First Simultaneous Determination of Inclusive and Exclusive |V_{ub}|.

The first simultaneous determination of the absolute value of the Cabibbo-Kobayashi-Maskawa matrix element V_{ub} using inclusive and exclusive decays is performed with the full Belle data set at the ϒ(4S) resonance, corresponding to an integrated luminosity of 711 fb^{-1}. We analyze collision events in which one B meson is fully reconstructed in hadronic modes. This allows for the reconstruction of the hadronic X_{u} system of the semileptonic b→uℓν[over ¯]_{ℓ} decay. We separate exclusive B→πℓν[over ¯]_{ℓ} decays from other inclusive B→X_{u}ℓν[over ¯]_{ℓ} and backgrounds with a two-dimensional fit that utilizes the number of charged pions in the X_{u} system and the four-momentum transfer q^{2} between the B and X_{u} systems. Combining our measurement with information from lattice QCD and QCD calculations of the inclusive partial rate as well as external experimental information on the shape of the B→πℓν[over ¯]_{ℓ} form factor, we determine |V_{ub}^{excl}|=(3.78±0.23±0.16±0.14)×10^{-3} and |V_{ub}^{incl}|=(3.88±0.20±0.31±0.09)×10^{-3}, respectively, with the uncertainties being the statistical error, systematic errors, and theory errors. The ratio of |V_{ub}^{excl}|/|V_{ub}^{incl}|=0.97±0.12 is compatible with unity.

Measurements of charged current lepton universality and |Vus| using tau lepton decays to e- ν(e) ν(τ), µ- ν(µ) ν(τ), π- ν(τ), and K- ν(τ).

Using 467 fb(-1) of e+e- annihilation data collected with the BABAR detector, we measure (B(τ- → µ- ν(µ) ν(τ)))/(B(τ- → e- ν(e) ν(τ))) =(0.9796±0.0016±0.0036), (B(τ- → π- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.5945±0.0014±0.0061), and (B(τ- → K- ν(τ)))/(B(τ- → e- ν(e) ν(τ))) = (0.03882±0.00032±0.00057), where the uncertainties are statistical and systematic, respectively. From these precision τ measurements, we test the standard model assumption of µ-e and τ-µ charge current lepton universality and provide determinations of |Vus| experimentally independent of the decay of a kaon.

Measurement of |V(cb)| and the form-factor slope in B --> Dl- nu(l) decays in events tagged by a fully reconstructed B meson.

We present a measurement of the Cabibbo-Kobayashi-Maskawa matrix element |V(cb)| and the form-factor slope rho2 in B --> Dl- nu(l) decays based on 460x10(6) BB events recorded at the Upsilon(4S) resonance with the BABAR detector. B --> Dl- nu(l) decays are selected in events in which a hadronic decay of the second B meson is fully reconstructed. We measure B(B- --> D0 l- nu(l))/B(B- --> Xl- nu(l)) = (0.255+/-0.009+/-0.009) and B(B0 --> D+ l- nu(l))/B(B0 --> Xl- nu(l)) = (0.230+/-0.011+/-0.011), along with the differential decay distribution in B --> Dl- nu(l) decays. We then determine G(1)|V(cb)| = (42.3+/-1.9+/-1.4)x10(-3) and rho2 = 1.20+/-0.09+/-0.04, where G(1) is the hadronic form factor at the point of zero recoil.

Searches for Lepton flavor violation in the decays tau{+/-}-->e{+/-}gamma and tau{+/-}-->mu{+/-}gamma.

Searches for lepton-flavor-violating decays of a tau lepton to a lighter mass lepton and a photon have been performed with the entire data set of (963+/-7)x10{6} tau decays collected by the BABAR detector near the Upsilon(4S), Upsilon(3S) and Upsilon(2S) resonances. The searches yield no evidence of signals and we set upper limits on the branching fractions of B(tau{+/-}-->e{+/-}gamma)<3.3x10{-8} and B(tau{+/-}-->mu{+/-}gamma)<4.4x10{-8} at 90% confidence level.

Evidence for the eta(b)(1S) meson in radiative Upsilon(2S) decay.

