We present measurements of branching fraction, polarization and charge
asymmetry in charmless hadronic B decays with eta, eta', omega, and b_1 in the
final state. All the results use the final BABAR dataset.Comment: 4 pages, contributed to the Proceedings of the EPS HEP 2009
  Conferenc

Biassoni, Pietro

English

arXiv

We present measurements of branching fraction, polarization and charge asymmetry in charmless hadronic B decays with eta, eta', omega, and b_1 in the final state. All the results use the final BaBar dataset

P. Biassoni

AIR Universita degli studi di Milano

Branching fractions and charge asymmetries in charmless hadronic B decays at BaBar

We present measurements of branching fraction and charge asymmetry in charmless hadronic B decays with η and η mesons in the final state. All

results use the final BaBar dataset corresponding to 465 × 106 BB pairs

Biassoni, P.

Scientific Open-access Literature Archive and Repository

DOI 10.1393/ncc/i2011-10782-4Colloquia: IFAE 2010IL NUOVO CIMENTO Vol. 33 C, N. 6 Novembre-Dicembre 2010Branching fractions and charge asymmetries in charmlesshadronic B decays at BaBarP. Biassoni on behalf of the BaBar CollaborationUniversita` and INFN, Sezione di Milano - Via Celoria 16, I-20133 Milano, Italy(ricevuto l’ 8 Ottobre 2010; pubblicato online l’8 Febbraio 2011)Summary. — We present measurements of branching fraction and charge asym-metry in charmless hadronic B decays with η and η′ mesons in the final state. Allresults use the final BaBar dataset corresponding to 465× 106 BB pairs.PACS 13.25.Hw – Decays of bottom mesons.PACS 12.15.Hh – Determination of Kobayashi-Maskawa matrix elements.PACS 11.30.Er – Charge conjugation, parity, time reversal, and other discretesymmetries.1. – IntroductionExperimental measurements of branching fraction (BF) and CP -violating chargeasymmetry in rare B decays are an important test of the Standard Model (SM) andits extensions. Several predictions are available for these quantities [1, 2]. The large BFdifference between η′K and ηK seems to be explained in the SM context [3]. Rates of thedecay modes to ηη, ηφ, η′η′, and η′φ are used in flavor SU(3)-based calculations [2, 4],to constrain the unsigned difference between the CP -violating parameter S measured inη′K0 and φK0 and sin 2β measured in J/ψK0. The charge asymmetry Ach is expectedto be sizable in ηK+ and suppressed in η′K+ decays [2].2. – Analysis techniqueResults shown in this paper are based on a sample of 465 × 106 BB pairs collectedat a center-of-mass energy√s = 10.58GeV at the PEP-II asymmetric e+e− collider,and recorded by the BABAR detector [5]. B meson is reconstructed into several finalstates with η or η′ mesons. These states are listed in table I. B meson is kinematicallycharacterized by ΔE ≡ EB− 12√s and mES ≡√s/4− p 2B , where (EB , pB) is the B mesonfour-momentum vector expressed in Υ(4S) rest frame. Background arises primarily fromrandom combinations of particles in e+e− → qq events (q = u, d, s, c). We suppress thisbackground with requirements on event shape variables and on the energy, invariant massand particle identification signature of the decay products. For each mode, results areobtained from extended maximum likelihood fits with input variables ΔE, mES, and theoutput of a Fisher discriminant that combines different event shapes variables. Whereuseful, the masses of B daughters are included in the fit.c© Societa` Italiana di Fisica 243244 P. BIASSONI on behalf of the BABAR COLLABORATIONTable I. – Results for modes presented in this paper.Decay B (10−6) B UL (10−6) S (σ) Achηπ+ 4.00± 0.40± 0.24 – – −0.03± 0.09± 0.03ηK0 1.15+0.43−0.38 ± 0.09 1.8 3.5 –ηK+ 2.94+0.39−0.34 ± 0.21 – – −0.36± 0.11± 0.03ηη 0.5± 0.3± 0.1 1.0 1.9 –ηω 0.94+0.35−0.30 ± 0.09 1.4 3.7 –ηφ 0.2± 0.2± 0.1 0.5 1.4 –η′π+ 3.5± 0.6± 0.2 – – +0.03± 0.17± 0.02η′K0 68.5± 2.2± 3.1 – – –η′K+ 71.5± 1.3± 3.2 – – +0.008+0.017−0.018 ± 0.009η′η′ 0.6+0.5−0.4 ± 0.4 1.7 1.0 –η′ω 1.01+0.46−0.38 ± 0.09 1.8 3.6 –η′φ 0.2± 0.2± 0.3 1.1 0.5 –3. – ResultsIn table I we report the results of BF (B) and charge asymmetry (Ach) for each decaymode [6]. The first error is statistical and second systematic. Significance (σ) is takenas√−2 lnLmax/L0, where Lmax (L0) is the value of the likelihood at its maximum (forzero signal). Bayesian upper limit at 90% CL is calculated for modes with significanceless than 5σ. For the well established decay modes η(′)K+, η′K0, and η(′)π+ significanceis not reported. Main contributions to systematic uncertainties come from fit bias anduncertainties in the probability density functions parameterization. Daughter branchingratios uncertainty limits BF measurement in B → η′K decay modes.4. – ConclusionsWe reported measurements for several charmless hadronic B decays. In B → ηK+we find evidence of direct CP violation at 3.3σ level.REFERENCES[1] Chen Y. H. et al., Phys. Rev. D, 60 (1999) 094014; Bauer C. W. and Steward I. W.,Phys. Lett. B, 516 (2001) 134; Xiao Z. et al., Phys. Rev. D, 75 (2007) 014018.[2] Beneke M. and Neubert M., Nucl. Phys. B, 675 (2003) 333; Chiang C. W. et al., Phys.Rev. D, 70 (2004) 034020 [and references therein].[3] Lipkin H. J., Phys. Lett. B, 254 (1991) 247; Beneke M. and Neubert M., Nucl. Phys.B, 651 (2003) 225.[4] Grossman Y. et al., Phys. Rev. D, 68 (2003) 015004; Gronau M. et al., Phys. Lett. B,596 (2004) 107.[5] Aubert B. et al. (BABAR Collaboration), Nucl. Instrum. Methods Phys. Res. A, 479(2002) 1.[6] Aubert B. et al. (BABAR Collaboration), Phys. Rev. D, 80 (2009) 112002.

Branching fractions and charge asymmetries in charmless

hadronic B decays at BaBar

http://eprints.bice.rm.cnr.it/17130/1/ncc9811.pdf

Branching fractions and charge asymmetries in charmless hadronic B decays at BABAR

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