New Physics search with LHCb. A.Hicheur (EPF Lausanne) Moriond QCD 2008

Transcription

1 New Phyic earch with LHC A.Hicheur (EPF Lauanne) Moriond QCD 2008

2 Outline General framework decriing weak decay here to dig for NP? Studie covered in thi talk B ocillation Meaurement of ocillation parameter with c car Radiative and E penguin decay (FCNC tranition) γ ll Very rare decay: B μμ 2

3 H New phyic and B decay: where? A. Fundamental eak decay of Hadron are decried y effective Hamiltonian: eff = i Derived uing Operator Product Expanion + renormalization group Ci ( μ) Oi ( μ) to um up the radiative correction i = 1-2: 1 tree i = 3-6,8: 3 g penguin i = 7: γ penguin i = 9,10: E penguin C i ilon coefficient integrate phyic from high energy (weak cale) down to μ ~ 1 GeV cale. Perturative regime. Matrix element of operator O i : non perturative calculation C i /O i mix under RG equation: ue effective C eff i New phyic will how up through C i coefficient Loop diagram: where we expect new particle to how up ox penguin,np NP?,NP NP? B. Impact on oervale: BR, time aymmetrie, forward/ackward aymmetry, polarization, Aymmetrie le penalized y uncertaintie coming from <O< i > 3

4 LHC experiment pp 14 TeV Correlated forward production σ 500 μ Forward pectrometer Vertexing RICH ytem for PID Need prim. & vertex reco for time meaurement + uequent decay eparation Proper time reolution ~ f Primary vertex B ignal D Tracking (δp/pp/p = 0.4%) Muon detector K π PID to identify K/ π L 1 cm tag Flavour tagging 4

5 New phyic in B ocillation (+ decay) B mixing phae φ M = ϕ 2Arg[V t* V t ] = -2λ 2 η in SM prediction ~ (5% error) Sutantial deviation can e detected early Golden decay c car tudied φ D 0 Tree dominated No NP contriution in decay q= Final phae for aymmetry ratio ϕ Time dependent aymmetry: extraction of ϕ and ΔΓ (ΔM otained from control ample B D - π + ) 5

6 Senitivitie on φ Admixture of CP eigentate (η f = -1,+1) B J/ J/Ψ(μ + μ - )Φ(K + K - ) Large yield, improved enitivity with 3 angle analyi CP Even eigentate (η f = +1) B J/ J/Ψ(μ + μ - )η(γγ,π + π - π 0 ), J/Ψ(μ + μ - )η (π + π - η,ρ 0 γ), η c (h + h - h + h - )Φ(K + K - ) Low yield, high ackground B D + (K + K - π + )D - (K + K - π - ) Low yield, degradation of proper time reolution Current experimental tatu (D0, arxiv: f - 1 ): < ϕ < 90% CL (0.06< ΔΓ <0.30 p 90% CL) Decay mode Yield (/2 f - 1 ) σ(φ ) J/Ψη γγ 8.5k J/Ψη πππ0 3k J/Ψη Ψη ππη 2.2k J/Ψη Ψη ργ 4.2k 0.08 η c Φ 3k D + D - 4k All CP eig J/ΨΦ CERN-LHC LHC CERN-LHC LHC CERN-THESIS THESIS CERN-LHC LHC k All mode

7 Impact of new phyic Model-independent modeling of NP effect: Δ M = C ( ΔM ) B SM in( ϕ ) in( ϕ 2 φ ) ΔΓ = B ( ΔΓ ) 2 co (2 φb ) Two NP cenario conidered: Minimal Flavour Violation B H SM No additional CP violating phae Next to Minimal Flavour Violation tot eff i B H SM eff Poile modification of the SM phae Recent fit how >3σ NP effect and tend to rule out MFV B B = C e B 2 φ B Ratio of NP/SM Amplitude UTfit Collaoration, arxiv: See alo arxiv: New phyic phae 68%/95% pro. ith ΔM mea. Adding recent ϕ /ΔΓ mea. Look forward to firt LHC data! UTfit Collaoration, arxiv:

8 /d γ ~ μν EM dipole operator: O ( ) 7 qσ mr+ mql F μν for q γ Contrain C eff 7 (+ looe NP contrain in the C 7 -C 8 plane) Meaured X γ BR (Belle, BaBar,, CLEO) in good agreement with SM prediction Sytematic limited Motly rely on aymmetrie a a enitive proe of new phyic Direct CP aymmetry uppreed in SM Γ( γ ) Γ( Γ( γ ) + Γ( Mixing induced CP aymmetry γ R-helicity uppreed t γ /d γ R polarization uppreed y m q /m t γ γ ) < 1% γ ) /d Γ( B ( t) V γ) Γ( B ( t) V γ) ΔΓt Cco( Δmt) Sin( Δmt) coh Γ( B ( t) V γ) +Γ( B ( t) V γ) 2 C ~ 0 S m q /m NP (e.g( MSSM with R-parity R violation) can generate utantial direct CP (O (10%)) 8 and/or γ R