We have performed a search for the eta_{b}(1S) meson in the radiative decay of the Upsilon(2S) resonance using a sample of 91.6x10(6) Upsilon(2S) events recorded with the BABAR detector at the PEP-II B factory at the SLAC National Accelerator Laboratory. We observe a peak in the photon energy spectrum at Egamma=609.3(-4.5)(+4.6)(stat)+/-1.9(syst) MeV, corresponding to an eta(b)(1S) mass of 9394.2(-4.9)(+4.8)(stat)+/-2.0(syst) MeV/c2. The branching fraction for the decay Upsilon(2S)-->gamma(eta)b(1S) is determined to be [3.9+/-1.1(stat)-0.9+1.1(syst)]x10(-4). We find the ratio of branching fractions B[Upsilon(2S)-->gamma(eta)b(1S)]/B[Upsilon(3S)-->gamma(eta)b(1S)]=0.82+/-0.24(stat)(-0.19)(+0.20)(syst).

Search for a low-mass higgs boson in Upsilon(3S)-->gammaA(0), A(0)-->tau(+)tau(-) at BABAR.

We search for a light Higgs boson A0 in the radiative decay Upsilon(3S)-->gammaA(0), A(0)-->tau+tau-, tau+-->e+nu(e)nu(tau), or tau+-->mu+nu(mu)nu(tau). The data sample contains 122x10(6) Upsilon(3S) events recorded with the BABAR detector. We find no evidence for a narrow structure in the studied tau+tau- invariant mass region of 4.03gammaA(0))xB(A(0)-->tau+tau-)>(1.5-16)x10(-5) across the m(tau+tau-) range. We also set a 90% C.L. upper limit on the tau+tau- decay of the eta(b) at B(eta(b)-->tau+tau-)<8%.

Measurement of D{0}-D[-over]{0} mixing from a time-dependent amplitude analysis of D{0}-->K+pi{-}pi{0} decays.

We present evidence of D{0}-D[-over ]{0} mixing using a time-dependent amplitude analysis of the decay D{0}-->K+pi{-}pi;{0} in a data sample of 384 fb{-1} collected with the BABAR detector at the PEP-II e+e{-} collider at the Stanford Linear Accelerator Center. Assuming CP conservation, we measure the mixing parameters x{Kpipi{0}}{'}=[2.61{-0.68}{+0.57}(stat)+/-0.39(syst)]%, y{Kpipi;{0}}{'}=[-0.06{-0.64}{+0.55}(stat)+/-0.34(syst)]%. This result is inconsistent with the no-mixing hypothesis with a significance of 3.2 standard deviations. We find no evidence of CP violation in mixing.

Measurement of B-->K{*}(892)gamma branching fractions and CP and Isospin asymmetries.

We present an analysis of the decays B{0}-->K{*0}(892)gamma and B{+}-->K{*+}(892)gamma using a sample of about 383 x 10{6} BB[-over ] events collected with the BABAR detector at the PEP-II asymmetric energy B factory. We measure the branching fractions B(B{0}-->K{*0}gamma)=(4.47+/-0.10+/-0.16) x 10{-5} and B(B{+}-->K{*+}gamma)=(4.22+/-0.14+/-0.16) x 10{-5}. We constrain the direct CP asymmetry to be -0.033K{*}gamma)<0.028 and the isospin asymmetry to be 0.017

Precise measurement of the e+e- --> pi+pi-(gamma) cross section with the initial state radiation method at BABAR.

A precise measurement of the cross section of the process e(+)e(-) --> pi(+)pi(-)(gamma) from threshold to an energy of 3 GeV is obtained with the initial state radiation (ISR) method using 232 fb(-1) of data collected with the BABAR detector at e(+)e(-) center-of-mass energies near 10.6 GeV. The ISR luminosity is determined from a study of the leptonic process e(+)e(-) --> mu(+)mu(-)gamma(gamma). The leading-order hadronic contribution to the muon magnetic anomaly calculated using the pipi cross section measured from threshold to 1.8 GeV is (514.1 +/- 2.2(stat) +/- 3.1(syst)) x 10(-10).

Search for invisible decays of the Upsilon(1S).

