Using the entire sample of 467 × 10 6 Υ ( 4 S ) → B ¯¯¯ B decays collected with the BABAR detector at the PEP-II asymmetric-energy B factory at the SLAC National Accelerator Laboratory, we perform an ...analysis of B ± → D K ± decays, using decay modes in which the neutral D meson decays to either C P -eigenstates or non- C P -eigenstates. We measure the partial decay rate charge asymmetries for C P -even and C P -odd D final states to be A C P + = 0.25 ± 0.06 ± 0.02 and A C P − = − 0.09 ± 0.07 ± 0.02 , respectively, where the first error is the statistical and the second is the systematic uncertainty. The parameter A C P + is different from zero with a significance of 3.6 standard deviations, constituting evidence for direct C P violation. We also measure the ratios of the charged-averaged B partial decay rates in C P and non- C P decays, R C P + = 1.18 ± 0.09 ± 0.05 and R C P − = 1.07 ± 0.08 ± 0.04 . We infer frequentist confidence intervals for the angle γ of the unitarity triangle, for the strong phase difference δ B , and for the amplitude ratio r B , which are related to the B − → D K − decay amplitude by r B e i ( δ B − γ ) = A ( B − → ¯¯¯ D 0 K − ) / A ( B − → D 0 K − ) . Including statistical and systematic uncertainties, we obtain 0.24 < r B < 0.45 ( 0.06 < r B < 0.51 ) and, modulo 180°, 11.3 ° < γ < 22.7 ° or 80.8 ° < γ < 99.2 ° or 157.3 ° < γ < 168.7 ° ( 7.0 ° < γ < 173.0 ° ) at the 68% (95%) confidence level.
A search is presented for the four-body decay ${B}^{0}{\rightarrow}pp\overline{p}\overline{p}$ in a sample of 471 million $B\overline{B}$ pairs collected with the BABAR detector, operated at the SLAC ...PEP-II asymmetric-energy ${e}^{+}{e}^{{-}}$ collider. The center-of-mass energy is 10.58 GeV. From a fit to the distribution of the energy-substituted mass ${m}_{\mathrm{ES}}$, the branching fraction $\mathcal{B}({B}^{0}{\rightarrow}pp\overline{p}\overline{p})=(1.1\pm{}0.5\pm{}0.2)\times{}{10}^{{-}7}$ is extracted, where the first uncertainty is statistical and the second is systematic. The significance of the signal, including the systematic uncertainty, is 2.9 standard deviations. The upper limit on the branching fraction is determined to be $2.0\times{}{10}^{{-}7}$ at 90% confidence level.
We report measurements of sin2β and cos2β using a time-dependent Dalitz plot analysis of B0 → D ( * ) h0 with D → KS0π+π- decays, where the light unflavored and neutral hadron h0 is a π0 , η , or ω ...meson. The analysis uses a combination of the final data sets of the B a B ar and Belle experiments containing 471×106 and 772×106 B B ¯ pairs collected at the Υ ( 4S ) resonance at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. We measure sin2β=0.80±0.14 ( stat ) ±0.06 ( syst ) ±0.03 ( model ) and cos2β=0.91±0.22 ( stat ) ±0.09 ( syst ) ±0.07 ( model ) . The result for the direct measurement of the angle is β= ( 22.5±4.4 ( stat ) ±1.2 ( syst ) ±0.6 ( model ) ) ° . The last quoted uncertainties are due to the composition of the D0 → KS0π+π- decay amplitude model, which is newly established by a Dalitz plot amplitude analysis of a high-statistics e+e- → c c ¯ data sample as part of this analysis. We find the first evidence for cos2β>0 at the level of 3.7 standard deviations. The measurement excludes the trigonometric multifold solution π / 2-β= ( 68.1±0.7 ) ° at the level of 7.3 standard deviations and therefore resolves an ambiguity in the determination of the apex of the CKM Unitarity Triangle. The hypothesis of β=0° is ruled out at the level of 5.1 standard deviations, and thus CP violation is observed in B0 → D ( * ) h0 decays. The measurement assumes no direct CP violation in B0 → D ( * ) h0 decays.
