dedicated experiment optimized for flavour study with b and c Trigger sensitive to leptonic and hadronic final states Very good and invariant-mass Particle identification e/μ/ /K/p T. Nakada ICFP2009 Hanoi September

25 LHCb LHCb: A dedicated experiment optimized for flavour study with b and c Trigger sensitive to leptonic and hadronic final states Very good and invariant-mass Particle identification e/μ/ /K/p Forward spectrometer: correlated and fast b-b pt of B-hadron 10 2 ATLAS/CMS μ LHCb 10 μ eta of B-hadron work with L cm 2 s 1 (available from the early days) T. Nakada ICFP2009 Hanoi September

26 Forward geometry LHCb bunch crossing rate = 40 MHz fast and efficient b trigger needed single high p T particle:, e, h (calorimeter) or μ (muon system) but not too high threshold p L p T p p T. Nakada ICFP2009 Hanoi September

27 Forward geometry LHCb bunch crossing rate = 40 MHz fast and efficient b trigger needed single high p T particle:, e, h (calorimeter) or μ (muon system) but not too high threshold Both require p > p min for resolution (calorimeter), 1/ E or filtering (muon system) muon identification p < p min p > p min Fe T. Nakada ICFP2009 Hanoi September

28 Forward geometry LHCb bunch crossing rate = 40 MHz fast and efficient b trigger needed single high p T particle:, e, h (calorimeter) or μ (muon system) but not too high threshold Both require p > p min for resolution (calorimeter), 1/ E or filtering (muon system) In the forward geometry, p is carried by p L central detector forward detector p p L > p min p p p T > p min p p p T. Nakada ICFP2009 Hanoi September

29 Forward geometry LHCb bunch crossing rate = 40 MHz fast and efficient b trigger needed single high p T particle:, e, h (calorimeter) or μ (muon system) but not too high threshold Both require p > p min for resolution (calorimeter), 1/ E or filtering (muon system) In the forward geometry, p is carried by p L Forward geometry allows to set the threshold low, limited by the bandwidth of the readout system. high b trigger efficiency T. Nakada ICFP2009 Hanoi September

30 Current status ATLAS, CMS and LHCb are ready to take data. They have been taking data with cosmic muons and injection beams. T. Nakada ICFP2009 Hanoi September

31 Current status ATLAS, CMS and LHCb are ready to take data. They have been taking data with cosmic muons and circulated and injection beams. T. Nakada ICFP2009 Hanoi September

32 Current status ATLAS, CMS and LHCb are ready to take data. They have been taking data with cosmic muons and circulated and injection beams. T. Nakada ICFP2009 Hanoi September

33 Current status ATLAS, CMS and LHCb are ready to take data. They have been taking data with cosmic muons and, circulated and injection beams. T. Nakada ICFP2009 Hanoi September

34 Current status ATLAS, CMS and LHCb are ready to take data. They have been taking data with cosmic muons and circulated and injection beams. LHC collision at s = 7 TeV is expected by the end of this year pb 1 data at s = 7 TeV (some at 10 TeV?) are expected in L = ~ cm 2 s 1 not bad for LHCb T. Nakada ICFP2009 Hanoi September

35 AT Current status Th inj LH his ye Fe e ex Machine is getting cold T. Nakada ICFP2009 Hanoi September

36 Current status ATLAS, CMS and LHCb are ready to take data. They have been taking data with cosmic muons and circulated and injection beams. LHC collision at s = 7 TeV is expected by the end of this year Few 100 pb 1 data at s = 7 TeV (some at 10 TeV?) are expected in For LHCb, 10 fb 1 data is foreseen for the final goal by ~2005(?). T. Nakada ICFP2009 Hanoi September

37 Reconstructable states Reconstruction of B decay vertex with a good resolution is essential to reduce combinatorial background: T. Nakada ICFP2009 Hanoi September

38 Reconstructable states Reconstruction of B decay vertex with a good resolution is essential to reduce combinatorial background: Decay vertex: > one well reconstructed tracks well reconstructed track = - charged particle seen by vertex detector - reconstructed particle from tracks measured by vertex detector D 0 ( K + ), D s (K + K + ), etc., also K S examples are B (s)0 l + l, h + h,..., B s0 D s ( K + K ) +, B + D( K S + ) + T. Nakada ICFP2009 Hanoi September

