Time-dependent CP violation

Transcription

1 Time-dependent CP violation experimental results and prospects Paul Seyfert on behalf of the collaboration INFN Milano Bicocca 13th October 216 Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

2 setting the scene recent results from run I golden modes φ s in B s J/ψK + K.58 ±.49 ±.6 rad sin(2β) in B J/ψK S.731 ±.35 ± CDF 9.6 fb 1.8 DØ 8fb 1 CMS 19.7 fb 1 3fb 1 Combined HFAG Summer % CL contours ( ) additional modes e.g. φ s in B s J/ψπ + π φ s in B s D + s D s.7 ±.68 ±.8 rad.2 ±.17 ±.2 rad.6 ICHEP 216 ATLAS 19.2 fb 1 SM φ s = 2β s + φ s + δ NP s β s φ s δ NP s CKM angle e.g. penguin contributions New Physics Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

3 Flavour tagging recent results from run I determines initial B flavour sensitivity σ stat 1 ε(1 2ω) 2 N ε tagging efficiency ω wrong tag rate OS tagging for any B (s) [EPJC 72 (212) 222] recently added OS charm [JINST 1 P15] SS kaon tagging for B s [JINST 11 P51] SS pion and proton tagging for B [-PAPER ] Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

4 recent results from run I B D + D β best constrained angle in the CKM triangle (b ccs transitions) complementary measurements in b ccd possible A DD (t) = Γ(B (t) D + D ) Γ(B (t) D + D ) Γ(B (t) D + D ) + Γ(B (t) D + D ) = S CP sin( m d t) C CP cos( m d t) S CP / 1 CCP 2 tree = sin(2β) B D + (K π + π + )D (K + π π ) B D ± (K K ± π ± )D (K ± π π ) 161 ± 5 candidates in run 1 (3 fb 1 ) [arxiv: ] Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

5 recent results from run I B D + D result [arxiv: ] calibration (B D + s D ) Raw mixing asymmetry t (ps) SS taggers Raw mixing asymmetry t (ps) OS taggers signal (B D + D ) Signal yield asymmetry t (ps) unprecedented tagging power ε(1 2ω) 2 = (8.1 ±.6)% partially thanks to new tagging algorithms partially due to hard momentum spectrum (don t expect the same in J/ψ modes) Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

6 recent results from run I B D + D result [arxiv: ] signal (B D + D ) Signal yield asymmetry t (ps) C CP D + D - S CP vs C CP BaBar Belle Average H F A G ICHEP 216 PRELIMINARY S CP =.54 ± (stat) ±.5(sys) HFAG:.98 ± ±.12 C CP =.26 ± (stat) ±.2(sys) HFAG:.31 ± ± S CP Contours give -2 (ln L) = χ 2 = 1, corresponding to 39.3% CL for 2 dof largest systematic uncertainty CP parameters for B D + K K + π assumed maximally biassing Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

7 recent results from run I Implications Tree (T) d(s) penguin contributions in B J/ψK S small S CP / 1 C 2 CP = sin(2β J/ψK S + φ d ) b W c c D + d(s) φ d = SU(3) symmetry: φ d = φ s controls size of penguin contributions to B s D + s D s (e.g. Bel et. al.[ ]; Jung and Schacht[ ]; Gronau et. al.[85.461]) Bd(s) d(s) Penguin (P) b Bd(s) d(s) W u, c, t g Dd(s) d(s) d(s) D d(s) + c c D d(s) d(s) Exchange (E) c b D d(s) B d(s) W d(s) d(s) d(s) D + d(s) c Penguin Annihilation (PA) c D d(s) b B d(s) W u, c, t Colour Singlet Exchange d(s) d(s) d(s) c Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16 D + d(s)

8 recent results from run I φ s in B s ψ(2s)φ φ s measurements traditionally done in B s J/ψφ never done with a higher cc resonance [HFAG] theory prediction: φ s = rad First measurement of φ s in B s ψ(2s)(µ + µ )φ(k + K ) final state no CP eigenstate angular analysis Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

9 recent results from run I B s ψ(2s)φ data (3 fb 1 ) [PLB (216) pp ] B s ψ(2s)φ (4697 ± 71 candidates) B ψ(2s)k (28676 ± 195 candidates) Candidates / (2.5 MeV/c 2 ) Candidates / (2.5 MeV/c 2 ) m(ψ(2s)k + K ) [MeV/c 2 ] m(ψ(2s)k + π ) [MeV/c 2 ] Multivariate selection for optimal statistical power new wrt. J/ψφ Data driven time acceptance from control mode new wrt. J/ψφ time resolution from prompt J/ψ µ + µ decays flavour tagging ε(1 2ω) 2 = (3.88 ±.18) % (B s system, softer than B D + D ) for comparison: B s J/ψK + K has 9569 ± 35 candidates Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

10 B s ψ(2s)φ result recent results from run I Candidates / (.1 ) cosθ K Candidates / (.1 ) cosθ µ [PLB (216) pp ] Candidates / (.314 rad ) ϕ [rad] systematics <.2σ stat (except Γ s) some systematics limited by statistics in control modes some other systematics due to fit model can be improved comparison φ s =.58±.49±.6 rad in B s J/ψK + K Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

11 recent results from run I pro τ(b s J/ψη) [arxiv: ] Another alternative to φ s measurement: B s J/ψη(γγ) CP eigenstate no angular analysis necessary con low statistics (321 ± 73 B s candidates) mass resolution worse with neutrals in the final state not yet attractive for direct φ s measurement BUT: effective lifetime holds sensitivity to φ s Fleischer et. al.[ ][ ] CP conservation B s J/ψη is a B s,l decay c 2 ) Candidates/ (12 MeV/ M(J/ψ η) [MeV/c ] Candidates/ (12 MeV/ c 2 ) M(J/ψ η) [MeV/c ] Pull 2 2 Pull 2 2 Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