We study the ϒ(1S) radiative decays to γπ+π− and γK+K− using data recorded with the BABAR detector operating at the SLAC PEP-II asymmetric-energy e+e− collider at center-of-mass energies at the ϒ(2S) ...and ϒ(3S) resonances. The ϒ(1S) resonance is reconstructed from the decay ϒ(nS)→π+π−ϒ(1S), n=2, 3. Branching fraction measurements and spin-parity analyses of ϒ(1S) radiative decays are reported for the I=0 S-wave and f2(1270) resonances in the π+π− mass spectrum, the f2′(1525) and f0(1500) in the K+K− mass spectrum, and the f0(1710) in both.
Background The vascular safety of electronic cigarettes (e-Cigarettes) must still be clarified. We compared the impact of e-Cigarettes vs traditional tobacco cigarettes on oxidative stress and ...endothelial function in healthy smokers and nonsmoker adults. Methods A crossover, single-blind study was performed in 40 healthy subjects (20 smokers and 20 nonsmokers, matched for age and sex). First, all subjects smoked traditional tobacco cigarettes. One week later, the same subjects smoked an e-Cigarette with the same nominal nicotine content. Blood samples were drawn just before and after smoking, and markers of oxidative stress, nitric oxide bioavailability, and vitamin E levels were measured. Flow-mediated dilation (FMD) was also measured. Results Smoking both e-Cigarettes and traditional cigarettes led to a significant increase in the levels of soluble NOX2-derived peptide and 8-iso-prostaglandin F2α and a significant decrease in nitric oxide bioavailability, vitamin E levels, and FMD. Generalized estimating equation analysis confirmed that all markers of oxidative stress and FMD were significantly affected by smoking and showed that the biologic effects of e-Cigarettes vstraditional cigarettes on vitamin E levels ( P = .413) and FMD ( P = .311) were not statistically different. However, e-Cigarettes seemed to have a lesser impact than traditional cigarettes on levels of soluble NOX2-derived peptide ( P = .001), 8-iso-prostaglandin F2α ( P = .046), and nitric oxide bioavailability ( P = .001). Conclusions Our study showed that both cigarettes have unfavorable effects on markers of oxidative stress and FMD after single use, although e-Cigarettes seemed to have a lesser impact. Future studies are warranted to clarify the chronic vascular effects of e-Cigarette smoking.
We present improved measurements of the branching fraction B , the longitudinal polarization fraction f L , and the direct C P asymmetry A C P in the B meson decay channel B + → ρ + ρ 0 . The data ...sample was collected with the BABAR detector at SLAC. The results are B ( B + → ρ + ρ 0 ) = ( 23.7 ± 1.4 ± 1.4 ) × 10 − 6 , f L = 0.950 ± 0.015 ± 0.006 , and A C P = − 0.054 ± 0.055 ± 0.010 , where the uncertainties are statistical and systematic, respectively. Based on these results, we perform an isospin analysis and determine the Cabibbo-Kobayashi-Maskawa phase angle α = arg ( − V t d V ∗ t b / V u d V ∗ u b ) to be ( 92.4 + 6.0 − 6.5 ) ° .
We present an analysis of the decays B{0}-->K{*0}(892)gamma and B{+}-->K{*+}(892)gamma using a sample of about 383 x 10{6} BB-over events collected with the BABAR detector at the PEP-II asymmetric ...energy B factory. We measure the branching fractions B(B{0}-->K{*0}gamma)=(4.47+/-0.10+/-0.16) x 10{-5} and B(B{+}-->K{*+}gamma)=(4.22+/-0.14+/-0.16) x 10{-5}. We constrain the direct CP asymmetry to be -0.033<A(B-->K{*}gamma)<0.028 and the isospin asymmetry to be 0.017<Delta{0-} < 0.116, where the limits are determined by the 90% confidence interval and include both the statistical and systematic uncertainties.