39 Reconstructable states Reconstruction of B decay vertex with a good resolution is essential to reduce combinatorial background: Decay vertex: > one well reconstructed tracks well reconstructed track = - charged particle seen by vertex detector - reconstructed particle from tracks measured by vertex detector D 0 ( K + ), D s (K + K + ), etc., also K S examples are B (s)0 l + l, h + h,..., B s0 D s ( K + K ) +, B + D( K S + ) + 0 and can be associated to a reconstructed vertex (if not too many) B 0 K 0 (K + ), 0 ( + ) 0, etc. are possible but not B 0 K S 0, + ( + 0 ) 0, 0, etc. B + μ +, K +, + T. Nakada ICFP2009 Hanoi September

40 Illustration of an interesting event primary vertex D s impact parameter > 0 B s vertex separation K + D s decay non pointing to primary B s 0 impact parameter = 0 B s 0 decay pointing to primary K + impact parameter > 0 D s vertex separation plus p T cut (LHCb) or isolation cut (ATLAS/CMS) and for some cases, decay angle cut p - K + K T. Nakada ICFP2009 Hanoi September

41 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 T. Nakada ICFP2009 Hanoi September

42 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 Current limit >10 SM by CDF and D0 Tevatron final reach (with 9 fb 1 per experiment ~2010): ~ T. Nakada ICFP2009 Hanoi September

43 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 Current limit >10 SM by CDF and D0 Tevatron final reach (with 9 fb 1 per experiment ~2010): ~ LHCb should be able to reach a similar sensitivity with ~150pb 1 data, expected to collect in 2010 T. Nakada ICFP2009 Hanoi September

44 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 Current limit >10 SM by CDF and D0 Tevatron final reach (with 9 fb 1 per experiment ~2010): ~ LHCb should be able to reach a similar sensitivity with ~150pb 1 data, expected to collect in fb 1 data: 5 measurements if SM T. Nakada ICFP2009 Hanoi September

45 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 Current limit >10 SM by CDF and D0 Tevatron final reach (with 9 fb 1 per experiment ~2010): ~ LHCb should be able to reach a similar sensitivity with ~150pb 1 data, expected to collect in fb 1 data: 5 measurements if SM A similar sensitivities for ATLAS and CMS running with L = for several years. T. Nakada ICFP2009 Hanoi September

46 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM from Tevatron T. Nakada ICFP2009 Hanoi September

47 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM from Tevatron LHCb should be able to overtake Tevatron with <200 pb 1 of data 2010 T. Nakada ICFP2009 Hanoi September

48 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM from Tevatron LHCb should be able to overtake Tevatron with <200 pb 1 of data 2010 With 10 fb 1 of data, CP can be established if SM T. Nakada ICFP2009 Hanoi September

49 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently ~350 reconstructed events (BABAR+Belle) already ~80% of the final statistics 1 < q 2 < 6 most interesting region Belle ~250 events SM prediction T. Nakada ICFP2009 Hanoi September

50 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently ~350 reconstructed events (BABAR+Belle) already ~80% of the final statistics 1 < q 2 < 6 most interesting region Belle: 30 events in this interval LHCb should get this with already 50 pb 1 of data T. Nakada ICFP2009 Hanoi September

51 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently ~350 reconstructed events (BABAR+Belle) already ~80% of the final statistics 1 < q 2 < 6 most interesting region Belle: 30 events in this interval LHCb should get this with already 50 pb 1 of data With 2fb 1 data 1 (>7 k of signal events) T. Nakada ICFP2009 Hanoi September

52 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently only ~350 events available Those results will be already interesting with 2010 data!!! T. Nakada ICFP2009 Hanoi September

53 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently only ~350 events available Other interesting channels are CP(B s ): measures the photon polarisation CP(B s ): measures b s penguin phase T. Nakada ICFP2009 Hanoi September

54 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently only ~350 events available CP(B s ): measures the photon polarisation CP(B s ): measures b s penguin phase T. Nakada ICFP2009 Hanoi September

