Latest results on B DK/Dπ decays from Belle Resmi P K (On behalf of Belle Collaboration) Indian Institute of Technology Madras Chennai, INDIA CKM 18 eptember 17, 18 Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 1 / 4
Outline Introduction Belle results B D(K π + π )K B D K GLW and AD B D(K + π π )K B D (Kπ)K B D (K π + π )K B D(K π + π π )K B D ρ Rediscoveries from Belle II data ummary sensitivity studies only Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle / 4
1 sol. w/ cos < 1 (excl. at CL >.95) CKM angles - current status η 1.5 1. sin 1.5..5 1. excluded area has CL >.95 ε K V ub 3 CKM f i t t e r ICHEP 16 3 3 excluded at CL >.95 ρ 1 & m s m d m d ε K sol. w/ cos < (excl. at CL >.95) 1.5 1..5..5 1. 1.5. Figure : Constraints on CKM parameters [1]. Current best results for CKM angles [] measured 1 = (1.9 +.7.7 ) measured 3 = (73.5 +4. 5.1 ) predicted 3 = (65.3 +1..5 ) η.7.6.5.4 excluded area has CL >.95 3 CKM f i t t e r ICHEP 16.3 η.7.6.5.4 excluded area has CL >.95 sin 1 m d m d & m s ε K CKM f i t t e r ICHEP 16.3...1 3..4....4.6.8 1. ρ Figure : Constraints from tree quantities. V ub 1 1 http://ckmfitter.inp3.fr http://www.slac.stanford.edu/xorg/hflav/triangle/moriond18/index.shtml.1 3..4....4.6.8 1. ρ Figure : Constraints from loop quantities. 1 Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 3 / 4
3 measurements from B DK decays Determine 3 via interference between B D K and B D K, tree-level diagrams 1 7 theoretical uncertainty [3]. colour allowed colour suppressed B D K V cb V us A 1 B D K V ub V cs A 1 r B e i(δb 3) The only CP-violating parameter that can be measured solely in tree-level processes. The results are statistically limited due to small branching fractions of decays involved. 3 J. Brod, J. Zupan, JHEP 1, 51 (14) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 4 / 4
3 measurements : GLW method [4] Both D and D decay to the same CP-eigenstate. CP-even: D 1 = K + K, π + π CP-odd: D = K π, K ω, K η The charge-averaged rate The partial-rate asymmetry R CP = B(B D 1, K ) + B(B + D 1, K + ) B(B D K ) + B(B + D K + ) = 1 + r B r B cos δ B cos 3 A CP = B(B D 1, K ) B(B + D 1, K + ) B(B D 1, K ) + B(B + D 1, K + ) = r B sin δ B sin 3 R CP For a multibody D decay, CP content F + needs to be considered; a dilution factor of (F + 1) on the asymmetry parameters [5]. 4 M. Gronau and D. London, PLB 53, 483 (1991); M. Gronau and D. Wyler, PLB 65, 17 (1991) 5 M. Nayak et. al., Phys. Lett. B 74, 1 (15). Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 5 / 4
3 measurements : AD method [6] Favoured B decay followed by a DC D decay, suppressed B decay followed by a CF D decay comparable amplitudes and max sensitivity. Eg: D K π The charge-averaged rate R AD = B(B [f ] D K ) + B(B + [ f ] D K + ) B(B [ f ] D K ) + B(B + [f ] D K + ) = r B + r D + r Br D cos(δ B + δ D ) cos 3 The partial-rate asymmetry A AD = B(B [f ] D K ) B(B + [ f ] D K + ) B(B [f ] D K ) + B(B + [ f ] D K + ) = r Br D sin(δ B δ D ) sin 3 R AD For multibody D decays (Eg: K π π, K π π π ), the interference term is modulated by coherence factor κ. 6 D. Atwood, I. Dunietz and A. oni, PRL 78, 3357 (1997) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 6 / 4
