How To Calculate Classificaron Of Pterosaur

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1 CP Violation at LHCb Contents: Indirect Probe for NP The Experiment Recent Measurements Marcel Merk Seminar Radboud Universiteit July 7, Nijmegen

2 KUN Radboud University

3 LHC: Search for physics beyond Standard Model Atlas CMS LHCb Atlas/CMS: direct observaron of new parrcles LHCb: observaron of new parrcles in quantum loops LHCb is aiming at search for New Physics in CP ViolaRon and in Rare Decays Focus of this talk

4 Direct vs Indirect observarons The absolute energy fronrer: The virtual energy fronrer: Direct observaron: Produce parrcles on shell and detect decay products More intuirve(?), really produced Limited by collision energy Indirect observaron: Less intuirve(?), quantum level Limited by precision, not by collision energy CP observables sensirve to imaginary couplings Indirect observarons in the past: Kaon decay K μμ hints at c quark via GIM in 197 (J/Ψ produced in 1974) 3 rd quark family predicted 1972 to explain CP violaron (b produced in 1977, t in 1994) Neutral current observed in neutrino experiment in 1973 (Z boson produced in 1983) BB mixing (1987) hints at large top mass, LEP predicts top mass (199) (top in 1994)

5 Indirect evidence for top mass and charm quark B mixing pointed to the top quark mass ARGUS Coll, Phys.Le2.B192:245,1987 K μμ pointed to the charm quark GIM, Phys.Rev.D2,1285,197 b d d s d b μ μ

6 Produce an bb bound state, ϒ(4S), in e + e collisions: e + e ϒ(4S) B B B B Mixing: ARGUS, 1987 and then observe: B1 D 1 µ + 1 ν 1 B2 D 2 µ + 2 ν 2 D 1 D [ K + 1 π 1 ] π 1 D 2 D [ K + 2 π 2 π 2 ] π [ γγ] ~17% of B mesons oscillate before they decay: Δm B ~.5/ps, t B ~ 1.5 ps Sept 28 29, 25 m B.2 ( mt GeV/c 2 ) 2 ps 1 First hint of a really large m top! 6

7 Higgs mass and Electroweak precision measurements W propagator: M W = M W + am 2 t + b ln ( MH M W ) July 4, 212

8 Flavour Physics: perhaps a bit diﬃcult?

9 A slide of History on CP ViolaRon Charge Parity ViolaRon in parrcle physics 1964 (CCFT): Discovered in neutral Kaon beam indirect CP violaron Also called: CPV in mixing Prob(K K ) Prob (K K ) ε = (2.228 ±.11 ) x 1 3 (PDG) 1999 (NA48 & KTeV): Seen in Kaon decays direct CP violaron Also called: CPV in decay Decay rates Γ(K π + π ) Γ(K π + π ) Re(ε /ε) = (1.65 ±.26) x 1 3 (PDG) James Watson Cronin 21 (Belle & Babar): Observed in B mesons decays CP violaron in interference Also called: mixing induced CPV Sin2β =.673 ±.23 (PDG) Val Logsdon Fitch Nobel prize 198 9

10 CP ViolaRon in the Standard Model Paul Dirac Peter Higgs Hideki Yukawa ) L = iψ L γ µ D µ ψ L + V (φ) + Y ij (ψ i Lφ The Yukawa flavour couplings Y ij make the theory CP violarng if they are complex. A er Spontaneous Symmetry Breaking the Yukawa terms give rise to quark masses. Expressing the quark flavour eigenstates in mass eigenstates leads to CP violarng flavour changing charged currents. The origin of CP violaron is related to the origin of mass and requires the existence of at least 3 generarons ψ j R 1

11 InteracRons between Quarks Cabibbo described V A quark interacrons with flavour changing charged currents: quark mixing A = g weak W + µ J µ+ J µ+ = ψ u 1 2 (1 γ5 ) γ µ V CKM ψ d W g weak J μ+ u, c, t d, s, b Nicola Cabibbo Makoto Kobayashi Toshihide Maskawa ParRcle AnRparRcle g weak g* weak Kobayashi and Maskawa predicted in 1972 the 3 rd quark generaron to explain CP ViolaRon within the Standard Model Nobel Prize 28 (shared with Nambu) 9 Coupling constants: g weak g V CKM 11

