New results on flavor anomalies at LHCb Paula Álvarez Cartelle on behalf of the LHCb collaboration Dark Matter @ LHC Heidelberg, April 2018
The indirect approach Study processes that are suppressed or even forbidden in the SM - possible NP effects relatively large Precision measurement of observables that are very well predicted in the SM Access to higher mass scales, due to virtual contributions, in a model independent way 2 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 2/38 25
Flavour anomalies A) Loop level b sl + l transitions Rates and angular observables in b sµ + µ Lepton Flavour Universality tests in µ/e ratios B) Tree level b clν transitions Lepton Flavour Universality tests in µ/τ ratios The following results are obtained using the full Run1 LHCb sample (3 fb 1 ) 3 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 3/38 25
b sll transitions Flavour Changing Neutral Current (FCNC) b s(d)l + l decays, such as B 0 K 0 µ + µ, are forbidden at tree level in the SM Veto out charmonium resonances, where the hadronic process dominates 4 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 4/38 25
Branching fraction measurements Branching fractions consistently below the SM prediction for many b sµµ processes SM predictions suffer from large hadronic uncertainties 5 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 5/38 25
Angular observables - B 0 K 0 µ + µ Complementary constraints on NP & orthogonal experimental systematics Good agreement with the SM in many of the observables Possibility to construct a set of optimised observables with reduced dependence on form-factor at leading order [JHEP 1204 (2012) 104] P 5 = S 5/ F L(1 F L) 6 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 6/38 25
Global fits to b sµ + µ observables Interpretation in effective theory, in terms of couplings (C i) and local operators (O i), describing e.g. photon (C 7), vector (C 9) or axial-vector (C 10) contributions W. Altmannshofer et al. EPJC 77 (2017) 377 Best fit prefers shifted vector coupling C 9 (3 4σ depending on the group/observables included) Branching fractions and angular observables consistent 7 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 7/38 25
Hadronic effects or New Physics? Dependence of observables on the vector coupling enters through C eff 9 = C 9 + C λ 9 (q 2 ) where C λ 9 (q 2 ) contains all vector-like contributions Unaccounted for c c-loop contributions would mimic vector-like NP shifts in C 9 Big effort ongoing to improve both theory and experimental precision in order to solve this puzzle 8 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 8/38 25
Lepton flavour universality tests In the Standard Model, couplings of the gauge bosons to leptons are independent of lepton flavour branching fractions of e, µ and τ differ only by phase space and helicity-suppressed contributions Free from QCD uncertainties that may affect other observables Any sign of lepton flavour non-universality would be a direct sign for new physics l γ,z 0 l + l l + b W s b LQ s NP models accomodating LFnU, often predict Lepton Flavour Violation too See Guido s talk tomorrow on the search for B eµ decays 9 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 9/38 25
LFU in B + K + l + l [JHEP 07 (2007) 040] R SM K = BR(B+ K + µ + µ ) BR(B + K + e + e ) = 1 ± O(10 4 ) Measurement performed with 3 fb 1 of data, in 1 < q 2 < 6 GeV/c 2 R K = 0.745 +0.090 0.074 ± 0.036 Compatible with SM at 2.6σ Clear motivation to explore related LFU ratios (R K 0, R φ,...) [LHCb, PRL 113 (2014) 151601] QED corrections can be O(10 2 ) [EPJC 76 (2016) 8,440] 10 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 10/38 25
