Charmless Bà VV decays

Transcription

1 Charmless Bà VV decays Antonio Romero Vidal University of San5ago de Compostela, on behalf of the LHCb Collabora5on LAKE LOUISE WINTER INSTITUTE, 17-3 February 13

2 outline Introduc5on Bà VV decay rate Triple Product Asymmetries LHCb results B s à φφ B s à K * KT* } B d,s à K S hh Foreseeable measurements Conclusions 19//13 Louise Winter Ins5tute, 17-3 february 13

3 Penguin decays Loops are par5culary sensi5ve to New Physics (NP: New heavy par5cles can enter in them. Devia5ons from the Standard Model (SM predic5on can be detected. 19//13 CP- Viola5on: Weak phases sin(β (B à φk S and φ s (B s à K * KT* and B s à φφ through a 5me- dependent analysis. f L : Longitudinal polariza5on frac5on f T : Transverse polariza5on frac5on Louise Winter Ins5tute, 17-3 february 13 Bà VV polariza5on puzzle: observed f T /f L in B à φk *, B s à φφ and B s à K * KT* in contradic5on with the naive expecta5on f T /f L <<1. 3

4 Covariant amplitude for Bà V 1 V B(p V 1 (k 1,ε 1 +V (k,ε A(B V 1 V = aε * 1 ε * + b m (p ε * 1 (p ε * + i B ε 1, : 4- vector polariza5on p = k 1 + k q = k 1 k c m ε µνρσ pµ q ν ε *ρ *σ 1 ε B a,b,c: complex quan55es containing, in general, both CP- conserving strong phases and CP- viola5ng weak phases. In Bà V 1 V decays, the final state can have total spin,1 or, which correspond to the V 1 and V having rela5ve orbital angular momentum l= (S- wave, l=1 (P- wave, or l= (D- wave, respec5vely. It is convenient to use the transversity basis: A, A and A are the longitudinal, parallel and perpendicular amplitudes in the transversity basis. 19//13 Louise Winter Ins5tute, 17-3 february 13 A = a A = ax m 1 m m B b(x 1 A = m 1 m m B c x 1 x = k 1 k m 1 m 4

5 Amplitude for B à V 1 V in the V 1 rest frame *L A(B V 1 V = A ε 1 ε *L A ε *T 1 ε *T i A ( ε *T 1 ε *T ˆp A i : A, A (CP- even and A (CP- odd Amplitudes in the transversity basis Applying CP on A(Bà V 1 V : *L A(B V 1 V = A ε 1 ε *L A ε 1, ε : ˆp : ε i *L ε i * ˆp ε i *T = ε i * ε i *L ˆp Polariza5on vectors opposite sign ε *T 1 ε *T + i A ( ε *T 1 ε *T ˆp Unit vector along the direc5on of mo5on of V Triple Product (TP (Odd under T transforma5ons (Amplitude for the CP- conjugated process 19//13 Louise Winter Ins5tute, 17-3 february 13 5

6 Triple Product asymmetries K + K + ˆn 1 ˆn ϕ V = sign(cosθ 1 cosθ sinϕ = sign(cosθ 1 cosθ ( ˆn 1 ˆn ˆp 1 θ 1 φ θ 1 φ U = sinϕ = ( ˆn 1 ˆn ( ˆn 1 ˆn ˆp 1 K B s K V and U are triple products: A V = N + V N V N + V + N = V π Im(A A * A + A + A A U = N + U N U N + U + N = 4 Im(A A * U π A + A + A θ 1( : angles between one of the daugthers of vector meson 1( with the oposite direc5on of the B (s meson. ϕ : angle between the decay planes defined by the decay products of V 1 and V. 19//13 Louise Winter Ins5tute, 17-3 february 13 The Triple Product Asymmetries (TPA are T- odd quan55es propor5onal to Im(A A * and Im(A A *. In an untagged analysis, in absence of CPV and for φ s =, the TPA vanish for every value of the decay 5me t. Any devia5on from zero would mean a CPV. We can measure the TPA just coun5ng events with V,U> and V,U<. 6

