We present new measurements of time-dependent CP-violation parameters in hadronic penguin decays: B{sup 0} {yields} K{sup +}K{sup -}K{sub L}{sup 0}, K{sub S}{sup 0}{pi}{sup 0}{pi}{sup 0}, K{sub S}{sup 0}K{sub S}{sup 0}K{sub S}{sup 0}, {omega}K{sub L}{sup 0}, and a radiative penguin decay B{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0}{gamma} in a dataset of around 230 {center_dot} 10{sup 6} B{bar B} pairs collected by the BABAR detector at the asymmetric B Factory at SLAC. These CP asymmetry measurements probe for amplitudes beyond the Standard Model in loop-dominated decays of neutral B mesons. While we find a puzzling deviation of CP-asymmetry parameters from predicted values, a full confirmation still awaits more data

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Dujmic, Denis

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Work supported in part by Department of Energy contract DE-AC02-76SF00515SLAC-PUB-11584July 2005BaBar: sin(2beta) with charmless and radiativedecaysDenis Dujmic∗†SLAC, USAE-mail: ddujmic@slac.stanford.eduWe present new measurements of time-dependent CP-violation parameters in hadronic pen-guin decays: B0 → K+K−K0L , K0S π0π0, K0S K0S K0S , ωK0S , η ′K0L , and a radiative penguin decayB0 → K0S π0γ in a dataset of around 230 · 106 BB pairs collected by the BABAR detector at theasymmetric B Factory at SLAC. These CP asymmetry measurements probe for amplitudes beyondthe Standard Model in loop-dominated decays of neutral B mesons. While we find a puzzling de-viation of CP-asymmetry parameters from predicted values, a full confirmation still awaits moredata.International Europhysics Conference on High Energy PhysicsJuly 21st - 27th 2005Lisboa, Portugal∗Speaker.†Representing the BABAR collaboration.BaBar: sin(2beta) with charmless and radiative decays Denis Dujmic1. IntroductionIn the standard model (SM), charged-current transitions among quarks are characterized byCKM [1] couplings that can have CP-violating phases and lead to large CP-asymmetry in B mesondecays. The time-dependent CP-asymmetry is obtained by measuring the proper time differenceΔt between a fully reconstructed neutral B meson and a partially reconstructed tagging B mesonwhose decay products are analyzed to determine its flavor. The decay rate f+(f−) when the flavorof the tagging meson is a B0 (B0) is given byf±(Δt) =e−|Δt|/τB04τB0[ 1±S · sin (ΔmdΔt)∓C · cos (ΔmdΔt)], (1.1)where τB0 is the mean B0 lifetime and Δmd is the B0–B0 oscillation frequency [2], and S and C areCP-violation coefficients.Decays of B mesons into charmless hadronic final states with the total strangeness of one aredominated by penguin-loop amplitudes. In the penguin decays to hadronic final states, we expectS ≈ −η f sin2β and C ≈ 0, where β is the B0 −B0 mixing phase, and η f is CP eigenvalue of thefinal state. Recently, there has been a progress in understanding hadronic uncertainties that canlead to deviations from these predictions. Studies based on the QCD factorization (QCDF) predictdeviations of several percent that depend on the decay channel [3]. Another set of estimates basedon the SU(3) symmetry of the quark flavor provides upper bounds on the absolute values of thedeviations [4] which are consistent but less constraining than the QCDF calculations.In the radiative decay B0(B0) → K0S π0γ the photon polarization is predominantly right (left)handed while decays to left (right) handed photons are suppressed by 2ms/mb, where ms, mb aremasses of s and b quarks, respectively. Interference between decay