P. Kyberd

We study initial-state radiation events, ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\gamma}}_{\mathrm{ISR}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$, with data collected with the BABAR detector. We observe an accumulation of events near $4.26\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ in the invariant-mass spectrum of ${\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}J/\ensuremath{\psi}$. Fits to the mass spectrum indicate that a broad resonance with a mass of about $4.26\text{ }\text{ }\mathrm{GeV}/{c}^{2}$ is required to describe the observed structure. The presence of additional narrow resonances cannot be excluded. The fitted width of the broad resonance is 50 to $90\text{ }\text{ }\mathrm{MeV}/{c}^{2}$, depending on the fit hypothesis.

We have observed a narrow state near 2.32 GeV/c2 in the inclusive D+sπ0 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 JP=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.Received 11 April 2003DOI:https://doi.org/10.1103/PhysRevLett.90.242001©2003 American Physical Society

We study the decay ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ using $117\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ events collected at the $Y(4S)$ resonance with the BABAR detector at the PEP-II ${e}^{+}{e}^{\ensuremath{-}}$ asymmetric-energy storage ring. We measure the branching fractions $\mathcal{B}$ $({B}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=(116\ifmmode\pm\else\textpm\fi{}7(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}9(\mathrm{syst}.))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and $\mathcal{B}$ $({B}^{\ensuremath{-}}\ensuremath{\rightarrow}X(3872){\mathrm{K}}^{\ensuremath{-}})\ifmmode\times\else\texttimes\fi{}$ $\mathcal{B}$ $(X(3872)\ensuremath{\rightarrow}\mathrm{J}/\ensuremath{\psi}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})=(1.28\ifmmode\pm\else\textpm\fi{}0.41)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$ and find the mass of the $X(3872)$ to be $3873.4\ifmmode\pm\else\textpm\fi{}1.4\text{ }\text{ }\mathrm{MeV}/{\mathrm{c}}^{2}$. We search for the ${h}_{c}$ narrow state in the decay ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{h}_{c}{K}^{\ensuremath{-}}$, ${h}_{c}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}$ and for the decay ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{D}^{0}{\ensuremath{\pi}}^{\ensuremath{-}}$, with ${D}^{0}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{+}$. We set the $90%$ C.L. limits $\mathcal{B}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}{h}_{c}{K}^{\ensuremath{-}})\ifmmode\times\else\texttimes\fi{}\mathcal{B}({h}_{c}\ensuremath{\rightarrow}J/\ensuremath{\psi}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}})<3.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $\mathcal{B}({B}^{\ensuremath{-}}\ensuremath{\rightarrow}J/\ensuremath{\psi}{D}^{0}{\ensuremath{\pi}}^{\ensuremath{-}})<5.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$.

We present a measurement of the cross section of the process e(+)e(-)-->pi(+)pi(-)psi(2S) from threshold up to 8 GeV center-of-mass energy using events containing initial-state radiation, produced at the SLAC PEP-II e(+)e(-) storage rings. The study is based on 298 fb(-1) of data recorded with the BABAR detector. A structure is observed in the cross section not far above threshold, near 4.32 GeV. We also investigate the compatibility of this structure with the Y(4260) previously reported by this experiment.

We report the observation of five events in which a missing transverse energy larger than 40 GeV is associated with a narrow hadronic jet and of two similar events with a neutral electromagnetic cluster (either one or more closely spaced photons). We cannot find an explanation for such events in terms of backgrounds or within the expectations of the Standard Model.

The GridPP Collaboration is building a UK computing Grid for particle physics, as part of the international effort towards computing for the Large Hadron Collider. The project, funded by the UK Particle Physics and Astronomy Research Council (PPARC), began in September 2001 and completed its first phase 3 years later. GridPP is a collaboration of approximately 100 researchers in 19 UK university particle physics groups, the Council for the Central Laboratory of the Research Councils and CERN, reflecting the strategic importance of the project. In collaboration with other European and US efforts, the first phase of the project demonstrated the feasibility of developing, deploying and operating a Grid-based computing system to meet the UK needs of the Large Hadron Collider experiments. This note describes the work undertaken to achieve this goal.

The e+e- -> p anti-p cross section is determined over a range of p anti-p masses, from threshold to 4.5 GeV/c^2, by studying the e+e- -> p anti-p gamma process. The data set corresponds to an integrated luminosity of 232 fb^-1, collected with the BABAR detector at the PEP-II storage ring, at an e+e- center-of-mass energy of 10.6 GeV. The mass dependence of the ratio of electric and magnetic form factors, |G_E/G_M|, is measured for p anti-p masses below 3 GeV/c^2; its value is found to be significantly larger than 1 for masses up to 2.2 GeV/c^2. We also measure J/psi -> p anti-p and psi(2S) -> p anti-p branching fractions and set an upper limit on Y(4260) -> p anti-p production and decay.

A clear signal is observed for the production of an isolated large-transverse-momentum lepton in association with two or three centrally produced jets. The two-jet events cluster around the W± mass, indicating a novel decay of the Intermediate Vector Boson. The rate and features of these events are not consistent with expectations of known quark decays (charm, bottom). They are, however, in agreement with the process W→ tb followed by t → bℓv, where t is the sixth quark (top) of the weak Cabibbo current. If this is indeed so, the bounds on the mass of the top quark are 30 GeV/c2 < mt <550 GeV/c2.

We report on a search for B0↔B¯0 oscillations (mixing) using events with two identified muons from data collected at the CERN p¯p collider. In the absence of B0↔B¯0 oscillations, dimuons coming directly from decays of beauty-antibeauty paris must have opposite signs. Like-sign dimuons are expected from events where one muon arises from beauty decay and the other from the charm decay of the associated beauty-charm cascade. Taking these processes into account, together with the contribution from charm production, the predicted ratio of like-sign to unlike-sign muon pairs is 0.26±0.03. Experimentally we measure 0.42±0.07±0.03. A natural explanation for the excess of like-sign events is the existence of a significant amount of B0↔B¯0 transitions. The fraction of beauty particles that produce first-generation decay muons with the opposite electric charge from that expected without mixing is deduced to be: χ = 0.121±0.047. Combined with the null result from searches for B0↔B¯0 oscillations at e+e− colliders, our results are consistent with transitions inthe B0s system, as favoured theoretically.

We present measurements of the flavor-changing neutral current decays B --> Kl+l- and B --> K*l+l-, where l+l- is either an e+e- or mu+mu- pair. The data sample comprises 229 x 10^6 Y(4s) -->to BBbar decays collected with the BaBar detector at the PEP-II e+e- storage ring. Flavor-changing neutral current decays are highly suppressed in the Standard Model and their predicted properties could be significantly modified by new physics at the electroweak scale. We measure the branching fractions B(B --> Kll) = (0.34 +- 0.07 +- 0.02) x 10^{-6}, B(B --> K*ll) = (0.78^{+0.19}_{-0.17} +- 0.11) x 10^{-6}, the direct CP asymmetries of these decays, and the relative abundances of decays to electrons and muons. For two regions in l+l- mass, above and below m(Jpsi), we measure partial branching fractions and the forward-backward angular asymmetry of the lepton pair. In these same regions we also measure the K* longitudinal polarization in B --> K*l+l- decays. Upper limits are obtained for the lepton flavor-violating decays B --> Kemu and B --> K*emu. All measurements are consistent with Standard Model expectations.

We measure the branching fraction for the flavor-changing neutral-current process B-->X(s)l(+)l(-) with a sample of 89x10(6) Upsilon(4S)-->BBmacr; events recorded with the BABAR detector at the PEP-II e(+)e(-) storage ring. The final state is reconstructed from e(+)e(-) or micro(+)micro(-) pairs and a hadronic system X(s) consisting of one K+/- or K(0)(S) and up to two pions, with at most one pi(0). We observe a signal of 40+/-10(stat)+/-2(syst) events and extract the inclusive branching fraction B(B-->X(s)l(+)l(-))=(5.6+/-1.5(stat)+/-0.6(exp syst)+/-1.1(model syst))x10(-6) for ml(+)(l(-))>0.2 GeV/c(2).

We present a measurement of the direct CP violating asymmetry in the decay B0-->K+pi(-) using a data sample of 227x10(6) Upsilon(4S)-->BB decays collected with the BABAR detector at the PEP-II asymmetric-energy e(+)e(-) collider at SLAC. We observe a total signal yield of nK-(pi(+))+nK+(pi(-))=1606+/-51 decays and measure the asymmetry (nK-(pi(+))-nK+(pi(-)))/(nK-(pi(+))+nK+(pi(-)))=-0.133+/-0.030(stat)+/-0.009(syst). The probability of observing such an asymmetry in the absence of direct CP violation is 1.3x10(-5), corresponding to 4.2 standard deviations.

We study e+e−→J/ψ cc¯ by measuring the invariant mass distribution recoiling against fully reconstructed J/ψ decays, using 124 fb−1 of data collected at a center-of-mass energy of 10.6 GeV with the BABAR detector. We observe signals for ηc(1S), χc0, and ηc(2S) in the recoil mass distribution, thus confirming previous measurements. We measure σ(e+e−→J/ψ+cc¯)B(cc¯→>2 charged) to be 17.6±2.8(stat)−2.1+1.5(syst) fb, 10.3±2.5(stat)−1.8+1.4(syst) fb, and 16.4±3.7(stat)−3.0+2.4(syst) fb with cc¯=ηc(1S), χc0, and ηc(2S), respectively.Received 25 June 2005DOI:https://doi.org/10.1103/PhysRevD.72.031101©2005 American Physical Society

This white paper addresses the hypothesis of light sterile neutrinos based on recent anomalies observed in neutrino experiments and the latest astrophysical data.

