Final results of the search for the standard model Higgs boson are presented for the data collected by the L3 detector at LEP at centre-of-mass energies up to about 209 GeV. These data are compared ...with the expectations of standard model processes for Higgs boson masses up to 120 GeV. A lower limit on the mass of the standard model Higgs boson of 112.0 GeV is set at the 95% confidence level. The most significant high mass candidate is a Hνν̄ event. It has a reconstructed Higgs mass of 115 GeV and it was recorded at s=206.4 GeV.
Search for excited leptons at LEP Aloisio, A.; Alviggi, M.G.; Arefiev, A. ...
Physics letters. B,
08/2003, Letnik:
568, Številka:
1-2
Journal Article
Recenzirano
Odprti dostop
A search for charged and neutral excited leptons is performed in 217 pb−1 of e+e− collision data collected with the L3 detector at LEP at centre-of-mass energies from 202 up to 209 GeV. The pair- and ...single-production mechanisms of excited electrons, muons and taus, as well as of excited electron-, muon- and tau-neutrinos, are investigated and no signals are detected. Combining with L3 results from searches at lower centre-of-mass energies, gives improved limits on the masses and couplings of excited leptons.
Anomalous couplings of the Higgs boson are searched for through the processes e+e−→Hγ, e+e−→e+e−H and e+e−→HZ. The mass range 70 GeV<mH<190 GeV is explored using 602 pb−1 of integrated luminosity ...collected with the L3 detector at LEP at centre-of-mass energies s=189–209 GeV. The Higgs decay channels H→ff̄, H→γγ, H→Zγ and H→WW(∗) are considered and no evidence is found for anomalous Higgs production or decay. Limits on the anomalous couplings d, dB, Δg1Z, Δκγ and ξ2 are derived as well as limits on the H→γγ and H→Zγ decay rates.
The process e+e−→W+W−γ is studied using the data collected by the L3 detector at LEP. New results, corresponding to an integrated luminosity of 427.4 pb−1 at centre-of-mass energies from 192 to ...207 GeV, are presented.
The W+W−γ cross sections are measured to be in agreement with Standard Model expectations. No hints of anomalous quartic gauge boson couplings are observed. Limits at 95% confidence level are derived using also the process e+e−→νν̄γγ.
Bose–Einstein correlations in W-pair production at LEP are investigated in a data sample of 629 pb−1 collected by the L3 detector at s=189–209 GeV. Bose–Einstein correlations between pions within a W ...decay are observed and found to be in good agreement with those in light-quark Z decay. No evidence is found for Bose–Einstein correlations between hadrons coming from different W's in the same event.
Los minadores de hojas son insectos cuyas larvas viven y se alimentan dentro de las hojas, consumiendo el mesófilo sin dañar la epidermis foliar. Varias especies son consideradas serias plagas de ...cultivos intensivos, hortícolas y ornamentales. Entre las fuentes de mortalidad más importantes para este gremio de fitófagos se citan a los enemigos naturales, de los que se destacan los parasitoides como el grupo más efectivo y mejor representado. Este artículo proporciona un resumen actualizado de la información disponible sobre parasitoides de minadores de hojas en relación al manejo de plagas. Por ser generalistas, los parasitoides de minadores de hojas pueden incluir rápidamente en su rango alimenticio a especies introducidas, muchas veces lográndose un control efectivo luego de unos pocos años de establecida la plaga. Control biológico clásico y aumentativo son estrategias ampliamente usadas para regular las poblaciones de minadores de hojas plaga. Numerosos estudios abordan la compatibilidad del uso de parasitoides con control químico y cultural. Si bien la mayoría de los insecticidas convencionales poseen efectos adversos para los parasitoides, otros serían compatibles con el control biológico. Se conoce que la combinación de diversas estrategias de control en programas de manejo integrado de plagas ha resultado efectivo contra minador de hojas plaga. Sin embargo, los efectos de prácticas culturales que podrían favorecer las poblaciones de parasitoides han sido escasamente estudiados
Measurement of W polarisation at LEP Aguilar-Benitez, M.; Alcaraz, J.; Aloisio, A. ...
Physics letters. B,
04/2003, Letnik:
557, Številka:
3-4
Journal Article
Recenzirano
Odprti dostop
The three different helicity states of W bosons produced in the reaction e+e−→W+W−→ℓνqq̄′ at LEP are studied using leptonic and hadronic W decays. Data at centre-of-mass energies s=183–209 GeV are ...used to measure the polarisation of W bosons, and its dependence on the W boson production angle. The fraction of longitudinally polarised W bosons is measured to be 0.218±0.027±0.016 where the first uncertainty is statistical and the second systematic, in agreement with the Standard Model expectation.
A flavour independent search for the CP-even and CP-odd neutral Higgs bosons h and A is performed in 624 pb−1 of data collected with the L3 detector at LEP at centre-of-mass energies between 189 and ...209GeV. Higgs boson production through the e+e−→Zh and the e+e−→hA processes is considered and decays of the Higgs bosons into hadrons are studied. No significant signal is observed and 95% confidence level limits on the hZZ and hAZ couplings are derived as a function of the Higgs boson masses. Assuming the Standard Model cross section for the Higgs-strahlung process and a 100% branching fraction into hadrons, a 95% confidence level lower limit on the mass of the Higgs boson is set at 110.3 GeV.
Z boson pair-production at LEP Aloisio, A.; Alviggi, M.G.; Arefiev, A. ...
Physics letters. B,
10/2003, Letnik:
572, Številka:
3-4
Journal Article
Recenzirano
Odprti dostop
Events stemming from the pair-production of Z bosons in e+e− collisions are studied using 217.4 pb−1 of data collected with the L3 detector at centre-of-mass energies from 200 GeV up to 209 GeV. The ...special case of events with b quarks is also investigated. Combining these events with those collected at lower centre-of-mass energies, the Standard Model predictions for the production mechanism are verified. In addition, limits are set on anomalous couplings of neutral gauge bosons and on effects of extra space dimensions.
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