[Show abstract][Hide abstract] ABSTRACT: This work is on the Physics of the B Factories. Part A of this book contains
a brief description of the SLAC and KEK B Factories as well as their detectors,
BaBar and Belle, and data taking related issues. Part B discusses tools and
methods used by the experiments in order to obtain results. The results
themselves can be found in Part C.
Please note that version 3 on the archive is the auxiliary version of the
Physics of the B Factories book. This uses the notation alpha, beta, gamma for
the angles of the Unitarity Triangle. The nominal version uses the notation
phi_1, phi_2 and phi_3. Please cite this work as Eur. Phys. J. C74 (2014) 3026.
European Physical Journal C 11/2014; DOI:10.1140/epjc/s10052-014-3026-9 · 5.08 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We report the result of a search for the rare decay B0→γγ in 426 fb-1 of data, corresponding to 226×106 B0B̅ 0 pairs, collected on the Υ(4S) resonance at the PEP-II asymmetric-energy e+e- collider using the BABAR detector. We use a maximum likelihood fit to extract the signal yield and observe 21-12+13 signal events with a statistical significance of 1.8σ. This corresponds to a branching fraction B(B0→γγ)=(1.7±1.1(stat.)±0.2(syst.))×10-7. Based on this result, we set a 90% confidence level upper limit of B(B0→γγ)<3.2×10-7.
[Show abstract][Hide abstract] ABSTRACT: We have performed a search for the rare leptonic decays B^+ → ℓ^+v_ℓ(l=e,µ), using data collected at the Y(4S) resonance by the BABAR detector at the PEP-II storage ring. In a sample of 468×10^6 BB pairs we find no evidence for a signal and set an upper limit on the branching fractions B(B^+ → µ^+v_µ)<1.0×10^(-6) and B(B^+ → e^+v_e)<1.9×10^(-6) at the 90% confidence level, using a Bayesian approach.
[Show abstract][Hide abstract] ABSTRACT: We present a study of the decays B0→D0K*0 and B0→D̅ 0K*0 with K*0→K+π-. The D0 and the D̅ 0 mesons are reconstructed in the final states f=K+π-, K+π-π0, K+π-π+π-, and their charge conjugates. Using a sample of 465×106 BB̅ pairs collected with the BABAR detector at the PEP-II asymmetric-energy e+e- collider at SLAC, we measure the ratio RADS≡[Γ(B̅ 0→[f]DK̅ *0)+Γ(B0 →[f̅ ]DK*0)]/[Γ(B̅ 0→[f̅ ]DK̅ *0)+Γ(B0→[f]DK*0)] for the three final states. We do not find significant evidence for a signal and set the following limits at 95% probability: RADS(Kπ)<0.244, RADS(Kππ0)<0.181, and RADS(Kπππ)<0.391. From the combination of these three results, we find that the ratio rS between the b→u and the b→c amplitudes lies in the range [0.07,0.41] at 95% probability.
[Show abstract][Hide abstract] ABSTRACT: We present a Dalitz plot analysis of charmless B-+/- decays to the final state pi(+/-)pi(+/-)pi(-/+) using a sample of (465 +/- 5)x10(6) B(B)over bar pairs collected by the BABAR experiment at root s=10.58 GeV. We measure the branching fractions B(B-+/-->pi(+/-)pi(+/-)pi(-/+))=(15.2 +/- 0.6 +/- 1.2 +/- 0.4)x10(-6), B(B-+/-->rho(0)(770)pi(+/-))=(8.1 +/- 0.7 +/- 1.2(-1.1)(+0.4))x10(-6), B(B-+/--> f(2)(1270)pi(+/-))=(1.57 +/- 0.42 +/- 0.16(-0.19)(+0.53))x10(-6), and B(B-+/-->pi(+/-)pi(+/-)pi(-/+) nonresonant)=(5.3 +/- 0.7 +/- 0.6(-0.5)(+1.1))x10(-6), where the uncertainties are statistical, systematic, and model-dependent, respectively. Measurements of branching fractions for the modes B-+/-->rho(0)(1450)pi(+/-) and B-+/--> f(0)(1370)pi(+/-) are also presented. We observe no significant direct CP asymmetries for the above modes, and there is no evidence for the decays B-+/--> f(0)(980)pi(+/-), B-+/-->chi(c0)pi(+/-), or B-+/-->chi(c2)pi(+/-).
Physical Review D 04/2009; 79(7). DOI:10.1103/PhysRevD.79.072006 · 4.64 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: We present new measurements of time-dependent CP asymmetries for B^0→D(*)+D(*)- decays using (467±5)×10^6 B[overline B] pairs collected with the BABAR detector located at the PEP-II B Factory at the Stanford Linear Accelerator Center. We determine the CP-odd fraction of the B^0→D*+D*- decays to be R[perpendicular]=0.158±0.028±0.006 and find CP asymmetry parameters S_+=-0.76±0.16±0.04 and C_+=+0.00±0.12±0.02 for the CP-even component of this decay and S[perpendicular]=-1.80±0.70±0.16 and C[perpendicular]=+0.41±0.49±0.08 for the CP-odd component. We measure S=-0.63±0.36±0.05 and C=-0.07±0.23±0.03 for B^0→D+D-, S=-0.62±0.21±0.03 and C=+0.08±0.17±0.04 for B^0→D*+D-, and S=-0.73±0.23±0.05 and C=+0.00±0.17±0.03 for B^0→D+D*-. For the B^0→D*±D-/+ decays, we also determine the CP-violating asymmetry A=+0.008±0.048±0.013. In each case, the first uncertainty is statistical and the second is systematic. The measured values for the asymmetries are all consistent with the standard model.