7 Bà VV decay rate Decay amplitude for Bà V 1 V and BTà VT1 VT A(B V 1 V = A cosθ 1 cosθ + A sinθ 1 sinθ cosϕ + i A sinθ 1 sinθ sinϕ A(B V 1 V = A cosθ 1 cosθ + A sinθ 1 sinθ cosϕ i A sinθ 1 sinθ sinϕ Squaring the amplitudes, we obtain the decay rate: K i f L /Γ L cos θ 1 cos θ f /Γ L f /Γ H (f f cosδ /Γ L f i sin θ 1 sin θ cos ϕ sin θ 1 sin θ sin ϕ 1/( sinθ 1 sinθ cosϕ dγ Γd cosθ 1 d cosθ dϕ = 6 i=1 K i f i (f 4 and f 6 are zero in the untagged 5me integrated analysis f L = f = f = A A + A + A A A + A + A A A + A + A (ϕ, θ 1, θ : helicity angles (Polariza5on frac5ons 19//13 Louise Winter Ins5tute, 17-3 february 13 7

8 LHCb results: B s à ϕϕ Golden channel for the measurement of the weak phase φ s in hadronic penguin decays (Raidal, arxiv, hep- ph/ ± 9 candidates in the full 11 data (1u - 1 Candidates / MeV/c S- wave LHCb 19//13 S- wave component in a ±5 MeV/c mass window around the phi nominal mass 1.3±1.% Candidates / 5 MeV/c 1 LHCb ± 9 candidates (1u (MeV/c LHCb- PAPER- 1-4 arxiv: m KKKK (MeV/c Four tracks with high probability of being a kaon are selected. Tracks have to form a vertex separated from the primary vertex. As a consecuence, very clean signal without almost background. Very good performace of the trigger and detector. m KK Louise Winter Ins5tute, 17-3 february 13 8

9 LHCb results: B s à ϕϕ angular analysis LHCb- PAPER- 1-4 arxiv: Parameter f L f f cos(δ - δ f L : longitudinal polariza5on frac5on f :perpendicular polariza5on frac5on f :parallel polariza5on frac5on Value.365±.(stat ±.1(syst.91±.4(stat ±.1(syst.344±.4(stat ±.14(syst -.844±.68(stat ±.9(syst Untagged 5me- integrated analysis was performed. Systema5cs dominated by the S- wave contamina5on and the angular acceptance. Polariza5on amplitudes in good agreement with CDF measurement. Low longitudinal polariza5on frac5on, in contradi5on with the naive expecta5on (f T /f L <<1. Candidates /. Candidates /. Candidates /.63 rad 14 b LHCb cos θ 1 14 c LHCb cos θ 14 a LHCb Φ (rad 19//13 Louise Winter Ins5tute, 17-3 february 13 9

10 LHCb results: B s à ϕϕ Triple Products Calculated as asymmetries in U=sin(ϕ and V=sign(cosθ 1 cosθ sinϕ Candidates / LHCb U V Candidates /.4 TPA Value A U A V ±.36(stat ±.18(syst.1±.36(stat ±.18(syst LHCb 19//13 Louise Winter Ins5tute, 17-3 february 13 Systema5cs dominated by the 5me acceptance. Results in agreement with CDF measurement and with no CPV. 1

11 LHCb results: B s à K * K@* First observa5on with 35pb - 1 of 1 data with very good signal to background ra5o. Β(B s K * K * = (.81±.46(stat±.45(syst±.34( f d / f s 1 5 Non negligible S- wave component in a ±15MeV/c window around the K * nominal mass. No significant B d à K * KT*. Needed to include 11+1 data. 19//13 Events / (3 MeV/c LHCb 49.8±7.5 B s B s à K * KT* B d à K * KT* background M(K π K π + (MeV/c Entries / ( 3 MeV/c 3 LHCb 1 S- wave K * mass M(Kπ (MeV/c Louise Winter Ins5tute, 17-3 february LHCb Collabora5on, R. Aaij et al., Phys. Lex. B 79 (arxiv:

