CP violation and rare decays at LHCb. Jibo HE (UCAS), for the LHCb collaboration Presented at CLHCP PKU

Transcription

1 CP violation and rare decays at LHCb Jibo HE (UCAS), for the LHCb collaboration Presented at CLHCP PKU

2 Beauty/charm production Large production 7 TeV Minibias ~60 mb Charm ~6 mb Beauty ~0.3 mb c.f. Flavor factory! Predominantly in forward/backward cones CPV and RDs at LHCb Jibo HE (UCAS) 2

3 Beauty/charm signature Compared to minibias (background) Relatively high mass à high p T Relatively long lifetime à large IP Requires excellent vertexing, tracking, PID CPV and RDs at LHCb Jibo HE (UCAS) 3

4 The LHCb experiment Dedicated to precision study of b/c-hadrons CPV and RDs at LHCb Jibo HE (UCAS) 4

5 The LHCb data flow: Run-I CPV and RDs at LHCb Jibo HE (UCAS) 5

6 The LHCb data flow: Run-I CPV and RDs at LHCb Jibo HE (UCAS) 6

7 Run-I to Run-II LHCb prospects Jibo HE (UCAS) 7

8 The turbo stream Turbo stream, µdst, event size 10 times smaller, maximize physics output! CPV and RDs at LHCb Jibo HE (UCAS) 8

9 Real-time analysis J/ψ TeV presented only one week after the data was taken CPV and RDs at LHCb Jibo HE (UCAS) 9

10 Bonus: full dimuon spectrum Useful for studies of, e.g., dark photon CPV and RDs at LHCb Jibo HE (UCAS) 10

11 LHCb luminosity prospects CPV and RDs at LHCb Jibo HE (UCAS) 11

12 Indirect searches for New Physics FCNC NP modify C i, NP introduce new O i CKM Over-constrain CKM CPV and RDs at LHCb Jibo HE (UCAS) 12

13 CP violation

14 CPV in B s àj/ψh + h - ϕ s =ϕ M -2ϕ d, small in SM, sensitive to New Physics Small penguin pollution CPV and RDs at LHCb Jibo HE (UCAS) 14

15 Latest results on ϕ s As experimental precision improves, important to control penguin contribution ATLAS, JHEP 08 (2016) 147 CMS, PLB 757 (2016) 97 LHCb, PRL 114 (2015) , PLB736 (2014) 186, arxiv: PRL 113 (2014) CPV and RDs at LHCb Jibo HE (UCAS) 15

16 Penguin pollution Small but hard to quantify from theory Using SU(3) partner, sàd CPV and RDs at LHCb Jibo HE (UCAS) 16

17 CPV in B + àj/ψπ + Similarly, B + àj/ψπ + useful to estimate penguin contribution to sin2β LHCb-PAPER Most precise estimate CPV and RDs at LHCb Jibo HE (UCAS) 17

18 CKM-γ Least well-measured angle Interference between bàu and bàc transitions q=u, X s =K +,K *+ q=d, X s =K *0 GLW/ADS CP observations => γ CPV and RDs at LHCb Jibo HE (UCAS) 18

19 CKM-γ combination at LHCb Most accurate determination of CKM-γ arxiv: Current one syst. ~2 o from CLEO strong phase measurements, BES-III can help CPV and RDs at LHCb Jibo HE (UCAS) 19

20 Λ b àpπ - h + h - CPV not-yet observed in baryon sector A cp ~20% expected in charmless Λ b decays in SM [Y. K. Hsiao et al., PRD 91 (2015) ] Λ b àpπ - h + h - : tree & loop comparable CPV and RDs at LHCb Jibo HE (UCAS) 20

21 Λ b àpπ - h + h - : signal yields arxiv: CPV and RDs at LHCb Jibo HE (UCAS) 21

22 Triple product asymmetry Search for CPV using TPA [M.Gronau, J. L. Rosner, arxiv: ] CPV and RDs at LHCb Jibo HE (UCAS) 22