9 B d K *0 γ & B φγ Selection: γ: : neutral ECAL cluter without aociation to a track, tranvere energy cut to remove (π( 0 ) kg Recontruct K *0 K + π - & φ K + K - : Particle ID and IP ignificance cut applied to K/π KK & KπK vertex quality cut Ue B flight to reject ackground from prim vtx Generic ackground: incluive ar Specific ackground: B d K *0 π 0 & B φ π 0, rejected y K *0 /φ Helicity cut Yield: expect 68k B d K *0 γ and 11k B φγ evt for 2f -1 B d K *0 γ ignal and kg for ~ 13 min. running at nominal lumi. CERN-LHC LHC Senitivity to A CP maller than 1% On-going tudie on extraction of γ R fraction in B φγ CERN-LHC LHC

10 l + l - γ,z t l + l - t γ,z l + l - l + l - ν t Amplitude dominated y contriution of C eff 9, C 10, and C eff 7 Motly governed y C eff 9 2, C 10 2 and ign of C eff 7 Look for aymmetrie to etter proe ize and magnitude of coefficient 10

11 B d K *0 μ + μ - CERN-LHC LHC CERN-LHC LHC CERN-LHC LHC Lepton pair forward-ackward aymmetry a a function of = m 2 (l + l - ) = q 2 l - l + θ B 2 q eff eff A ( ˆ ) ˆ FB = C10(ReC9 + 2 C7 ) m New phyic can dratically affect A FB hape 2 A. Ali et al.,, Phy. Rev. D 55,, 4105 (1997) In particular, zero A FB point 0, A FB ( 0 )=0 i very enitive to NP and could e predicted with le theoretical uncertaintie in SM Selection require cut that don t t ditort m 2 (μ + μ - ) Removal of J/Ψ and Ψ ma window. Expect 7.2 k for 2 f - 1 (auming BR = ) A FB LHC,, for 2f -1 σ( 0 ) ~ 1.2 σ th (SM) ~0.6 A FB Theory hep-ph/ ph/ (GeV 2 ) (GeV 2 ) ith 10 f - 1 : preciion on 0 etter than theoretical uncertaintie 11

12 B + K + l + l - CERN-LHC LHC R X m a x m in = = 1 + m a x m in d Γ ( B X μμ ) d 2 d m μ O in SM 2 d Γ ( B X ee ) m d d 2 min = 4 m, max = mb mx R K (Theory) ) = 1 (to a high preciion) Phy. Rev.D69:074020, Sizeale deviation could come from Scalar and Peudo-Scalar lepton operator enhanced y neutral Higg coupling Background from X l + l - with adly recontructed X Peaking ackground from J/ψK K removed with m(ll) ) cut Expected yield for 2f -1 - B + K + μ + μ - : 3.8k, B + K + e + e - : 1.9k Experimental error on R K expected to e 4.3% for 10 f -1 μ ( ) 2 12

13 B μμ +, H +? t h 0,A 0,H 0? Z - μ + μ - t +, H +? - ν μ + μ - SM rate i uppreed y ~ m μ2 /m B2. Prediction: (current Tevatron UL i 20 time larger) Poile enhancement in CMSSM (with MFV hypothei): ame operator or a for R K hep-ph/ ph/ mm μ tan β BR( B μ + μ ) hep-ph/ ph/ M hep-ph/ ph/ A hep-ph/ ph/ Rate could e utantially enhanced Experimentally ideal for recontruction in LHC: Eay to trigger, good ma reolution (18 MeV), good μ ID Suffer from large ackground, main contriution come from μx. Comine PID, vertice and invariant ma to reduce it. Expect ~ 70 evt for 2 f -1 CERN-LHC LHC

14 B μμ: : enitivity reult 3σ oervation poile with 2f - 1, 5σ dicovery with 5f -1 Limit at 90% CL already with 0.5 f -1 14

15 Concluion Excluion limit on NP cenario will how up with the firt month of data taking Very important 2 f - 1 miletone: will know the anwer to everal quetion, e.g: φ SM or not SM? Firt exciting hint are already howing up! Zero point poition for A FB in K * ll mode? B μμ SM or not SM? After 5 year: clear view of NP impact on phyic. NP will e either uncovered or dratically contrained LHC upgrade: run with 10 x (nominal luminoity) further proe the flavour tructure of NP or Make SM CP violation preciion tet + reduce tatitical uncertaintie on rare decay 15