We search for the production of doubly charmed baryons in e+e− annihilations at or near a center-of-mass energy of 10.58 GeV, in a data sample with an integrated luminosity of 232 fb−1 recorded with the BABAR detector at the PEP-II storage ring at the Stanford Linear Accelerator Center. We search for Ξ+cc baryons in the final states Λ+cK−π+ and Ξ0cπ+, and Ξ++cc baryons in the final states Λ+cK−π+π+ and Ξ0cπ+π+. We find no evidence for the production of doubly charmed baryons.Received 18 May 2006DOI:https://doi.org/10.1103/PhysRevD.74.011103©2006 American Physical Society

The process e+e- --&gt; pi+ pi- pi0 gamma has been studied at a center-of-mass energy near the Y(4S) resonance using a 89.3 fb-1 data sample collected with the BaBar detector at the PEP-II collider. From the measured 3pi mass spectrum we have obtained the products of branching fractions for the omega and phi mesons, B(omega --&gt; e+e-)B(omega --&gt; 3pi)=(6.70 +/- 0.06 +/- 0.27)10-5 and B(phi --&gt; e+e-)B(phi --&gt; 3pi)=(4.30 +/- 0.08 +/- 0.21)10-5, and evaluated the e+e- --&gt; pi+ pi- pi0 cross section for the e+e- center-of-mass energy range 1.05 to 3.00 GeV. About 900 e+e- --&gt; J/psi gamma --&gt; pi+ pi- pi0 gamma events have been selected and the branching fraction B(J/psi --&gt; pi+ pi- pi0)=(2.18 +/- 0.19)% has been measured.

We observe a new Ds meson with mass (2856.6±1.5stat±5.0syst) MeV/c2 and width (48±7stat±10syst) MeV/c2 decaying into D0K+ and D+K0S. In the same mass distributions, we also observe a broad structure with mass (2688±4stat±3syst) MeV/c2 and width (112±7stat±36syst) MeV/c2. To obtain this result, we use 240 fb−1 of data recorded by the BABAR detector at the PEP-II asymmetric-energy e+e− storage rings at the Stanford Linear Accelerator Center running at center-of-mass energies near 10.6 GeV.Received 27 July 2006DOI:https://doi.org/10.1103/PhysRevLett.97.222001©2006 American Physical Society

With a sample of approximately 89 x 10(6) B(-)B pairs collected with the BABAR detector, we perform a search for B meson decays into pairs of charmless vector mesons (phi, rho, and K*). We measure the branching fractions, determine the degree of longitudinal polarization, and search for CP violation asymmetries in the processes B+-->phiK(*+), B0-->phiK(*0), B+-->rho(0)K(*+), and B+-->rho(0)rho(+). We also set an upper limit on the branching fraction for the decay B0-->rho(0)rho(0).

A silicon strip microvertex detector has been designed, constructed and commissioned in the OPAL experiment at the LEP electron-positron collider. The microstrip devices incorporate a new FoxFET biassing scheme developed together with Micron Semiconductor Ltd., UK. The devices digitise with a precision close to 5 μm and have an exceptionally high signal-to-noise ratio. The associated microelectronics were all custom made for the OPAL project. The detector began operation in 1991 and has since continued to be part of the OPAL experiment, performing to a very high standard and opening up new areas of physics studies.

We study the processes e+ e- --> 3(pi+pi-)gamma, 2(pi+pi-pi0)gamma and K+ K- 2(pi+pi-)gamma, with the photon radiated from the initial state. About 20,000, 33,000 and 4,000 fully reconstructed events, respectively, have been selected from 232 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the effective e+e- center-of-mass energy, so that these data can be compared with the corresponding direct e+e- measurements. From the 3(pi+pi-), 2(pi+pi-pi0) and K+ K- 2(pi+pi-) mass spectra, the cross sections for the processes e+ e- --> 3(pi+pi-), e+ e- --> 2(pi+pi-pi0) and e+ e- --> K+ K- 2(pi+pi-) are measured for center-of-mass energies from production threshold to 4.5 GeV. The uncertainty in the cross section measurement is typically 6-15%. We observe the J/psi in all these final states and measure the corresponding branching fractions.

A search for the nonconservation of lepton flavor number in the decay τ±→μ±γ has been performed using 2.07×108 e+e−→τ+τ− 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(τ±→μ±γ)<6.8×10−8 at 90% confidence level.Received 16 February 2005DOI:https://doi.org/10.1103/PhysRevLett.95.041802©2005 American Physical Society

We study the initial-state-radiation processes e+e−→K+K−π+π−γ and e+e−→K+K−π0π0γ using an integrated luminosity of 232 fb−1 collected at the Υ(4S) mass with the BABAR detector at SLAC. Even though these reactions are dominated by intermediate states with excited kaons, we are able to study for the first time the cross section for e+e−→ϕ(1020)f0(980) as a function of center-of-mass energy. We observe a structure near threshold consistent with a 1−− resonance with mass m=2.175±0.010±0.015 GeV/c2 and width Γ=58±16±20 MeV. We observe no Y(4260) signal and set a limit of BY→ϕπ+π−⋅ΓYee<0.4 eV (90% confidence level), which excludes some models.Received 10 October 2006DOI:https://doi.org/10.1103/PhysRevD.74.091103©2006 American Physical Society

An extensive study of production and decay properties of charged and neutral Intermediate Vector Bosons (IVB) at the CERN proton-antiproton collider is presented. Intermediate Vector Bosons were detected in the electron, muon, and tau decay modes at centre-of-mass energies of 0.546 and 0.630 TeV. This paper is a summary, based on all the available data from the UA1 experiment from the running periods 1982–1985. Results are presented and compared with expectations of the Standard Eletroweak Model and QCD-improved Drell-Yan annihilation processes. The general conclusion is that there is an excellent agreement between the predictions of the Standard Model and our measurements.

In a study of B+→J/ψγK+ decays, we find evidence for the radiative decay X(3872)→J/ψγ with a statistical significance of 3.4σ. We measure the product of branching fractions B(B+→X(3872)K+)⋅B(X(3872)→J/ψγ)=(3.3±1.0±0.3)×10−6, where the uncertainties are statistical and systematic, respectively. We also measure the branching fraction B(B+→χc1K+)=(4.9±0.2±0.4)×10−4. These results are obtained from (287±3) million B¯¯¯B decays collected at the Υ(4S) resonance with the BABAR detector at the PEP-II B Factory at SLAC.Received 25 July 2006DOI:https://doi.org/10.1103/PhysRevD.74.071101©2006 American Physical Society

We report evidence for beauty particle production through the observation of dimuon events from proton-antiproton collisions at energies of √s=546 GeV and √s=630 GeV at the CERN collider. Our data indicate that semi-leptonic decays of beauty particles are the dominant source of pairs of high-pT muons. The beauty flavour creation (gg or q¯q→b¯b) cross-section needed to explain the dimuon rate is σ{p¯p→b¯b+X, pbT5 GeV/c, |η|<2.0}=(1.1±0.1±0.4) μb, which is in good agreement with QCD calculations. We also observe clear signals for ϒ→μ+μ− (hidden beauty) and high-pT J/ψ→μ+μ−, well above the backgraound of continuum muon pairs from the Drell-Yan mechanism.

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 $K^+ K^- \pi^+\pi^-$ and $K^+ K^- K^+ K^-$. We observe the $J/\psi$ in all three final states and measure the corresponding branching fractions. We search for X(3872) in $J/\psi (\to\mu^+\mu^-) \pi^+\pi^-$ and obtain an upper limit on the product of the $e^+e^-$ width of the X(3872) and the branching fraction for $X(3872) \to J/\psi\pi^+\pi^-$.

We present a detailed study of hadronic jets obtained in a data sample taken in the UA1 detector with a localized transverse energy trigger. We discuss the average shape of jets in terms of energy and charged particle content, and compare this to data generated in Monte Carlo programs. We further extend the previously reported inclusive jet cross section to the region of ET = 100 GeV. A comparison with theoretical models of cross sections for events with more than two jets is also given.

A search for charmed baryons decaying to $D^0 p$ reveals two states: the $Λ_c(2880)^+$ baryon and a previously unobserved state at a mass of [$2939.8\pm 1.3 \text{(stat.)}\pm 1.0 \text{(syst.)}$]~\mevcc and with an intrinsic width of [$17.5\pm 5.2 \text{(stat.)}\pm 5.9 \text{(syst.)}$]~\mev. Consistent and significant signals are observed for the $K^-π^+$ and $K^-π^+π^-π^+$ decay modes of the $D^0$ in 287 ${\rm fb}^{-1}$ annihilation data recorded by the BaBar detector at a center-of-mass energy of 10.58~${\rm GeV}/c^2$. There is no evidence in the $D^+ p$ spectrum of doubly-charged partners. The mass and intrinsic width of the $Λ_c(2880)^+$ baryon and relative yield of the two baryons are also measured.

A search for the nonconservation of lepton flavor in the decay τ±→e±γ has been performed with 2.07×108 e+e−→τ+τ− events collected by the BABAR detector at the SLAC PEP II storage ring at a center-of-mass energy near 10.58 GeV. We find no evidence for a signal and set an upper limit on the branching ratio of B(τ±→e±γ)<1.1×10−7 at 90% confidence level.Received 5 August 2005DOI:https://doi.org/10.1103/PhysRevLett.96.041801©2006 American Physical Society

The OPAL experiment at the CERN LEP collider recently upgraded its silicon strip microvertex detector from one coordinate readout (φ only) to two coordinate readout (φ and z). This allows three dimensional vertex reconstruction and should improve lifetime measurements as well as b quark jet identification. This paper describes the new microvertex detector system with emphasis on the novel techniques and new components used to obtain the second coordinate information. These include the use of back-to-back single-sided detectors with orthogonally oriented readout strips, a gold printed circuit on a thin glass substrate to route the z strip signals to the electronics at the end of the detector, and the use of MX7 readout chips. Results on the performance of the new detector are presented.