We search for invisible decays of the Upsilon(1S) meson using a sample of 91.4 x 10(6) Upsilon(3S) mesons collected at the BABAR/PEP-II B factory. We select events containing the decay Upsilon(3S) --> pi(+)pi(-)Upsilon(1S) and search for evidence of an undetectable Upsilon(1S) decay recoiling against the dipion system. We set an upper limit on the branching fraction B(Upsilon(1S) --> invisible) < 3.0 x 10(-4) at the 90% confidence level.

Search for the rare decay B-->pil+ l-.

We have performed a search for the flavor-changing neutral-current decays B-->pil+ l-, where l+ l- is either e+ e- or mu+ mu-, using a sample of 230 x 10(6) Upsilon(4S)-->BB decays collected with the BABAR detector. We observe no evidence of a signal and measure the upper limit on the isospin-averaged branching fraction to be B(B-->pil+ l-)<9.1 x 10(-8) at 90% confidence level. We also search for the lepton-flavor-violating decays B-->pie+/- mu-/+ and measure an upper limit on the isospin-averaged branching fraction of B(B-->pie+/- mu-/+)<9.2 x 10(-8) at 90% confidence level.

The muskrat (Ondatra zibethicus) as a new reservoir for puumala-like hantavirus strains in Europe.

We have used an indirect immunofluorescent assay (IFA) and reverse transcription-PCR (RT-PCR) to screen the sera and tissues of muskrats (Ondatra zibethica) caught in the northwest of Brandenburg and in the northeast of Saxony-Anhalt, Germany, for hantavirus infection. Kidney and/or lung tissue from 6 (3.1%, CI = 1.1-6.5%) out of 197 muskrats were found to be positive for genomic sequences of hantavirus by RT-PCR. We could also demonstrate that 14 (5%, CI = 2.9-8.7%) out of 266 muskrat's sera available for testing contained hantavirus-specific antibodies in IFA. Thus, a total of 8% of the investigated muskrat population was found to be positive for hantavirus infection by RT-PCR and IFA. None of the animals was found positive in both tests. Further analysis of the RT-PCR amplified fragments by genomic sequencing revealed sequences mostly related to the puumala (PUU) S segment sequence of the Hällnäs B1 hantavirus strain (97-99% similarity). Our data therefore demonstrate that Ondatra zibethicus serves as an additional reservoir for puumala-like hantavirus strains in Europe. The epidemiological implications of this finding for hantavirus infection in Europe and elsewhere are discussed.

Echinococcosis: an emerging or re-emerging zoonosis?

The aim of this review is a critical discussion of factors actually or potentially contributing to persistence or emergence of echinococcosis in humans. Alveolar echinococcosis (AE), a life-threatening infection of humans, is caused by a larval stage of Echinococcus multilocularis. The adult parasite inhabits the intestine of foxes and other carnivores and has a wide distribution in the northern hemisphere (North America and northern and central Eurasia). Recent surveys in central Europe have extended the known geographical occurrence of E. multilocularis in foxes from four countries at the end of the 1980s to at least 11 countries in 1999. Cases of human AE previously regularly reported from only four countries are now recorded from seven countries, but the annual incidences are low. Since adequate information from earlier surveys is not available, it is not possible to conclude if the new findings reflect a recent extension of the parasite's range or just the first identification of hitherto unnoticed endemic areas. Evidence of parasite spreading has been reported from North America and Japan. Factors with the potential of enhancing the infection risk for humans in the future include increasing fox populations and parasite prevalences, progressing invasion of cities by foxes, the establishment of urban cycles of the parasite, and the spill-over of the E. multilocularis infection from wild carnivores to domestic dogs and cats. In view of the potential severity and fatality of AE in humans health authorities should initiate internationally coordinated countermeasures. Although control programmes against human cystic echinococcosis (CE), caused by E. granulosus, have been established in some countries and effective control strategies are available, the parasite has still a wide geographical distribution affecting many countries of all continents. Thus, human CE is persisting in many parts of the world with high incidences, and in some areas it is a re-emerging problem. For example, alarming increases of the number of human cases have been reported from Bulgaria and Kazakhstan, and the People's Republic of China. Progress in control can only be expected if health authorities attribute a higher priority to this disease and if all modern diagnostic and control options (for example vaccination of intermediate host animals) can be used.

