0.2 0.2 ? 0.0 0.0 -0.2 -0.2 -0.4 -0.4 New Physics - PowerPoint PPT Presentation

Measurement of CP Violation in B s → J / ψφ at CDF Michal Kreps for the CDF collaboration Physics Department -1 -1 CDF Run II Preliminary L = 1.35 fb CDF Run II Preliminary L = 2.8 fb ) ) SM prediction 0.6 0.6 95% C.L. 95% C.L. -1 -1 68% C.L. 68% C.L. (ps (ps 0.4 0.4 SM prediction Γ Γ ⇒ ⇒ ∆ ∆ 0.2 0.2 ? 0.0 0.0 -0.2 -0.2 -0.4 -0.4 New Physics -0.6 -0.6 -1 0 1 -1 0 1 β β (rad) (rad) s s www2.warwick.ac.uk

Discovery of CP violation Neutral kaon puzzle in late 1950s Two particles ( K 1 , K 2 ) with same mass, but different lifetime and different decay mode K 2 is CP odd and if CP is conserved can decay only to 3 π Observation of K 2 → π + π − in 1964 by Cronin and Fitch ⇔ CP is not conserved Michal Kreps – Measurement of CP Violation in Bs → J 2 17 November 2010 ψφ at CDF /

Explaining CP violation Observation by Cronin and Fitch requires ≈ 10 − 3 admixture of wrong CP state in wave function In 1973 Kobayashi and Maskawa concludes that No reasonable way to include CP violation in model with 4 quarks Introduction of CP violation needs new particles One of the suggested ways uses 6 quark model CP violation ⇔ complex phase in quark mixing (CKM) matrix V ud V us V ub A λ 3 ( ρ − i η )     1 − λ 2 / 2 λ V cd V cs V cb A λ 2 1 − λ 2 / 2  = − λ        V td V ts V tb A λ 3 (1 − ρ − i η ) − A λ 2 1 Nobel prize in 2008 Michal Kreps – Measurement of CP Violation in Bs → J 3 17 November 2010 ψφ at CDF /

Implications When Kobayashi and Maskawa proposed their explanations, only 3 quarks were known The six quark model had several implications: Existence of another 3 quarks to be seen by experiment In 1980/1981 several people predicted large CP violation in B system B A B AR 1 Start of dedicated B physics (a) Combined sin2 φ 1 . sin( ∆ m d ∆ t) 1 0.5 0 0 experiments -1 -0.5 Asymmetry − (b) ( cc ) K S ( ξ f = − 1) -1 In 2001 Belle and Babar 1 1 0 0.5 experiments observe large CP -1 0 violation in B 0 decay (c) J / ψ K L ( ξ f = + 1) -0.5 1 Asymmetry -1 0 -5 0 5 ∆ t (ps) Since then many measure- -1 ln(L/L max ) 0 -1 (d) Non- CP sample ments performed to check idea -2 1 -3 0 -4 -1 0 1 2 -1 sin2 β -8 -4 0 4 8 ∆ t (ps) Michal Kreps – Measurement of CP Violation in Bs → J 4 17 November 2010 ψφ at CDF /

Global status A λ 3 ( ρ − i η )   1 − λ 2 / 2 λ V CKM = A λ 2 1 − λ 2 / 2 − λ     A λ 3 (1 − ρ − i η ) − A λ 2 1 1.5 e x c excluded area has CL > 0.95 l u d e γ d a t C L > ∆ ∆ 1.0 0 . m & m 9 5 s d β sin 2 0.5 ∆ m d ε α K β γ η 0.0 α V ub SL α V ub τ ν -0.5 ε -1.0 K CKM γ β sol. w/ cos 2 < 0 f i t t e r (excl. at CL > 0.95) ICHEP 10 -1.5 -1.0 -0.5 0.0 0.5 1.0 1.5 2.0 ρ Michal Kreps – Measurement of CP Violation in Bs → J 5 17 November 2010 ψφ at CDF /