55 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently only ~350 events available CP(B s ): measures the photon polarisation CP(B s ): measures b s penguin phase Tree level determination: currently -tree 20 Interfere B DK and DK with D f and D f due to DCSD, D-D or K-K mixing not affected by new physics T. Nakada ICFP2009 Hanoi September

56 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently only ~350 events available CP(B s ): measures the photon polarisation CP(B s ): measures b s penguin phase Tree level determination: currently -tree 20 Interfere B DK and DK with D f and D f due to DCSD, D-D or K-K mixing not affected by new physics cf. global fit gives -fit 4 could be affected by new physics Comparison is important! T. Nakada ICFP2009 Hanoi September

57 Goal of Flavour Physics at LHC Search for d area Br(B s μ + CP(B s J/ A FB (B d K lable CP(B s CP(B s Tree level Interfe f due cf. glo T. Nakada ICFP2009 Hanoi September

58 Goal of Flavour Physics at LHC Search for d area Br(B s μ + CP(B s J/ A FB (B d K lable CP(B s CP(B s Tree level Interfe f du cf. glo T. Nakada ICFP2009 Hanoi September

59 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently only ~350 events available CP(B s ): measures the photon polarisation CP(B s ): measures b s penguin phase Tree level determination: currently -tree 20 Interfere B DK and DK with D f and D f due to DCSD, D-D or K-K mixing cf. global fit gives now -fit 4 LHCb should give -tree 2-3 with 10 fb 1 of data (also with B s ) PID is an important feature T. Nakada ICFP2009 Hanoi September

60 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B μ + μ ): SM prediction (3 35±0 32) 10 9 LHCb should give -tree 2-3 with 10 fb 1 of data (also with B s ) PID is an important feature T. Nakada ICFP2009 Hanoi September

61 Goal of Flavour Physics at LHC Search for new physics in the not yet well explored area Br(B s μ + μ ): SM prediction (3.35±0.32) 10 9 CP(B s J/ ): current sensitivity >10 SM A FB (B d K 0 μ + μ ): currently only ~350 events available CP(B s ): measures the photon polarisation CP(B s ): measures b s penguin phase Tree level determination: currently -tree 20 CP in D decays And much more b and c hadron spectroscopy W and Z production in the forward direction search for long-living neutral particles etc. T. Nakada ICFP2009 Hanoi September

62 Conclusions Flavour physics had a successful track record. T. Nakada ICFP2009 Hanoi September

63 Conclusions Flavour physics had a successful track record. BABAR and Belle made a quantum jump in flavour physics, showing successfully that the CK mechanism is the dominant source of CP violation in particle physics. T. Nakada ICFP2009 Hanoi September

64 Conclusions Flavour physics had a successful track record. BABAR and Belle made a quantum jump in flavour physics, showing successfully that the CK mechanism is the dominant source of CP violation in particle physics. Current flavour physics data is compatible with the Standard Model expectations. T. Nakada ICFP2009 Hanoi September

65 Conclusions Flavour physics had a successful track record. BABAR and Belle made a quantum jump in flavour physics, showing successfully that the CK mechanism is the dominant source of CP violation in particle physics. Current flavour physics data is compatible with the Standard Model expectations. BABAR and Belle will come with their final results soon. T. Nakada ICFP2009 Hanoi September

66 Conclusions Flavour physics had a successful track record. BABAR and Belle made a quantum jump in flavour physics, showing successfully that the CK mechanism is the dominant source of CP violation in particle physics. Current flavour physics data is compatible with the Standard Model expectations. BABAR and Belle will come with their final results soon. Tevatron continue to collect more data. T. Nakada ICFP2009 Hanoi September

67 Conclusions Flavour physics had a successful track record. BABAR and Belle made a quantum jump in flavour physics, showing successfully that the CK mechanism is the dominant source of CP violation in particle physics. Current flavour physics data is compatible with the Standard Model expectations. BABAR and Belle will come with their final results soon. Tevatron continue to collect more data. When LHC will become operational in November 2009, a quantum jump is again expected in flavour physics, providing a complementary study for New Physics (mainly LHCb) to that by the direct search of new particles (ATLAS and CMS). T. Nakada ICFP2009 Hanoi September