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.

We observe both the JPC=1++ f1(1285) and the JPC=0-+ (958) in tagged two-photon interactions and the (958) in untagged interactions. The measured Q2 dependence and decay distribution support the f1(1285) spin and parity assignment. The radiative width of the f1(1285) is measured as (M2/Q2)*=9.4±2.5±1.7 keV, on the assumption of a -pole form factor. © 1987 The American Physical Society.

We confirm the observation of a spin-1 resonance at 1423 MeV in the KS0K± system produced in single-tagged two-photon interactions. The Dalitz plot indicates that this resonance decays primarily via a K*K intermediate state. We measure a radiative width times branching ratio BKK»(M2/Q2)*=3.2±1.4±0.6 keV on the assumption of a -pole form factor. © 1987 The American Physical Society.

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.

Four data sets collected with the Mark II detector during its operation at the SPEAR and PEP e+e- storage rings at SLAC are used to study the Bose-Einstein correlation between pairs and triplets of like-sign charged pions. The data sets represent four different regions of energy available for hadron production: the J at s =3.095 GeV, typical hadronic energy of 5 GeV in two-photon events, and annihilation in the energy regions s =47 GeV above the J, and s =29 GeV. The Bose-Einstein correlation is studied as a function of Q2, the four-momentum difference squared of the pair, and of Q32, an analogous quantity defined for triplets. After corrections for Coulomb effects and pion misidentification, pair analyses indicate a nearly full Bose-Einstein enhancement (1) in the J and the two-photon data, and about half the maximum value in the two higher-energy data sets. The pair analysis parameter r lies within a band of ±0.1 fm around 0.7 fm and is essentially the same for all four data sets. Pion triplet analyses give consistent results for the triplet parameters 3 and r3. In an attempt to investigate the shape of the pion source, we also study the Bose-Einstein correlation in pion pairs using two-dimensional distributions in components of Q2. © 1989 The American Physical Society.

We report a measurement of the lifetime of the B0 meson based upon 29-GeV e+e- annihilation data taken with the Mark II detector at the SLAC storage ring PEP. The B0 mesons are tagged by their decays into D*- and D*+, where the D*- is tagged by its decay into -D 0. We reconstruct the decay vertices of 15 B0-meson candidates and measure the B0 lifetime to be 1.20-0.360.14+0.52+0.16 psec. © 1990 The American Physical Society.