amplitudes is suppressed by thesame factor and we expect to measure S ≈ −2ms/mb sin2β and C ≈ 0. These predictions can beaffected by hadronization uncertainties of order 0.1 [5].Many models beyond the SM introduce new particles with CP-violating couplings that canappear in penguin decays and modify CP-violation observables. Therefore, any significant devia-tion in S and C from SM predictions beyond possible hadronization corrections would indicate newphenomena.2. Summary of ResultsThe time-dependent CP-violation parameters are measured in a dataset of around 230 ·106 BBpairs collected by the BABAR detector [6] at the asymmetric B Factory at SLAC.The CP eigenvalue of the final state is well defined when all final-state particles are also CPeigenstates [7]. However, the final state in B0 → K+K−K0L decays is a mixture of CP-even and-odd eigenstates. Assuming that K0L is a pure CP eigenstate, the CP eigenvalue of the 3-bodyfinal state is given by the angular momentum between K+K− pair. Existence of non-CP finalstates can additionally complicate the measurement, but this has been disfavored by theory [8] andrecent searches [9, 10]. We use results of angular-moment analysis that extracted fractions of Sand P partial waves in K+K− mass bins from B0 → K+K−K0S decays [10] and scale them to theobserved yield in B0 → K+K−K0L decays. When φK0L decays are excluded, we find a dominance2BaBar: sin(2beta) with charmless and radiative decays Denis DujmicTable 1: Summary of new measurements of CP asymmetry parameters in hadronic B meson decays that aredominated by penguin diagrams at BABAR. Results combined with decay modes that have K 0S instead of K0Lin the final state are shown in parentheses.Mode sin 2β CK+K−K0L [12] 0.09±0.33+0.13−0.14 ±0.10 0.54±0.22+0.08−0.09(0.41±0.18±0.07±0.11) 0.23±0.12±0.07K0S K0S K0S [14] 0.63+0.28−0.32 ±0.04 −0.10±0.25±0.05K0S π0π0 [16] −0.84±0.71±0.08 0.27±0.52±0.13η ′K0L [17] 0.60±0.31±0.04 0.10±0.21±0.03(0.36±0.13±0.03) (−0.16±0.09±0.02)ωK0S [18] 0.50+0.34−0.38 ±0.02 −0.56+0.29−0.27 ±0.03Table 2: Summary of new measurements of CP asymmetry parameters in radiative B meson decays that aredominated by penguin diagrams at BABAR. † K ∗0 → K0S π0. ‡ 1.1 < M(K0S π0) < 1.8 GeV/c2.Mode S CK∗0γ † [19] −0.21±0.40±0.05 −0.40±0.23±0.03K0S π0γ ‡ [19] 0.9±1.0±0.2 −1.0±0.5±0.2of S-waves and CP-odd final states with a fraction of fCP−odd = 0.92± 0.07± 0.06. This result isconsistent with an analysis using isospin symmetry [11] and a time-integrated Dalitz plot analysisof B0 → K+K−K0S decays which describes the decay rate over the Dalitz plot as a function oftwo invariant masses and the flavor tag and assumes nonexistence of direct CP violation in decayamplitudes [15].The decay B0 → K+K−K0L is reconstructed from combination of charged kaons and K0L candi-dates and we find 777± 80 signal events. The final state η′K0L is reconstructed from K0S → π+π−and η ′ → ργ , η(γγ)π+π− candidates and we get 137±22 and 303±49 signal events, respectively.In both B0 → K+K−K0L and K0L η ′, the K0L is identified by the shape of the energy cluster depositedin the electromagnetic calorimeter, or as a set of hits in two or more layers of the muon detectorthat cannot be associated with any charged track in the event. Since the K0L energy is not measured,it is calculated from a constraint that the momentum sum of all decay products equal the B0 mesonmass.The final state for decay B0 → K0S K0S K0S is reconstructed from combination of three K0S can-didates. When all K0S ’s decay to a π+π− pair we find 88± 10 signal