12 B s à K * K * : Angular analysis Bà VV decay: Three polariza5on amplitudes f L, f and f Untagged 5me- integrated angular fit to helicity angles. f L =.3 ±.1(stat±.4(syst f =.38±.11(stat±.4(syst Remarkable difference with its U- spin partner B d à K * KT* (BaBar: f L =.8±.1(stat±.4(syst dγ dcosθ Γ 1 dϕ Γ 1 dγ LHCb cosθ LHCb.4. 19//13 Louise Winter Ins5tute, 17-3 february ϕ 1

13 Foreseeable measurements of mixing induced CPV in the VV loop diagrams Azer including all 11+1 LHCb data we expect to collect ~3 events for both B s à φφ and B s à K * KT*, enough to perform a 5me- dependent analysis. In Bà VV decays, we find contribu5ons from S- waves (i.e. f (98 in the φ mass window. The analysis we have to perform is Bà V/S+V/S (V:vector,S:scalar in reality. The decay of B in VV, VS, SV and SS can all yield to mixing- induced weak phase through a 5me- dependent analysis. The charmless three- body decay Bà K S hh (not VV permits also a 5me- dependent analysis as in the VV case. Branching ra5o analysis has been already performed (LHCb- CONF //13 Louise Winter Ins5tute, 17-3 february 13 13

14 Three body decay Bà K S h 1+ h - Poten5ally, very sensi5ve to γ angle. LHCb- CONF- 1-3 Search for the three unobserved modes B s à K S π + π -, B s à K S Kπ and B s à K S K + K - in 1u - 1 of 11 data and measurement of the branching frac5ons (BF rela5ve to the well- stablished BF of B à K S ππ from B- factories. The 5me- dependent analyses are possible with more sta5s5cs (11+1 data. The events are divided into two categories: K S candidates with informa5on only in the tracking sta5ons ( Down- Down, DD K S candidates with informa5on also in the Vertex Locator ( Long- Long,LL The candidates are requested to fit the criteria: Sum of daughters transverse momenta p T > 3 GeV/c Impact parameter (IP wrt Primary Vertex (PV of highest p T daughter >.5 mm Transverse momenta of the B candidate > 1.5 GeV/c Cuts in the quality of the tracks 19//13 Louise Winter Ins5tute, 17-3 february 13 14

15 Bà K S h 1+ h - Events / ( 1 MeV/c Events / ( 1 MeV/c 18 Preliminary Preliminary LHCb Bd K S π π Bs K π - π + S Charmed part. rec. Charmless part. rec. Cross Feed Bs K K π S Combinatorial 5 Charmed part. rec. 7 Charmless part. rec. 6 DD K DD K S 4 S DD K Cross Feed Bs K K π S S Combinatorial 5 B s à K S π + π - 3 B s à K S K + K LHCb Bd K S π π Bs K π - π + S Charmed part. rec. Charmless part. rec. Cross Feed Bs K S K π Combinatorial First evidence of the decay B s à K S ππ Sta5s5cal significance B s à K S ππ =4.3σ m π π [MeV/c ] - KS LL K S B d à K S π + π - B d à K S π + π - B s à K S π + π - m π π [MeV/c ] - KS Events / ( 1 MeV/c Events / ( 1 MeV/c LHCb Preliminary Bd K S K K Bs K - + K K S m - + KS K K LHCb Preliminary Bd K S K K Bs - + B d à K S Charmed part. rec. Charmless S K + K - part. rec. Cross Feed Bs K S K π Combinatorial LL K S B d à K S K + K - B s à K S K + K - m - + KS K K Hint of the B s à K S K + K - [MeV/c ] [MeV/c ] Events / ( 1 MeV/c Events / ( 1 MeV/c 8 LHCb Preliminary LHCb Preliminary Bd K S K π Bs K K π S Charmed part. rec. Charmless part. rec. Cross Feed Bd K S ππ Cross Feed Bd K S K K Combinatorial m K π [MeV/c KS ] LL K S B d à K S Kπ B s à K S Kπ Bd K S K π Bs K K π S Charmed part. rec. Charmless part. rec. Cross Feed Bd K S ππ Cross Feed Bd K S K K Combinatorial B d à K S Kπ B s à K S Kπ m K π [MeV/c KS ] First evidence of the decay B s à K S Kπ Sta5s5cal significance B s à K S Kπ =7.6σ 19//13 Louise Winter Ins5tute, 17-3 february 13 15