Are we done? Does not look to be case Many unanswered questions SM has many free parameters What is the meaning of generation, why we need more than one? What is the origin of dark matter and dark energy? How current matter-antimatter asymmetry is generated? No baryon number violation in SM CP violation in SM is many order of magnitude too small In SM cannot generate needed phase transition SM is probably just low energy approximation of final big theory of everything Michal Kreps – Measurement of CP Violation in Bs → J 6 17 November 2010 ψφ at CDF /

Role of flavor physics Several extensions of SM exists, each postulating new particles Some examples Fourth generation introduces two additional quark, V CKM is changed to 4 × 4 matrix Supersymmetry has partner for each SM particle In supersymmetry squarks/sleptons mix through 3 × 3 matrix m 2 m 2 m 2   11 12 13 m 2 m 2 m 2   21 22 23   m 2 m 2 m 2 31 32 33 Looking for indirect effects of new physics to discover it If new physics is discovered, understand which model is right one Michal Kreps – Measurement of CP Violation in Bs → J 7 17 November 2010 ψφ at CDF /

CPV in B s → J / ψφ V ud V us V ub A λ 3 ( ρ − i η )     1 − λ 2 / 2 λ V cd V cs V cb A λ 2 1 − λ 2 / 2  = − λ        V td V ts V tb A λ 3 (1 − ρ − i η ) − A λ 2 1 V ts known from unitarity Need to check also by experiment Best testing ground is decay B s → J / ψφ s s t, c, u s c b s c ¯ ¯ W + W − c s ¯ s b ¯ c ¯ ¯ ¯ t, ¯ c, ¯ u b New physics in mixing can have large effect on CP violation Search for large CP violation in B s → J / ψφ Michal Kreps – Measurement of CP Violation in Bs → J 8 17 November 2010 ψφ at CDF /

Sidenote on phases B s system is described by equation � B 0 s ( t ) � B 0 s ( t ) �� � � �� � M − i � � � i d = 2 Γ d t B 0 s ( t ) B 0 s ( t ) � ¯ � ¯ � � � � Box diagram of mixing give rise to M 12 and Γ 12 Interesting quantities and relation to observables: ∆ M s = 2 | M SM 12, s | · | ∆ s | φ s = arg( − M 12 / Γ 12 ) = φ SM s , in SM φ s = (4.2 ± 1.4) · 10 − 3 + φ ∆ s φ SM � + φ ∆ � ∆Γ s = 2 | Γ 12, s | · cos s s CP Violation in B s → J / ψφ measures φ J / Ψ φ s + δ SM Peng. + δ NP = − 2 β s + φ ∆ s Peng. in SM 2 β s = 2 arg( − V ts V ∗ tb / V cs V ∗ cb ) ≈ 0.04 With current CDF precision we really test presence of large φ ∆ s Michal Kreps – Measurement of CP Violation in Bs → J 9 17 November 2010 ψφ at CDF /

Analysis logic Principle is to measure time dependent asymmetry of CP eigenstate A = N ( B , t ) − N ( B , t ) N ( B , t ) + N ( B , t ) We need to find in data B s → J / ψφ decays Measure decay time Find out whether it was produced as B or B K l − µ K + µ B q B s K − K + Michal Kreps – Measurement of CP Violation in Bs → J 10 17 November 2010 ψφ at CDF /

Likelihood anatomy Signal PDF for single tag 1 + ξ D P s ( t , � P ( t , � ρ , ξ |D , σ t ) = ρ | σ t ) ǫ ( � ρ ) 2 +1 − ξ D P ( t , � ¯ ρ | σ t ) ǫ ( � ρ ) 2 ξ = − 1, 0, 1 is tagging decision D is event-specific dilution ǫ ( � ρ ) - acceptance function in angular space P ( t , � P ( t , � ρ | σ t )) is PDF for B s ( B s ) ρ | σ t ) ( ¯ Michal Kreps – Measurement of CP Violation in Bs → J 11 17 November 2010 ψφ at CDF /

