LHCb Physics Program On behalf of LHCb collaboration
LHCb Physics Program On behalf of LHCb collaboration M. N Minard (LAPP) Status LHCb ( R. Jacobson) Single arm spectrometer B- physics dedicated M. N Minard Aspen Winter Meeting 2009 1
Improve precision on CKM parameters • Impressive results from B factories & K sector Good agreement with SM • • Bs emerging Tevatron results Belle • • • LHCb will contribute Indirect Direct measurement Strong constraints from SM on KM sector Direct measurement : LHCb M. N Minard Aspen Winter Meeting 2009 2
LHCb hints for NP § Hints for NP contribution in loop processes as tree and box / penguin diagrams. Strong penguin EW penguin Radiative penguin Oscillation box • NP from CPV domain precision measurements : Observe deviations from SM expectations Confront measurements between channels expecting different NP interference Fs , mixing phase of the Bs system measurements • NP from rare decays high precision measurements : - Branching ratio - Time asymmetry measurements M. N Minard Aspen Winter Meeting 2009 3
LHCb apparatus characteristics • High statistics on all b and c species : – 2 fb-1: 1012 bb pairs – Heavy flavor precision experiment • • Lepton and hadron trigger (HLT) Efficient particle ID Decay time resolution Flavour tagging ε(K K) : 97% ε(π K) : 5% , K Bs Ds Primary vertex K K btag Bs→ Ds K Bs Ds(KKπ)K B 0 -> J/ K 0 s Bs →Ds Sensitivity: 236 k events/2 fb-1 (sin 2 ) = 0. 020 [B factories: 0. 025 (850 fb 1)] M. N Minard proper time resolution ~ 40 fs Aspen Winter Meeting 2009 4
Bs mixing phase s M. N Minard Aspen Winter Meeting 2009 5
Bs phase Fs b B 0 s s W c c s s b B 0 s s t W +NP? t W Lifetime B 0 s, B 0 s distributions give oscillation pattern of frequency ms and amplitude ~ sin s trough the phase in the mixing box diagram. s =-2 s s B 0 s b Φs can be extracted from CP time-dependent asymmetry decay rates : with nf = ± 1 CP eigenstate Bs J/Ψ η, Bs J/Ψ η’, Bs ηc Φ Bd Ds+ Ds- CP eigenstate Bs -> J/Ψ , mixing +-1 CP eigenstate NP may modify the mixing phase M. N Minard Aspen Winter Meeting 2009 6
Bs phase Fs (2) Current results from Tevatron: D 0 CDF s= 0. 57 + 0. 24 -0. 30 with 2. 8 fb-1 s = [0. 28, 1. 28] @ 68%CL with 2. 8 fb-1 Use of pure CP eigenstates statistic limited Bs -> J/Ψ large yield, low background mixture of CP = +1 and CP = -1 states angular analysis to disentangle the two states SM FS(Bs -> J/Ψ ) = -2 s = -0. 0368 ± 0. 0017 (ΔGs/Gs) = 0. 0092 With 10 fb-1 stat(Fs) 0. 009 > 3 for non-zero Fs of SM M. N Minard Aspen Winter Meeting 2009 7
Room for NP in Bs mixing The effects of New Physics in the oscillation can be parameterized as: M. N Minard ar. Xiv: 0810. 3139 Aspen Winter Meeting 2009 8
b sss hadronic penguin decays + NP? Bs In SM CP violation < 1% due to cancellation of the mixing and penguin phase: Bs SM 2 arg(Vts*Vtb) – arg(Vts. Vtb*) = 0 Vtb Vts Mixing box + NP? In presence of NP expect different contributions in boxes and in penguins: Bs NP = Mixing. NP - Decay. NP Mixing CP asymmetry angular analysis & time dependance of flavour tagged events For 2 fb– 1 stat( SM) = 0. 11 Bd related quark penguin Bd KS & Bd J/ KS expected precision: (sin(2 eff)) ≈0. 23 M. N Minard Channel Yield (2 fb-1) B/S (90%CL) Bs 3100 < 0. 8 Bd KS 920 < 1. 1 Aspen Winter Meeting 2009 9
related measurements M. N Minard Aspen Winter Meeting 2009 10