16 Bà K S h 1+ h - branching fractions BR(B K S K ± π =.117±.18(stat±.18(syst BR(B K S π + π BR(B K S K + K BR(B K S π + π =.53±.4(stat±.4(syst BR(B s K S π + π =.4 ±.6(stat±.4(syst BR(B K S π + π BR(B s K S K ± π =1.96 ±.15(stat±.(syst BR(B K S π + π BR(B s K S K + K BR(B K S π + π =.84 ±.31(stat±.19(syst Using the World Average BR(B à K S π + π - =(4.96±. 1-5 BR(B K S K ± π = (5.8±.9 ±.9 ±. 1 6 BR(B K S K + K = (.63±. ±. ± BR(B s K S π + π = (1.19 ±.3 ±. ± BR(B s K S K ± π = (9.7±.7±1. ± BR(B s K S K + K = (4. ±1.5±.9 ± //13 Louise Winter Ins5tute, 17-3 february 13 16

17 Conclusions Penguin mediated Bà VV decays are very sensi5ve to NP searches. LHCb has published first results for B s à K * KT* and B s à φφ. Extension of these analyses and new ones expected with 11 (and 1 data. Time dependent analysis in Bà VV are coming (B s à K * KT* and B s à φφ. Charmless Bà VV are golden channels for LHCb upgrade (σ(φ s =. rad for B s à K * KT* and B s à φφ 19//13 Louise Winter Ins5tute, 17-3 february 13 17

18 Backup 19//13 Louise Winter Ins5tute, 17-3 february 13 18

19 True and Fake Triple Products General amplitude contains both strong and weak phases: A k = A k e iδ k eiφ k A k = A k e iδ k e iφ k δ k: : Strong CP- conserving phase φ k : Weak CP- viola5ng phase 19//13 The power ot the TP comes from the comparison between B and Bbar: B+Bbar Im(A A * k A A * k = A A k cos(δ δ k sin(φ φ k (True Triple product : B minus Bbar (FakeTP : Im(A A k * + A A k * = A A k sin(δ δ k cos(φ φ k Louise Winter Ins5tute, 17-3 february 13 Fake TP s can only be measured in self- tagged decays (B- >φk * True TP s can be measured in flavour- neutral (B s à φφ and also in self- tagged modes. 19

20 New Physics in f T ~f L? Due to the V- A couplings and helicity conserva5on: r T = A + A = Λ QCD m b A = 1 ( A + A +, A = 1 ( A A + In the helicity formalism 19//13 In the heavy quark limit A + <<A -, so A =- A perp. Therefore A T ( vanishes. [A. Daxa, M. Duraisamy, D. London. PLB 71 (11 357] If the large f T /f L is due to SM, we should find A ( T = New Physics in f T /f L ~1 could alter this predic5on. If NP interac5ons have a different phase than the SM, the can be detected by the true TPA. If they have the same phase, then the fake TPA can discriminate. Louise Winter Ins5tute, 17-3 february 13

21 LHCb results: B s à ϕϕ systematics Candidates / MeV/c LHCb 19// (MeV/c m KK Louise Winter Ins5tute, 17-3 february 13 1

22 outline Events / ( 4 MeV/c LHCb M(J/ψ K π (MeV/c 19//13 Louise Winter Ins5tute, 17-3 february 13

23 outline Louise Winter Ins5tute, 17-3 february 13 19//13 3

24 outline Louise Winter Ins5tute, 17-3 february 13 19//13 4

25 Summary Louise Winter Ins5tute, 17-3 february 13 19//13 5

26 outline Louise Winter Ins5tute, 17-3 february 13 19//13 6

27 outline Louise Winter Ins5tute, 17-3 february 13 19//13 7

28 outline Louise Winter Ins5tute, 17-3 february 13 19//13 8

29 LHCb results: B s à ϕϕ Golden channel for the measurement of the weak phase φ s in hadronic penguin decays (Raidal, arxiv, hep- ph/ ± 9 candidates in the full 11 data (1u - 1 S- wave component in a ±5 MeV/c mass window around the phi nominal mass 1.3±1.% Candidates / 5 MeV/c 1 LHCb ± 9 candidates (1u - 1 Candidates / MeV/c S- wave (MeV/c m KK LHCb 19//13 Louise Winter Ins5tute, 17-3 february (MeV/c LHCb- PAPER- 1-4 arxiv: m KKKK 9