The two-jet cross section measured in the UA1 apparatus at the CERN pp Collider has been analysed in terms of the centre-of-mass scattering angle θ and the scaled longitudinal parton momenta x1 and x2. The angular distribution dσ/d cos σ rises rapidly as cos → 1, independent of x2 and x2, as expected in vector gluon theories (QCD). The differential cross section in x1 and x2 is consistent with factorization and provides a measurement of the proton structure function F(x) = G(x) + 49[Q(x) + Q(x)] at values of the four-momentum transfer squared, -t̂ ≈ 2000 GeV2. Over the range x = 0.10−0.80 the structure function shows an exponential x dependence and may be parametrized by the form F(x) = 6.2 exp (−9.5x).

We report a Dalitz-plot analysis of the charmless hadronic decays of charged B mesons to the final state K±π∓π±. Using a sample of 226.0±2.5 million B¯¯¯B pairs collected by the BABAR detector, we measure the magnitudes and phases of the intermediate resonant and nonresonant amplitudes for both charge-conjugate decays. We present measurements of the corresponding branching fractions and their charge asymmetries that supersede those of previous BABAR analyses. We find the charge asymmetries to be consistent with zero.Received 1 July 2005DOI:https://doi.org/10.1103/PhysRevD.72.072003©2005 American Physical Society

We report the first observation of an excited singly-charm baryon OmegaC* (css) in the radiative decay OmegaC0 Gamma, where the OmegaC0 baryon is reconstructed in the decays to the final states Omega-pi+, Omega-pi+pi0, Omega-pi+pi-pi+, and Cascade-K-pi+pi+. This analysis is performed using a dataset of 230.7 fb$-1} collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at the Stanford Linear Accelerator Center. The mass difference between the OmegaC* and the OmegaC0 baryons is measured to be 70.8 +/- 1.0 (stat) +/- 1.1 (syst) MeV/c2. We also measure the ratio of inclusive production cross sections of OmegaC* and OmegaC0 in e+e- annihilation.

The inclusive jet cross section has been measured in the UA1 experiment at the CERN pp Collider at centre-of-mass energies √s = 546 GeV and √s = 630 eV. The cross sections are found to be consistent with QCD predictions, The observed change in the cross section with the centre-of-mass energy √s is accounted for in terms of xT scaling.

We present results on time-dependent CP asymmetries in neutral B decays to several CP eigenstates. The measurements use a data sample of about 227 x 10(6) upsilon(4S) --> BB decays collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. The amplitude of the CPasymmetry, sin2beta in the standard model, is derived from decay-time distributions from events in which one neutral B meson is fully reconstructed in a final state containing a charmonium meson and the other B meson is determined to be either a B0 or B0 from its decay products. We measure sin2beta = 0.722 +/- 0.040(stat) +/- 0.023(syst) in agreement with the standard model expectation.

A narrow state, which we label DsJ(2458)+, with a mass 2458.0±1.0(stat)±1.0(syst)MeV/c2, is observed in the inclusive D+sπ0γ mass distribution in 91fb−1 of e+e− annihilation data recorded by the BABAR detector at the SLAC PEP-II asymmetric-energy e+e− storage ring. The observed width is consistent with the experimental resolution. The data favor decay through D*s(2112)+π0 rather than through D*sJ(2317)+γ. An analysis of D+sπ0 data accounting for the influence of the DsJ(2458)+ produces a D*sJ(2317)+ mass of 2317.3±0.4(stat)±0.8(syst)MeV/c2. Received 24 October 2003DOI:https://doi.org/10.1103/PhysRevD.69.031101©2004 American Physical Society

We present results of a search for the X(3872) in B0→X(3872)K0S,X(3872)→J/ψπ+π−, improved measurements of B−→X(3872)K−, and a study of the J/ψπ+π− mass region above the X(3872). We use 232×106 B¯¯¯B pairs collected at the Υ(4S) resonance with the BABAR detector at the PEP-II e+e− asymmetric-energy storage rings. The results include the 90% confidence interval 1.34×10−6<B(B0→X(3872)K0,X→J/ψπ+π−)<10.3×10−6 and the branching fraction B(B−→X(3872)K−,X→J/ψπ+π−)=(10.1±2.5±1.0)×10−6. We observe a (2.7±1.3±0.2)MeV/c2 mass difference of the X(3872) produced in the two decay modes. Furthermore, we search for the Y(4260) in B decays and set the 95% C.L. upper limit B(B−→Y(4260)K−,Y(4260)→J/ψπ+π−)<2.9×10−5.Received 21 July 2005DOI:https://doi.org/10.1103/PhysRevD.73.011101©2006 American Physical Society

We search for a charged partner of the X(3872) in the decay B --&gt; X- K, X- --&gt; 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 --&gt; X- K+, X- --&gt; J/psi pi- pi0) &lt; 5.4 x 10(-6) and BR(B- --&gt; X- K0bar,X- --&gt; J/psi pi- pi0) &lt; 22 x 10(-6) at the 90% confidence level.

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.

The properties of a sample of 172 charged intermediate vector bosons decaying in the (eve) channel and 16 neutral intermediate vector bosons decaying in the (e+e−) channel are summarized. Masses, decay widths, decay angular distributions, and production cross sections are given, and a limit is put on the number of light neutrino types Nv ⩽ 10 at 90% CL.

We present results on $B\to J/ψ\xspace Kπ$ decays using $e^+e^-$ annihilation data collected with the BABAR detector at the $Υ(4S)$ resonance. The detector is located at the PEP-II asymmetric-energy storage ring facility at the Stanford Linear Accelerator Center. Using approximately 88 million $B\bar{B}$ pairs, we measure the decay amplitudes for the flavor eigenmodes and observe strong-phase differences indicative of final-state interactions with a significance of 7.6 standard deviations. We use the interference between the $Kπ$ $S$-wave and $P$-wave amplitudes in the region of the $K^*(892)$ to resolve the ambiguity in the determination of these strong phases. We then perform an ambiguity-free measurement of $\cos2β$ using the angular and time-dependent asymmetry in $B\to J/ψ\xspace K^{*0}(K_S^0π^0$) dec With $\sin 2 β$ fixed at its measured value and $\cos 2 β$ treated as an in we find $\cos 2β=2.72_{-0.79}^{+0.50}\mathrm{(stat)} \pm 0.27\mathrm{(syst)}$, de sign of $\cos 2β$ to be positive at 86% CL.

With a sample of 232x10^6 Upsilon(4S) --> BBbar events collected with the BaBar detector, we study the decay B+ --> p pbar K+ excluding charmonium decays to ppbar. We measure a branching fraction Br(B+ --> p pbar K+)=(6.7+/-0.5+/-0.4)x10^{-6}. An enhancement at low ppbar mass is observed and the Dalitz plot asymmetry suggests dominance of the penguin amplitude in this B decay. We search for a pentaquark candidate Theta*++ decaying into pK+ in the mass range 1.43 to 2.00 GeV/c2 and set limits on Br(B+ --> Theta*++pbar)xBr(Theta*++ --> pK+) at the 10^{-7} level.

We study the two-body decays of B^\pm mesons to K^\pm and a charmonium state, X_{c\bar c}, in a sample of 210.5 fb^{-1} of data from the BaBar experiment. We perform measurements of absolute branching fractions BR(B^\pm --> K^\pm X_{c\bar c}) using a missing mass technique, and report several new or improved results. In particular, the upper limit BR(B^\pm --> K^\pm X(3872))<3.2 10^-4 at 90% CL and the inferred lower limit BR(X(3872) --> J/\psi\pi^+\pi^-)>4.2% will help in understanding the nature of the recently discovered X(3872).

We report on further analysis of events with large missing transverse energy from 715 nb−1 of data from the UA1 experiment at the CERN proton-antiproton collider. Measured W and Z0 rates and heavy flavour cross sections are used to predict rates of missing transverse energy event from all known standard model process. Limits are derived on two possible new sources, namely: (1) semi-hadronic decays of a fourth sequential charged heavy lepton coupling to the W boson, (2) Z0 decays into additional pairs of non-interacting particles. After taking into additional pairs of non-interacting particles. After taking into account all known sources of missing transverse energy events, we find a mass limit on a fourth-generation charged lepton of mL>41 GeV/c2 (90% CL) and a limit on the number of additional neutrino species of n⩽7 (90% CL).

Using a data sample corresponding to an integrated luminosity of 342 fb−1 collected with the BABAR detector at the SLAC PEP-II electron-positron storage ring operating at a center-of-mass energy near 10.58 GeV, we measure B(τ−→π−π−π+ντ(ex.KS0))=(8.83±0.01±0.13)%, B(τ−→K−π−π+ντ(ex.KS0))=(0.273±0.002±0.009)%, B(τ−→K−π−K+ντ)=(0.1346±0.0010±0.0036)%, and B(τ−→K−K−K+ντ)=(1.58±0.13±0.12)×10−5, where the uncertainties are statistical and systematic, respectively. These include significant improvements over previous measurements and a first measurement of B(τ−→K−K−K+ντ) in which no resonance structure is assumed. We also report a first measurement of B(τ−→ϕπ−ντ)=(3.42±0.55±0.25)×10−5, a new measurement of B(τ−→ϕK−ντ)=(3.39±0.20±0.28)×10−5 and a first upper limit on B(τ−→K−K−K+ντ(ex.ϕ)).Received 19 July 2007DOI:https://doi.org/10.1103/PhysRevLett.100.011801©2008 American Physical Society

The spin dependence of π0 inclusive production by 24 GeV/c protons has been measured using a polarized target for Fhe Feynman x near 0 in the transverse momentum range 1.0 < pT < 2.5 GeV/c. The results indicate a negative updown asymmetry growing strongly with pT and greater than 50% in absolute value for pT greater than 2 GeV/c.