12 The CKM Matrix V CKM u c t d s b V ud V us V ub V cd V cs V cb V td V ts V tb 12

13 The CKM Matrix V CKM u c t d s b V ud V us V ub V cd V cs V cb V td V ts V tb Wolfenstein parametrizaron: V CKM From unitarity (V CKM V CKM =1) CKM has four free parameters: λ2 λ Aλ 3 (ρ iη) λ λ2 Aλ 2 Aλ 3 (1 ρ iη) Aλ real: λ (.22), A ( 1), ρ 1 imaginary: iη ParRcle AnRparRcle: V ij V ij * => 1 CP ViolaRng phase 13

14 The CKM Matrix V CKM u c t d s b V ud V us V ub V cd V cs V cb V td V ts V tb Wolfenstein parametrizaron: V CKM V ud V us V ub e iγ V cd V cs V cb V td e iβ V ts e iβ s V tb 14

15 Observing CP ViolaRon in B decays CP ViolaRon occurs in interference of two quantum amplitudes that have a different CP odd (as well as CP even) phase Use the phenomenon of B B mixing: Interference of direct decay and decay via mixing leads to CP violaron. Standard Model: B B phase ϕ d = arg(v td ) = 2β B s B s phase ϕ s = arg(v ts ) = 2β s 15

16 Observing CP ViolaRon in B decays CP ViolaRon occurs in interference of two quantum amplitudes that have a different CP odd (as well as CP even) phase Use the phenomenon of B B mixing: Interference of direct decay and decay via mixing leads to CP violaron. Standard Model: B B phase ϕ d = arg(v td ) = 2β B s B s phase ϕ s = arg(v ts ) = 2β s B f iϕ CP e d B B s f CP e iϕ s B s V ud V us V ub e iγ V cd V cs V cb V td e iβ V ts e iβ s V tb 16

17 Double slit experiment with quantum waves B s SM NP J/ψ ϕ LHCb is a completely analogous interference experiment using B mesons

18 Probing New Physics Flavour Physics: indirect search for new parrcles or interacrons Measure CP violaron in many B, D decay modes All observarons should be consistent with a single CP phase Measure branching rates of decays that are suppressed in SM Look for interference of CKM physics with New Physics Expect sensirvity for new physics where SM amplitudes are suppressed: loop diagrams Measure CP phases with tree decays and with loops Box diagram: ΔB=2 Penguin diagram: ΔB=1 b s s b b s μ μ 18

19 ClassificaRon of CP ViolaRon LHCb Many methods have been developed for B decays ClassificaRon more complex than direct and indirect E.g.: methods with intermediate Charm states We use also experimental classificarons Time dependent vs Time independent methods Observe CP ViolaRon as funcron of B decay Rme vs integrated over Rme Tagged vs Untagged methods Require knowledge of b flavour at producron or not I can t give a complete overview Examples of several prominent ongoing analyses 19

20 CP ViolaRon LHCb Time Integrated measurements (CP violaron in Decay): (1) Direct CP ViolaRon in charmless decay B (s) Kπ Interference of trees with penguins (2) CP ViolaRon in charmed B decays: B D K and B D π Measurement of γ with trees using ADS/GLW method Time dependent measurements (interference of mixing and decay): (3) CP violaron in charmless B (s) decays B s K + K and B π + π Measurement of γ with loops (4) CP ViolaRon in charmed B s Decays B s D s K Measurement of γ with trees (5) CP ViolaRon in B s decays to CP eigenstate B s J/ψ ϕ Measurement of B s mixing phase Φ s (β s ) CP ViolaRon in B s mixing (6) Charge asymmetry in semi leptonic decays B s D s+ X μ ν and c.c. A charming surprise: CP ViolaRon in charm (7) CP ViolaRon in two prong hadronic D decays Measurement of ΔA CP, difference of CP violaron in D K + K and D π + π 2

21 LHC 21

22 B s D s K + Primary vertex B s b tag D s B LHCb K + K + K - π - Background Suppression Flavour tagging Decay Rme measurement ~1 cm Design: LHCb event rate: ~3 MHz 1 in 16 is a b b event 1 12 b b events per year Vertex and momenta reconstrucron ParRcle idenrficaron (π, К, μ, е, γ) Trigger 22

