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Determination of Unitarity Triangle parameters Achille Stocchi LAL-Orsay Phenomenology Workshop on Heavy Flavours Ringberg Schloss 28 April – 2 May 2003
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-Introduction (Unitarity Triangle) - Statistical method – Comparison (very brief) -The measurements/theoretical inputs - Results. Determination of the Unitarity Triangle parameters
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All these topics extensively discussed at
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~ 46 theorists ~ 52 experimentalists 98 authors Organised as a coherent document 330 pages THE CKM MATRIX AND THE UNITARITY TRIANGLE (work during 12 months between the 2 Workshops) hep-ph/0304132 will be submitted as CERN-Yellow Book
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(b u)/(b c) 2 + 2, λ 1,F(1),… KK [ ( 1– ) + P] BKBK mdmd (1– ) 2 + 2 f B B B m d / m s (1– ) 2 + 2 ξ A CP (J/ψ,K S ) sin (2β) - ρη η ρ ρ η ρη 2 Λ theories which give the link from quarks to hadrons OPE /HQET/Lattice QCD …. Need to be tested,m t Standard Model+
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Short review on the inputs
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b c l V cb b sl Br Fclb )( f( 2 m b,, m c s, D (or 1/m b 3 mbmb ( Fermi movement)( also named ) 22 cb V 2 Based on OPE sl = (0.434 (1 ± 0.018)) 10 -10 MeV V cb - Inclusive Method 2% Moments of distributions HADRONIC mass, LEPTON Momentum, Photon energy b s M b,kin (1GeV) = 4.59 ± 0.08 ± 0.01GeV m c,kin. (1GeV) = 1.13 ± 0.13 ± 0.03GeV 2 = 0.31 ± 0.07 ± 0.02GeV 2 D 2 = 0.05 ± 0.04 ± 0.01GeV 2 terms 1/m b 3 (under control?)/small ! 4.23(mb(mb)) V cb (inclusive)= ( 41.4 ± 0.6 ± 0.7(theo.) ) 10 -3 Exp 2 m b,, D ….absorbed !) Pert. QCD. s, terms 1/m b 4 hep-ph/0210027 C.Bauer,Z.Ligeti,M.Luke,A.Manohar hep-ph/0210319, M.Battaglia et al. (P.Gambino,N.Uraltsev) hep-ph/0302262 D. Benson,I.Bigi,T.Mannel,N.Uralstev
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Based on HQET At zero recoil (w=1), as M Q F(1) 1 V cb -Exclusive Method 38.1 ± 1.0F(1) |V cb |= F(1) |V cb 22 V cb (exclusive)= ( 42.1± 1.1 ± 1.9 ) 10 -3 F(1) ~ 0.91 ± 0.04
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V ub Inclusive methods B X u l + (End Point) b u b c b u \\\\ b c Backgr. BABAR Backg. substructed b c b u b c b u DELPHI CLEO D Fit q2 and M X E l
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Conservative approach syst. fully correlated V ub = ( 4.09 ± 0.46 ± 0.36) 10 -3
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Exclusive methods B ( l … Error : dominated by form factor errors as F(1) in V cb V ub = ( 3.30 ± 0.24 ± 0.46) 10 -3 Common to all analyses
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Oscillations in B 0 d system : m d d, sb b t,c,u WW WW B 0 d,s t,c,u V ts V td ))1(( 222 2 2 cbBB d VBf m dd 2 2 2 2 tdcbBB VVBf dd m d = 0.502 ± 0.006 ps -1 LEP/SLD/CDF/B-factories ( today dominated by Belle-BaBar ) Precise measurement (1.2%)
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m s > 14.4 ps -1 at 95% CL Sensitivity at 19.3 ps -1 LEP/SLD/CDF-I Oscillations in B 0 s system : m s 2 2 2 2 cbBBtdBBs VBfVBfm ssss
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1.02±0.02 Calculation partially unquenched (N f =2 or 2+1) in agreement Chiral extrapolation : light quarks simulated typically in a range [m s /2 - m s ]
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(syst not correlated ~m b ) Calculation partially unquenched (N f =2 or 2+1) in agreement 1.09±0.06 1.05±0.15 unquenching factor 1.05±0.05 SU(3) effects factor
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CP violation comes from interference between decays with and without mixing mixing decay
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Determination of V ud, V us Attributing it to an understimate of syst. error (theo/exp) or (an unlikely stat. fluctuaction) inflate the error V us = 0.2240 ± 0.0036 Neutron decay transition of J P =0 + nuclei K l3 decays : K l V ud =0.9736 ± 0.0005 V us = 0.2196 ± 0.0026 Using unitarity V 2 ud +V 2 us +V 2 ub =1, (V us ) = 1/ (V ud ) V us = 0.2269 ± 0.0021 2.2 discrepancy 1%
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Rfit Bayesian p.d.f. from convolution (sum in quadrature) Likelihood Delta Likelihood Likelihood summing linearly the two errors Delta Likelihood [0.68-1.06] [0.76-0.98]At 68% CL Scan Treatment of the inputs Ex : B K = 0.86 ± 0.06 (Gaus.) ± 0.14 (theo.)
