0000000000072598
AUTHOR
E. Grauges-pous
Measurements of the Mass and Width of theηcMeson and of anηc(2S)Candidate
The mass m(eta(c)) and total width Gamma(eta(c))(tot) of the eta(c) meson have been measured in two-photon interactions at the SLAC e(+)e(-) asymmetric B Factory with the BABAR detector. With a sample of approximately 2500 reconstructed eta(c)-->K(0)(S)K+/-pi(-/+) decays in 88 fb(-1) of data, the results are m(eta(c))=2982.5+/-1.1(stat)+/-0.9(syst) MeV/c(2) and Gamma(eta(c))(tot)=34.3+/-2.3(stat)+/-0.9(syst) MeV/c(2). Using the same decay mode, a second resonance with 112+/-24 events is observed with a mass of 3630.8+/-3.4(stat)+/-1.0(syst) MeV/c(2) and width of 17.0+/-8.3(stat)+/-2.5(syst) MeV/c(2). This observation is consistent with expectations for the eta(c)(2S) state.
Study of Time-DependentCPAsymmetry in NeutralBDecays toJ/ψπ0
We present the first study of the time-dependent CP-violating asymmetry in B0-->J/psi pi(0) decays using e(+)e(-) annihilation data collected with the BABAR detector at the Upsilon(4S) resonance during the years 1999-2002 at the PEP-II asymmetric-energy B Factory at SLAC. Using approximately 88 x 10(6) BB; pairs, our results for the coefficients of the cosine and sine terms of the CP asymmetry are C(J/psi pi(0))=0.38+/-0.41(stat)+/-0.09(syst) and S(J/psi pi(0))=0.05+/-0.49(stat)+/-0.16(syst).
Search for the radiative decay B0→γ
We perform a search for the exclusive radiative decay B0→γ, which is dominated by b̄d annihilation, in a sample of 124×106 BB̄ events collected with the BABAR detector at the PEP-II asymmetric-energy e+e- storage ring at SLAC. No significant signal is seen. We set an upper limit on the branching fraction of B(B0→γ)<8. 5×10-7 at the 90% confidence level. © 2005 The American Physical Society.
Search for Strange-Pentaquark Production ine+e−Annihilation ats=10.58 GeV
We search for strange-pentaquark states that have been previously reported by other experiments--the Theta (1540)(+), Xi(5)(1860)(--), and Xi(5)(1860)(0)--in 123 fb(-1) of data recorded with the BABAR detector at the PEP-II e(+)e(-) storage ring. We find no evidence for these states and set 95% confidence level upper limits on the number of Theta(1540)(+) and Xi(5)(1860)(--) pentaquarks produced per e(+)e(-) annihilation into qq and Gamma(4S) decay. For qq events the Theta(1540)(+) [Xi(5)(1860)(--)] limit is about 8 [4] times lower than the rates measured for ordinary baryons of similar mass.
Limit on theB0→ρ0ρ0Branching Fraction and Implications for the Cabibbo-Kobayashi-Maskawa Angleα
The authors search for the decay B{sup 0} {yields} {rho}{sup 0}{rho}{sup 0} in a data sample of about 227 million {Upsilon}(4S) {yields} B{bar B} decays collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. They find no significant signal and set an upper limit of 1.1 x 10{sup -6} at 90% CL on the branching fraction. As a result, the uncertainty due to penguin contributions on the CKM unitarity angle {alpha} measured in B {yields} {rho}{rho} decays is 11{sup o} at 68% CL.
Measurement of the branching fraction and theCP-violating asymmetry for the decayB0→KS0π0
The authors measure the branching fraction and the CP-violating asymmetry of B{sup 0} {yields} K{sub S}{sup 0}{pi}{sup 0} decays with 227 million {Upsilon}(4S) {yields} B{bar B} events collected with the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} collider at SLAC. They obtain a branching fraction {Beta}(B{sup 0} {yields} K{sup 0}{pi}{sup 0}) = (11.4 {+-} 0.9 {+-} 0.6) x 10{sup -6} and CP-violating asymmetry parameters C{sub K{sub S}{sup 0}{pi}{sup 0}} = 0.06 {+-} 0.18 {+-} 0.03 and S{sub K{sub S}{sup 0}{pi}{sup 0}} = 0.35{sub -0.33}{sup +0.30} {+-} 0.04, where the first error is statistical and the second systematic.