Charged-particle tracking in the international Muon Ionisation Cooling Experiment (MICE) will be performed using two solenoidal spectrometers, each instrumented with a tracking detector based on 350 {\mu}m diameter scintillating fibres. The design and construction of the trackers is described along with the quality-assurance procedures, photon-detection system, readout electronics, reconstruction and simulation software and the data-acquisition system. Finally, the performance of the MICE tracker, determined using cosmic rays, is presented.

A search for the lepton-flavor-violating decay of the tau into three charged leptons has been performed using 91.5 fb−1 of data collected at an e+e−center-of-mass energy around 10.58 GeV with the BABAR detector at the SLAC storage ring PEP-II. In all six decay modes considered, the numbers of events found in data are compatible with the background expectations. Upper limits on the branching fractions are set in the range (1–3)×10−7 at 90% confidence level.Received 8 December 2003DOI:https://doi.org/10.1103/PhysRevLett.92.121801©2004 American Physical Society

With a sample of about 227x10(6) BB pairs recorded with the BABAR detector we perform a full angular analysis of the decay B0-->phiK(*0)(892). We make novel measurements of five parameters sensitive to CP violation. We also measure the branching fraction to be (9.2+/-0.9+/-0.5)x10(-6) and determine the fractions of longitudinal and parity-odd transverse contributions as f(L)=0.52+/-0.05+/-0.02 and f( perpendicular)=0.22+/-0.05+/-0.02. The phases of the parity-even and parity-odd transverse amplitudes relative to the longitudinal amplitude are found to be phi( parallel)=2.34(+0.23)(-0.20)+/-0.05 rad and phi( perpendicular)=2.47+/-0.25+/-0.05 rad. We also observe the decay B0-->phiK(*0)(1430).

We report on a measurement of the Cabibbo-Kobayashi-Maskawa CP-violating phase γ through a Dalitz analysis of neutral D decays to KS0π−π+ in the processes B∓→D(*)K∓, D*→Dπ0, Dγ. Using a sample of 227×106 BB¯ pairs collected by the BABAR detector, we measure the amplitude ratios rB=0.12±0.08±0.03±0.04 and rB*=0.17±0.10±0.03±0.03, the relative strong phases δB=(104±45−21−24+17+16)° and δB*=(−64±41−12+14±15)° between the amplitudes A(B−→D¯(*)0K−) and A(B−→D(*)0K−), and γ=(70±31−10−11+12+14)°. The first error is statistical, the second is the experimental systematic uncertainty, and the third reflects the Dalitz model uncertainty. The results for the strong and weak phases have a twofold ambiguity.Received 20 April 2005DOI:https://doi.org/10.1103/PhysRevLett.95.121802©2005 American Physical Society

We report the results of a search for $T$, $CP$, and $CPT$ violation in ${B}^{0}\mathrm{\text{\ensuremath{-}}}{\overline{B}}^{0}$ mixing using an inclusive dilepton sample collected by the BABAR experiment at the PEP-II $B$ factory. Using a sample of $232\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs, we measure the $T$ and $CP$ violation parameter $|q/p|\ensuremath{-}1=\mathbf{(}\ensuremath{-}0.8\ifmmode\pm\else\textpm\fi{}2.7(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}1.9(\mathrm{syst})\mathbf{)}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$, and the $CPT$ and $CP$ parameters $\mathrm{Im}z=\mathbf{(}\ensuremath{-}13.9\ifmmode\pm\else\textpm\fi{}7.3(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}3.2(\mathrm{syst})\mathbf{)}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ and $\ensuremath{\Delta}\ensuremath{\Gamma}\ifmmode\times\else\texttimes\fi{}\mathrm{Re}z=\mathbf{(}\ensuremath{-}7.1\ifmmode\pm\else\textpm\fi{}3.9(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}2.0(\mathrm{syst})\mathbf{)}\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}\text{ }\text{ }{\mathrm{ps}}^{\ensuremath{-}1}$. The statistical correlation between the measurements of $\mathrm{Im}z$ and $\ensuremath{\Delta}\ensuremath{\Gamma}\ifmmode\times\else\texttimes\fi{}\mathrm{Re}z$ is 76%.

We report a study of the processes e+e- -> eta gamma and e+e- -> etaprime gamma at a center-of-mass energy of 10.58 GeV, using a 232 fb^-1 data sample collected with the BABAR detector at the PEP-II collider at SLAC. We observe 20+6-5 eta gamma and 50+8-7 etaprime gamma events over small backgrounds, and measure the cross sections sigma(e+e- -> eta gamma) =4.5+1.2-1.1(stat)+-0.3(sys) fb and sigma(e+e- -> etaprime gamma)=5.4+-0.8(stat)+-0.3(sys) fb. The corresponding transition form factors at q^2 = 112 GeV^2 are q^2|F_eta(q^2)|=0.229+-0.030+-0.008 GeV, and q^2|F_etaprime(q^2)|=0.251+-0.019+-0.008 GeV, respectively.

We report a measurement of the inclusive electron energy spectrum for semileptonic decays of B mesons in a data sample of 52 million $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ decays collected with the BABAR detector at the PEP-II asymmetric-energy B-meson factory at SLAC. We determine the branching fraction, first, second, and third moments of the spectrum for lower cutoffs on the electron energy between 0.6 and 1.5 GeV. We measure the partial branching fraction to be $\mathcal{B}(\stackrel{\ensuremath{\rightarrow}}{B}\mathrm{Xe}\ensuremath{\nu}{,E}_{e}&gt;0.6\mathrm{GeV})=[10.36\ifmmode\pm\else\textpm\fi{}0.06(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.23(\mathrm{sys}.)]%.$

We analyze the three-body charmless decay B+- -> K+-K+-K-+ using a sample of 226.0 +- 2.5 million BBbar pairs collected by the BABAR detector. We measure the total branching fraction and CP asymmetry to be B = (35.2 +- 0.9 +-1.6) x 10^{-6} and A_CP = (-1.7 +- 2.6 +- 1.5)%. We fit the Dalitz plot distribution using an isobar model and measure the magnitudes and phases of the decay coefficients. We find no evidence of CP violation for the individual components of the isobar model. The decay dynamics is dominated by the K+K- S-wave, for which we perform a partial-wave analysis in the region m(K+K-) < 2 GeV/c^2. Significant production of the f0(980) resonance, and of a spin zero state near 1.55 GeV/c^2 are required in the isobar model description of the data. The partial-wave analysis supports this observation.

We report the results of a study of the exclusive charmless semileptonic decay, B --> pi l nu, undertaken with approximately 227 million BBbar pairs collected at the Upsilon(4S) resonance with the BaBar detector. The analysis uses events in which the signal B decays are reconstructed with an innovative loose neutrino reconstruction technique. We obtain partial branching fractions in 12 bins of q2, the momentum transfer squared, from which we extract the f+(q2) form-factor shape and the total branching fraction BF(B0 --> pi l nu) = (1.46 +- 0.07(stat) +- 0.08(syst)) x 10^-4. Based on a recent unquenched lattice QCD calculation of the form factor in the range q2 > 16 GeV^2, we find the magnitude of the CKM matrix element |Vub| to be (4.1 +- 0.2(stat) +- 0.2(syst) +0.6-0.4(FF)) x 10^-3, where the last uncertainty is due to the normalization of the form factor.

Results are presented on two-jet and three-jet cross sections, measured in the UA1 experiment at the CERN Super Proton Synchrotron (SPS) pp̄ Collider, at the highest available subprocess cms energies (ŝ>150 GeV). Precise measurements of the two-jet angular distribution are consistent with previous results but show significant scale-breaking effects. The three-jet Dalitz plot and the three-jet angular distributions show evidence for final- and initial-state bremsstrahlung processes, in agreement with the leading-order QCD predictions. A comparison of the yield of wide-angle three-jet events with the yield of two-jet events at smaller scattering angles gives for the strong interaction coupling constant: αs(K3JK2J)=0.16±0.02±0.03 at Q2≈4000 GeV2, where the factor K3JK2J may plausibly be assumed to be close to unity.

We report results based on a sample of events with large missing transverse energy corresponding to 715 nb−n of data from the UA1 experiment at the CERN proton-antiproton collider. High transverse-momentum tau-leptons from W decays are observed for the first time through their semi-hadronic decay modes and associated missing transverse energy. The measured relative rates of W→eν, W→μν, and W→τν provide the first direct tests of the electron-muon-tau universality of the weak charged couplings at Q2=mw2. We determine gτge=1.01±0.09±0.05 and gμge=1.05±0.07±0.08.

The photon spectrum in B→Xsγ decay, where Xs is any strange hadronic state, is studied using a data sample of 88.5×106 e+e−→Υ(4S)→B¯¯¯B decays collected by the BABAR experiment at the Stanford Linear Accelerator Center. The partial branching fraction, ΔB(B→Xsγ)=(3.67±0.29(stat)±0.34(syst)±0.29(model))×10−4, the first moment ⟨Eγ⟩=2.288±0.025±0.017±0.015 GeV, and the second moment ⟨E2γ⟩=0.0328±0.0040±0.0023±0.0036 GeV2 are measured for the photon energy range 1.9 GeV<Eγ<2.7 GeV. They are also measured for narrower Eγ ranges. The moments are then fit to recent theoretical calculations to extract the heavy quark expansion parameters mb and μ2π and to extrapolate the partial branching fraction to Eγ>1.6 GeV. In addition, the direct CP asymmetry ACP(B→Xs+dγ) is measured to be −0.110±0.115(stat)±0.017(syst).Received 26 July 2006DOI:https://doi.org/10.1103/PhysRevLett.97.171803©2006 American Physical Society

Angular distributions of high-mass jet pairs (180<m2J<350 GeV) have been measured in the UA1 experiment at the CERN pp̄ Collider (s=630GeV). We show that angular distributions are independent of the subprocess centre-of-mass (CM) energy over this range, and use the data to put constraints on the definition of the Q2 scale. The distribution for the very high mass jet pairs (240<m 2J<300 GeV) has also been used to obtain a lower limit on the energy scale Λc of compositeness of quarks. We find Λc>415 GeV at 95% confidence level.