23 Vertex Locator Vertex Topology 23

24 Momentum and Mass ReconstrucRon Trigger Tracker Magnet Outer Tracker 24

25 ParRcle IdenRficaRon: π, K, μ, γ, e RICH Calorimeter Muon 25

26 23 sep 21 19:49:24 Run Event Marcel Merk SSP

27 23 sep 21 19:49:24 Run Event Marcel Merk SSP

28 LHCb Running Ž 1.7 Ž 1 28

29 CP ViolaRon LHCb Time Integrated measurements: (1) Direct CP ViolaRon in charmless decays B (s) >Kπ. (2) CP ViolaRon in charmed decays B D K and B D π Time dependent measurements (interference of mixing and decay): (3) CP violaron in charmless B (s) decays B s KK and B ππ (4) CP ViolaRon in charmed B s decays B s D s K (5) CP ViolaRon in B s decays to CP eigenstate B s J/ψ φ CP ViolaRon in B s mixing: (6) Charge asymmetry in semi leptonic B s D s X μ ν A charming surprise: (7) CP violaron difference in D KK D ππ 29

30 (1) Direct CP ViolaRon with B (s) Kπ γ + Interference of trees and penguins New physics can contribute to penguin loop SensiRve to V ub phase: CKM angle γ Measure the untagged CP asymmetry for B and B s decays: ) (N B f N B f { A CP = ) B B f = (N K + π B f + N B s π + K B f A raw = A CP + A det + κ A prod Instrumental asymmetry Mixing diluron Rmes producron asymmetry (The correcron factor is ~1%, measured from data) 3

31 (1) Direct CP ViolaRon with B (s) Kπ γ + B K π PRL A CP =.88 ±.11 ±.8 Most precise and first 5σ observaron of CP violaron in a hadronic machine ) 2 Events / (.2 GeV/c LHCb (a).35 Ž 1 B K + π ) 2 Events / (.2 GeV/c 3 LHCb K "! 2 invariant mass (GeV/c ) K "! + invariant mass (GeV/c ) 5 (b) B #K! B s#k! B #!! B s#kk B#3-body Comb. bkg B K π + B s π K PRL A CP =.27 ±.8 ±.2 First 3σ evidence for CP asymmetry in B s decays ) 2 Events / (.2 GeV/c LHCb (c) K + "! invariant mass (GeV/c ).35 Ž 1 B s K + π ) 2 Events / (.2 GeV/c LHCb (d) B s K π K "! + invariant mass (GeV/c ) 31

33 (2) The GLW/ADS method with B DK and B Dπ Interfere decays b c with b u to final states common to D and D A(B D K ) A(B D K ) = r B e iδ B e iγ color suppression 33

34 (2) The GLW/ADS method with B DK and B Dπ Interfere decays b c with b u to final states common to D and D A(B D K ) A(B D K ) = r B e iδ B e iγ GLW method: f D is a CP eigenstate common to D and D : f D = K + K, π + π, Measure: B D K, B D K, B D 1 K Large event rate; small interference B D K Observables: Gronau, London, Wyler: Phys. LeD. B 265, 172 (1991) A CP+ = Γ ( B f D K ) Γ ( B + f D K +) Γ (B f D K )+Γ (B + f D K + ) R CP+ = Γ ( B f D K ) + Γ ( B + f D K +) Γ (B D K + ) r B e i(δ B γ) color suppression D K f D K Unknown phases: Weak phase γ Strong phase δ B 34

35 (2) The GLW/ADS method with B DK and B Dπ Interfere decays b c with b u to final states common to D and D A(B D K ) A(B D K ) = r B e iδ B e iγ ADS method: Use common flavour state f D =(K + π ) Note: decay D K + π is double Cabibbo suppressed Lower event rate; large interference Observables: Atwood, Dunietz, Soni: Phys Rev LeD 78, 3257 (1997) Phys Rev D 63, 365 (21) B A ADS = Γ ( B f D K ) Γ ( B + f D K +) Γ (B f D K )+Γ ( B + f D K +) R ADS = Γ ( B f D K ) + Γ ( B + f D K +) Γ ( B f D K ) + Γ (B + f D K + ) D K r B e i(δ B γ) r D e iδ D color suppression D K f D K Unknown phases: Weak phase γ Strong phase δ B, δ D 35