3 measurements : GGZ method [7] Binned Dalitz plot analysis of multibody self-conjugate D final states like K π+ π, K K + K, K π+ π π. Avoids modelling error by optimal binning. Figure : A typical Dalitz plot binning for a three body D decay. For the decay B D(K h+ h )K Γ i = K i + rb K i + K i K i (c i x + s i y ). x = r B cos(δ B 3 ); y = r B sin(δ B 3 ). 7 A. Giri, Yu. Grossman, A. offer and J. Zupan, PRD 68, 5418 (3) K i, K i - fraction of flavour-tagged D and D events. c i, s i - cos and sin of the strong phase difference between D and D averaged over the region of phase space. Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 7 / 4
3 measurements : charm inputs AD and GGZ methods need input from charm: r D, δ D coherence factor κ c i, s i New D modes can be added for GLW: 3-body final states CP-content F + Inputs from charm threshold are crucial! e + e Ψ(377) D D 1 CL 1.8.6.4 HFLAV Moriond 18 GLW AD GGZ Combined 68.3%. 95.5% 5 1 15 γ [ ] ( D D D D ) http://www.slac.stanford.edu/xorg/hflav/triangle/moriond18/index.shtml Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 8 / 4
B D(K π+ π )K (GGZ) Golden mode to determine 3 via GGZ formalism at B factories. A model-independent Dalitz analysis needs D decay inputs. Optimal binning of Dalitz plot guided by amplitude model. c i and s i in each bin measured from quantum correlated D mesons at CLEO-c [8]. 8 PRD 8, 116 (1) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 9 / 4
B D(K π+ π )K (GGZ) Full Belle data set of 711 fb 1. First model-independent Dalitz analysis : 3 = (77 +15.1 14.9 4.1 4.3) [9]. In this approach, the model uncertainty is replaced by statistical uncertainty from CLEO-c. Model-dependent analyses have model uncertainty 3 9 Latest model-dependent result (with D K) : 3 = (78.4 +1.8 11.6 3.6 8.9) [1]. For future model-independent measurements, inputs from BE III will be imperative. 9 PRD 85, 1114 (1) 1 PRD 81, 11 (1) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 1 / 4
B D(K π+ π )K (GGZ) - Belle II prospects imulations with B D(K hh)k (GGZ) More improvements needed: Continuum suppression Particle ID. 3 sensitivity 5 ab 1 σ 3 = 3. by GGZ (with 1 fb 1 BE III data) Belle II data Overall precision improvement as expected. These are conservative estimates; more studies are going on. Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 11 / 4
B D K (GLW and AD) Full Belle data set of 711 fb 1. GLW modes : KK, ππ, K π, K η GLW AD AD mode : Kπ With the CP modes for D Dπ, Dγ decays combined, A CP+ =.14.1.1 A CP = +..11.1 R D K,Dπ = [1. +.8.7 (stat)+.1. (syst)] 1 R D K,Dγ = [3.6 +1.4 1. (stat).(syst)] 1 Figure : B and B + for D CP+ To be published... Figure : B and B + for D CP Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 1 / 4