23 CPV in baryon decays Measurements integrated over phase space arxiv: Local measurements 3.3σ localized CPV in Λ b àpπ - π + π - Compatible with SM First evidence of CPV in baryon decays CPV and RDs at LHCb Jibo HE (UCAS) 23

24 CPV in other Λ b decays First observation of CPV and RDs at LHCb Jibo HE (UCAS) 24

25 Observation of B 0 àk + K - B 0 àk + K -, weak annihilation QCD dynamics, CKM-γ arxiv: CPV and RDs at LHCb Jibo HE (UCAS) 25

26 Semi-leptonic asymmetries a sl quantifies CPV in mixing, using flavor specific decays, e.g., Expected to be small in SM [A. Lenz, U. Nierste JHEP 06 (2007) 072] [M. Artuso, et al., arxiv: ] CPV and RDs at LHCb Jibo HE (UCAS) 26

27 LHCb results on a sl Some tension with D0 results PRL 117 (2016) CPV and RDs at LHCb Jibo HE (UCAS) 27

28 Rare decays

29 B 0 àk *0 μ + μ - FCNC process, rates and angular distributions sensitive to NP CPV and RDs at LHCb Jibo HE (UCAS) 29

30 B 0 àk *0 μ + μ - : P 5 Updated with 3 fb -1, anomaly still there Belle s results supports deviation from SM JHEP 02 (2016) 104 CPV and RDs at LHCb Jibo HE (UCAS) 30

31 Photon polarization in B s àϕγ Photons in bàsγ mainly left-handed Time-dependent signal rate arxiv: with 24.8k 4.1k CPV and RDs at LHCb Jibo HE (UCAS) 31

32 Photon polarization in B s àϕγ Ratio between B 0 /B s as t Compatible with SM in 2σ arxiv: CPV and RDs at LHCb Jibo HE (UCAS) 32

33 B (s) àμ + μ - B (s) àl + l - attracts continuous efforts CPV and RDs at LHCb Jibo HE (UCAS) 33

34 B (s) àτ + τ - B (s) àτ + τ - not helicity suppressed in SM, predicted BR ~200 higher than B (s) àμ + μ - B(B (s) àτ + τ - ) enhanced in NP scenarios, current best limit from Babar [Babar, PRL 96 (2006) ] CPV and RDs at LHCb Jibo HE (UCAS) 34

35 B (s) àτ + τ - Using τà3πν (a 1 ) mode Normalized to BàD + D s LHCb-CONF CPV and RDs at LHCb Jibo HE (UCAS) 35

36 Σ + àpμ + μ - Hint of intermediate particle, Σ + àpp 0, X 0 àμ + μ -, mass MeV [HyperCP, PRL 94 (2005) ] P 0? CPV and RDs at LHCb Jibo HE (UCAS) 36

37 Σ + àpμ + μ - at LHCb Studied with Run-I data Σ + àpμ + μ - signal of seen, 4.0σ LHCb-CONF CPV and RDs at LHCb Jibo HE (UCAS) 37

38 P 0 àμ + μ -? Scan for P 0 in the m(μ + μ - ) within Σ + signal region, no sign of narrow peak LHCb-CONF CPV and RDs at LHCb Jibo HE (UCAS) 38

39 The LHCb upgrade Lumi, from 4x10 32 cm -2 s -1 to 20x10 32 cm -2 s -1 Increase trigger efficiency of hadronic decays èhardware trigger removed LHCb prospects Jibo HE (UCAS) 39

40 Projections after the upgrade See X. Yuan s talk this afternoon EPJC 73 (2013) 2373 LHCb prospects Jibo HE (UCAS) 40

41 Summary The LHC(b) is a flavor factory LHCb performed world-leading CPV and RD measurements, with Run-I data ϕ s,ckm-γ, CPV in baryon, a sl P 5, photon polarization, B s àτ + τ - Analysis with Run-II ongoing, stay tuned LHCb upgrade under its way CPV and RDs at LHCb Jibo HE (UCAS) 41