Observation of a Significant Excess ofπ0π0Events inBMeson Decays
We present a study of the decay B0 -> p0p0 based on a sample of 124 * 106 B.hivin.B pairs recorded by the BABAR detector at the PEP-II asym.-energy B Factory at SLAC. We observe 46 +- 13 +- 3 events, where the first error is statistical and the second is systematic, corresponding to a significance of 4.2 std. deviations including systematic uncertainties. We measure the branching fraction B(B0 -> p0p0) = (2.1 +- 0.6 +- 0.3) * 10-6, averaged over B0 and .hivin.B0 decays. [on SciFinder (R)]
Measurement of the Inclusive Charmless Semileptonic Branching Ratio ofBMesons and Determination of|Vub|
We report a measurement of the inclusive charmless semileptonic branching fraction of B mesons in a sample of 89 x 10(6) (-)BB events recorded with the BABAR detector at the Upsilon(4S) resonance. Events are selected by fully reconstructing the decay of one B meson and identifying a charged lepton from the decay of the other B meson. The number of signal events is extracted from the mass distribution of the hadronic system accompanying the lepton and is used to determine the ratio of branching fractions B((-)B-->X(u)lnu;)/B((-)B-->Xlnu;)=[2.06+/-0.25(stat)+/-0.23(syst)+/-0.36(theo)]x10(-2). Using the measured branching fraction for inclusive semileptonic B decays, we find B((-)B-->X(u)lnu;)…
Measurement of the branching fraction forB±→χc0K±
We present a measurement of the branching fraction of the decay ${B}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\chi}}_{c0}{K}^{\ifmmode\pm\else\textpm\fi{}}$ from a sample of $89\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs collected by the BABAR detector at the SLAC PEP-II asymmetric-energy B factory. The ${\ensuremath{\chi}}_{c0}$ meson is reconstructed through its two-body decays to ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and ${K}^{+}{K}^{\ensuremath{-}}.$ We measure $\mathcal{B}{(B}^{\ifmmode\pm\else\textpm\fi{}}\stackrel{\ensuremath{\rightarrow}}{}{\ensuremath{\chi}}_{c0}{K}^{\ifmmode\pm\else\textpm\fi{}})\ifmmode\times\e…
Evidence forB+→J/ψpΛ¯and Search forB0→J/ψpp¯
We have performed a search for the decays ${B}^{+}\ensuremath{\rightarrow}J/\ensuremath{\psi}p\overline{\ensuremath{\Lambda}}$ and ${B}^{0}\ensuremath{\rightarrow}J/\ensuremath{\psi}p\overline{p}$ in a data set of $(88.9\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\ensuremath{\Upsilon}(4S)$ decays collected by the BABAR experiment at the PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ storage ring at the Stanford Linear Accelerator Center. Four charged $B$ candidates have been observed with an expected background of $0.21\ifmmode\pm\else\textpm\fi{}0.14$ events. The corresponding branching fraction is $({12}_{\ensuremath{-}6}^{+9})\ifmmode\times\else\texttimes\fi{}{10}^…
Search for the Radiative DecaysB→ργandB0→ωγ
A search for the exclusive radiative decays B {yields} {rho}(770){gamma} and B{sup 0} {yields} {omega}(782){gamma} is performed on a sample of about 84 million B{bar B} events collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} storage ring. No significant signal is seen in any of the channels. We set upper limits on the branching fractions {Beta} of {Beta}(B{sup 0} {yields} {rho}{sup 0}{gamma}) < 1.2 x 10{sup -6}, {Beta}(B{sup +} {yields} {rho}{sup +}{gamma}) < 2.1 x 10{sup -6}, and {Beta}(B{sup 0} {yields} {omega}{gamma}) < 1.0 x 10{sup -6} at 90% confidence level (C.L.). Using the assumption that {Lambda}(B {yields} {rho}{gamma}) = {Lambda}(B{sup +} {yields} …
Measurement of theB0→D*−Ds*+andDs+→ϕπ+branching fractions