B D(K + π π )K (AD) Figure : B and B + Full Belle data set of 711 fb 1. First evidence for suppressed B DK decay with 3.σ significance [11]. Coherence factor κ close to 1 dilution due to strong phase from D decay multi-particle phase space is quite small. R DK = (1.98.6.4) 1 A DK = (.41.3.5) 1 11 PRD 88, 9114(R) (13) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 13 / 4
B D (Kπ)K (AD) Full Belle data set of 711 fb 1. elf-tagging due to K K + π decay. R DK = (4.1 +5.6 5. (stat)+.8 [1] 1.8 (syst)) 1 Figure : uppressed mode As the value is not significant, an upper limit is established. R DK <.16 (95% C.L.) Figure : Favoured mode 1 PRD 86, 1111(R) (1) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 14 / 4
B D (K π+ π )K (GGZ) Full Belle data set of 711 fb 1. First model-independent Dalitz analysis of B D K [13]. x = r s cos(δ s 3 ) y = r s sin(δ s 3 ) +1. +. x = +.4.6.1. +.8 +.1 y =.6 1...1 +.7 +. x + = +.1.4.1.1 +.5 +. y + = +.3.8.1.1 r s <.87 68% C.L. 13 PTEP, 16(4) (16) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 15 / 4
B D (K π+ π π )K (GGZ) Relatively large branching fraction of 5.% Interesting resonance substructures. K ω - CP eigenstate - GLW like. K π + π - Cabibbo-favored state (CF) - AD like. Binning the phase space around these resonances in the absence of an amplitude model. c i, s i results available with CLEO-c data. Bin Resonance c i s i 1 ω 1.11.9 +..1. K ρ +.3.5.1.3.9 +.1. 3 K + ρ.41.7 +..1.4.1 +.1. 4 K.79.9.5.44.18.6 5 K +.6.1 +.3..4..6 6 K.19.11.. 7 ρ +.8.11.3.11.19 +.4.3 8 ρ.63.18.3.3.41 +.4.3 9 remainder.69.15 +.15.1. s i 1.5 1.5 5 8 3 9 1 6 7 4 -.5-1 -1.5-1.5-1 -.5.5 1 1.5 c i Figure : c i and s i results in various bins. 14 JHEP 1, 8 (18) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 16 / 4
B D (K π+ π π )K (GGZ) Estimates of 3 sensitivity with B D(K π+ π π )K give σ 3 5 with full Belle dataset. σ 3 = 4.4 with 5 ab 1 data from Belle II. Assumed ɛ BF similar to K π+ π. Improvements expected with knowledge of an amplitude model, finer binning from a larger statistics (BE III). Analysis ongoing with full Belle dataset. Entries/ 9 χ / ndf.56 / 8 8 Constant 79.85 3.36 7 Mean 7.5.15 igma 4.384.11 6 5 4 3 1 5 55 6 65 7 75 8 85 9 γ [ ] 14 JHEP 1, 8 (18) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 17 / 4
Time-dependent measurements Time-dependent measurements possible with B D ( ) π/ρ modes. CPV induced from mixing. All physics parameters can be extracted from data using B VV decays like B D ρ. 6k B D ρ events in Belle full dataset. With angular time dependent fit, 1 + 3 can be extracted. σ( 1 + 3 ) 8 for Belle. σ( 1 + 3 ) 11 for Belle II at 5 ab 1. Analysis ongoing with full Belle dataset. Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 18 / 4
tatus of phase of Belle II experiment First collision on 6 April & completed on 17 July 18. Accumulated.5 fb 1 data Phase 3 kick-off from early 19 Target luminosities : Lint = 5 ab 1 (5 Belle) Lpeak = 8 135 cm 1 s 1 (4 KEKB) Resmi P K, IIT Madras Latest results on B DK /Dπ decays from Belle 19 / 4