The energy dependence of the spin-parallel and spin-antiparallel cross sections for ${p}_{\ensuremath{\uparrow}}+{p}_{\ensuremath{\uparrow}}\ensuremath{\rightarrow}p+p$ at ${90\mathrm{\ifmmode^\circ\else\textdegree\fi{}}}_{\mathrm{c}.\mathrm{m}.}$ was measured for beam momenta between 6 and 12.75 GeV/c. The ratio ${(\frac{d\ensuremath{\sigma}}{\mathrm{dt}})}_{\mathrm{parallel}}:{(\frac{d\ensuremath{\sigma}}{\mathrm{dt}})}_{\mathrm{antiparallel}}$ at 90\ifmmode^\circ\else\textdegree\fi{} is about 1.2 up to 8 GeV/c and then increases rapidly to a value of almost 4 near 11 GeV/c. Our data indicate that this ratio may depend only on the variable ${{P}_{\ensuremath{\perp}}}^{2}$, and suggests that the ratio may reach a limiting value of about 4 for large ${{P}_{\ensuremath{\perp}}}^{2}$.

The OPAL experiment at the CERN LEP collider recently increased the geometrical acceptance of its silicon microvertex detector. The azimuthal coverage is improved by adding one pair of detector modules to each of the two layers, while the polar angle coverage is extended by adding new detector modules in line with the existing ones. This improves the efficiency for high quality tracking in OPAL and in particular for b quark tagging in Higgs boson searches. A description of the detector is given, with emphasis on new or modified elements with respect to the earlier version. Results on the performance of the new detector are presented.

We present evidence for the flavor-changing neutral current decay B-->K*l+l- and a measurement of the branching fraction for the related process B-->K l+l-, where l+l- is either an epsilon+epsilon- 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 123 x 10(6) Upsilon(4S)-->B(-)B decays collected with the BABAR detector at the SLAC PEP-II epsilon+epsilon- storage ring. Averaging over K(*) isospin and lepton flavor, we obtain the branching fractions B(B-->Kl+l-)=(0.65(+0.14)(-0.13)+/-0.04)x10(-6) and B(B-->K*l+l-)=(0.88(+0.33)(-0.29)+/-0.10)x10(-6), where the uncertainties are statistical and systematic, respectively. The significance of the B-->Kl+l- signal is over 8sigma, while for B-->K*l+l- it is 3.3sigma.

We determine the inclusive B→Xcℓν branching fraction, Bcℓν, the Cabibbo-Kobayashi-Maskawa matrix element |Vcb|, and other heavy-quark parameters from a simultaneous fit to moments of the hadronic-mass and lepton-energy distributions in semileptonic B-meson decays, measured as a function of the lower limit on the lepton energy, using data recorded with the BABAR detector. Using heavy-quark expansions (HQEs) to order 1/m3b, we extract Bceν=(10.61±0.16exp±0.06HQE)% and ∣∣Vcb∣∣=(41.4±0.4exp±0.4HQE±0.6th)×10−3. The stated errors refer to the experimental, HQE, and additional theoretical uncertainties.Received 12 April 2004DOI:https://doi.org/10.1103/PhysRevLett.93.011803©2004 American Physical Society

We report the observation of the $B$ meson decay $B^\pm\to J/\psi \eta K^\pm$ and evidence for the decay $B^0\to J/\psi \eta K^0_S$, using {90} million $BBbar$ events collected at the $\ensuremath{\Upsilon{(4S)}}\xspace$ resonance with the $BaBar$ detector at the PEP-II $e^+ e^-$ asymmetric-energy storage ring. We obtain branching fractions of $\cal{B}$$(B^\pm\to J/\psi \eta K^{\pm}$)=$(10.8\pm 2.3(\rm{stat.})\pm 2.4(\rm{syst.}))\times 10^{-5}$ and $\cal{B}$$(B^0\to J/\psi\eta K_{\rm{S}}^{0}$)=$(8.4\pm 2.6(\rm{stat.})\pm 2.7(\rm{syst.}))\times 10^{-5}$. We search for the new narrow mass state, the X(3872), recently reported by the Belle Collaboration, in the decay $B^\pm\to X(3872)K^\pm, X(3872)\to \jpsi \eta$ and determine an upper limit of $\cal{B}$$(B^\pm \to X(3872) K^\pm \to \jpsi \eta K^\pm$) $<7.7\times 10^{-6}$ at 90% C.L.

The branching fractions of the decays B0→K*0γ and B+→K*+γ are measured using a sample of 88×106BB¯ events collected with the BABAR detector at the PEP-II asymmetric-energy e+e− collider. We find B(B0→K*0γ)=[3.92±0.20(stat)±0.24(syst)]×10−5, B(B+→K*+γ)=[3.87±0.28(stat)±0.26(syst)]×10−5. Our measurements also constrain the direct CP asymmetry to be −0.074<A(B→K*γ)<0.049 and the isospin asymmetry to be −0.046<Δ0−<0.146, both at the 90% confidence level.Received 30 June 2004DOI:https://doi.org/10.1103/PhysRevD.70.112006©2004 American Physical Society

We report observations of the $b\ensuremath{\rightarrow}d$ penguin-dominated decays ${B}^{+}\ensuremath{\rightarrow}{\overline{K}}^{0}{K}^{+}$ and ${B}^{0}\ensuremath{\rightarrow}{K}^{0}{\overline{K}}^{0}$ in $316\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of ${e}^{+}{e}^{\ensuremath{-}}$ collision data collected with the BABAR detector. We measure the branching fractions $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{\overline{K}}^{0}{K}^{+})=(1.61\ifmmode\pm\else\textpm\fi{}0.44\ifmmode\pm\else\textpm\fi{}0.09)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $\mathcal{B}({B}^{0}\ensuremath{\rightarrow}{K}^{0}{\overline{K}}^{0})=(1.08\ifmmode\pm\else\textpm\fi{}0.28\ifmmode\pm\else\textpm\fi{}0.11)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and the $CP$-violating charge asymmetry ${\mathcal{A}}_{CP}({\overline{K}}^{0}{K}^{+})=0.10\ifmmode\pm\else\textpm\fi{}0.26\ifmmode\pm\else\textpm\fi{}0.03$. Using a vertexing technique previously employed in several analyses of all-neutral final states containing kaons, we report the first measurement of time-dependent $CP$-violating asymmetries in ${B}^{0}\ensuremath{\rightarrow}{K}_{S}^{0}{K}_{S}^{0}$, obtaining $S=\ensuremath{-}{1.28}_{\ensuremath{-}0.73\ensuremath{-}0.16}^{+0.80+0.11}$ and $C=\ensuremath{-}0.40\ifmmode\pm\else\textpm\fi{}0.41\ifmmode\pm\else\textpm\fi{}0.06$. We also report improved measurements of the branching fraction $\mathcal{B}({B}^{+}\ensuremath{\rightarrow}{K}^{0}{\ensuremath{\pi}}^{+})=(23.9\ifmmode\pm\else\textpm\fi{}1.1\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $CP$-violating charge asymmetry ${\mathcal{A}}_{CP}({K}^{0}{\ensuremath{\pi}}^{+})=\ensuremath{-}0.029\ifmmode\pm\else\textpm\fi{}0.039\ifmmode\pm\else\textpm\fi{}0.010$.

We present measurements of the branching fractions and charge asymmetries (where appropriate) of two-body B decays to ${\ensuremath{\eta}}^{(\ensuremath{'})}{K}^{*},$ ${\ensuremath{\eta}}^{(\ensuremath{'})}\ensuremath{\rho},$ ${\ensuremath{\eta}}^{(\ensuremath{'})}{\ensuremath{\pi}}^{0},$ $\ensuremath{\omega}{\ensuremath{\pi}}^{0},$ and $\ensuremath{\varphi}{\ensuremath{\pi}}^{0}.$ The data were recorded with the BABAR detector at PEP-II and correspond to $89\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs produced in ${e}^{+}{e}^{\ensuremath{-}}$ annihilation through the $\ensuremath{\Upsilon}(4S)$ resonance. We find significant signals for two decay modes and measure the branching fractions $\mathcal{B}{(B}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{K}^{*+})=(25.6\ifmmode\pm\else\textpm\fi{}4.0\ifmmode\pm\else\textpm\fi{}2.4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}$ and $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\eta}{K}^{*0})=(18.6\ifmmode\pm\else\textpm\fi{}2.3\ifmmode\pm\else\textpm\fi{}1.2)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ where the first error is statistical and the second systematic. We also find evidence with significance 3.5\ensuremath{\sigma} for a third decay mode and measure $\mathcal{B}{(B}^{+}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\rho}}^{+})=(9.2\ifmmode\pm\else\textpm\fi{}3.4\ifmmode\pm\else\textpm\fi{}1.0)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}.$ For other channels, we set 90% C.L. upper limits of $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\rho}}^{0})&lt;1.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{K}^{*+})&lt;14\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{K}^{*0})&lt;7.6\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{+}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{\ensuremath{\rho}}^{+})&lt;22\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{\ensuremath{\rho}}^{0})&lt;4.3\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\eta}{\ensuremath{\pi}}^{0})&lt;2.5\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{\ensuremath{\pi}}^{0})&lt;3.7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\omega}{\ensuremath{\pi}}^{0})&lt;1.2\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6},$ and $\mathcal{B}{(B}^{0}\ensuremath{\rightarrow}\ensuremath{\varphi}{\ensuremath{\pi}}^{0})&lt;1.0\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}6}.$ For self-flavor-tagging modes with significant signals, the time-integrated charge asymmetries are ${\mathcal{A}}_{\mathrm{ch}}(\ensuremath{\eta}{K}^{*+})=+0.13\ifmmode\pm\else\textpm\fi{}0.14\ifmmode\pm\else\textpm\fi{}0.02$ and ${\mathcal{A}}_{\mathrm{ch}}(\ensuremath{\eta}{K}^{*0})=+0.02\ifmmode\pm\else\textpm\fi{}0.11\ifmmode\pm\else\textpm\fi{}0.02.$

