Takeo Higuchi. The Belle Collaboration / The Belle II Collaboration. T.Higuchi (KEK) / EPS2011 (Grenoble) Jul.21,2011

Transcription

1 CP an CPT Violation Measurements in Decays at elle Takeo Higuchi Instituteof Particle an Nuclear Stuies, KEK The elle Collaboration / The elle II Collaboration Jul.1,11 T.Higuchi (KEK) / EPS11 (Grenoble)

2 Contents Introuction Very new CP an CPT violation measurements at elle CP violation in ⁰ (cc )K⁰ ) Latest ranching fraction of ⁰ DD an CP violation New! ranching fraction of ⁰ D*D* an CP violation New! CPT violation in ⁰ J/ψK⁰, D ( * ) h, an D*lν l New! Summary Jul.1,11 T.Higuchi (KEK) / EPS11 (Grenoble)

3 One Page Summary of KEK Factory 3 KEK accelerator elle etector t 8. GeV e x 3.5 GeV e collier Complex of vertex etector, rift to prouce pairs of mesons. chamber, PID etectors, an EM 3km in circumference. calorimeter. e (3.5GeV) KEK ring e (8.GeV) LINAC Complete ata taking on Jun.3 th, 1 to start SuperKEK/elle II upgrae. Total recore luminosity fb¹. # of Υ(4S) is 77x1⁶.

4 Manifestation of CP Violation 4 e e Υ (4 S ) The e e collision prouces a pair of mesons through Υ(4S). Mixing inuce CPV manifests itself in a signe time uration Δt t CP t tag, an a meson flavor q, where t CP time when one ecays to the CP eigenstate. t tag time when the other ecays to the flavor specific state. q 1 for tag ⁰ an 1 for tag ⁰. P sig ( Δt, q; S, A) Δt e 4τ τ [ 1± q ( Acos Δm S sin Δm Δt) Δt ] S.65 A. tag ⁰ tag ⁰ Δt (ps)

5 CPV in ⁰ (cc )K⁰ (cc)k an D ( * ) D D ( * ) Decays 5 ⁰ (cc )K⁰ ⁰ D ( * ) D ( * ) (b cc s tree transition) (b cc tree transition) ⁰ b W c c s J/ψ, ψ(s), χ c ₁ K⁰ ⁰ b W c c D ( * ) D ( * ) oth ecays are mainly meiate by a tree iagram. The iagrams inclue neither V ub nor V t φ₁ is accessible. SM preiction: S CP sinφ 1, A CP ±1 CP eigenvalue of the final state. Jul.1,11 T.Higuchi (KEK) / EPS11 (Grenoble)

6 ⁰ (cc )K⁰ (cc)k Reconstruction 6 (cc )K S ⁰ from 77 x 1⁶ pairs final elle ata sample J/ψK L ⁰ elle preliminary J/ψK S ⁰ J/ψK L ⁰ ψ(s)k S ⁰ χ c ₁K S ⁰ N (x 1⁶) Signal yiel 177± ± ±46 943±33 33 Purity[%] Signal yiel (ICHEP6) 7484±87 651±13 Purity (ICHEP6) [%] K. F. Chen et al., Phys. Rev. Lett. 98, 318 (7) for ICHEP6. Improvement ue to reprocessing with better tracking algorithm in aition to ~4% increase in N

7 Extraction of CP Violating Parameters 7 are Δt istribution ib ti P sig ( Δt, q; S, A) Δt τ e 4 τ [ 1± q ( Acos Δm Δt S sin Δm Δt) ] ackgroun contamination Δt resolution Wrong flavor etermination 4 Moifie Δt istribution P ( Δ t, q ; S, A ) wrong tag prob. f sig Δt τ e 4τ [ 1± q(1 w)( Acos Δm Δt S sin Δm Δt) ] 1 f ) P ( Δt) backgroun ( sig bkg Δt reosl. R Unbinnemaximum likelihoo fit all events ( i, qi Search for S an A that maximize L S, A) P( Δt i1 ; S, A) Jul.1,11 T.Higuchi (KEK) / EPS11 (Grenoble)

