Results from a partial-wave analysis of the decay J/y/-+ yK §K ± n "*" in the K §K ± n + invariant-mass range 1.35-1.6 GeV/c 2 are presented. Within the isobar model, the data in this mass range are best described by a mixture of 0~+ and 1 ++ amplitudes, corresponding to the A r *A' + c.c. (P wave), A^A' + c.c. (5 wave), and <2o(980)/r (5 wave) channels. These results show that r/(1430) is not a J PCs =0 ~ + flo(980);r resonance, but a mixture of overlapping states.
We have measured the differential production cross sections as a function of scaled momentum x p ϭ2 p/E c.m. of the identified hadron species ϩ , K ϩ , K 0 , K* 0 , , p, ⌳ 0 , and of the corresponding antihadron species in inclusive hadronic Z 0 decays, as well as separately for Z 0 decays into light (u, d, s), c and b flavors. Clear flavor dependences are observed, consistent with expectations based upon previously measured production and decay properties of heavy hadrons. These results were used to test the QCD predictions of Gribov and Lipatov, the predictions of QCD in the modified leading logarithm approximation with the ansatz of local parton-hadron duality, and the predictions of three fragmentation models. The ratios of production of different hadron species were also measured as a function of x p and were used to study the suppression of strange meson, strange and non-strange baryon, and vector meson production in the jet fragmentation process. The light-flavor results provide improved tests of the above predictions, as they remove the contribution of heavy hadron production and decay from that of the rest of the fragmentation process. In addition we have compared hadron and antihadron production as a function of x p in light quark ͑as opposed to antiquark͒ jets. Differences are observed at high x p , providing direct evidence that higher-momentum hadrons are more likely to contain a primary quark or antiquark. The differences for pseudoscalar and vector kaons provide new measurements of strangeness suppression for high-x p fragmentation products. ͓S0556-2821͑99͒06101-9͔
A new technique is applied to data collected at the 0(3770) resonance to derive charmed-Dmeson branching fractions without relying on the measurement of D-production cross sections. Measurements are presented for three decay modes of the D° (K~TT + , D~ * and K-TT + TT 0 ) and four decay modes of the D + (K~7r + 7r + , K-TT + TT + TT 0 , K$<7T + , and tf 5°i r + ir 0 ). The resulting branching fractions are significantly larger than previous measurements.
We present measurements of the two-body decays of the J/$ into a vector and a pseudoscalar meson. The data, taken with the Mark I11 detector at the SLAC e + e -storage ring SPEAR, consist of 5.8 X lo6 produced J/+'s. The branching ratios for the J/$ decays into pn, pg, pq', on0, og, wg', $17, r#Jgl, and K*K are measured; an upper limit on J / $ -~T ' is obtained. Using the measured branching ratios we obtain parameters of a phenomenological model of J/$ decays, indicating that the g and g' are consistent with being composed only of light and strange quarks. The model is used to obtain the mixing angle in the pseudoscalar nonet. The m a 0 electromagnetic form factor is determined. The upper limit on J/*-+r#Jno is used to study the contributions from electromagnetic doubly-Okubo-Zweig-Iizuka-suppressed decays of the J/+.
We present a measurement of the left-right cross-section asymmetry (A LR ) for Z boson production by e + e − collisions. The measurement includes the final data taken with the SLD detector at the SLAC Linear Collider (SLC) during the period 1996-1998. Using a sample of 383,487 Z decays collected during the 1996-1998 runs we measure the pole-value of the asymmetry, A 0 LR , to be 0.15056±0.00239 which is equivalent to an effective weak mixing angle of sin 2 θ eff W = 0.23107±0.00030. Our result for the complete 1992-1998 dataset comprising 537 thousand Z decays is sin 2 θ eff W = 0.23097 ± 0.00027. The SLD Collaboration has performed a series of increasingly precise measurements of the left-right cross-section asymmetry in the production of Z bosons by e + e − collisions [1][2][3]. Submitted to Physical Review LettersIn this letter, we present a measurement based upon data recorded during the 1996 and 1997-98 runs of the SLAC Linear Collider (SLC), which represents about three quarters of our total sample and leads to improved statistical precision and reduced systematic uncertainty.The overall average given at the end of this Letter is based upon all the data from the completed SLD experimental program [4].The left-right asymmetry is defined as, where σ L and σ R are the e + e − production cross sections for Z bosons at the Z-pole energy with left-handed and right-handed electrons, respectively. The Standard Model predicts that this quantity depends upon the effective vector (v e ) and axial-vector (a e ) couplings of the Z boson to the electron current,where the effective electroweak mixing parameter is defined [5] as sin 2 θ eff W ≡ (1 − v e /a e )/4. 3The quantity A 0 LR is a sensitive function of sin 2 θ eff W and depends upon virtual electroweak radiative corrections including those which involve the Higgs boson and those arising from new phenomena outside of the scope of the Standard Model (SM). Presently, the most stringent upper bounds on the SM Higgs mass are provided by measurements of sin 2 θ eff W . We measured the left-right asymmetry by counting hadronic and (with low efficiency) τ + τ − final states produced in e + e − collisions near the Z-pole energy for each of the two longitudinal polarization states of the electron beam. The asymmetry formed from these rates, A LR , was then corrected for residual effects arising from pure photon exchange and Z-photon interference to extract A 0 LR . The measurement required knowledge of the absolute beam polarization, but did not require knowledge of the absolute luminosity, detector acceptance, or efficiency [6].The operation of the SLC with a polarized electron beam has been described previously [7]. The maximum luminosity of the collider was approximately 3×10 30 cm −2 sec −1 , and the longitudinal electron polarization at the e + e − collision point was typically ∼75%. Beginning in 1996, two additional detectors were operated in order to assist in the calibration of the primary spectrometer-based polarimeter. Both devices detected Comptonscattere...
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