12 recent results from run I τ(b s J/ψη) [arxiv: ] constrain B s/b production fractions, B q J/ψη branching fractions, and B lifetime dedicated calorimeter calibration for η γγ τ(j/ψη) = ±.34(stat) ±.11(sys)ps SM prediction: τ = (1.43±.3) ps [arxiv: ] Candidates/ (.22 ps) Pull t [ps] B D + s s Ds B s J/ψ η Avg. (CP even) 1.42 ±.2 HFAG 215 (B J/ψ φ ) s + B s K K [ps] τ L lifetime measurements with neutrals established at Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

13 upcoming analyses Ongoing activities with run I data B s J/ψ(e + e )φ yield 11 (reminder 9569 ± 35 in B s J/ψ(µ + µ )φ) B s J/ψ(µ + µ )K + K with m(k + K ) above φ(12) Candidates/ (2 MeV) B s (K + π )(K π + ) 9 combinations of K (892), K 2(143) and S wave aim for φ dd s resolution.18 rad m(k K ) (GeV) many events above the φ(12) in the m(k + K ) spectrum statistical sensitivity on φ s, Γ s and Γ s about 2 of J/ψφ Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

14 upcoming analyses... and run II data is there with run II we can double all our B (s) samples already B s φφ B s φπ + π [-PAPER ] should reach O(.1 rad) by the end of run II first run II analyses started we see this decay in run I 697 ± 3 B s candidates CP measurements with run II Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

15 what we ll do in the future going to 3 fb 1 in φ s B s J/ψK + K with 3 fb 1 φ s =.58 ±.49 ±.6 rad [PRL 114 (215) 4181] B s J/ψπ + π with 3 fb 1 φ s =.7 ±.68 ±.8 rad [PLB 736 (214) 186] + the analyses mentioned before φ s statistically limited scaling with statistics should reach mrad range theory uncertainties start to become interesting complementary modes B s D + s D s should reach O(.1 rad) B s J/ψK + K (high mass) similar φ sss s in B s φφ similarly O(.7 rad) controlling penguin contributions B J/ψρ, B J/ψω(π + π π ) (penguins to φ s) B s J/ψρ /B J/ψφ (exchange and penguin annihilation to φ s) B s J/ψK B s J/ψK S, B J/ψπ (penguins to φ d ) B s J/ψπ (exchange and penguin annihilation to φ d ) Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

16 Conclusion what we ll do in the future exploring more than just the golden modes with run I data CP violation in B D + D τ(b s J/ψη) B s ψ(2s)φ more run I analyses to come B s J/ψ(e + e )φ B s J/ψ(µ + µ )K + K at high m(k + K ) B s (K + π )(K π + ) run II and beyond updates to double statistics in preparation many analyses will stay statistically limited case for 3 fb 1 Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 16

17 Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 9

18 Lifetime measurements overview of lifetime resolutions in different final states Lifetime measurements at ±.4(stat) ±.3(sys)ps B J/ψK ±.6(stat) ±.4(sys)ps B J/ψK S ±.13(stat) ±.5(sys)ps Λ b ±.9(stat) ±.1(sys)ps B s J/ψφ 1.48 ±.11(stat) ±.5(sys)ps B s D s D s ±.26(stat) ±.17(sys)ps B s K + K 1.47 ±.16(stat) ±.7(sys)ps B s J/ψf 1.7 ±.4(stat) ±.26(sys)ps Ω b 1.78 ±.26(stat) ±.5(sys)ps ±.6(cal)ps B s D s π ±.15(stat) ±.14(sys)ps B s J/ψη ±.34(stat) ±.11(sys)ps... B + Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 9

19 ... and run II data is there run II statistics matches run I statistics already first studies show data is in excellent shape decay time resolution in run II Time Resolution [fs] Preliminary B s J/ψ φ 215 Momentum Distribution 215 Resolution 212 Resolution p [GeV/c] decay time resolution even better than in run I! Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 9

20 B D s D calibration sample ± 134 candidates for tagging calibration assume maximum oscillation and compare to observed oscillation calibrate tagging performance Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 9

21 B DD mass model [arxiv: ] signal: triple crystal ball shape (except one resolution factor) fixed from simulation B s and B share shape B s B mass difference fixed not included B Dhhh or B hhhhhh same position in mass as signal, wider resolution estimated up to 2 % of signal yield (invert D mass window) unknown CP parameter treated as systematic (generate with CP parameters opposite to signal) Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 9

22 B DD systematics S C B Dhhh ±.5 ±.13 Γ d = ±.14 ε(t) ±.7 mass time factorisation ±.7 time resolution length scale production asymmetry mass models m total sys ±.5 ±.2 stat ± ± Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 9

23 B s ψ(2s)φ BDT optimisation modified s s+b take tagging behaviour into account (weight events with low predicted mistag probability higher) take time resolution into account (weight events with good predicted decay time resolution higher) Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 9

24 B s ψ(2s)k + K systematics Source Γs Γs A 2 A 2 δ δ φs λ FS δs [ps 1 ] [ps 1 ] [rad] [rad] [rad] [rad] Stat. uncertainty Mass factorisation Mass model Angular eff. (stat.) Angular resolution Time resolution Time resolution (stat.).2.2 Time eff. (stat.) Time eff. (mass model).1.1 Time eff. (τ B ).2 B c + feed-down.1 Fit bias Quad. sum of syst Total uncertainties Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 9

25 B s J/ψη systematics Paul Seyfert (INFN MIB) time dependent CPV implications workshop / 9