Early Belle II data analysis Looked at R distribution to check if the collisions happen really at Υ(4). R is the ratio of second and zeroth Fox-Wolfram moment. FW moment is similar to multipolar expansion of vector potential. Events / (.4 ) 6 5 4 3 1 data MC total MC BB MC qq MC ττ Belle II 18 Preliminary -1 L dt = 15 pb B B events, R. q q events, R higher values. o the collisions happen at Υ(4) resonance producing B B pairs..1..3.4.5.6.7.8.9 1 R Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle / 4
Rediscovering the CP modes from phase D D(K π )π slow decays ) Entries/ (.6 GeV/c 35 *+ + D D (K π )π 3 Belle II 18 (preliminary) -1 5 L dt = 47 pb 15 ) Entries/ (.133 GeV/c *+ + 3 D D (K π )π Belle II 18 (preliminary) 5-1 L dt = 47 pb 15 1 1 5 5.14.14.144.146.148.15.15.154.156.158.16 1.7 1.75 1.8 1.85 1.9 1.95.5.1 M (GeV/c ) M (K π ) (GeV/c ) D D(K + K )π slow decays ) Entries/ (.66 MeV/c 4 35 3 5 *+ D - D (K K + )π + Belle II 18 (preliminary) -1 L dt = 47 pb ) Entries/ (5 MeV/c 5 15 *+ D - D (K K + )π + Belle II 18 (preliminary) -1 L dt = 47 pb 15 1 1 5 5.14.14.144.146.148.15.15.154.156.158.16 M (GeV/c ) 1.8 1.8 1.84 1.86 1.88 1.9 1.9 1.94 - + M (K K ) (GeV/c ) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 1 / 4
Rediscovery of D D(K π+ π (π ))π slow from phase D D(K π+ π )π slow decays ) Entries/ (.6 GeV/c 1 *+ - + D D (K π π + )π Belle II 18 (preliminary) 8-1 L dt = 47 pb 6 4 ) Entries/ (.133 GeV/c 1 1 8 6 4 *+ D D (K π - π + )π + Belle II 18 (preliminary) -1 L dt = 47 pb.14.14.144.146.148.15.15.154.156.158.16 M (GeV/c ) 1.7 1.75 1.8 1.85 1.9 1.95.5.1 - M (K π π + ) (GeV/c ) D D(K π+ π π )π slow decays ) Entries/ (.8 MeV/c 1 1 8 6 *+ D D (K π + π - π )π + Belle II 18 (preliminary) -1 L dt = 47 pb ) Entries/ (.16 GeV/c 5 45 4 35 3 5 *+ D D (K π + π - π )π + Belle II 18 (preliminary) -1 L dt = 47 pb 4 15 1 5.14.145.15.155.16 M (GeV/c ) - 1.8 1.8 1.84 1.86 1.88 1.9 1.9 M(K π + π 1.94 π ) (GeV/c ) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle / 4
Rediscovery of B meson Entries / (16 MeV) 9 8 7 6 5 4 3 1 B ->D(Kπ,K3π,Kππ B ->D(Kπ, K3π)ρ,KK,K B ->D * (Kπ, K3π, Kππ )π * B ->D (Kπ, K3π, Kππ )π * B ->D (Kπ, K3π)ρ B ->D (Kππ)π B ->D (Kππ)ρ + - + - (*) B ->J/ψ(e e, µ µ ) K () π,k ππ)π Belle II 18 (preliminary) -1 L dt = 47 pb ) Entries / (4 MeV/c 14 B ->D(Kπ,K3π,Kππ,KK,K π,k ππ)π 1 1 8 6 4 B ->D(Kπ, K3π)ρ B ->D * (Kπ, K3π, Kππ )π * B ->D (Kπ, K3π, Kππ )π * B ->D (Kπ, K3π)ρ B ->D (Kππ)π B ->D (Kππ)ρ + - + - (*) B ->J/ψ(e e, µ µ ) K () Belle II 18 (preliminary) L dt -1 = 47 pb -. -.15 -.1 -.5.5.1.15. E (GeV) 5. 5.1 5. 5.3 5.4 5.5 5.6 5.7 5.8 5.9 M bc (GeV/c ) Total 45 B candidates were found. B Dπ decays are good calibration modes for B DK for 3. Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 3 / 4
ummary Measuring 3 precisely is important to establish the tandard Model description of CP violation. Interesting analyses ongoing with full Belle dataset now. trong prospects at Belle II. B D(K π+ π )K : 3 sensitivity will improve to at least 3. B D(K π+ π π )K : 3 sensitivity will improve to 4.4 Motivation to go for 1 precision. Conservatively, combined sensitivity σ 3 = 1.6 Figure : Future (5 ab 1 Belle II data) Resmi P K, IIT Madras Latest results on B DK/Dπ decays from Belle 4 / 4