8 CPV in ⁰ (cc )K⁰ (cc)k 8 elle preliminary sin φ1.668 ±.3 ±.13 A.7 ±.16 ±.13 Entries/..5ps (cc )K S ⁰ tag ⁰ tag ⁰ 77 x 1⁶⁶ pairs ⁰ (cc)k S ⁰ J/ψK L ⁰ combine Asymmetry y Sources of systematic errors Entrie es/.5ps J/ψK L ⁰ metry Asymm Δt [ps] Jul.1,11 T.Higuchi (KEK) / EPS11 (Grenoble)

9 ranching Fraction of ⁰ DD D New! 9 ⁰ reconstruction D is reconstructe in one of D A Kππ, D K S ⁰π, an D C K S ⁰ππ⁰. D A D A D A D D A D C A A A A C from 77 x 1⁶ pairs final elle ata sample N sig 1.4±18.6 N sig 48.±8.9 N sig 54.1±14.6 F(.16±.18)x1⁴ F(1.96±.36)x1⁴ F(1.83±.49)x1⁴ elle preliminary F (.9 ±.15 ± Previous measurement (535x1⁶ pairs):.18) 1 4 S. Fratina et al., Small contribution from ⁰ DK ( * ) ⁰π to peaking backgroun is estimate t by D* mass sieban an subtracte. Sources of systematic errors 4 F (1.97 ±. ±.) 1 Phys. Rev. Lett. 98, 18 (7). Efficiency increase is larger than (cc )K⁰, because of larger track multiplicity in DD.

10 CPV in ⁰ DD D New! 1 CP violation in control sample: ⁰ D s DD S.9 ±.6, A. ±.4 consistent to zero. elle preliminary S 1.6 ±.1±.7 A.43 ±.17 ± x 1⁶ pairs ⁰ (Kππ)(Kππ) ππ)(k ππ), (Kππ)(K ππ)(k S π⁰)c )c.c. c tag ⁰ tag ⁰ Sources of systematic errors Previous measurement (535x1⁶ pairs): S 1.13 ±.37 ±.9, A.91±.3 ±.6 Unexpectely large A come closer to zero with more statistics.

11 11 ranching Fraction of ⁰ D*D* D New! ⁰ reconstruction from 77 x 1⁶ pairs final elle ata sample ⁰ is reconstructe in one of (D⁰π)(D ⁰π), (D⁰π)(Dπ⁰), c.c. Employe sub ecays of D meson: V/c² / 1.75Me D⁰ Kπ(π⁰), ( ) D⁰ Kπππ, D⁰ K S⁰ππ, D⁰ KK D Kππ, D K S ⁰π(π⁰), D KKπ F (7.8 ± elle preliminary.38 ±.6) 1 Sources of systematic errors 4 Events N sig 15±59 Mbc [GeV/c²] Previous measurement (657x1⁶ pairs): N sig 553±3 K. Vervink et al., Phys. Rev. D 8, 11114(R) (9). More tracks in the ecay final state, larger improvement.

12 CPV in ⁰ D*D* D 1 Angular analysis is neee to access the CPV in the P VV ecay Distributions of θ tr an θ₁ give polarization amplitue ratios, R₀ an R. We etermine S, A, R₀, an R simultaneously by a fit to 5 imensional (Δt, cos(θ tr ), cos(θ₁), ΔE,, M bc) ) istribution..5 Events / MC simulation cos(θ tr ) cos(θ₁) signal backgroun A A₀ A // MC simulate cos(θ tr ) an cos(θ₁) istributions with input values of R₀.55 an R.16 together with fitte curves.