We report a study of D∗sJ(2317)+ and DsJ(2460)+ meson production in B decays. We observe the decays B+→D(*)+sJ¯¯¯D(*)0 and B0→D(*)+sJD(*)− with the subsequent decays D∗sJ(2317)+→D+sπ0, DsJ(2460)+→D+sγ, and DsJ(2460)+→D*+sπ0. Based on a data sample of 122.1×106 B¯¯¯B pairs collected with the BABAR detector at the PEP-II B factory, we obtain branching fractions for these modes, including the previously unseen decays B→D(*)+sJD∗. In addition, we perform an angular analysis of DsJ(2460)+→D+sγ decays to test the different DsJ(2460)+ spin hypotheses.Received 11 August 2004DOI:https://doi.org/10.1103/PhysRevLett.93.181801©2004 American Physical Society

A study of the ${D}_{sJ}^{*}(2317{)}^{+}$ and ${D}_{sJ}(2460{)}^{+}$ mesons in inclusive $c\overline{c}$ production is presented using $232\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ of data collected by the BABAR experiment near $\sqrt{s}=10.6\text{ }\text{ }\mathrm{GeV}$. Final states consisting of a ${D}_{s}^{+}$ meson along with one or more ${\ensuremath{\pi}}^{0}$, ${\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}$, or $\ensuremath{\gamma}$ particles are considered. Estimates of the mass and limits on the width are provided for both mesons and for the ${D}_{s1}(2536{)}^{+}$ meson. A search is also performed for neutral and doubly charged partners of the ${D}_{sJ}^{*}(2317{)}^{+}$ meson.

A search for lepton flavor violating decays of the $\tau$ lepton to a lighter mass lepton and a pseudoscalar meson has been performed using 339 fb$^{-1}$ of $e^+e^-$ annihilation data collected at a center-of-mass energy near 10.58 GeV by the BaBar detector at the SLAC PEP-II storage ring. No evidence of signal has been found, and upper limits on the branching fractions are set at $10^{-7}$ level.

It is now widely accepted within the electrical power supply industry that future power systems operates with significantly larger numbers of small-scale highly dispersed generation units that use renewable energy sources and also reduce carbon dioxide emissions. In order to operate such future power systems securely and efficiently it will be necessary to monitor and control output levels and scheduling when connecting such generation to a power system especially when it is typically embedded at the distribution level. Traditional monitoring and control technology that is currently employed at the transmission level is highly centralized and not scalable to include such significant increases in distributed and embedded generation. However, this paper proposes and demonstrates the adoption of a relatively new technology 'grid computing' that can provide both a scalable and universally adoptable solution to the problems associated with the distributed monitoring and control of future power systems

We present a measurement of the inclusive electron spectrum in charmless semileptonic B decays near the kinematic limit for B->X_c e\nu transitions, using a sample of 88 million Upsilon(4S) decays recorded by the BABAR detector. Partial branching fraction measurements are performed in five overlapping intervals of the electron momentum. For the interval of 2.0-2.6 GeV/c we obtain \Delta Br(B->X_u e\nu) = (0.572+-0.041(stat)+-0.065(syst))x10^{-3}. Combining this result with shape function parameters extracted from BABAR measurements of moments of the inclusive photon spectrum in B->X_s+gamma decays and moments of the hadron mass and lepton energy spectra in B->X_c l\nu decays we determine |V_{ub}|=((4.44+-0.25(exp) ^{+0.42}_{-0.38}(SF)+-0.22(theory))x10^{-3}. Here the first error represents the combined statistical and systematic experimental uncertainties of the partial branching fraction measurement, the second error refers to the uncertainty of the determination of the shape function parameters, and the third error is due to theoretical uncertainties in the QCD calculations.

A facility that can deliver beams of electron and muon neutrinos from the decay of a stored muon beam has the potential to unambiguously resolve the issue of the evidence for light sterile neutrinos that arises in short-baseline neutrino oscillation experiments and from estimates of the effective number of neutrino flavors from fits to cosmological data. In this paper, we show that the nuSTORM facility, with stored muons of $3.8\text{ }\mathrm{GeV}/\mathrm{c}\text{ }\ifmmode\pm\else\textpm\fi{}\text{ }10%$, will be able to carry out a conclusive muon neutrino appearance search for sterile neutrinos and test the LSND and MiniBooNE experimental signals with $10\ensuremath{\sigma}$ sensitivity, even assuming conservative estimates for the systematic uncertainties. This experiment would add greatly to our knowledge of the contribution of light sterile neutrinos to the number of effective neutrino flavors from the abundance of primordial helium production and from constraints on neutrino energy density from the cosmic microwave background. The appearance search is complemented by a simultaneous muon neutrino disappearance analysis that will facilitate tests of various sterile neutrino models.

A measurement of the time-integrated $CP$ asymmetry in the Cabibbo-suppressed decay $D^0\rightarrow K^-K^+$ is performed using pp collision data, corresponding to an integrated luminosity of 3fb$^{-1}$, collected with the LHCb detector at centre-of-mass energies of 7 and 8 TeV. The flavour of the charm meson at production is determined from the charge of the pion in $D^{*+}\rightarrow D^0 π^+$ and $D^{*-}\rightarrow \bar{D^0} π^-$ decays. The time-integrated $CP$ asymmetry $A_{CP}(K^-K^+)$ is obtained assuming negligible $CP$ violation in charm mixing and in Cabibbo-favoured $D^0\rightarrow K^-π^+$, $D^+\rightarrow K^-π^+π^+$ and $D^+\rightarrow \bar{K^0}π^+$ decays used as calibration channels. It is found to be $A_{CP}(K^-K^+)=(0.14\pm0.15(stat)\pm0.10(syst))\%$. A combination of this result with previous LHCb measurements yields $A_{CP}(K^-K^+)=(0.04\pm0.12(stat)\pm0.10(syst))\%$, $A_{CP}(π^-π^+)=(0.07\pm0.14(stat)\pm0.11(syst))\%$. These are the most precise measurements from a single experiment. The result for $A_{CP}(K^-K^+)$ is the most precise determination of a time-integrated $CP$ asymmetry in the charm sector to date, and neither measurement shows evidence of CP asymmetry.

We present measurements of branching fractions and CP-violating asymmetries in B0→ρ±π∓ and B0→ρ−K+ decays. The results are obtained from a data sample of 88.9×106 Υ(4S)→B¯¯¯B decays collected with the BABAR detector at the SLAC PEP-II asymmetric-energy B Factory. From a time-dependent maximum likelihood fit we measure the branching fractions B(B0→ρ±π∓)=[22.6±1.8 (stat)±2.2 (syst)]×10−6 and B(B0→ρ−K+)=(7.3 +1.3 −1.2±1.3)×10−6, and the CP-violating charge asymmetries AρπCP=−0.18±0.08±0.03 and AρKCP=0.28±0.17±0.08, the direct CP violation parameter Cρπ=0.36±0.18±0.04 and the mixing-induced CP violation parameter Sρπ=0.19±0.24±0.03, and the dilution parameters ΔCρπ=0.28 +0.18 −0.19±0.04 and ΔSρπ=0.15±0.25±0.03.Received 13 June 2003DOI:https://doi.org/10.1103/PhysRevLett.91.201802©2003 American Physical Society

We have studied the process e+e−→μ+μ−γ at a center-of-mass energy near the Υ(4S) resonance for a μ+μ− invariant mass range near the J/ψ mass and measured the cross section σ(e+e−→J/ψγ→μ+μ−γ). The data set, corresponding to an integrated luminosity of 88.4fb−1, was collected using the BABAR detector at the SLAC PEP-II collider. From the measured cross section we extract the product Γ(J/ψ→e+e−)B(J/ψ→μ+μ−)=0.330±0.008±0.007keV. Using the world averages for B(J/ψ→μ+μ−) and B(J/ψ→e+e−), we derive the J/ψ electronic and total widths: Γ(J/ψ→e+e−)=5.61±0.20keV and Γ=94.7±4.4keV. Received 14 October 2003DOI:https://doi.org/10.1103/PhysRevD.69.011103©2004 American Physical Society

We have measured the W transverse momentum distribution (pTW) using a sample of 323 W → eν and W → μν events produced in proton-antiproton collisions at the CERN collider. In the present letter we extend the study of the distribution up to pTW ∼- m W and compare to leading and higher order QCD. This comparison is a precise test of QCD with hadron colliders and the inclusive spectrum gives good agreement over a large range of pTW. However we observed two events at very large pTW (∼- 100 GeV/c) in which the W candidate recoils against an energetic di-jet system. Both events have a very large missing transverse energy and a jet-jet mass compatible with the W mass. In a separate analysis, a topologically similar event has been observed in which a high-mass di-jet system is balanced by a large missing transverse energy which could be interpreted as Z0 → νν decay. We cannot easily explain these three events in terms of explicit second-order QCD calculations. However we cannot exclude at this stage the possibility that they are the result of non-gaussian fluctuations in the response of UA1 calorimetry or a statistical fluctuation in the data.

