151 research outputs found
Observation of an event of pair photoproduction of charmed anti D D -mesons
No full textTranslated from RussianOriginally published in PISMA JETF, v. 34(8) p. 477-482. / FIZ - Fachinformationszzentrum Karlsruhe / TIB - Technische InformationsbibliothekSIGLEDEGerman
Charged charmed particle lifetime
No full textWe present the lifetime values obtained for D± and Λc+, photoproduced in nuclear emulsion in the WA58 experiment. In photohadronic interactions, pairs of charmed particles are produced. Out of 20 charged charmed particles used for lifetime evaluation, 17 have their charmed partner seen emulsion, being then essentially free from any background. The values of the lifetime are τD± = (3.91−1.25+2.35) × 10−13 s, τΛc+ = (2.22−0.75+1.34) × 10−13 s
Measurement of the lifetime of neutral charmed mesons
No full textThe lifetime of neutral charmed particles photoproduced in emulsion has been measured. The lifetime value presented here was obtained from a sample of 22D 0 mesons, 18 of which have their charmed partner seen in emulsion. The sample is essentially background-free. The result obtained is tau D0=(2.11 {+1.21}/{-0.63})×10 13s The D 0 mass derived from 8 3C events is mD 0 = 1856 ± 36 MeV/ c2
OBSERVATION OF PAIRS OF CHARMED PARTICLE PRODUCED BY HIGH-ENERGY PHOTONS IN NUCLEAR EMULSIONS COUPLED WITH A MAGNETIC SPECTROMETER
No full textPreliminary results of an experiment using nuclear emulsions exposed to a tagged photon beam at the CERN SPS (experiment WA58) are presented. Six events showing pairs of charmed particles have been found. One of these has been interpreted as an associated production of Λc+ and View the MathML source0. The mean lifetime of the neutral D meson based on three events is τ0 = (0.58−0.2+0.8 × 10−13 s,, whereas a statistical analysis of eight charged charmed particles, assumed to be D mesons, leads to an estimate of the mean lifetime of τ± ≈ 4.4 × 10−13 s
UvA-DARE (Digital Academic Repository) Link to publication Citation for published version (APA): Inclusive search for the charmless radiative decay of the b-quark (b L3 Collaboration
No full textGeneral rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Download date: 29 Jun 2019 Physics Letters B 317 ( 1993 ) We report on the search for the electromagnetic penguin decay b --* s7 at v~ ~ mz. We find no evidence for a signal and place an upper limit on the decay rate Br(b ~ s~,) < 1.2 × 10 -3 at 90% C.L
Measurement of energetic single-photon production at LEP
No full textGeneral rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. PHYSICS LETTERS 6 Physics Letters B 346 ( 1995) 190-198 Measurement of energetic single-photon production at LEP Abstract We describe the sample of energetic single-photon events (E, > 15 GeV) collected by L3 in the 1991-1993 LEP runs. The event distributions agree with expectations from the Standard Model. The data are used to constrain the ZZy coupling and to set an upper limit of 4.1 x 10-6p~ (90% CL.) on the the magnetic moment of the T neutrino
UvA-DARE (Digital Academic Repository) Determination of the effective electroweak mixing angle from Z decays L3 Collaboration
No full textGeneral rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. The effective electroweak mixing angle sin 20w is measured from the production and decay of the Z boson in e+e -interactions. The data sample corresponds to an integrated luminosity of 18 pb-l with about 420 000 hadronic and 40 000 leptonic Z decays. The mixing angle sin 20w is determined from several independent measurements: the leptonic and hadronic cross sections, the forward-backward asymmetries of charged leptons and b-quarks, and the z-polarization. The results are found to be in good agreement with each other. The value of sin 20w from a fit to the asymmetries in a model independent method is 0.2321-4-0.0021 and from a global fit to the data in the Standard Model framework is 0.2328+0.0013
Measurement of inclusive eta production in hadronic decays of the Z0
No full textGeneral rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Download date: 29 Jun 2019 Physics Letters B 286 (1992) We present a study of the inclusive ~/ production based on 300000 hadronic Z ° decays. The measured inclusive momentum distribution can be reproduced by parton shower Monte Carlo programs and also by an analytical QCD calculation. Comparing our results with low energy e+e -data, we find that QCD describes both the shape and the energy evolution of the r/ spectrum. The comparison of q production rates in quark-and gluon-enriched jet samples does not show statistically significant evidence for more abundant production of q mesons in gluon fragmentation. l Deceased. 2 Supported by the German Forschung und Technologie. Bundesministerium f'ti
UvA-DARE (Digital Academic Repository) A test of QCD based on 3-jet events from Z ° decays L3 Collaboration
No full textA test of QCD based on three jet events from Z0 decays Adeva, B.; Adriani, O.; Aguilar-Benitez, M.; Ahlen, S.P.; Akbari, H.; Alcaraz, J.; Aloisio, A.; Alverson, G.; Linde, F.L. General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. We present a study of 43 000 3-jet events from Z ° boson decays. Both the measured jet energy distributions and the event orientation are reproduced by second order QCD. An alternative model with scalar gluons fails to describe the data
High mass photon pairs in lepton+ lepton-gamma gamma events at LEP
No full textHigh mass photon pairs in lepton+ lepton-gamma gamma events at LEP Adriani, O.; Aguilar-Benitez, M.; Ahlen, S.P.; Alcaraz, J.; Aloisio, A.; Alverson, G.; Alviggi, M.G.; Ambrosi, G.; Linde, F.L. Published in: Physics Letters B DOI: 10.1016/0370-2693(92)91576-U Link to publication Citation for published version (APA): Adriani, O., Aguilar-Benitez, M., Ahlen, S. P., Alcaraz, J., Aloisio, A., Alverson, G., ... Linde, F. L. (1992). High mass photon pairs in lepton+ lepton-gamma gamma events at LEP. Physics Letters B, 295,[337][338][339][340][341][342][343][344][345][346] https://doi.org/10.1016/0370-2693(92)91576-U General rights It is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), other than for strictly personal, individual use, unless the work is under an open content license (like Creative Commons). Disclaimer/Complaints regulations If you believe that digital publication of certain material infringes any of your rights or (privacy) interests, please let the Library know, stating your reasons. In case of a legitimate complaint, the Library will make the material inaccessible and/or remove it from the website. Please Ask the Library: https://uba.uva.nl/en/contact, or a letter to: Library of the University of Amsterdam, Secretariat, Singel 425, 1012 WP Amsterdam, The Netherlands. You will be contacted as soon as possible. Download date: 28 Jun 2019 Physics Letters B 295 (1992) From the analysis of the reactions e + e-~ g + g-(n?) (g = e, #, ~) we observe four events, one e+e -~'7 and three #+ ~-??, with the invariant mass of the photon pairs close to 60 GeV. These events were selected from a data sample collected in the L3 detector corresponding to 950000 produced Z°'s. More data are necessary to ascertain the origin of these events
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