13 CPV in ⁰ D*D* D New! 13 Fit result of S, A, R₀, an R S R.79 ±.13 ± A.15 ± R.6 ±.14 ±.8 ±.33 ±. ± x 1⁶ pairs e elle pre elimina ary / 1ps Events tag ⁰ tag ⁰ Sources of systematic errors Δt (ps) Events /.5 cos(θ tr ) cos(θ₁)

14 Manifestation of CPT Violation 14 CPT violating i l i complex parameter: z Re(z) an/or Im(z) The CPT is violate. The Δt istribution function with CP an CPT violation Applicable for any neutral ecay. Γ P( Δt, q; z) e Γ Δt Example of CPT violate Δt istribution ib ti in ⁰ J/ψK S ⁰ ΔΓ cosh cos Δm No CPTV (only CPV) Δt Re( )sinh ΔΓ Δt Im( ) sin Δm If CPT is violate Δt Δt A A 1 A A, 1 p q 1 z A1 A A1 A q p A f H, A f H, A Re(z). Im(z) f H, A f H, The q ±1 is taken into account of the A. tag ⁰ tag ⁰

15 15 Determination of the CPTV Parameters meson caniates in 535x1⁶ pairs Decay moes (event counts) J/ψK S ⁰(7,713), J/ψK L ⁰(1,966) Dπ(39,366), D*π(46,9), D*ρ(45,913) D*lν l (383,818) D⁰π(16,65), J/ψK(3,15) Unbinne maximum likelihoo fit # of free parameters Main physics parameters 3 Other physics parameters 5 Δt resolution function 34 Wrong tagging probabilities bbl 4 D * l ν l backgroun moel 6 Sensitivity Mainly to Re(z) an ΔΓ /Γ Mainly to Im(z) Only to Δt resolution CPTV Re(z), Im(z), ΔΓ /Γ λ CP, arg( CP λ CP ), Δm, τ ⁰, τ Two iniviual sets epening on configuration i of the silicon vertex etector

16 CPTV in ⁰ Decays New! 16 ΔΓ Re( z) Im( z) Γ elle preliminary ( 1.9 ± 3.7 ± 3.) 1 ( 5.7 ± 3.3± 6.) 1 ( 1.7 ± 1.8 ± 1.1) x 1⁶ pairs Ev vents /.4 ps J/ψK S ⁰ goo flavor tag events tag ⁰ tag ⁰ Light lines inicate Re(z). Im(z). case. arg( Other parameters CP τ Δm λ λ τ CP CP 1.531± ± ± ±.44 ).7 ±.4 (ps) (ps) (ps Above λ CP correspons to S.645, CP p, which matches elle s latest result, S.668±.3±.1. 1 ) Δt [ps] Sources of systematic errors

17 Towar SuperKEK / elle II 17 We are to start SuperKEK KEKfrom 14. x4 luminosity accelerator (8x1³⁵/cm²s), SuperKEK. More hermetic, granular, an faster signal etector, elle II. The final integrate luminosity will be 5ab¹. We hunt for new physics at the luminosity frontier. So far we have foun several hints of NP. These hints will be investigate further at SuperKEK/elle II. Present status Future prospects of elle II

18 18 Summary We have reporte very recent results relate to the CPan CPT violating parameter measurements at elle. elle preliminary CP violation ⁰ (cc)k⁰( ) sinφ₁.668±.3±.13 A.7±.16±.13 ⁰ DD D S 1.6±.1±.7 A.43±.17±.4 ⁰ D*D* D S.79±.13±.3 3 A.15±.8±. CPT violation Re(z) (1.9±3.7±3.) x 1² Im(z) ( 5.7±3.3±6.) x 1³ ΔΓ /Γ ( 1.7±1.8±1.1) 17±1 1)x 1² Jul.1,11 T.Higuchi (KEK) / EPS11 (Grenoble)

19 ackup Slies 19 Jul.1,11 T.Higuchi (KEK) / EPS11 (Grenoble)