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FIT COMPARISON-same inputs Quantitative differences in the selected ( ) regions between Bayesian and frequentist are small Ratio between sizes of intervals corresponding to a given CL
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Both methods use the same likelihood Conclusion of the CERN Workshop: “The main origin of the difference on the output quantities between the Bayesian and the Rfit method comes from the likelihood associated to the input quantities” “ If same (and any) likelihood are used the output results are very similar ”
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ParameterValueError(Gaussian)Error(Flat) 0.22400.036 V cb ( 10 -3 ) (excl.) 42.12.1 V cb ( 10 -3 ) (incl.) 41.60.70.6 V ub ( 10 -4 ) (excl.) 33.02.44.6 V ub ( 10 -4 ) (incl.) 40.94.63.6 m d (ps -1 ) 0.5030.006 m s (ps -1 ) > 14.4 ps -1 at 95% CL m t (GeV)1675 m c (GeV)1.30.1 (MeV)2233312 1.240.040.06 BKBK 0.860.060.14 sin2 0.7340.054
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If the theoretical/statistical errors are - Convoluted (Bayesian) - Linearly (frequentist-Rfit) V cb know at ~2% Differences if : (difference of ~20% @ 95% C.L.) V cb = ( 41.5 ± 0.8) 10 -3 No correlation between the incl/excl measurements Combination of V cb and V ub incl/excl V ub know at ~10% V ub = ( 35.7 ± 3.1) 10 -4 Precision driven by incl. method
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Results on Unitarity Triangle parameters Buras,Ciuchini,Franco,Lubicz,Martinelli,Parodi,Roudeau,Silvestrini,Stocchi
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sin2 0.734 ± 0.054 (0.628 - 0.840) B J/ K 0 s Coherent picture of CP Violation in SM from sides-only Crucial Test of the SM in the fermion sector
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Fit of the Unitarity Triangle in SM
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Indirect determination of the UT angles : sin2α, sin2β and γ > 90° Prob~0.001 90° Without m s > 90° Prob~0.005
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RED: WITH ALL CONSTRAINTS / BLUE: WITHOUT Δ m s By removing the constraint from Δm s : γ = (65 ± 7)° → γ = (60 ± 9)° > 90° Prob~0.005
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Prediction for m s Without limit on m s With limit on m s
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Indirect determination of the non-perturbative QCD parameters
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V ub / V cb m d / m s A CP (J/ψ,K S ) Using : So in particular knowing V ub / V cb A CP (J/ψ,K S ) Using : You can take this examples to show how the system is starting to be overconsrained
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Looking for “ New physics ” by measuring Δm s Δm s > 26ps -1 New Physics at 3 >30.5ps -1 New Physics at 5 Almost independently of the precision on the measurement of Δm s If the value measured for Δm s will fall in the SM region [(12-26) ps -1 ] important theoretical improvements have to be forseen to test the SM Red lines: σ(Δm s ) = 1.0, 0.5, 0.2, 0.1 ps -1 Blue line: all errors divided by 2 33 55 ΔmsΔms 51015202530 indirectdirect Delta(Δm s ) -10-50510
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Looking for “ New physics ” by measuring Red lines: σ = 20, 15, 10, 5 degrees Blue line: all errors divided by 2 Suppose can be measured with an error of 10 o >100 o New Physics at 3 Importance of reducing some theo. errors ( ,B K …) to perform a more powerful test of the SM for ex: if all theo. errors/2 >90 o New Physics at 3 >80 o New Physics at 3 with an error of 5 o
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SM prediction without A(J/ψK s ) sin2 = 0.685 ± 0.055 Red lines: σ(sin2 ) = 0.2, 0.1, 0.05, 0.02 Blue line: all errors divided by 2 ° [0.52-0.85] 3 SM region if (sin2 )=0.02 [0.46-0.91] 3 SM region if (sin2 )=0.05 (today) Improving the precision on sin2 using A(J/ψK s ) ? Obviously difficult to find any discrepancy with SM
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SM prediction with A(J/ψK s ) sin2 = 0.705 ± 0.035 Measuring sin2 using a different channel B →φK s ? A( φK s ) = –0.39 0.41 2.7 If the experimental error goes down by a factor 2 ( 0.2) A( φK s ) < 0 4 Red lines: σ(sin2 ) = 0.4, 0.2, 0.1, 0.05 2.7 A( φK s ) ~ -0.4 5.7
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Important progress in the last years Next (in a ~year-time scale) hopes : m s, A( φK s ) V cb ~2% V ub ~10% m d ~ 1.2% m s > 14.4 ps -1 at 95% CL sin2 -1 ~ 20-25% B K ~ 15% ~ 15% m t ~ 3% Success of SM + LQCD/OPE/HQET Standardissssssimo
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ADDITIONAL MATERIAL
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f(,, x|c 1,...,c m ) ~ ∏ f j (c|,,x) ∏ f i (x i ) f o (, ) ηρρηρη j=1,mi=1,N The Bayes Theorem: f(, |c) ~ L (c|, ) f o (, ) ρρρηηη x x 1,...,x n = m t, B K, F B …. c c 1,...,c m = K, m d / m s, A CP (J/ψ,K S )
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