Likelihood anatomy d 4 P ( t , � ρ ) | A 0 | 2 T + f 1 ( � ρ ) + | A � | 2 T + f 2 ( � ρ ) + | A ⊥ | 2 T − f 3 ( � ∝ ρ ) dtd � ρ | A � || A ⊥ |U ± f 4 ( � ρ ) + | A 0 || A � | cos( δ � ) T + f 5 ( � + ρ ) | A 0 || A ⊥ |V ± f 6 ( � + ρ ) T ± = e − Γ t [cosh( ∆Γ t / 2) ∓ cos(2 β s ) sinh( ∆Γ t / 2) × ∓ η sin(2 β s ) sin( ∆ m s t )] , U ± = ± e − Γ t sin( δ ⊥ − δ � ) cos( ∆ m s t ) � × cos( δ ⊥ − δ � ) cos(2 β s ) sin( ∆ m s t ) − cos( δ ⊥ − δ � ) sin(2 β s ) sinh( ∆Γ t / 2) � , ± V ± = ± e − Γ t [sin( δ ⊥ ) cos( ∆ m s t ) × cos( δ ⊥ ) cos(2 β s ) sin( ∆ m s t ) − cos( δ ⊥ ) sin(2 β s ) sinh( ∆Γ t / 2)] . ± Michal Kreps – Measurement of CP Violation in Bs → J 12 17 November 2010 ψφ at CDF /

Issue of s-wave We reconstruct B s → J / ψφ with φ → K + K − But wide resonance f 0 (980) can also decay to K + K − and ψ K + K − is also possible (called s-wave) B s → J / There are arguments that s-wave can be large Stone et al, PRD79, 07024 (2009) predicts B ( B s → J / ψ f 0 (980)) B ( f 0 (980) → ππ ) ≃ 0.2 − 0.3 B ( B s → J / ψφ ) B ( φ → KK ) Best upper bound from Belle ψ f 0 (980)) B ( f 0 (980) → ππ ) < 1.63 · 10 − 4 at 90% C.L. B ( B s → J / S-wave can contribute to reconstructed signal It is CP-odd eigenstate with its own angular and time dependence Sizeable contribution which is not accounted for can bias result ⇒ Account for it in the likelihood Michal Kreps – Measurement of CP Violation in Bs → J 13 17 November 2010 ψφ at CDF /

Treatment of s-wave Add amplitude for s-wave ⇔ four angular terms (amplitude 2 + 3 interference terms) S-wave amplitude is pure CP-odd eigenstate with its own angular dependence Strong phases vary over resonance ⇒ Need to start with K + K − mass included Relativistic Breit-Wigner propagator for p-wave Constant for s-wave Keep K + K − mass as unobserved ⇔ integrate over it Interference between p-wave and s-wave could break last symmetry Full math spelled out in arXiv:1008.4283 Michal Kreps – Measurement of CP Violation in Bs → J 14 17 November 2010 ψφ at CDF /

Previous results -1 -1 CDF Run II Preliminary L = 1.35 fb CDF Run II Preliminary L = 2.8 fb ) ) SM prediction 0.6 0.6 95% C.L. 95% C.L. -1 -1 68% C.L. 68% C.L. (ps CDF 1.35 fb − 1 (ps 0.4 0.4 SM prediction Γ Γ ∆ ∆ p-value = 15% 0.2 0.2 0.0 0.0 -0.2 -0.2 CDF 2.8 fb − 1 -0.4 -0.4 p-value = 7% New Physics -0.6 -0.6 -1 0 1 -1 0 1 β β (rad) (rad) s s CDF 2.8 fb − 1 + DØ 2.8 fb − 1 p-value = 3.4% What next? Michal Kreps – Measurement of CP Violation in Bs → J 15 17 November 2010 ψφ at CDF /