3,047 research outputs found

    Conservation genetics of the pond bat (Myotis dasycneme) with special focus on the populations in northwestern Germany and in Jutland, Denmark

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    Conservation genetics is important in the management of endangered species, helping to understand their connectivity and long‐term viability, thus identifying populations of importance for conservation. The pond bat (Myotis dasycneme) is a rare species classified as “Near Threatened” with a wide but patchy Palearctic distribution. A total of 277 samples representing populations in Denmark, Germany, Latvia, Hungary, and Russia were used in the genetic analyses; 224 samples representing Denmark, Germany, and Russia were analyzed at 10 microsatellite loci; 241 samples representing all areas were analyzed using mitochondrial D‐loop and cytochrome B sequences. A Bayesian clustering approach revealed two poorly resolved clusters, one representing the Danish and German groups and the other the Russian group. However, significantly different pairwise FST and DEST estimates were observed between the Danish and German groups and between the Danish and Russian groups suggesting a recent population structure. These conflicting results might be attributed to the effect of migration or low resolution due to the number of microsatellite markers used. After concatenating the two mitochondrial sequences, analysis detected significant genetic differentiation between all populations, probably due to genetic drift combined with a founder event. The phylogenetic tree suggested a closer relationship between the Russian and Northern European populations compared to the Hungarian population, implying that the latter belongs to an older ancestral population. This was supported by the observed haplotype network and higher nucleotide diversity in this population. The genetic structuring observed in the Danish/German pond bat stresses the need for a cross‐border management between the two countries. Further, the pronounced mtDNA structuring, together with the indicated migration between nearby populations suggest philopatric female behavior but male migration, emphasizes the importance of protecting suitable habitat mosaics to maintain a continuum of patches with dense pond bat populations across the species' distribution range

    Measurement of the WW Boson Mass

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    A measurement of the mass of the WW boson is presented based on a sample of 5982 W→eÎœW \rightarrow e \nu decays observed in pp‟p\overline{p} collisions at s\sqrt{s} = 1.8~TeV with the D\O\ detector during the 1992--1993 run. From a fit to the transverse mass spectrum, combined with measurements of the ZZ boson mass, the WW boson mass is measured to be MW=80.350±0.140(stat.)±0.165(syst.)±0.160(scale)GeV/c2M_W = 80.350 \pm 0.140 (stat.) \pm 0.165 (syst.) \pm 0.160 (scale) GeV/c^2.Comment: 12 pages, LaTex, style Revtex, including 3 postscript figures (submitted to PRL

    Search for Top Squark Pair Production in the Dielectron Channel

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    This report describes the first search for top squark pair production in the channel stop_1 stopbar_1 -> b bbar chargino_1 chargino_1 -> ee+jets+MEt using 74.9 +- 8.9 pb^-1 of data collected using the D0 detector. A 95% confidence level upper limit on sigma*B is presented. The limit is above the theoretical expectation for sigma*B for this process, but does show the sensitivity of the current D0 data set to a particular topology for new physics.Comment: Five pages, including three figures, submitted to PRD Brief Report

    The Azimuthal Decorrelation of Jets Widely Separated in Rapidity

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    This study reports the first measurement of the azimuthal decorrelation between jets with pseudorapidity separation up to five units. The data were accumulated using the D{\O}detector during the 1992--1993 collider run of the Fermilab Tevatron at s=\sqrt{s}= 1.8 TeV. These results are compared to next--to--leading order (NLO) QCD predictions and to two leading--log approximations (LLA) where the leading--log terms are resummed to all orders in αS\alpha_{\scriptscriptstyle S}. The final state jets as predicted by NLO QCD show less azimuthal decorrelation than the data. The parton showering LLA Monte Carlo {\small HERWIG} describes the data well; an analytical LLA prediction based on BFKL resummation shows more decorrelation than the data.Comment: 6 pages with 4 figures, all uuencoded and gzippe

    Measurement of Branching Fractions and Rate Asymmetries in the Rare Decays B -> K(*) l+ l-