We present the first measurement of $\Upsilon(4S)$ decays to $\pi^+pi^-\Upsilon(1S)$ and $\pi^+pi^-\Upsilon(2S)$ based on a sample of 230$\times10^6$ $\Upsilon(4S)$ mesons collected with the BABAR detector. We measure the product branching fractions ${\cal B}(\Upsilon(4S)\to \pi^+pi^-\Upsilon(1S))\times{\cal B}(\Upsilon(1S)\to\mu^+\mu^-)=(2.23\pm0.25_{stat} \pm0.27_{sys})\times 10^{-6}$ and ${\cal B}(\Upsilon(4S)\to \pi^+pi^-\Upsilon(2S))\times{\cal B}(\Upsilon(2S)\to\mu^+\mu^-)=(1.69\pm0.26_{stat}\pm0.20_{sys})\times 10^{-6}$, from which we derive the partial widths $\Gamma(\Upsilon(4S)\to \pi^+pi^-\Upsilon(1S))=(1.8\pm0.4)$~keV and $\Gamma(\Upsilon(4S)\to \pi^+pi^-\Upsilon(2S))=(2.7\pm0.8)$~keV.

We report the observation of five muonic Z0 decays. The mass and cross section times branching ratio is consistent with the previous measurements of Z0→e+e−. Three of the muonic decays have unexpected features. One event is of the type Z0→μ+μ−γ. Two of the Z0→μ+μ− decays are accommpanied by several (>4) energetic (ET > 10 GeV) jets which are difficult to explain within the framework of standard QCD corrections.

Using 230.2 fb−1 of e+e− annihilation data collected with the BABAR detector at and near the peak of the Υ(4S) resonance, 489±55 events containing the pure leptonic decay D+s→μ+νμ have been isolated in charm-tagged events. The ratio of partial widths Γ(D+s→μ+νμ)/Γ(D+s→ϕπ+) is measured to be 0.143±0.018±0.006 allowing a determination of the pseudoscalar decay constant fDs=(283±17±7±14) MeV. The errors are statistical, systematic, and from the D+s→ϕπ+ branching ratio, respectively.Received 1 August 2006DOI:https://doi.org/10.1103/PhysRevLett.98.141801©2007 American Physical Society

The properties of a sample of 172 charged intermediate vector bosons decaying in the (eνe) channel and 16 neutral intermediate vector bosons decaying in the (e+e-) channel are described. Masses, decay widths, decay angular distributions, and production cross-sections are given; they are shown to be in excellent agreement with the expectations of the SU2 ⊗ U1 standard model. A limit is put on the number of light-neutrino types Nν ⩽ 10 at 90% c.l.

We perform an amplitude analysis of the decays B0→ϕK∗2(1430)0, ϕK∗(892)0, and ϕ(Kπ)0S−wave with a sample of about 384×106 B¯¯¯B pairs recorded with the BABAR detector. The fractions of longitudinal polarization fL of the vector-tensor and vector-vector decay modes are measured to be 0.853+0.061−0.069±0.036 and 0.506±0.040±0.015, respectively. Overall, twelve parameters are measured for the vector-vector decay and seven parameters for the vector-tensor decay, including the branching fractions and parameters sensitive to CP violation.Received 24 October 2006DOI:https://doi.org/10.1103/PhysRevLett.98.051801©2007 American Physical Society

We present measurements of the branching fractions for the charmless two-body decays B0→π+π− and B0→K+π−, and a search for the decay B0→K+K−. We include the effects of final-state radiation from the daughter mesons for the first time, and quote branching fractions for the inclusive processes B0→h+h'−nγ, where h and h′ are pions or kaons. The maximum value of the sum of the energies of the n undetected photons, Emaxγ, is mode-dependent. Using a data sample of approximately 227×106 Υ(4S)→B¯¯¯B decays collected with the BABAR detector at the PEP-II asymmetric-energy e+e− collider at SLAC, we measure: B(B0→π+π−nγ;Emaxγ=150 MeV)=(5.1±0.4±0.2)×10−6, B(B0→K+π−nγ;Emaxγ=105 MeV)=(18.1±0.6±0.6)×10−6, B(B0→K+K−nγ;Emaxγ=59 MeV)<0.5×10−6(90% confidence level), where the first uncertainty is statistical and the second is systematic. Theoretical calculations can be used to extrapolate from the above measurements the nonradiative branching fractions, B0. Using one such calculation, we find: B0(B0→π+π−)=(5.5±0.4±0.3)×10−6, B0(B0→K+π−)=(19.1±0.6±0.6)×10−6, B0(B0→K+K−)<0.5×10−6(90% confidence level). Meaningful comparison between theory and experiment, as well as combination of measurements from different experiments, can be performed only in terms of these nonradiative quantities.Received 2 August 2006DOI:https://doi.org/10.1103/PhysRevD.75.012008©2007 American Physical Society

We report the results of a CP violation analysis of the decay B+/- --> D(pipipi0)K+/-, where D(pipipi0) indicates a neutral D meson detected in the final state pi+pi-pi0, excluding K_S pi0. The analysis makes use of 324 million e+e- --> BB events recorded by the BaBar experiment at the PEP-II e+e- storage ring. By analyzing the pi+pi-pi0 Dalitz plot distribution and the B+/- --> D(pipipi0)K+/- branching fraction and decay rate asymmetry, we calculate parameters related to the phase gamma of the CKM unitarity triangle. We also measure the magnitudes and phases of the components of the D0 --> pi+pi-pi0 decay amplitude.

A sample of two-jet events from the UA1 experiment at the CERN pp̄ Collider has been used to study the fragmentation of high-energy quark and gluon jets into charged hadrons. Compared with lower-energy jets observed in e+e− and pp collisions, the fragmentation function measured in the present experiment is softer (i.e. peaked to smaller values of z) and the mean internal transverse momentum is larger, mainly because of the effects of the QCD scaling violations. Using our knowledge of the quark and gluon structure functions in the proton, together with the QCD matrix elements, a statistical separation of quark and gluon jets is achieved within the present experiment. The fragmentation function for the gluon jets is found to be softer, and the angular spread of the fragmentation products larger, than is the case for quark jets.

The production properties of a sample of 172 charged intermediate vector bosons produced at the CERN Super Proton Synchrotron Collider are described. The production cross-section, the longitudinal- and transverse-momentum distributions and the properties of hadronic jet activity produced in association with the weak bosons are in agreement with the expectations of the QCD-improved Drell-Yan mechanism.

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;)=[2.24+/-0.27(stat)+/-0.26(syst)+/-0.39(theo)]x10(-3) and derive the Cabibbo-Kobayashi-Maskawa matrix element |V(ub)|=[4.62+/-0.28(stat)+/-0.27(syst)+/-0.48(theo)]x10(-3).

Using events in which one of two neutral B mesons from the decay of an $\ensuremath{\Upsilon}(4S)$ resonance is fully reconstructed, we set limits on the difference between the decay rates of the two neutral B mass eigenstates and on CP, T, and CPT violation in ${B}^{0}{B}^{0}$ mixing. The reconstructed decays, comprising both CP and flavor eigenstates, are obtained from 88 million $\ensuremath{\Upsilon}(4S)\ensuremath{\rightarrow}B\overline{B}$ decays collected with the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC. We determine six independent parameters governing oscillations $(\ensuremath{\Delta}m,\ensuremath{\Delta}\ensuremath{\Gamma}/\ensuremath{\Gamma}),$ CPT and CP violation $(\mathrm{Re}\mathsf{z},\mathrm{Im}\mathsf{z}),$ and CP and T violation $(\mathrm{Im}{\ensuremath{\lambda}}_{\mathrm{CP}},|q/p|),$ where ${\ensuremath{\lambda}}_{\mathrm{CP}}$ characterizes ${B}^{0}$ and ${B}^{0}$ decays to states of charmonium plus ${K}_{S}^{0}$ or ${K}_{L}^{0}.$ The results are $\mathrm{sgn}(\mathrm{Re}{\ensuremath{\lambda}}_{\mathrm{CP}})\ensuremath{\Delta}\ensuremath{\Gamma}/\ensuremath{\Gamma}=\ensuremath{-}0.008\ifmmode\pm\else\textpm\fi{}0.037(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.018(\mathrm{syst}.)[\ensuremath{-}0.084,0.068],$$|q/p|=1.029\ifmmode\pm\else\textpm\fi{}0.013(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.011(\mathrm{syst}.)[1.001,1.057],$$(\mathrm{Re}{\ensuremath{\lambda}}_{\mathrm{CP}}/|{\ensuremath{\lambda}}_{\mathrm{CP}}|)\mathrm{Re}\mathrm{z}=0.014\ifmmode\pm\else\textpm\fi{}0.035(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.034(\mathrm{syst}.)[\ensuremath{-}0.072,0.101],$$\mathrm{Im}\mathrm{z}=0.038\ifmmode\pm\else\textpm\fi{}0.029(\mathrm{stat}.)\ifmmode\pm\else\textpm\fi{}0.025(\mathrm{syst}.)[\ensuremath{-}0.028,0.104].$The values inside square brackets indicate the 90% confidence-level intervals. The values of $\mathrm{Im}{\ensuremath{\lambda}}_{\mathrm{CP}}$ and $\ensuremath{\Delta}m$ are consistent with previous analyses and are used as cross checks. These measurements are in agreement with standard model expectations.

We present a measurement of the branching fraction of the decay B0 --> a1(1260)^{+-} pi^{-+} with a1(1260)^{+-} --> pi^{-+} pi^{+-} pi^{+-}. The data sample consists of 218 million B B-bar pairs collected at the Y(4S) resonance and recorded by the BaBar detector at the PEP-II asymmetric-energy e+e- collider at SLAC. The analysis is based on unbinned multivariate maximum likelihood fit. The measured branching fraction is: (16.6 +/- 1.9 +/- 1.5) 10^{-6}. The decay mode, observed for the first time, is seen with a significance of 9.2 sigma (systematic uncertainties included).