36 (2) The GLW/ADS method with B DK and B Dπ Observe ADS mode B [π K + ] D K with 1 σ significance arxiv: LHCb: 1. S 1 B [π K + ] D K B + [π + K ] D K + B DK B [π K + ] D π B + [π + K ] D π + B Dπ B DK shows 4. σ evidence of CPV: A ADS (K) = R ADS (K) = B Dπ shows 2.4σ hint of possible asym: A ADS (π) = R ADS (π) =

38 Time Dependent CP ViolaRon B f CP B s f CP e iφ d B e iφ s B s A CP (t) = Γ B f (t) Γ B f (t) Γ B f (t) +Γ B f (t) = Adir cos ( Mt) +A mix sin ( Mt) cosh ( Γ 2 t) A Γ sinh ( Γ 2 t) ( A dir ) 2 + ( A mix ) 2 + ( A Γ ) 2 =1 A dir A mix ExtracRon of and require flavour tagging: knowing the flavour of the B meson at producron 38

39 (3) Charmless B (s) decays B π + π and B s K + K + + β (s) γ A measurement of γ with loops (Fleisher: Phys.LeD.B459:36 32,1999) SensiRvity to new physics enters via the penguin loop Combined analysis of B KK, B ππ with B Kπ - Make use of U spin flavour symmetry to extract common hadronic factors A mix ππ 2β +2γ A mix KK 2β s +2γ A dir ππ 2γ A dir KK 2γ 39

40 (3) Charmless B (s) decays B π + π and B s K + K Events / ( 8 MeV/c 2 ) LHCb Preliminary s = 7 TeV B ππ Events / ( 8 MeV/c 2 ) LHCb Preliminary s = 7 TeV B s KK LHCb CONF Raw asymmetry (GeV/c ) LHCb Preliminary s = 7 TeV m!! t [ps] A dir ππ =.11 ±.21(stat) ±.3(sys) =.56 ±.17(stat) ±.3(sys) A mix ππ Raw asymmetry (GeV/c ) LHCb Preliminary s = 7 TeV m KK (t-t ) modulo (2"/!m s ) [ps] A dir KK =.2 ±.18(stat) ±.4(sys) A mix KK =.17 ±.18(stat) ±.5(sys) First (preliminary) evidence of mixing induced CP violaron seen at hadron collider (3.2σ) 4

42 (4) Charmed B s decays: B s D s K Two decay amplitudes to the same final state: 1) via mixing B s B s D s K + : β s γ : + 2) direct: B s D s K + : : Golden mode for a Rme dependent measurement of γ with trees - Hadronic uncertainres small SensiRvity to new physics enters via the mixing loop: expected to be small Combined analysis of B D s K with B s D s π: - For B s D s π only decay amplitude 2) is possible (no CP violaron) - Use B s D s π decay as a calibraron process for B s mixing 42

43 (4) Charmed B s decays: B s D s K arxiv: LHCb CONF ) 2 Events / ( 7 MeV/c 1 LHCb B s D s π.37 Ž sπ + - π + Bs D B D s B D *- π + s s B D - ρ + s s B D - π + Combinatorial A mix LHCb preliminary -1 s=7tev, 34 pb OST+SSKT ) 2 Events / ( 14 MeV/c m(d π + s ) [MeV/c ] arxiv: LHCb.37 Ž 1 B s D s K - + Bs DsK - + B DsK - + B D K - Bs Dsπ + (*)- (*)+ Bs Ds K (*)- Λb D s p (*)- Bs Ds ( π +, ρ + ) Combinatorial m(dsk ) [MeV/c ] t modulo (2" /!m s ) [ ps ] B s D s π LHCb CONF and arxiv: Flavour tagging: Opposite side: εd 2 = 3.2 ±.8 % Same side: addironal power - Measurement of B s mixing: Δm s = ±.11 ±.2 ps 1 B s D s K arxiv: Branching raro: BR = (1.9 ±.12 ±.18) x