The authors present measurements of the branching fractions {Beta}(B{sup 0} {yields} D*{sup -}D*{sub s}{sup +}) and {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}), based on 123 x 10{sup 6} {Upsilon}(4S) {yields} B{bar B} decays collected by the BABAR detector at the PEP-II asymmetric-energy e{sup +}e{sup -} B factory. A partial reconstruction technique is used to measure {Beta}(B{sup 0} {yields} D*{sup -}D*{sub s}{sup +}) and the decay chain is fully reconstructed to measure the branching fraction product {Beta}(B{sup 0} {yields} D*{sup -} D*{sub s}{sup +}) x {Beta}(D{sub s}{sup +} {yields} {phi}{pi}{sup +}). Comparing these two measurements provides a model-independent determination of …
Measurement of Branching Fractions and Charge Asymmetries inB±→ρ±π0andB±→ρ0π±Decays, and Search forB0→ρ0π0
We present measurements of branching fractions and charge asymmetries in $B$-meson decays to ${\ensuremath{\rho}}^{+}{\ensuremath{\pi}}^{0}$, ${\ensuremath{\rho}}^{0}{\ensuremath{\pi}}^{+}$, and ${\ensuremath{\rho}}^{0}{\ensuremath{\pi}}^{0}$. The data sample comprises $89\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ decays collected with the BABAR detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. We find the charge-averaged branching fractions $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\ensuremath{\rho}}^{+}{\ensuremath{\pi}}^{0})=[10.9\ifmmode\pm\else\textpm\fi{}1.9\mathrm{(}\mathrm{s}\mathrm{t}\mathrm{a}\mathrm{…
e+e−→π+π−π+π−,K+K−π+π−, andK+K−K+K−cross sections at center-of-mass energies 0.5–4.5 GeV measured with initial-state radiation
We study the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-\gamma$, with a hard photon radiated from the initial state. About 60,000 fully reconstructed events have been selected from 89 $fb^{-1}$ of BaBar data. The invariant mass of the hadronic final state defines the effective \epem center-of-mass energy, so that these data can be compared with the corresponding direct $e^+e^-$ measurements. From the $4\pi$-mass spectrum, the cross section for the process $e^+e^-\to\pi^+\pi^-\pi^+\pi^-$ is measured for center-of-mass energies from 0.6 to 4.5 $GeV/c^2$. The uncertainty in the cross section measurement is typically 5%. We also measure the cross sections for the final states $K^+ K^- \pi^+\pi^-$ an…
Search for Lepton Flavor Violation in the Decayτ±→μ±γ
A search for the nonconservation of lepton flavor number in the decay tau(+/-)->mu(+/-)gamma has been performed using 2.07 x 10(8) e(+)e(-)->tau(+)tau(-) events produced at a center-of-mass energy near 10.58 GeV with the BABAR detector at the PEP-II storage ring. We find no evidence for a signal and set an upper limit on the branching ratio of B(tau(+/-)->mu(+/-)gamma) < 6.8 x 10(-8) at 90% confidence level.
Branching Fractions andCPAsymmetries inB0→π0π0,B+→π+π0, andB+→K+π0Decays and Isospin Analysis of theB→ππSystem
We measure the branching fractions and CP asymmetries in the decays B0-->K(+)K(-)K(0)(S) and B+-->K(+)K(0)(S)K(0)(S) using a sample of approximately 122x10(6) BB pairs collected by the BABAR detector. From a time-dependent analysis of the K(+)K(-)K(0)(S) sample that excludes phiK(0)(S), the values of the CP-violation parameters are S=-0.56+/-0.25+/-0.04 and C=-0.10+/-0.19+/-0.10, where the first uncertainty is statistical and the second is systematic. We confirm that the final state is nearly purely CP even and extract the standard model parameter sin(2beta=0.57+/-0.26+/-0.04(+0.17)(-0) where the last error is due to uncertainty on the CP content. We present the first measurement of the CP-…
Measurement of branching fractions and charge asymmetries for exclusive B decays to charmonium
We report measurements of branching fractions and charge asymmetries of exclusive decays of neutral and charged B mesons into two-body final states containing a charmonium state and a light strange meson. The charmonium mesons considered are J/Psi, Psi(2S) and Chi_c1, and the light meson is either K or K*. We use a sample of about 124 million BBbar events collected with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center.