Processes leading to a spatial aggregation of Echinococcus multilocularis in its natural intermediate host Microtus arvalis.

The small fox tapeworm (Echinococcus multilocularis) shows a heterogeneous spatial distribution in the intermediate host (Microtus arvalis). To identify the ecological processes responsible for this heterogeneity, we developed a spatially explicit simulation model. The model combines individual-based (foxes, Vulpes vulpes) and grid-based (voles) techniques to simulate the infections in both intermediate and definite host. If host populations are homogeneously mixed, the model reproduces field data for parasite prevalence only for a limited number of parameter combinations. As ecological parameters inevitably vary to a certain degree, we discarded the homogeneous mixing model as insufficient to gain insight into the ecology of the fox tapeworm cycle. We analysed five different model scenarios, each focussing on an ecological process that might be responsible for the heterogeneous spatial distribution of E. mulitlocularis in the intermediate host. Field studies revealed that the prevalence ratio between intermediate and definite host remains stable over a wide range of ecological conditions. Thus, by varying the parameters in simulation experiments, we used the robustness of the agreement between field data and model output as quality criterion for the five scenarios. Only one of the five scenarios was found to reproduce the prevalence ratio over a sufficient range of parameter combinations. In the accentuated scenario most tapeworm eggs die due to bad environmental conditions before they cause infections in the intermediate host. This scenario is supported by the known sensitivity of tapeworm eggs to high temperatures and dry conditions. The identified process is likely to lead to a heterogeneous availability of infective eggs and thus to a clumped distribution of infected intermediate hosts. In conclusion, areas with humid conditions and low temperatures must be pointed out as high risk areas for human exposure to E. multilocularis eggs as well.

Geographic information system-aided analysis of factors associated with the spatial distribution of Echinococcus multilocularis infections of foxes.

To investigate the influence of environmental factors on the spatial epidemiology of infections with Echinococcus multilocularis, foxes were sampled in a focal endemic region in the Northwest of Brandenburg, Germany, and examined for infection by the parasite. The locations where foxes were obtained were recorded in a geographic information system database. Positions of infected and uninfected foxes were analyzed on the background of geographic vector data of water, settlements, streets, forests, crop, and pasture. Fox positions were allocated to different land-use classes by use of a Landsat Thematic Mapper (TM) satellite image. Infected foxes were more frequently shot near water, in areas of high soil humidity, and on pastures, suggesting that dryness may limit the tenacity of E. multilocularis oncospheres. Thus open landscapes with humid soil seem to be favorable for the life cycle of the parasite. In contrast, infected foxes were significantly underrepresented in forest areas.

Is it possible to orally vaccinate juvenile red foxes against rabies in spring campaigns?

The rabies antibody status of juvenile foxes (Vulpes vulpes) was evaluated in large-scale, long-term oral vaccination campaigns. Between 9% (n = 659) and 21% (n = 42) of the juvenile foxes examined in 1993-94 and 1997, respectively, showed rabies virus neutralizing antibody (nAb)-titers > or = 0.5 IU/ml following bait distribution in spring. The presence of nAb may be due to either the passive transfer of maternal antibodies, or active immunization derived from spring vaccination campaigns. The latter alternative is supported by the finding of nAb throughout late spring and the summer months, and the finding of the tetracycline (TC) biomarker, used in the vaccine-baits, in 27% (n = 43) and 37% (n = 155) of juveniles in 1993-94 and 1997, respectively. It was not possible to distinguish nAb originating from passive immunity from that arising from active immunization. However, biological data on the whelping period of red foxes, on dynamics of maternal antibodies and the timing of oral vaccination, gave evidence that a superposition of these processes is likely. Evidence from these studies suggests that oral vaccination coinciding with the spring perinatal period may produce immunity in both parents and only in a certain percentage of the offspring simultaneously. This phenomenon should be useful in further enhancing the efficacy of oral vaccination in red foxes.

[Neospora caninum causes abortions in a cattle herd in North Rhine Westphalia]. / Neospora caninum verursacht Aborte in einem Rinderbestand in Nordrhein-Westfalen.