45 (5) B s decays to a CP eigenstate: B s J/ψϕ Two decay amplitudes to the same CP eigenstate final state. 1) via mixing B s B s J/ψϕ: β s : + 2) direct: B s J/ψϕ: : Golden mode for a Rme dependent measurement of β s via mixing diagram - Hadronic uncertainres small High sensirvity to new physics that enters via the mixing loop B s is a pseudoscalar (s=) while J/ψ and ϕ are vector parrcles (s=1) Final state is superposiron of CP even (L= and L=2) CP odd (L=1) Requires angular analysis to disentangle AlternaRve analysis in pure CP odd eigenstate B s J/ψ f (98) 45

46 (5) B s decays to a CP eigenstate: B s J/ψϕ Events / 2 MeV 25 data sig. component bkg. component LHCb Preliminary 1Ž 1 B s J/ψϕ Events / LHCb Preliminary ψ θ ϕ Events /.2 ps LHCb Preliminary B s mass [MeV] data sig. component cp-even sig. component cp-odd sig. component s-wave component bkg. component complete pdf Events / LHCb Preliminary cos! CP even CP odd cos! LHCb CONF Events /.31 rad 14 LHCb Preliminary Preliminary: -2 2! [rad] Decay time t [ps] ϕ s =.1 ±.11 ±.27 rad ΔΓ s =.116 ±.18 ±.6 ps 1 ϕ s =2β s Consistent with no CP violaron as predicted in SM 46

48 CP ViolaRon in Mixing Interference of the dispersive and absorp[ve amplitudes Similar to measurement ε in kaon physics Hamiltonian: i d dt ( B s B s ) = Eigenstates: ( M11 i 2 Γ 11 M 12 i 2 Γ 12 M 12 i 2 Γ 12 M 22 i 2 Γ 22 )( B s B s ) B M 12 Γ 12 π + π > B M L,M H ; M = M H M L Γ L, Γ H ; Γ = Γ H Γ L φ 12 = arg ( M 12 /Γ 12 ) Observable: a sl = Γ ( B(t) f ) Γ ( B(t) f ) Γ ( B(t) f ) + Γ ( B(t) f ) = Γ M tan φ 12 In the Standard Model φ 12.2 for B s B factories observed no deviaron for B B s : measure with flavor specific decays: B s D s+ X µ ν and C.C.

49 Semi leptonic Charge Asymmetry LHCb: measure Rme integrated asymmetry: - Magnet up and Magnet down data LHCb CONF (ICHEP Melbourne) A meas = Γ [ Ds µ+] Γ [ D s + µ ] Γ [ Ds µ+] + Γ [ D s + ( ) µ ] = as sl 2 + κ a p as sl 2 Correct for producron asymmetry (very small!) and acceptance factor κ a sls = 2 A a s sl = (.24 ±.54 ±.33) % meas = (.24 ±.54 ±.33) % Correct for detecron asymmetry: ɛ (D s µ+) ɛ (Ds+ µ ) Agrees with SM: a sls =(.19 ±.3)% Lenz, arxiv:

51 (6) CP ViolaRon in mixing: A Charming Surprise CP ViolaRon in charm: The mixing amplitude is small. Expect no significant interference between mixing and decay Difference D D and D >D expected to be very small O(1 4 ) Direct CP violaron (in decay) Expected negligible in Cabibbo favoured modes ( Trees ) In Cabibbo suppressed mode plausible up to O( ) ExpectaRon: observaron of any CP asymmetry in charm is a sign of New Physics 51

52 (6) CP ViolaRon in mixing: A Charming Surprise CP asymmetry from charm decays: A f CP (t) = Γ D f (t) Γ D f (t) Γ D f (t) +Γ D f (t) Measure Rme integrated CP asymmetries in D π + π and D K + K Use decays D *± D π s± to tag the flavour of the D (D or D) using the charge of the slow pion π s M.Gersabeck et. al., J.Phys. G39 (212) 455 Observed asymmetry includes detector effects and possible producron asymmetry of D * A raw (f) = A CP (f) + A D (f) + A D (π s ) + A P (D + ) A f CP = adir CP (f)+ t τ aind CP Cancel these to first order by measuring difference between D π + π and D K + K: A CP A raw (KK) A raw (ππ) = A CP (KK) A CP (ππ) = [ a dir CP (KK) a dir CP (ππ) ] + t τ ContribuRon from possible indirect CP violaron term small a ind CP 52