Evidence for the Rare DecayB→K*ℓ+ℓ−and Measurement of theB→Kℓ+ℓ−Branching Fraction
We present evidence for the flavor-changing neutral current decay B-->K-*.(+).(-) and a measurement of the branching fraction for the related process B-->K.(+).(-), where .(+).(-) is either an e(+)e(-) or a mu(+)mu(-) pair. These decays are highly suppressed in the standard model, and they are sensitive to contributions from new particles in the intermediate state. The data sample comprises 123x10(6) Y(4S)-->B (B) over bar decays collected with the BABAR detector at the SLAC PEP-II e(+)e(-) storage ring. Averaging over K-(*) isospin and lepton flavor, we obtain the branching fractions B(B-->Kl(+)l(-))=(0.65(-0.13)(+0.14)+/-0.04)x10(-6) and B(B-->K(*)l(+)l(-))=(0.88(-0.29)(+0.33)+/-0.10)x10(…
Limits onD0−D¯0Mixing andCPViolation from the Ratio of Lifetimes for Decay toK−π+,K−K+, andπ−π+
We present a measurement of D0-macro D0 mixing parameters using the ratios of lifetimes extracted from samples of D0 mesons decaying to K-pi(+), K-K+, and pi(-)pi(+). Using 91 fb(-1) of data collected by the BABAR detector at the PEP-II asymmetric-energy B Factory, we obtain a value Y=[0.8+/-0.4(stat.)(+0.5)(-0.4)(syst.)]%, which, in the limit of CP conservation, corresponds to the mixing parameter y=Delta Gamma/2 Gamma. Using the difference in lifetimes of D0 and macro D0 mesons, we obtain the CP-violation parameter Delta Y=[-0.8+/-0.6(stat.)+/-0.2(syst.)]%.
Measurement of Time-DependentCPAsymmetries and Constraints onsin(2β+γ)with Partial Reconstruction ofB0→D*∓π±Decays
We present a preliminary measurement of the time-dependent CP-violating asymmetry in decays of neutral B mesons to the final states D*-+ pi+- using approximately 178 million BB events recorded by the BaBar experiment at the PEP-II e+e- storage ring. Events containing these decays are selected with a partial reconstruction technique, in which only the high-momentum pi+- from the B decay and the low-momentum pi-+ from the D*-+ decay are used. % We measure the amplitude of the asymmetry to be $-0.041 \pm 0.016 (stat.) \pm 0.010 (syst.)$ and determine bounds on $|\sin(2 \beta + \gamma)|$.
Search forCPviolation and a measurement of the relative branching fraction inD+→K−K+π+decays
We report on a search for the CP asymmetry in the singly Cabibbo-suppressed decays $D^+ \to K^-K^+\pi^+$ and in the resonant decays $D^+ \to \phi\pi^+$ and $D^+ \to \overline{K}^{\star0}K^+$ based on a data sample of 79.9 fb$^{-1}$ recorded by the BABAR detector. We use the Cabibbo-favored $D_s^+ \to K^-K^+\pi^+$ branching fraction as normalization in the measurements to reduce systematic uncertainties. The CP asymmetries obtained are $A_{CP}(K^-K^+\pi^{\pm}) = (1.4 \pm 1.0 (stat.) \pm 0.8 (syst.) \times 10^{-2}, A_{CP}(phi pi) = (0.2 +/- 1.5 (stat.) +/- 0.6 (syst.) x 10^-2$, and $A_{CP}(\overline{K}^{\star0} K^{\pm}) = (0.9 \pm 1.7 (stat.) \pm 0.7 (syst.) \times 10^{-2}$. The relative bran…
Measurements of the branching fractions and bounds on the charge asymmetries of charmless three-body charged B decays.
We present measurements of branching fractions and charge asymmetries for charmless B-meson decays to three-body final states of charged pions and kaons. The analysis uses 81.8 fb^-1 of data collected at the Upsilon(4S) resonance with the BaBar detector at the SLAC PEP-II asymmetric B Factory. We measure the branching fractions B(B+ -> pi+ pi- pi+) = (10.9 +/- 3.3 +/- 1.6) x 10^-6, B(B+ -> K+ pi- pi+) = (59.1 +/- 3.8 +/- 3.2) x 10^-6, and B(B+ -> K+ K- K+) = (29.6 +/- 2.1 +/- 1.6) x 10^-6, and provide 90% C.L. upper limits for other decays. We observe no charge asymmetries for these modes.