We present a Dalitz-plot analysis of charmless B+- decays to the final state pi+- pi+- pi-+ using 210 fb^-1 of data recorded by the BABAR experiment at sqrt(s) = 10.58 GeV. We measure the branching fractions B(B+- -> pi+- pi+- pi-+) = (16.2 +- 1.2 +- 0.9) x 10^-6 and B(B+- -> rho^0(770) pi+-) = (8.8 +- 1.0 +- 0.6 +0.1-0.7) x 10^-6. Measurements of branching fractions for the quasi-two-body decays B+- -> rho^0(1450) pi+-, B+- -> f_0(980) pi+- and B+- -> f_2(1270) pi+- are also presented. We observe no charge asymmetries for the above modes, and there is no evidence for the decays B+- -> chic0 pi+-, B+- -> f_0(1370) pi+- and B+- -> sigma pi+-.

We search for the rare flavor-changing neutral-current decay B+→K+ν¯ν in a data sample of 82 fb−1 collected with the BABAR detector at the PEP-II B-factory. Signal events are selected by examining the properties of the system recoiling against either a reconstructed hadronic or semileptonic charged-B decay. Using these two independent samples we obtain a combined limit of B(B+→K+ν¯ν)<5.2×10−5 at the 90% confidence level. In addition, by selecting for pions rather than kaons, we obtain a limit of B(B+→π+ν¯ν)<1.0×10−4 using only the hadronic B reconstruction method.Received 17 November 2004DOI:https://doi.org/10.1103/PhysRevLett.94.101801©2005 American Physical Society

Based on a sample of 227×106 BB¯ pairs collected by the BABAR detector at the PEP-II asymmetric-energy B Factory at SLAC, we measure the branching fraction B(B0→π0π0)=(1.17±0.32±0.10)×10−6, and the asymmetry Cπ0π0=−0.12±0.56±0.06. The B0→π0π0 signal has a significance of 5.0σ. We also measure B(B+→π+π0)=(5.8±0.6±0.4)×10−6, B(B+→K+π0)=(12.0±0.7±0.6)×10−6, and the charge asymmetries Aπ+π0=−0.01±0.10±0.02 and AK+π0=0.06±0.06±0.01. Using isospin relations, we find an upper bound on the angle difference |α−αeff| of 35° at the 90% C.L.Received 13 December 2004DOI:https://doi.org/10.1103/PhysRevLett.94.181802©2005 American Physical Society

We measure the time-dependent $CP$ asymmetry parameters in ${B}^{0}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{K}^{0}$ based on a data sample of approximately $227\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B$-meson pairs recorded at the $\ensuremath{\Upsilon}(4S)$ resonance with the BABAR detector at the PEP-II $B$-meson Factory at SLAC. We reconstruct two-body ${B}^{0}$ decays to $\ensuremath{\phi}(1020){K}_{S}^{0}$ and $\ensuremath{\phi}(1020){K}_{L}^{0}$, and the three-body decay ${K}^{+}{K}^{\ensuremath{-}}{K}_{S}^{0}$ with $\ensuremath{\phi}(1020){K}_{S}^{0}$ excluded. For the ${B}^{0}\ensuremath{\rightarrow}\ensuremath{\phi}{K}^{0}$ decays, we measure $\mathrm{sin}2{\ensuremath{\beta}}_{\mathrm{eff}}(\ensuremath{\phi}{K}^{0})=+0.50\ifmmode\pm\else\textpm\fi{}0.25(\mathrm{stat}{)}_{\ensuremath{-}0.04}^{+0.07}(\mathrm{syst})$. The ${B}^{0}\ensuremath{\rightarrow}{K}^{+}{K}^{\ensuremath{-}}{K}_{S}^{0}$ decays are dominated by ${K}^{+}{K}^{\ensuremath{-}}$ $S$ wave, as determined from an angular analysis; we measure $\mathrm{sin}2{\ensuremath{\beta}}_{\mathrm{eff}}({K}^{+}{K}^{\ensuremath{-}}{K}_{S}^{0})=+0.55\ifmmode\pm\else\textpm\fi{}0.22(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.04(\mathrm{syst})\ifmmode\pm\else\textpm\fi{}0.11(CP)$, where the last error is due to the uncertainty in the fraction of $CP$-even contributions to the decay amplitude. We find no evidence for direct $CP$ violation.

Received 26 October 2006DOI:https://doi.org/10.1103/PhysRevD.74.099903©2006 American Physical Society

We report a measurement of the B→πℓν branching fraction based on 211 fb−1 of data collected with the BABAR detector. We use samples of B0 and B+ mesons tagged by a second B meson reconstructed in a semileptonic or hadronic decay and combine the results assuming isospin symmetry to obtain B(B0→π−ℓ+ν)=(1.33±0.17stat±0.11syst)×10−4. We determine the magnitude of the Cabibbo-Kobayashi-Maskawa matrix element |Vub| by combining the partial branching fractions measured in ranges of the momentum transfer squared and theoretical calculations of the form factor. Using a recent lattice QCD calculation, we find |Vub|=(4.5±0.5stat±0.3syst+0.7−0.5FF)×10−3, where the last error is due to the normalization of the form factor.Received 8 August 2006DOI:https://doi.org/10.1103/PhysRevLett.97.211801©2006 American Physical Society

We present the results of a search for the decay B0→τ+τ− in a data sample of (232±3)×106 Υ(4S)→B¯¯¯B decays using the BABAR detector. Certain extensions of the standard model predict measurable levels of this otherwise rare decay. We reconstruct fully one neutral B meson and seek evidence for the signal decay in the rest of the event. We find no evidence for signal events and obtain B(B0→τ+τ−)<4.1×10−3 at the 90% confidence level.Received 9 November 2005DOI:https://doi.org/10.1103/PhysRevLett.96.241802©2006 American Physical Society

We present measurements of the time-dependent $CP$-violation parameters $S$ and $C$ in ${B}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{K}^{0}$ decays. The data sample corresponds to $384\ifmmode\times\else\texttimes\fi{}{10}^{6}$ $B\overline{B}$ pairs produced by ${e}^{+}{e}^{\ensuremath{-}}$ annihilation at the $\ensuremath{\Upsilon}(4S)$. The results are $S=0.58\ifmmode\pm\else\textpm\fi{}0.10\ifmmode\pm\else\textpm\fi{}0.03$ and $C=\ensuremath{-}0.16\ifmmode\pm\else\textpm\fi{}0.07\ifmmode\pm\else\textpm\fi{}0.03$. We observe mixing-induced $CP$ violation with a significance of 5.5 standard deviations in this $b\ensuremath{\rightarrow}s$ penguin dominated mode.

We present measurements of branching fractions of $B^0$ decays to multi-body final states containing protons, based on 232 million $\Upsilon(4S)\to B\bar{B}$ decays collected with the BaBar detector at the SLAC PEP-II asymmetric-energy $B$ factory. We measure the branching fractions ${\cal B}(B^0 \to \bar{D}^0\proton\antiproton)=(1.13\pm0.06\pm0.08)\times 10^{-4}$, ${\cal B}(B^0 \to \bar{D}^{*0}\proton\antiproton)=(1.01\pm0.10\pm0.09)\times 10^{-4}$, ${\cal B}(B^0 \to D^{-}\proton\antiproton\pi^+)=(3.38\pm0.14\pm0.29)\times 10^{-4}$, and ${\cal B}(B^0 \to D^{*-}\proton\antiproton\pi^+)=(4.81\pm0.22\pm0.44)\times 10^{-4}$ where the first error is statistical and the second systematic. We present a search for the charmed pentaquark state, $\Theta_c(3100)$ observed by H1 and put limits on the branching fraction ${\cal B} (B^0 \to \Theta_c \antiproton\pi^+)\times{\cal B}(\Theta_c \to D^{*-}\proton)<14\times10^{-6}$ and ${\cal B}(B^0 \to \Theta_c \antiproton\pi^+)\times{\cal B}(\Theta_c\to D^-\proton)<9\times10^{-6}$. Upon investigation of the decay structure of the above four $B^{0}$ decay modes, we see an enhancement at low $p\bar{p}$ mass and deviations from phase-space in the $\bar{D}\bar{p}$ and $\bar{D}p$ invariant mass spectra.

We present results of a search for D0-D(-)0 mixing and a measurement of R(D), the ratio of doubly Cabibbo-suppressed decays to Cabibbo-favored decays, using D0-->K+pi- decays from 57.1 fb(-1) of data collected near sqrt[s]=10.6 GeV with the BABAR detector at the PEP-II collider. At the 95% confidence level, allowing for CP violation, we find the mixing parameters x('2)<0.0022 and -0.056<y(')<0.039, and the mixing rate R(M)<0.16%. In the limit of no mixing, R(D)=[0.357+/-0.022(stat)+/-0.027(syst)]% and the CP-violating asymmetry A(D)=0.095+/-0.061(stat)+/-0.083(syst).

We report a measurement of the first four moments of the hadronic mass distribution in ¯B→Xcl−¯ν decays. The measurements are based on 89 million Υ(4S)→B¯B events where the hadronic decay of one of the B mesons is fully reconstructed and a charged lepton from the decay of the other B meson is identified. The moments are presented for minimum lepton momenta ranging from 0.9 to 1.6 GeV in the B rest frame. It is expected that such measurements will lead to improved determinations of |Vcb| and |Vub|. Received 23 January 2004DOI:https://doi.org/10.1103/PhysRevD.69.111103©2004 American Physical Society