20 CKM Matrix an Unitarity Triangle V CKM 3 V u Vus Vub 1 λ λ Aλ ( ρ i) Vc Vcs Vcb λ 1 λ Aλ 3 Vt Vts Vtb Aλ (1 ρ i) Aλ 1 Wolfenstein Parameterization Irreucible complex phases (in V ub an V t in so calle Wolfenstein parameterization) cause the CP violation. One of the unitarity conitions: V u V * ub * * V cv cb V tv tb Unitarity conition forms a untarity triangle in the complex plane. (φ 1, φ, φ 3 ) (β, α, γ) i O ρ

21 Mixing Inuce CP Violation 1 V* tb V t b t ⁰ W W ⁰ ~ (V t )² ~ e² iφ₁ t b V t V* tb ⁰ an ⁰ mix with each other through a box iagram as above. There is an interference in (⁰ f CP ) process between a irect (⁰ f CP ) ecay an a ecay through the mixing as (⁰ ⁰ f CP ). ⁰ f CP phase (V t )² ⁰ ⁰ f CP phase ff ifference φ₁φ interference CP violation ue to the interference is calle mixing inuce CP violation.

22 3 ranching Fraction of ⁰ DD D D reconstruction D is reconstructe in one of D A Kππ, D K S ⁰π, an D C K S ⁰ππ⁰. M Drec M DPDG istributions ib ti D A Kππ D K S ⁰π D C K S ⁰ππ⁰

23 CPT Violation 4 The CPT theorem is consiere a very strong constraint onto the physics laws. On the other han, a CPT violating parameter can be artificially introuce into the stanar physics moel. We can test the CPT theorem experimentally by measuringthe CPT violating parameter. Thanks to the large CP violation in the meson system, the CPT violation can be expecte to manifest itself to the measurable extent if it really exists. Jul.1,11 T.Higuchi (KEK) / EPS11 (Grenoble)

24 Mixing Inuce CPT Violation 5 Mixing Inuce CPT Violation CPT i l i CPT violating parameter: z CPT violation q p L 1 1 z q z p L Re(z) an/or Im(z) The CPT is violate In mixing q p H 1 1 z q z p H The golen Δt istribution function Re(z) an/or Im(z) The CPT is violate. Applicable for any neutral ecays with CP an CPT violations. ΔΓ ΔΓ Γ Δ ΔΓ Δ ΔΓ Γ Δ Δ Γ t t e z q t P t )sinh Re( cosh ) ;, ( Δ Δ Δ Δ t m t m sin ) Im( cos The q ±1 is taken into account of the A , A A p q A A q p z A A A A,, 1 1 H f A H f A,, 1 1 H f A H f A

25 Example of the Δt Distributions 6 rec CP eigenstate t ( CP 1); tag flavor specific final state tt (log scale) Re(z). Re(z). Re(z). Im(z). Im(z). Im(z). Δt (ps) lue for q 1 ( tag ⁰) Re for q 1 ( tag ⁰) ol soli lines for z, thin ashe lines for z. Re(z). sinφ 1.65 Re(z). Im(z). Im(z). Δt (ps) Δt (ps)

26 CPTV Measurements at Factories 7 elle Decay moes Dilepton events Amount of ata 3 fb 1 Re ( cosθ ). ±.1 ±. 1 ( cosθ ).3 ±.1. 3 Im ± Results cosθ z, sinθ 1 z N. Hastings et al., Phys. Rev. D67, 54 (3). Haronic ecays 535M This talk. ( ) 1 3 aar Dilepton 33M q p 1 (.88 ±.77 ± 1.99 ) 1 3 events Im z ( 13.9 ± 7.3± 3.) 1 ΔΓ Re z 3 ( 7.1± 3.9 ±.) 1. Aubert et al., Phys. Rev. Lett. 96, 518 (6). Haronic ecays 88M q p 1.9 ±.13±.11 Im z.38 ±.9 ±.5 (Re λ CP λ CP ) Re z.14 ±.35 ±.34 sgn(re ) ΔΓ Γ.8 ±.37 ±.18 λ CP. Aubert et al., Phys. Rev. Lett. 9, (4).