LFU in B 0 K 0 l + l [EPJC 76 (2016) 440, JHEP 04 (2017) 016, PRD 95 (2017) 035029, EPJC 77 (2017) 377, PRD 93 (2016) 014028] R SM K 0 = BR(B0 K 0 µ + µ ) BR(B + K 0 e + e ) = 1 ± O(10 3 ) R K 0 is measured in 2 bins in q 2 Low: [0.045, 1.1] GeV/c 2 Central: [1.1, 6.0] GeV/c 2 QED corrections can be O(10 2 ) [EPJC 76 (2016) 8,440] 11 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 11/38 25
Experimental challenge [LHCb, JHEP 08 (2017) 055] Differences between electrons and muons in the detector Electron Bremsstrahlung Degraded momentum, and mass/q 2 resolutions (bkg from B Kππee) Trigger less efficient for electrons Cancel most systematics arising from these differences by computing R K 0 as a double ratio B 0 K 0 µ + µ / B 0 K 0 e + e R K 0 = B 0 K 0 J/ψ(µ + µ ) B 0 K 0 J/ψ(e + e ) 12 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 12/38 25
Experimental challenge [LHCb, JHEP 08 (2017) 055] Differences between electrons and muons in the detector Electron Bremsstrahlung Degraded momentum, and mass/q 2 resolutions (bkg from B Kππee) Trigger less efficient for electrons Cancel most systematics arising from these differences by computing R K 0 as a double ratio B 0 K 0 µ + µ / B 0 K 0 e + e R K 0 = B 0 K 0 J/ψ(µ + µ ) B 0 K 0 J/ψ(e + e ) 12 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 12/38 25
R K 0 result [LHCb, JHEP 08 (2017) 055] 2.0 R K 0 1.0 0.8 R K 0 1.5 0.6 0.4 0.2 0.0 LHCb LHCb BIP CDHMV EOS flav.io JC 0 1 2 3 4 5 6 q 2 [GeV 2 /c 4 ] 1.0 0.5 0.0 LHCb LHCb BaBar Belle 0 5 10 15 20 q 2 [GeV 2 /c 4 ] R K 0(0.045 < q 2 < 1.1 GeV/c 2 ) = 0.66 +0.11 0.07 ± 0.03 R K 0(1.1 < q 2 < 6.0 GeV/c 2 ) = 0.69 +0.11 0.07 ± 0.05 Compatibility with the SM is estimated to be at the level of 2.1 2.3σ for low q 2 and 2.4 2.5σ at central q 2 13 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 13/38 25
Global fits with LFU observables Picture is consistent with b sµµ anomalies, if NP couples only to muons and not electrons [JHEP 01 (2018) 093] [PRD 96 (2017) 055008] 14 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 14/38 25
s 0 B 0 (s) µ+ µ observation [PRL 118, 191801 (2017)] Sensitive to new (pseudo)scalar or axial vector operators and precisely predicted in the SM B SM (B 0 s µ + µ ) = (3.65 ± 0.23) 10 9 B SM (B 0 µ + µ ) = (1.06 ± 0.09) 10 10 [PRL 112, 101801 (2014)] First single-experiment observation using Run1 (3 fb 1 ) + Run2 (2 fb 1 ) data B(B 0 s µ + µ ) = (3.0 ± 0.6 +0.3 0.2 ) 10 9 B(B 0 µ + µ ) < 3.4 10 10 @ 95% CL ) µ + µ BF(B 9 0.9 10 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 0 SM 68.27% 0 2 4 6 8 0 BF(B µ + s µ ) 95.45% 99.73% 99.99% LHCb 9 10 First measurement of the effective lifetime for this decay (extremely clean theoretically and complementary sensitivity) τ µµ = 2.04 ± 0.44 ± 0.05 ps 0 5 10 Decay time 15 [ps] / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 15/38 25 candidates / (1 ps) µ + µ 0 Weighted B 8 6 4 2 0 LHCb Effective lifetime fit
Search for B 0 s K µ + µ [LHCb-PAPER-2018-004 in preparation] FCNC b dll transition, CKM-suppressed with respect to b sll in the SM (B O(10 8 )) Interesting to probe MFV nature of new physics First evidence of this decay is observed with a significance of 3.4σ The branching ratio is estimated using B 0 K J/ψ B(B 0 s K µ + µ ) = (3.0 ± 1.0(stat) ± 0.2(syst) ± 0.3(ext)) 10 8 Dataset: Run1 (3 fb 1 ) + Run2 (1.6 fb 1 ) 16 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 16/38 25
LFU in trees - B 0 D + l ν l In the SM the only difference between the two decays is the mass of the lepton Theoretically clean R(D ) SM = BR( B 0 D + τ ν τ ) BR( B 0 D + µ ν = 0.252 ± 0.003 µ ) 2 measurements at LHCb Leptonic τ µ ν µν τ [PRL 115 (2015) 111803] Hadronic τ π π + π (π 0 )ν τ [arxiv:1708.08856] [S.Fajfer et al., PRD85 (2012) 094025] 17 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 17/38 25