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    In a sample of 471 million BB events collected with the BABAR detector at the PEP-II e+e- collider we study the rare decays B -> K(*) l+ l-, where l+ l- is either e+e- or mu+mu-. We report results on partial branching fractions and isospin asymmetries in seven bins of di-lepton mass-squared. We further present CP and lepton-flavor asymmetries for di-lepton masses below and above the J/psi resonance. We find no evidence for CP or lepton-flavor violation. The partial branching fractions and isospin asymmetries are consistent with the Standard Model predictions and with results from other experiments.Comment: 16 pages, 14 figures, accepted by Phys. Rev.

    Measurement of the Branching Fraction for B- --> D0 K*-

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    We present a measurement of the branching fraction for the decay B- --> D0 K*- using a sample of approximately 86 million BBbar pairs collected by the BaBar detector from e+e- collisions near the Y(4S) resonance. The D0 is detected through its decays to K- pi+, K- pi+ pi0 and K- pi+ pi- pi+, and the K*- through its decay to K0S pi-. We measure the branching fraction to be B.F.(B- --> D0 K*-)= (6.3 +/- 0.7(stat.) +/- 0.5(syst.)) x 10^{-4}.Comment: 7 pages, 1 postscript figure, submitted to Phys. Rev. D (Rapid Communications

    First Observation of CP Violation in B0->D(*)CP h0 Decays by a Combined Time-Dependent Analysis of BaBar and Belle Data

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    We report a measurement of the time-dependent CP asymmetry of B0->D(*)CP h0 decays, where the light neutral hadron h0 is a pi0, eta or omega meson, and the neutral D meson is reconstructed in the CP eigenstates K+ K-, K0S pi0 or K0S omega. The measurement is performed combining the final data samples collected at the Y(4S) resonance by the BaBar and Belle experiments at the asymmetric-energy B factories PEP-II at SLAC and KEKB at KEK, respectively. The data samples contain ( 471 +/- 3 ) x 10^6 BB pairs recorded by the BaBar detector and ( 772 +/- 11 ) x 10^6, BB pairs recorded by the Belle detector. We measure the CP asymmetry parameters -eta_f S = +0.66 +/- 0.10 (stat.) +/- 0.06 (syst.) and C = -0.02 +/- 0.07 (stat.) +/- 0.03 (syst.). These results correspond to the first observation of CP violation in B0->D(*)CP h0 decays. The hypothesis of no mixing-induced CP violation is excluded in these decays at the level of 5.4 standard deviations.Comment: 9 pages, 2 figures, submitted to Physical Review Letter

    Search for W~1Z~2\widetilde{W}_1\widetilde{Z}_2 Production via Trilepton Final States in ppˉp\bar{p} collisions at s=1.8\sqrt{s}=1.8 TeV

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    We have searched for associated production of the lightest chargino, W~1\widetilde{W}_1, and next-to-lightest neutralino, Z~2\widetilde{Z}_2, of the Minimal Supersymmetric Standard Model in ppˉp\bar{p} collisions at \mbox{s\sqrt{s} = 1.8 TeV} using the \D0 detector at the Fermilab Tevatron collider. Data corresponding to an integrated luminosity of 12.5±0.7\pm 0.7 \ipb were examined for events containing three isolated leptons. No evidence for W~1Z~2\widetilde{W}_1\widetilde{Z}_2 pair production was found. Limits on σ(W~1Z~2)\sigma(\widetilde{W}_1\widetilde{Z}_2)Br(W~1→lÎœZ~1)(\widetilde{W}_1\to l\nu\widetilde{Z}_1)Br(Z~2→llˉZ~1)(\widetilde{Z}_2\to l\bar{l}\widetilde{Z}_1) are presented.Comment: 17 pages (13 + 1 page table + 3 pages figures). 3 PostScript figures will follow in a UUEncoded, gzip'd, tar file. Text in LaTex format. Submitted to Physical Review Letters. Replace comments - Had to resumbmit version with EPSF directive
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