30 LHCb results: B s à ϕϕ angular analysis Parameter f L f perp f cos(δ - δ Candidates /.63 rad 14 a LHCb Φ (rad Value.365±.(stat ±.1(syst.91±.4(stat ±.1(syst.344±.4(stat ±.14(syst -.844±.68(stat ±.9(syst Candidates /. 14 b LHCb cos θ 1 Candidates /. LHCb- PAPER- 1-4 arxiv: c LHCb cos θ 19//13 Louise Winter Ins5tute, 17-3 february 13 Untagged 5me- integrated analysis. Polariza5on amplitudes in good agreement with CDF measurement. Low longitudinal polariza5on, in contradi5on with the naive expecta5on (f T /f L <<1. 3

31 Three body decay Bà K S h 1+ h - Decay mode BaBar BELLE World average B à K S π + π - 5. ± ± ±. B à K S K +- π ± 1. < ± 1. B à K S K + K ± ± ±.3 (New B à K S KK from BaBar not yet in the average (5.4 ± arxiv: u - 1 of 11 data analyzed. Search for the three unobserved modes B s à K S π + π -, B s à K S Kπ and B s à K S KK Measurement of the branching frac5ons (BF rela5ve to the well- stablished BF of B à K S ππ from B- factories. Poten5ally, very sensi5ve to γ angle. The 5me- dependent analyses are possible with more sta5s5cs. 19//13 Louise Winter Ins5tute, 17-3 february 13 (LHCb- CONF

32 Bà K S h 1+ h - Events / ( 1 MeV/c Events / ( 1 MeV/c 18 Preliminary Preliminary LHCb Bd K S π π - Bs K π + S π Charmed part. rec. Charmless part. rec. Cross Feed Bs K K π S Combinatorial 5 Charmed part. rec. 7 Charmless part. rec. 6 DD K DD K S 4 S DD K Cross Feed Bs K K π S S Combinatorial LHCb Bd K S π π - Bs K π + S π Charmed part. rec. Charmless part. rec. Cross Feed Bs K S K π Combinatorial First evidence of the decay B s à K S ππ Sta5s5cal significance B s à K S ππ =4.3σ m π π [MeV/c ] - KS LL K S 689±35 B d 47±18 B s 355±1 B d 4±8 B s m π π [MeV/c ] - KS Events / ( 1 MeV/c Events / ( 1 MeV/c LHCb Preliminary Bd K S K K - + Bs K S K K m - + KS K K LHCb Preliminary Bd K S K K - + Bs K S K K Charmed part. rec. Charmless part. rec. Cross Feed Bs K S K π Combinatorial LL K S 3±17 B d 13±7 B s 189±14 B d 9±4 B s m - + KS K K Hint of the B s à K S K + K - [MeV/c ] [MeV/c ] Events / ( 1 MeV/c Events / ( 1 MeV/c 8 LHCb Preliminary LHCb Preliminary Bd K S K π Bs K S K π Charmed part. rec. Charmless part. rec. Cross Feed Bd K S ππ Cross Feed Bd K S K K Combinatorial m K π [MeV/c KS ] LL K S 85±19 B d 65±3 B s Bd K S K π Bs K S K π Charmed part. rec. Charmless part. rec. Cross Feed Bd K S ππ Cross Feed Bd K S K K Combinatorial 5±11 B d 17±16 B s m K π [MeV/c KS ] First evidence of the decay B s à K S Kπ Sta5s5cal significance B s à K S Kπ =7.6σ 19//13 Louise Winter Ins5tute, 17-3 february 13 3