R(D ) experimental challenge Missing neutrinos No narrow peak to fit (in any distribution) Calculate m 2 missing, q 2 and E µ in approximate rest frame Main backgrounds are partially reconstructed B decays B D µν, B D µν, B D D(µX)X... Isolation MVA used to reject physics backgrounds with additional cuts and to select control samples of specific backgrounds 18 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 18/38 25
R(D ) with τ µ ν µ ν τ [LHCb, PRL 115 (2015) 111803] Three dimensional template fit (m 2 missing, E µ, q 2 shown) Large MC samples for signal and physics backgrounds (data-driven syst.) Background from µ misid and combinatorial from data Shape and form factor dependence systematics included in the fit The obtained result R(D ) = 0.336 ± 0.027 ± 0.030 is consistent with the SM at 2.1σ level 19 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 19/38 25
R(D ) with τ π π + π (π 0 )ν τ [LHCb, arxiv:1708.08856] Measure the B(B 0 D τ + ν τ ) relative to the B 0 D 3π Use external inputs for B(B 0 D 3π) and B(B 0 D µ + ν µ) to compute R(D ) Similar experimental challenges associated with missing neutrino Main backgrounds are partially reconstructed B decays B D 3πX (τ lifetime), B DD (s) X (BDT)... 20 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 20/38 25
R(D ) with τ π π + π (π 0 )ν τ [LHCb, arxiv:1708.08856] 3D template fit to τ lifetime, q 2 and BDT output Templates are extracted from simulation and validated in data control samples Candidates / (0.25ps) 2200 2000 1800 1600 1400 1200 1000 800 600 400 200 14000 0.0005 0.001 0.0015 0.002 τ (ns) 1200 1000 800 /c 4 ) 2 Candidates / (1.375GeV 1800 1600 LHCb 1400 1200 1000 800 600 400 200 10000 5 10 2 (GeV / c 4 ) q 2 800 600 Result R(D ) = 0.286 ± 0.019 ± 0.025 ± 0.021 compatible with the SM at 1σ level Dominant systematic uncertainty comes from the size of the simulated samples 600 400 200 500 400 300 200 100 50 40 30 20 10 0 0.5 1.0 1.5 2.0 t τ [ps] 400 200 5000 5 10 2 q 2 (GeV / c 4 ) 400 300 200 100 60 Data Total model 50 B 0 D * τ + ν τ 40 B D ** τ + ν τ + B D * D s (X) + 30 B D * D (X) B D * 3π X 0 20 B D * D (X) Comb. bkg 10 0 2 4 6 8 10 2 q 2 [GeV /c 4 ] 21 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 21/38 25
R(D ( ) ) combination R(D*) BaBar, PRL109,101802(2012) 0.5 Belle, PRD92,072014(2015) LHCb, PRL115,111803(2015) Belle, PRD94,072007(2016) Belle, PRL118,211801(2017) LHCb, FPCP2017 Average 0.45 0.4 2 χ = 1.0 contours SM Predictions R(D)=0.300(8) HPQCD (2015) R(D)=0.299(11) FNAL/MILC (2015) R(D*)=0.252(3) S. Fajfer et al. (2012) 0.35 0.3 2σ 4σ 0.25 0.2 HFLAV FPCP 2017 P(χ 2 ) = 71.6% 0.2 0.3 0.4 0.5 0.6 R(D) Latest HFAG average: 4.1σ from SM expectation (Recent theory input reduces tension [JHEP 11 (2017) 061]) 22 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 22/38 25
LFU in B c J/ψl + ν l [LHCb, PRL 120, 121801 (2018)] R(J/ψ) SM = BR(B+ c J/ψτ + ν τ ) BR(B + c J/ψµ + ν µ ) [PLB 452 (1999) 129-136, arxiv:hep-ph/0211021, PRD 73 (2006) 054024, PRD 74 (2006) 074008] [0.25, 0.28] FF parameters determined from fit to normalisation mode Use τ µ ν µ ν τ decays: similar exp. method as for leptonic R(D ) 23 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 23/38 25
R(J/ψ) result [LHCb, PRL 120, 121801 (2018)] 3D template fit to m 2 miss, B+ c Z(Eµ, q 2 ) lifetime and Templates are extracted from simulation and validated in data control samples Result R(J/ψ) = 0.71 ± 0.17(stat) ± 0.18(syst) compatible with the SM at 2σ level Dominant systematic uncertainty comes from the size of the simulated samples and the B c + J/ψ FF First evidence fro the decay B c J/ψτ + ν τ 24 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 24/38 25