[Show abstract][Hide abstract] ABSTRACT: A search for the lepton flavor violating decays tau(-) --> l(-)K(S)(0) (l = e or mu) has been performed using a data sample corresponding to an integrated luminosity of 469 fb(-1), collected with the BABAR detector at the SLAC PEP-II e(+) e(-) asymmetric energy collider. No statistically significant signal has been observed in either channel and the estimated upper limits on branching fractions are B(tau(-) --> e(-)K(S)(0)) < 3.3 x 10(-8) and B(tau(-) --> mu K--(S)0) < 4.0 x 10(-8) at 90% confidence level.
[Show abstract][Hide abstract] ABSTRACT: We present measurements of the CP-violation parameters S and C for the radiative decay B0→ηKS0γ; for B→ηKγ we also measure the branching fractions and for B+→ηK+γ the time-integrated charge asymmetry Ach. The data, collected with the BABAR detector at the Stanford Linear Accelerator Center, represent 465×106 BB̅ pairs produced in e+e- annihilation. The results are S=-0.18-0.46+0.49±0.12, C=-0.32-0.39+0.40±0.07, B(B0→ηK0γ)=(7.1-2.0+2.1±0.4)×10-6, B(B+→ηK+γ)=(7.7±1.0±0.4)×10-6, and Ach=(-9.0-9.8+10.4±1.4)×10-2. The first error quoted is statistical and the second systematic.
[Show abstract][Hide abstract] ABSTRACT: Semileptonic B̅ decays to DXℓν̅ (ℓ=e or μ) are selected by reconstructing D0ℓ and D+ℓ combinations from a sample of 230×106 Υ(4S)→BB̅ decays recorded with the BABAR detector at the PEP-II e+e- collider at SLAC. A global fit to these samples in a three-dimensional space of kinematic variables is used to determine the branching fractions B(B-→D0ℓν̅ )=(2.34±0.03±0.13)% and B(B-→D*0ℓν̅ )=(5.40±0.02±0.21)% where the errors are statistical and systematic, respectively. The fit also determines form-factor parameters in a parametrization based on heavy quark effective theory, resulting in ρD2=1.20±0.04±0.07 for B̅ →Dℓν̅ and ρD*2=1.22±0.02±0.07 for B̅ →D*ℓν̅ . These values are used to obtain the product of the Cabibbo-Kobayashi-Maskawa matrix element |Vcb| times the form factor at the zero recoil point for both B̅ →Dℓν̅ decays, G(1)|Vcb|=(43.1±0.8±2.3)×10-3, and for B̅ →D*ℓν̅ decays, F(1)|Vcb|=(35.9±0.2±1.2)×10-3.
[Show abstract][Hide abstract] ABSTRACT: We perform a study of the exclusive production of D[overline D], D^*[overline D], and D^*[overline D]^* in initial-state-radiation events, from e^+e^- annihilations at a center-of-mass energy near 10.58 GeV, to search for charmonium and possible new resonances. The data sample corresponds to an integrated luminosity of 384 fb^(-1) and was recorded by the BABAR experiment at the PEP-II storage rings. The D[overline D], D^*[overline D], and D^*[overline D]^* mass spectra show clear evidence of several psi resonances. However, there is no evidence for Y(4260)-->D^*[overline D] or Y(4260)-->D^*[overline D]^*.
[Show abstract][Hide abstract] ABSTRACT: We present a study of B decays into semileptonic final states containing charged and neutral D_1(2420) and D^*_2(2460). The analysis is based on a data sample of 208 fb^(-1) collected at the Y(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. With a simultaneous fit to four different decay chains, the semileptonic branching fractions are extracted from measurements of the mass difference Δ=m(D^(**))-m(D) distributions. Product branching fractions are determined to be B(B^+-->D_1^0ℓ+v_ℓ) x B D^0_1-->D^(*+)π^-) =(2.97±0.17±0.17)×10^(-3), B(B^+-->D^(*0)_2ℓ+v_ℓ)× B(D_2^(*0)-->D^((*)+)π-)=(2.29±0.23±0.21)×10^-3, B(B^0-->D_1^-ℓ+v_ℓ) × B(D_1^--->D^(*0)π^-)=(2.78±0.24±0.25)×10^(-3) and B(B^0-->D_2^(*-)ℓ^+ v_ℓ)× B(D_2^(*-)-->D^((*)0)π^-)=(1.77±0.26±0.11)×10^(-3). In addition we measure the branching ratio Γ(D_2^*-->Dπ^-)/Γ(D_2^*-->D^(*)π^-)=0.62±0.03±0.02.
[Show abstract][Hide abstract] ABSTRACT: We present updated measurements of time-dependent CP asymmetries in fully reconstructed neutral B decays containing a charmonium meson. The measurements reported here use a data sample of (465±5)×10^6 Upsilon(4S)-->B[overline B] decays collected with the BABAR detector at the PEP-II asymmetric energy e^+e^- storage rings operating at the SLAC National Accelerator Laboratory. The time-dependent CP asymmetry parameters measured from JpsiK_S^0, JpsiK_L^0, psi(2S)K_S^0, eta_cK_S^0, chi_(c1)K_S^0, and J/psiK^*(892)^0 decays are: C_f=0.024±0.020(stat)±0.016(syst) and eta_fS_f=0.687±0.028(stat)±0.012(syst).