94 research outputs found
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Limits on new-lepton pairs (L-,L0) with arbitrary neutrino mass.
We have searched 205 pb-1 of s =29 GeV data from the Mark II detector at the SLAC e+e- storage ring PEP for events which may signify the existence of a new lepton pair (L-,L0) where the L0 may be massive, but does not exceed the L- mass. Three event signatures for L+L- decay are examined: (i) e, (ii) (e or)(+4), and (iii) (e or )(3+0). The numbers of signature events are found to be in good agreement with Monte Carlo simulations of known background sources. The ranges of L- and L0 masses for which new lepton pairs are excluded are obtained using a likelihood-ratio method to compare the number of observed signature events to the expected background, and to the expected background plus Monte Carlo predictions of (L-,L0) signals. © 1989 The American Physical Society
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Test of QED to fourth order by study of four-lepton final states in e+e- interactions at 29 GeV with the Mark II detector.
We have tested QED to fourth order in the coupling constant in the large-Q2 region by studying four-lepton final states in e+e- interactions with the Mark II detector at the SLAC storage ring PEP (s=29 GeV). All four final-state particles were detected at large angles with respect to the beam axis. For an integrated luminosity of 205 pb-1, we observed ten e+e-e+e-, ten e+e-+-, and one events with opposite-charge pair masses greater than 1 GeV/c2. These events show good agreement with the complete 4 QED calculation. © 1990 The American Physical Society
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Test of QED to fourth order by study of four-lepton final states in e+e- interactions at 29 GeV with the Mark II detector.
We have tested QED to fourth order in the coupling constant in the large-Q2 region by studying four-lepton final states in e+e- interactions with the Mark II detector at the SLAC storage ring PEP (s=29 GeV). All four final-state particles were detected at large angles with respect to the beam axis. For an integrated luminosity of 205 pb-1, we observed ten e+e-e+e-, ten e+e-+-, and one events with opposite-charge pair masses greater than 1 GeV/c2. These events show good agreement with the complete 4 QED calculation. © 1990 The American Physical Society
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Inclusive charged hadron and K0 production in two-photon interactions
The inclusive transverse momentum distributions of charged hadrons and K0's produced in tagged photon-photon collisions, are measured and compared to model calculations up to a pT of 5 GeV/c. The relative abundance of K0's favor the inclusion of charm. © 1993
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Inclusive charged hadron and K0 production in two-photon interactions
The inclusive transverse momentum distributions of charged hadrons and K 's produced in tagged photon-photon collisions, are measured and compared to model calculations up to a p of 5 GeV/c. The relative abundance of K 's favor the inclusion of charm. © 1993. 0 0
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Measurement of the D0 lifetime
We have used an electronic tracking system to measure the lifetime of D0 mesons produced in e+e- annihilation at 29 GeV. Based on a sample of 27 events, the lifetime is found to be (4.2-1.0+1.3 1.0) × 10-13 s. © 1984 The American Physical Society
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Two-photon production of pion pairs.
We present a new high-statistics measurement of the cross section for the process e+e-e+e-+- at a center-of-mass energy of 29 GeV for invariant pion-pair masses M(+-) between 350 MeV/c2 and 1.6 GeV/c2. We observe the f2(1270) and measure its radiative width to be 3.15±0.04±0.39 keV. We also observe an enhancement in the +- spectrum near 1 GeV. General agreement is found with unitarized models of the +- reaction that include final-state interactions. © 1990 The American Physical Society
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Radiative tau production and decay.
We have studied the muon decay channel of the lepton with the presence of a photon in e+e- annihilation data at Ec.m.=29 GeV from the Mark II detector. Included in this study is the first direct measurement of radiative decay. We find the ratio of the measured branching fraction to the expected value from QED to be 1.03±0.42. © 1990 The American Physical Society
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eta and eta ' production in e+e- annihilation at 29 GeV. Evidence for the Dx+/- decays into eta pi +/- and eta ' pi +/-
The Production has been investigated by the Mark II collaboration at the SLAC e+e- storage ring PEP. particles are reconstructed by their decay mode. The fragmentation function has been measured and found to be in good agreement with the Lund-model prediction. production has been measured for the first time in high-energy e+e- annihilation. There is evidence at the 3 level for Ds± decay into ± and ±. © 1988 The American Physical Society
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eta and eta ' production in e+e- annihilation at 29 GeV. Evidence for the Dx+/- decays into eta pi +/- and eta ' pi +/-
The Production has been investigated by the Mark II collaboration at the SLAC e+e- storage ring PEP. particles are reconstructed by their decay mode. The fragmentation function has been measured and found to be in good agreement with the Lund-model prediction. production has been measured for the first time in high-energy e+e- annihilation. There is evidence at the 3 level for Ds± decay into ± and ±. © 1988 The American Physical Society
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