Summary LHCb Run1 has left us with an interesting set of anomalies B s and angular observables in b sµµ transitions Hints of lepton non-universality in loop dominated b sll processes...... and in tree level b clν decays Many new measuremens expected at LHCb that will confirm or disprove these results 25 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 25/38 25
Backup 26 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 26/38 25
LHC schedule 26 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 26/38 25
Angular observables In multibody final states, other observables sensitive to NP are accessible through the study of the angular distribution of the decay products Complementary constraints on NP & orthogonal experimental systematics For B 0 K 0 µ + µ, the final state is described by three angles Ω = {θ K, θ l, φ} and q 2 = m 2 µµ 1 d 3 (Γ + Γ) d(γ + Γ)/dq 2 = 9 [ 3 dω 32π 4 (1 F L) sin 2 θ K + F L cos 2 θ K + F L, A F B and S i contain dependence with the Wilson coefficients (C 7, C 9, C 10) and hadronic form factors + 1 4 (1 F L) sin 2 θ K cos 2θ l F L cos 2 θ K cos 2θ l + S 3 sin 2 θ K sin 2 θ l cos 2φ + S 4 sin 2θ K sin 2θ l cos φ + S 5 sin 2θ K sin θ l cos φ + 4 3 A F B sin 2 θ K cos θ l + S 7 sin 2θ K sin θ l sin φ + S 8 sin 2θ K sin 2θ l sin φ + S 9 sin 2 θ K sin 2 θ l sin 2φ ] 27 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 27/38 25
Interference with charmonia 28 / P. Álvarez Cartelle (ICL) LHCB-PAPER-2016-045-001 Flavour anomalies @ LHCb 28/38 25 At low q 2, main SM c c contribution comes from J/ψ and extends to q 2 = 0 Effect on C eff 9 strongly depends on the phase difference with the short distance process Fit B Kµµ data including resonance region with C eff 9 (q 2 ) = C 9 + j n j e iδj BW i (q 2 )
R K 0 systematics R K 0/R K 0 [%] low- q 2 central- q 2 Trigger category L0E L0H L0I L0E L0H L0I Corrections to simulation 2.5 4.8 3.9 2.2 4.2 3.4 Trigger 0.1 1.2 0.1 0.2 0.8 0.2 PID 0.2 0.4 0.3 0.2 1.0 0.5 Kinematic selection 2.1 2.1 2.1 2.1 2.1 2.1 Residual background 5.0 5.0 5.0 Mass fits 1.4 2.1 2.5 2.0 0.9 1.0 Bin migration 1.0 1.0 1.0 1.6 1.6 1.6 r J/ψ ratio 1.6 1.4 1.7 0.7 2.1 0.7 Total 4.0 6.1 5.5 6.4 7.5 6.7 29 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 29/38 25
R K 0 xchecks - control ratios Control the absolute scale of the efficiencies with the single ratio r J/ψ = B(B0 K 0 J/ψ(µ + µ )) B(B 0 K 0 J/ψ(e + e )) = 1.043 ± 0.006 ± 0.045 Independent of the decay kinematics, such as and η of the B 0 candidate and final-state particles, and the charged-track multiplicity in the event Extra checks R ψ(2s) = B(B0 K 0 ψ(2s)(µ + µ )) / B(B 0 K 0 ψ(2s)(e + e )) B(B 0 K 0 J/ψ(µ + µ )) B(B 0 K 0 J/ψ(e + e )) [2%] r γ = B(B0 K 0 γ(e + e )) B(B 0 K 0 J/ψ(e + e )) [7%] B(B 0 K 0 γ(e + e )) in good agreement with [JHEP 04 (2017) 142] 30 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 30/38 25
R K 0 x-checks - Brem. recovery Fraction of candidates [%] 80 70 60 50 40 30 20 10 LHCb 0 B K *0 γ ( e + e ) Data Simulation Fraction of candidates [%] 60 50 40 30 20 10 LHCb 0 B K *0 J/ψ Data Simulation 0 L0E L0H L0I L0E L0H L0I L0E L0H L0I 0 clusters 1 cluster 2 clusters 0 L0E L0H L0I L0E L0H L0I L0E L0H L0I 0 clusters 1 cluster 2 clusters 31 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 31/38 25
R K 0 distributions - low q 2 Fraction of candidates [%] 0.5 LHCb 2 0.045<q 2 <1.1 [GeV /c 4 ] B Data Simulation 0 K *0 µ + µ 0.4 B Data Simulation 0 K *0 e + e 0.3 0.2 0.1 Fraction of candidates [%] 0.5 LHCb 2 0.045<q 2 <1.1 [GeV /c 4 ] B Data Simulation 0 K *0 µ + µ 0.4 B Data Simulation 0 K *0 e + e 0.3 0.2 0.1 Fraction of candidates [%] 0 0.4 0.3 0.2 0.1 0.5 1 2 q 2 [GeV /c 4 ] 0.6 LHCb 2 0.045<q 2 <1.1 [GeV /c 4 ] 0.5 B Data Simulation 0 K *0 µ + µ B Data Simulation 0 K *0 e + e 0 0 0.02 0.04 0.06 0.08 0.1 θ lepton [mrad] Fraction of candidates [%] 0 800 850 900 950 + m(k π ) [MeV/c 2 ] 0.7 0.6 0.5 0.4 0.3 0.2 0.1 LHCb 2 0.045<q 2 <1.1 [GeV /c 4 ] B Data Simulation 0 K *0 µ + µ B Data Simulation 0 K *0 e + e 0 10 5 0 5 10 [mm] z vertex 32 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 32/38 25