Observation of a Narrow Meson State Decaying toDs+π0at a Mass of2.32 GeV/c2
We have observed a narrow state near 2.32 GeV/c(2) in the inclusive D(+)(s)pi(0) invariant mass distribution from e(+)e(-) annihilation data at energies near 10.6 GeV. The observed width is consistent with the experimental resolution. The small intrinsic width and the quantum numbers of the final state indicate that the decay violates isospin conservation. The state has natural spin-parity and the low mass suggests a J(P)=0(+) assignment. The data sample corresponds to an integrated luminosity of 91 fb(-1) recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e(+)e(-) storage ring.
Measurement of the ratioB(B+→Xeν)/B(B0→Xeν)
We report measurements of the inclusive electron momentum spectra in decays of charged and neutral B mesons, and of the ratio of semileptonic branching fractions B(B+-> Xe nu) and B(B-0 -> Xe nu). These were performed on a sample of 231x10(6) B (B) over bar events recorded with the BABAR detector at the Upsilon(4S) resonance. Events are selected by fully reconstructing a hadronic decay of one B meson and identifying an electron among the decay products of the recoiling (B) over bar meson. We obtain B(B+-> Xe nu)/B(B-0 -> Xe nu)=1.074 +/- 0.041((stat))+/- 0.026((syst)).
Observation of the DecayB±→π±π0, Study ofB±→K±π0, and Search forB0→π0π0
We present results for the branching fractions and charge asymmetries in B+/--->h(+/-)pi(0) (where h(+/-)=pi(+/-),K+/-) and a search for the decay B0-->pi(0)pi(0) using a sample of approximately 88 x 10(6) BBmacr; pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We measure B(B+/--->pi(+/-)pi(0))=(5.5(+1.0)(-0.9)+/-0.6)x10(-6), where the first error is statistical and the second is systematic. The B+/--->pi(+/-)pi(0) signal has a significance of 7.7sigma including systematic uncertainties. We simultaneously measure the K+/-pi(0) branching fraction to be B(B+/--->K+/-pi(0))=(12.8(+1.2)(-1.1)+/-1.0)x10(-6). The charge asymmetries are Api(+/-)(pi(0))=-0.0…
Measurement of the Branching Fraction and Polarization for the DecayB−→D*0K*−
We present a study of the decay B- --> D*K-0*(-) based on a sample of 86 X 10(6) Y(4S) --> B (B) over bar decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We measure the branching fraction 23(B- --> D*K-0*(-)) = (8.3 +/- 1.1(stat) +/- 1.0(syst)) X 10(-4), and the fraction of longitudinal polarization in this decay to be Gamma(L)/Gamma = 0.86 +/- 0.06(stat) --> +/- 0.03(syst).
Measurements of the branching fractions of chargedBdecays toK±π∓π±final states
We present results of searches for B-meson decays to K+ pi- pi+ with the BaBar detector. With a data sample of 61.6 million BBbar pairs, we measure the branching fractions and 90% confidence-level upper limits averaged over charge-conjugate states (the first error is statistical and the second is systematic): B+ --> K*0 pi+ = (15.5 +/- 1.8 +1.5 -4.0) x 10^-6, B+ --> f0 K+, f_0 --> pi+ pi- = (9.2 +/- 1.2 +2.1 -2.6) x 10^-6, B+ --> D0bar pi+, D0bar --> K+ pi- = (184.6 +/- 3.2 +/- 9.7) x 10^-6. B+ --> rho K+ K+ pi- pi+ non-resonant < 17 x 10^-6.
Search for a charged partner of theX(3872)in theBmeson decayB→X−K,X−→J/ψπ−π0
We search for a charged partner of the X(3872) in the decay B --> X- K, X- --> J/psi pi- pi0, using 234 million BBbar events collected at the Y(4S) resonance with the BaBar detector at the PEP-II e+e- asymmetric-energy storage ring. The resulting product branching fraction upper limits are BR(B0 --> X- K+, X- --> J/psi pi- pi0) X- K0bar,X- --> J/psi pi- pi0) < 22 x 10(-6) at the 90% confidence level.