events, and if we allow atmost one K0S to decay to π0π0 we find additional 41.0+9.2−8.3 signal events. The final state K0S π0π0 isreconstructed from K0S → π+π− and π0 → γγ candidates, and we find 117±27 signal events. Wereconstruct B0 → K0S π0γ decays from K0S → π+π− and π0 → γγ and find 157± 16 signal eventsconsistent with K∗0 → K0S π0 and 59±13 signal events when 1.1 < M(K0S π0) < 1.8 GeV/c2. Sincethere are no charged tracks coming from the neutral B vertex, the decay point for B0 → K0S K0S K0S ,B0 → K0S π0π0 and B0 → K0S π0γ is found by constraining momenta of the decay products to origi-nate from the interaction point [13].3BaBar: sin(2beta) with charmless and radiative decays Denis DujmicThe final state K0S ω is reconstructed from K0S → π+π− and ω → π+π−π0 candidates, and wefind a total of 92±13 signal events.New results of CP asymmetry measurements from BABAR are given in Table 1 for hadronicand Table 2 for radiative decays. The sin2β parameter in Table 1 is extracted from S coefficientafter taking into account the CP content of the final state.3. ConclusionMeasurements of CP asymmetry in penguin-dominated decays probe for possible CP-violatingphases in addition to SM phase β . New BABAR measurements are listed in Tables 1,2 while a sum-mary of all existing measurements is given in [2]. There is a hint that the value of the sin 2βparameter extracted from penguin decays can be smaller than predicted by the SM, but a confir-mation awaits more data. Future prospects for such measurements at the BABAR depend on theavailable luminosity and the character of new physics amplitudes.References[1] N. Cabibbo, Phys. Rev. Lett. 10, 531 (1963); M. Kobayashi and T. Maskawa, Prog. Theor. Phys. 49,652 (1973).[2] Heavy Flavor Averaging Group, http://www.slac.stanford.edu/xorg/hfag/[3] see e.g. M. Beneke, Phys. Lett. B 620, 143 (2005) ; H. Y. Cheng, C. K. Chua and A. Soni, Phys. Rev.D 72, 094003 (2005) .[4] see e.g. Y. Grossman, Z. Ligeti, Y. Nir and H. Quinn, Phys. Rev. D 68, 015004 (2003) ; M. Gronauand J. L. Rosner, Phys. Lett. B 564, 90 (2003) ; G. Engelhard, Y. Nir and G. Raz, Phys. Rev. D 72,075013 (2005) ; G. Engelhard and G. Raz, arXiv:hep-ph/0508046.[5] B. Grinstein, Y. Grossman, Z. Ligeti and D. Pirjol, Phys. Rev. D 71, 011504 (2005) .[6] B. Aubert et al. [BABAR Collaboration], Nucl. Instrum. Meth. A 479, 1 (2002) .[7] T. Gershon and M. Hazumi, Phys. Lett. B 596, 163 (2004) .[8] V. Chernyak, Phys. Lett. B 509, 273 (2001) .[9] B. Aubert et al. [BABAR Collaboration], Phys. Rev. D 70, 111102 (2004).[10] B. Aubert et al. [BABAR Collaboration], Phys. Rev. D 71, 091102 (2005) .[11] K. Abe et al. [Belle Collaboration], arXiv:hep-ex/0507037.[12] B. Aubert et al. [BABAR Collaboration], arXiv:hep-ex/0507016.[13] B. Aubert et al. [BABAR Collaboration], Phys. Rev. Lett. 93, 131805 (2004) .[14] B. Aubert et al. [BABAR Collaboration], arXiv:hep-ex/0507052; B. Aubert [BABAR Collaboration],Phys. Rev. Lett. 95, 011801 (2005).[15] B. Aubert et al. [BABAR Collaboration], arXiv:hep-ex/0507094.[16] B. Aubert et al. [BABAR Collaboration], arXiv:hep-ex/0508017.[17] B. Aubert et al. [BABAR Collaboration], arXiv:hep-ex/0507087.[18] B. Aubert et al. [BABAR Collaboration], arXiv:hep-ex/0503018.[19] B. Aubert et al. [BaBar Collaboration], Phys. Rev. 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BaBar: sin(2beta) with Charmless and Radiative Decays

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BaBar: sin(2beta) with Charmless and Radiative Decays

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