We report results from an updated study of the suppressed decays B- to D K- and B- to D* K- followed by D to K+pi-, where D(*) indicates a D(*)0 or an anti-D(*)0 meson, and D* decays to D pi0 or D ...gamma. These decays are sensitive to the CKM unitarity triangle angle gamma, due to interference between the b to c transition B- to D(*)0K- followed by the doubly Cabibbo-suppressed decay D0 to K+pi-, and the b to u transition B- to anti-D(*)0K- followed by the Cabibbo-favored decay anti-D0 to K+pi-. We also report an analysis of the decay B- to D(*)pi- with the D decaying into the doubly Cabibbo-suppressed mode D to K+pi-. Our results are based on 467 million Upsilon (4S) to B anti-B decays collected with the BaBar detector at SLAC. We measure the ratios R(*) of the suppressed (K+pi-_D K-/pi-) to favored (K-pi+_D K-/pi-) branching fractions as well as the CP asymmetries A(*) of those modes. We see indications of signals for the B- to D K- and B- to D*K-, D*->D pi0 suppressed modes, with statistical significances of 2.1 and 2.2 sigma, respectively, and we measure: R_{DK} = (1.1\pm 0.6 \pm 0.2)\times 10^{-2}, A_{DK} = -0.86 \pm 0.47 \ ^{+0.12}_{-0.16}, R*_{(D pi0)K} = (1.8\pm 0.9 \pm 0.4)\times 10^{-2}, A*_{(D pi0)K} = +0.77 \pm 0.35\pm 0.12, R*_{(D gamma)K} = (1.3\pm 1.4\pm 0.8 )\times 10^{-2}, A*_{(D gamma)K} = +0.36 \pm 0.94\ ^{+0.25}_{-0.41}, where the first uncertainty is statistical and the second is systematic. We use a frequentist approach to obtain the magnitude of the ratio r_B = |A(B- to anti-D0 K-) / A(B- to D0K-)|= (9.5^{+5.1}_{-4.1})%, with r_B<16.7% at 90% confidence level. In the case of B- to D* K- we find r*_B = |A(B^- to anti-D*0 K-)/A(B- to D*0 K-)|=(9.6^{+3.5}_{-5.1})%, with r*_B<15.0% at 90% confidence level.
We search for single-photon decays of the Υ(1S) resonance, Υ → γ + invisible, where the invisible state is either a particle of definite mass, such as a light Higgs boson A⁰, or a pair of dark matter ...particles, χχ. Both A⁰ and χ are assumed to have zero spin. We tag Υ(1S) decays with a dipion transition Υ(2S) → π⁺π⁻Υ(1S) and look for events with a single energetic photon and significant missing energy. We find no evidence for such processes in the mass range m(A⁰) ≤ 9.2 GeV and m(χ) ≤ 4.5 GeV in the sample of 98 × 10⁶ Υ(2S) decays collected with the BABAR detector and set stringent limits on new physics models that contain light dark matter states.
Here, we study the processes e+e- → γ ISR J/ψ , where J/ψ → π +π-π0, J/ψ → K +K-π0 , and J / ψ → K$0\atop{S}$ K ± π ∓ using a data sample of 519 fb-1 recorded with the BABAR detector operating at the ...SLAC PEP-II asymmetric-energy e+e- collider at center-of-mass energies at and near the Υ (nS) (n = 2 , 3 , 4) resonances. We measure the ratio of branching fractions R1 = $B(J/ψ →K^+K^- π^0)\atop{B(J/ψ →π^+π^- π^0)}$ and R2= $B(J/ψ →K^0_SK^±π^∓)\atop{B(J/ψ →π^+π^- π^0)}$. We perform Dalitz plot analyses of the three J/ψ decay modes and measure fractions for resonances contributing to the decays. We also analyze the J/ψ → $π^+π^- π^0$ decay using the Veneziano model. We observe structures compatible with the presence of ρ (1450) in all three J/ψ decay modes and measure the relative branching fraction: R (p(1450)) = $Bp(1450)→K^+K^-)\atop{B(p(1450)→π^+π^-)}$ +0.307 ± 0.084 (stat) ± 0.082 (sys).
PDF