53 (6) CP ViolaRon in mixing: A Charming Surprise CP asymmetry from charm decays: A f CP (t) = Γ D f (t) Γ D f (t) Γ D f (t) +Γ D f (t) Measure Rme integrated CP asymmetries in D π + π and D K + K (both SCS) Use decays D *± D π s± to tag the flavour of the D (D or D) using the charge of the slow pion π s M.Gersabeck et. al., J.Phys. G39 (212) 455 Observed asymmetry includes detector effects and possible producron asymmetry of D * A raw (f) = A CP (f) + A D (f) + A D (π s ) + A P (D + ) A f CP = adir CP (f)+ t τ aind CP Cancel these to first order by measuring difference between D π + π and D K + K: A CP A raw (KK) A raw (ππ) = A CP (KK) A CP (ππ) = [ a dir CP (KK) a dir CP (ππ) ] + t τ ContribuRon from possible indirect CP violaron term small a ind CP 53

54 1.4 M tagged D K + K and.4m tagged D π + π Signal Yields LHCb,.6 S 1, PRL 18, (212) Entries / (.5 MeV/c 2 ) 6 LHCb 4 2 D K + K!" Entries / (.1 MeV/c 2 ) LHCb!" D *+ D (K + K )π (%)!A CP LHCb m(k K ) (MeV/c 2 ) !m (MeV/c 2 ) -2 Entries / (.5 MeV/c 2 ) 1 LHCb #" D π + π m(!! + ) (MeV/c 2 ) Entries / (.1 MeV/c 2 ) LHCb !m (MeV/c 2 ) #" D *+ D (π + π )π Run block ΔA CP =(.82±.21(stat)±.11(sys) )% 3.5 σ deviaron from zero. Value is larger than was expected from SM before measurement was available Postdic[on: general agreement that we cannot yet exclude that it is caused by hadronic uncertainres - Currently hot acrvity in experiment and in theory. 54

55 In the news

56 Summary & Outlook CP ViolaRon: 1964 CP ViolaRon with K 21 CP ViolaRon with B 211 Evidence for CP ViolaRon with B s and CP ViolaRon with D Dominant source of CP ViolaRon consistent with CKM mechanism LHCb carrying out full physics program Looking for indirect evidence of New Physics Collected 1.8 Ž 1, expect 5 Ž 1 before upgrade Time dependent and Rme integrated CP observables for B decays Towards measurements of CKM angle γ with trees and γ with loops World best measurement of B s mixing phase ϕ s (consistent with SM β s ) World best measurement of a sl s (consistent with SM) CP violaron in charm Evidence for CP violaron in ΔA CP. Hadronic effects to be clarified. LHCb upgrade in 218 Higher luminosity: expect to collect 5 Ž 1 in the upgrade New 4 MHz Trigger, extend the physics program 56

57 Thank you for your a enron

58 (2) The GLW/ADS method with B DK and B Dπ Mass spectra for B (K+K )K and B (K+K )pi arxiv: LHCb: 1. Ž 1 ) Events / ( 5 MeV/c LHCb B [K K ] K D LHCb B [K K ] K D 8 6 LHCb LHCb B [K K ] π - D B [K K ] π D A CP (K) = R CP (K) = ± m(dh 56 ) (MeV/c 2 ) Observe a posirve asymmetry (consistent with other experiments)

59 L SM = L Kinetic + L Higgs + L Yukawa ( ) φ L Yuk = Yij d(u L I, d I + L ) i φ d I Rj +... L kinetic = g 2 u Li I γ µ W µ d I Li + g 2 d Li I γ µ W + µ u I Li +... Diagonalize Yukawa matrix Y ij Mass terms Quarks rotate Off diagonal terms in charged current couplings d I s I b I V CKM d s b L Mass = ( d, s, b ) m d m L s m b d s b R + ( u, c, t ) m u m L c m t u c t R... L CKM = g 2 u i γ µ ( 1 γ 5) W µ V ij d j + g 2 d j γ µ ( 1 γ 5) W µ V ij u i L SM = L CKM + L Higgs + L Mass Niels Tuning (59)

60 Recap Diagonalize Yukawa matrix Y ij Mass terms Quarks rotate Off diagonal terms in charged current couplings Niels Tuning (6)