Fs + from Bs Ds. K 2 Trees : b->c & b->u interfere through Bs mixing Measure Fs+ . Ratio extracted from data -K id Channel Yield (2 fb-1) B/S (90%CL) B s Ds K 6200 < 0. 2 B s Ds 140 k 0. 4 Include Bs Ds to constrain ms Fit time-dependent rates of Bs→Ds. K and Bs→Ds Sensitivity with M. N Minard 2 fb– 1: Fs + 9 -12 ms 0. 007 ps-1 Aspen Winter Meeting 2009 Bs→ Ds-K+ 11
from trees: B DK • Two tree amplitudes (b c & b u) _ interfere in 0 0 decays to a common D and D state f. D For each mode parameters , (rb, db) • Exploit interference according the decay mode ( analysis from B-factories). § GLW : CP eigenstate of D (*)0 D 0 -> K+K-/ + - , Ks 0 § ADS : Use common flavor state - doubly cabbibo supressed D 0 -> K+ - Lower event rate / large asymmetry - Favoured mode: Large event rate / tiny asymmetry b c D 0 K – B– f. D(CP)K– f. D(K+p-)K– b u D 0 K – f. D(K-p+)K– § Dalitz for 3 body decays M. N Minard Aspen Winter Meeting 2009 12
from loops: B 0 d/s h+h • Interference of b u tree & b d(s) penguin diagrams leads to CP violation depending on (Sensitive to NP) • Adir & Amix depend on mixing phase 2 , , and ratio of penguin to tree amplitudes = d eiq • • NP B 0 and Bs 0 K+K- (d->s) diagrams U-spin symmetry. 4 observables: (Adir & Amix ) , (Adir & Amix )kk – Parameters : , penguin to tree amplitudes (d eiq) , , kk Yield (2 fb 1) B/S B 0 36 k 0. 5 Bs 0 K+K- 36 k 1. 5 decay Compare to from trees to get hints of NP in (g) penguins In 2 fb-1 M. N Minard 10° Winter Meeting 2009 Aspen 13
from trees: B DK B mode D mode Method Yield (2 fb-1) Bs→Ds. K KK tagged, ACP(t) 6. 2 K B+→D K+ K ADS 56 K favo B+→D K+ tree sensitivity +2 s 8. 2 K ADS KK/ counting, GLW * 9. 6 ° suppr B+→D K+ Parameter Strong phases 8. 6 k B± D 0 K 3 ADS 61 K D 0 0/D 0 GLW +ADS 42 K K+K- GLW Dalitz 1. 7 K± B± D 0*K± B± D 0 K± B 0 D 0 K*0 B→ , KK M. N Minard 18° Global fit from ADS/GLW under d. B°assumption =35° Rb K , KK, ADS+GLW 5 K 6 -25 tagged, ACP(t) 36 K 10 / d / s Aspen Winter Meeting 2009 HLT trigger K- PID Mass resolution Combine tree – 2 fb-1 ( ) : 4° 14
Rare decays M. N Minard Aspen Winter Meeting 2009 15
Rare decays seeking for NP Z, g + - NP? in Bs g B 0 K* + Bs + M. N Minard d. C 7, d. C 9 S-P coupling Z, g + - BR(SM) Large Theory Error On br - + BR exp @ LHCb « Te. Vatron (3. 35± 0. 32)· 10 -9 @ 90% CL (2 fb-1) helicity suppressed Aspen Winter Meeting 2009 < 45 10 -9 BR 16
Bs SM § Helicity suppressed – NP sensitivity in SM: BR(Bs→ ) (3. 35 ± 0. 32) x 10 -9 Ex: NUHM 1 § Enhancement from SUSY model : BR(Bs→ ) tan 6 /MH 2 Sensitive to new physics coupling with Scalar & pseudo scalar Ex : Possible enhancement BR(Bs + -)~20 x 10 -9 J. Ellis et al. ar. Xiv: 0709. 0098 v 1 [hep-ph] (2007) M. N Minard Aspen Winter Meeting 2009 17
Bs Analysis relies on : Geometry Likelihood (GL) : geometrical properties ( muon IPS, B lifetime, isolation, IP) Good mass resolution Particle ID : DLL ( - ) & DLL( -K) - Sensitive Region: GL > 0. 5 - Statistical method applied to separate signal from background (arbitrary normalizatio n) (arbitrary normalization) SM BR, in 2 fb-1 21 signal events 172 background events Major uncertainty on BR from relative Bs, B hadronization fractions 14%. Bs branching ratio determination useful M. N Minard Aspen Winter Meeting 2009 18
Bs Expected CDF+D 0 limit 8 fb-1 90% exclusion Main uncertainty hadronization fraction Within SM BR: 2 fb– 1 3 evidence 10 fb– 1 5 observation M. N Minard Aspen Winter Meeting 2009 19