R K 0 distributions - central q 2 Fraction of candidates [%] Fraction of candidates [%] 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 0 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 LHCb 2 1.1<q 2 <6.0 [GeV /c 4 ] B Data Simulation 0 K *0 µ + µ B Data Simulation 0 K *0 e + e 2 3 4 5 6 2 q 2 [GeV /c 4 ] LHCb 2 1.1<q 2 <6.0 [GeV /c 4 ] B Data Simulation 0 K *0 µ + µ B Data Simulation 0 K *0 e + e 0 0 0.05 0.1 0.15 0.2 θ lepton [mrad] Fraction of candidates [%] Fraction of candidates [%] 0.5 0.45 0.4 0.35 0.3 0.25 0.2 0.15 0.1 0.05 LHCb 2 1.1<q 2 <6.0 [GeV /c 4 ] B Data Simulation 0 K *0 µ + µ B Data Simulation 0 K *0 e + e 0 800 850 900 950 + m(k π ) [MeV/c 2 ] 0.8 0.7 0.6 0.5 0.4 0.3 0.2 0.1 LHCb 2 1.1<q 2 <6.0 [GeV /c 4 ] B Data Simulation 0 K *0 µ + µ B Data Simulation 0 K *0 e + e 0 10 5 0 5 10 [mm] z vertex 33 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 33/38 25
LFU prospects For ratios of B s (e.g. R K, R K 0) we could reach 1-2% precision For comparison Belle 2 expects to reach a precision of 4-5% with a 50 ab 1 dataset [S. Sandilya at CKM 2016] Angular analyses with electrons have orthogonal systematics with respect to R X s and these can also be kept under control Expect good sensitivity to differences in the angular distributions for electron/muon final states [LHCb, EOI for phase II upgrade CERN-LHCC-2017-003] 34 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 34/38 25
b dl + l transitions As for B d µ + µ /B s µ + µ and m d / m s, ratio of b s and b d decays is a test of MFV FNAL/MILC PRD93,113016 (2016) EW penguins have additional uncertainty from ratio of form factors, will need improvements from Lattice too 35 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 35/38 25
Baryonic decays Give access to different combinations of Wilson coefficients Unique sensitivity to these processes at LHCb Candidates / (8 MeV/c 2 ) 0 100 Λ pk b µ + µ data Full fit Signal 80 Background 60 40 LHCb Candidates / (8 MeV/c 2 ) 0 100 Λ pk + b µ µ + data Full fit Signal 80 Background 60 40 LHCb 20 20 5.4 5.5 5.6 5.7 5.8 m(pk µ + µ ) [GeV/c 2 ] 5.4 5.5 5.6 5.7 5.8 + m(pk µ µ + ) [GeV/c 2 ] [JHEP 06 (2017) 108] 36 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 36/38 25
Effective theory Can describe these interactions in terms of an effective Hamiltonian that describes the full theory at lower energies (µ) H eff i C i (µ)o i (µ) C i (µ) Wilson coefficient (integrating out scales above µ) O i Local operators with different Lorentz structures 37 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 37/38 25
Effective theory Can describe these interactions in terms of an effective Hamiltonian that describes the full theory at lower energies (µ) H eff i C i (µ)o i (µ) C i (µ) Wilson coefficient (integrating out scales above µ) O i Local operators with different Lorentz structures Contributions from New Physics will modify SM contributions (Wilson coefficients) or introduce new operators H eff = c NP Λ NP O NP Depending on the choice of coupling c NP (e.g. MFV inherits SM CKM suppression), access to different NP scales Λ NP (up to hundreds of TeV) Complementarity with direct searches for new particles 37 / P. Álvarez Cartelle (ICL) Flavour anomalies @ LHCb 37/38 25
The LHCb detector Forward arm spectrometer to study b- and c-hadron decays (2 < η < 5) Good vertex and impact parameter resolution (σ(ip ) = 15 + 29/pT )m) Excellent momentum resolution (σ(mb ) 25 MeV/c2 for 2-body decays) Excellent particle ID (µ ID 97% for (π µ) misid of 1-3%) Versatile & efficient trigger [JINST 3 (2008) S080005] 38 P. A lvarez Cartelle (ICL) Flavour anomalies @ LHCb /25 38/38