In a cattle herd in North Rhine-Westphalia a series of eight abortions occurred between 15th August and 14th October, 1996. Four of the aborted fetuses were histopathologically, virologically, bacteriologically and parasitologically examined. A multifocal necrotising encephalitis was observed in two fetuses. In addition, the liver of two fetuses and the placenta of one fetus contained infected foci. In three fetuses protozoan stages were detected which were identified as N. caninum by immunohistochemistry. A polymerase chain reaction conducted with histological material revealed N. caninum-DNA in the placenta of an aborted fetus. When seven cows that had aborted were tested for antibodies directed against N. caninum, six animals were positive by immunofluorescence and all seven by immunoblotting. The serological examination of the entire herd revealed a high herd seroprevalence of antibodies directed against N. caninum. Potential modes of infection with N. caninum in the herd are discussed, in particular the possibility of exposure to a point source (definitive host).

Measurement of semileptonic B decays into orbitally excited charmed mesons.

We present a study of B decays into semileptonic final states containing charged and neutral D1(2420) and D_{2};{*}(2460). The analysis is based on a data sample of 208 fb;{-1} collected at the Upsilon(4S) resonance with the BABAR detector at the PEP-II asymmetric-energy B factory at SLAC. With a simultaneous fit to four different decay chains, the semileptonic branching fractions are extracted from measurements of the mass difference Deltam=m(D;{**})-m(D) distributions. Product branching fractions are determined to be B(B;{+}-->D_{1};{0}l;{+}nu_{l})xB(D_{1};{0}-->D;{*+}pi;{-})=(2.97+/-0.17+/-0.17)x10;{-3}, B(B;{+}-->D_{2};{*0}l;{+}nu_{l})xB(D_{2};{*0}-->D;{(*)+}pi;{-})=(2.29+/-0.23+/-0.21)x10;{-3}, B(B;{0}-->D_{1};{-}l;{+}nu_{l})xB(D_{1};{-}-->D;{*0}pi;{-})=(2.78+/-0.24+/-0.25)x10;{-3} and B(B;{0}-->D_{2};{*-}l;{+}nu_{l})xB(D_{2};{*-}-->D;{(*)0}pi;{-})=(1.77+/-0.26+/-0.11)x10;{-3}. In addition we measure the branching ratio Gamma(D_{2};{*}-->Dpi;{-})/Gamma(D_{2};{*}-->D;{(*)}pi;{-})=0.62+/-0.03+/-0.02.

Search for dimuon decays of a light scalar boson in radiative transitions Upsilon-->gammaA0.

We search for evidence of a light scalar boson in the radiative decays of the Upsilon(2S) and Upsilon(3S) resonances: Upsilon(2S,3S)-->gammaA0, A0-->mu+mu-. Such a particle appears in extensions of the standard model, where a light CP-odd Higgs boson naturally couples strongly to b quarks. We find no evidence for such processes in the mass range 0.212 < or = mA0 < or = 9.3 GeV in the samples of 99 x 10(6) Upsilon(2S) and 122 x 10(6) Upsilon(3S) decays collected by the BABAR detector at the SLAC PEP-II B factory and set stringent upper limits on the effective coupling of the b quark to the A0. We also limit the dimuon branching fraction of the etab meson: B(etab-->mu+mu-)<0.9% at 90% confidence level.

Measurement of B-->Xgamma decays and determination of |Vtd/Vts|.

Using a sample of 383 x 10;{6} BB[over ] events collected by the BABAR experiment, we measure sums of seven exclusive final states B-->X_{d(s)}gamma, where X_{d}(X_{s}) is a nonstrange (strange) charmless hadronic system in the mass range 0.6-1.8 GeV/c;{2}. After correcting for unmeasured decay modes in this mass range, we obtain a branching fraction for b-->dgamma of (7.2+/-2.7(stat)+/-2.3(syst))x10;{-6}. Taking the ratio of X_{d} to X_{s} we find Gamma(b-->dgamma)/Gamma(b-->sgamma)=0.033+/-0.013(stat)+/-0.009(syst), from which we determine |V_{td}/V_{ts}|=0.177+/-0.043.