B 0 K 0* + • • • Suppressed Loop FCNC process (EW penguins) Several observables to test the dynamics – Afb (s=mll 2) – Angular distributions: ql, , q. K* , Z 0 – Invariant mass + - s =(m )2 =q 2 NP can affect: – Forward-backward asymmetry AFB(s) in ql distribution – Dependence on s (predicted by several models) Zero of AFB(s) SM s 0=4. 36+0. 33 -0. 31 Ge. V 2/c 4 Example 2 fb-1 Afb experiment Mmm 2 (Ge. V 2) M. N Minard Aspen Winter Meeting 2009 20 NP
g polarization in Bs g • • Bs FCNC radiative penguin Time dependent CP asymmetry probe SM/NP – SM= Adir 0, Amix sin 2 , A cos 2 cos fraction of wrongly polarized photon tan = |b→s R| / | b→s L|~0 cos 1 • • Sensitivity ; (Adir, Amix ) = 0. 11 (A ) =0. 22 for 2 fb-1 SM extensions (left-right-symmetric, unconstrained MSSM) predict large tan while no change on inclusive BR (b s ) M. N Minard Aspen Winter Meeting 2009 21
Conclusions • LHCb is looking forward for the 1 st collisions • Interesting results can comme early ( 0. 5 fb-1) – Bs→ J/j Fs measurement with 0. 05 precision – Bs -> BR limit close SM value – Direct measurement ( ) 10° • • LHCb able to provide strong improvement in Bs sector Channels variety allows field for indirect NP discovery M. N Minard Aspen Winter Meeting 2009 22
Backup M. N Minard Aspen Winter Meeting 2009 23
Physics from (very) first data Exploit minimum bias data (almost no trigger) Number of selected signal events: 108 minimum bias @ 2 k. Hz M. N Minard Aspen Winter Meeting 2009 24
Sensitivities for 100 fb-1 Also studying Lepton Flavour Violation in M. N Minard Aspen Winter Meeting 2009 25
Upgrade • • Increase L 0 hadron bandwidth Manage a factor 110 in luminosity – Go from 1 Mhz to 40 Mhz data flow • Implications : – Electronics and detector upgrade is being investigated – Change Vertex Locator to pixels 3 D device M. N Minard Aspen Winter Meeting 2009 26
Rare decays • In the SM, b s only through loops (FCNC) implies: – Processes are rare – Powerful to find/constraint NP! • Operator Product Expansion parametrize new physics effects through # b s observables : • Observables are functions of. C’s. – Branching ratios (BR) Cs – Polarizations (C 9) – Angular distributions (C 7/C 9) • Three examples for LHCb: M. N Minard B 0 K*(K+p-) + B s + - Aspen Winter Meeting 2009 Bs (K+K-)g 27
Full 3 D Angular Analysis M. N Minard Aspen Winter Meeting 2009 28
M. N Minard Aspen Winter Meeting 2009 29
Charm Physics • • Sensitivity to NP : loop diagrams involves d quarks Mixing observed in Babar & Belle x = 0. 89± 0. 26% y = 0. 75± 0. 17% . Time-dependent D 0 mixing with wrong-sign D 0 K+ – decays. Direct CP violation in D 0 K+K– M. N Minard Aspen Winter Meeting 2009 30
• • With luminosity increase level of interest emerge: 0. 5 fb-1 • Bs→ J/j : 0. 05 precision on s • Bs -> : improved limit 2 fb -1 (1 year) CPV • from tree : 5 • from penguins 10 Bs mixing phase : 0. 023 s eff from penguins : 0. 11 Rare decays s 0 0. 5 Ge. V 2 from B K* Bs -> 6 10 -9 at 5 M. N Minard 10 fb-1 CPV from tree & loop : 4 from penguins : 6 Bs mixing phase : 0. 009 MS level Rare decays s 0 0. 3 Ge. V 2 from B K* Bs -> SM at 5 Bs-> (Ad) =0. 09 Aspen Winter Meeting 2009 31
Room for NP in Bs mixing Ligeti, Paucci, Perez, hep-ph/0604112 s 2006 including ms measurement New Physics in Bs mixing amplitude M 12 parameterized with hs and s: Additional constraints can come from semileptonic Asymmetry. In SM: ASLs 10 -5: . Bs Ds n ASLs With 2 s from Bs J/ LHCb 2 fb-1 hs LHCb expects M. N Minard hs 109 events/ 2 fb-1 d(ASLs )stat 2 x 10 -3 in 2 fb-1 Aspen Winter Meeting 2009 32
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