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A high-gradient-doping technique is applied to strained polarized photocathodes. A 5.0–7:5 nm p-type surface layer doped to 5 Â 10 19 cm À3 is found sufficient to overcome the surface charge limit while maintaining high beam polarization. This technique can be employed to meet the charge requirements of the Next Linear Collider with a polarization(More)
The MAC detector at PEP features a large solid-angle electromagnetic/hadronic calorimeter system, augmented by magnetic charged-particle tracking, muon analysis and scintillator triggering. Its implementation in the context of electron-positron annihilation physics is described. with emphasis on the utilization of calori-metry. Description Detector The MAC(More)
The s and t dependence of incoherent +(3100) photoproduction from deuterium has been measured at the Stanford Linear Accelerator Center. $(3'700) photoproduction and #(3100) photoproduction from hydrogen have also been measured,Two narrow resonances have recently been discovered, the $(3100) and the zjJ(3700). l Since the original discovery, the $(3100) has(More)
Dark sectors charged under a new Abelian interaction have recently received much attention in the context of dark matter models. These models introduce a light new mediator, the so-called dark photon (A^{'}), connecting the dark sector to the standard model. We present a search for a dark photon in the reaction e^{+}e^{-}→γA^{'}, A^{'}→e^{+}e^{-},(More)
The photon spectrum in the inclusive electromagnetic radiative decays of the B meson, B → X(s)γ plus B → X(d)γ, is studied using a data sample of (382.8 ± 4.2) × 10(6)Υ(4S) → BB decays collected by the BABAR experiment at SLAC. The spectrum is used to extract the branching fraction B(B → X(s)γ) = (3.21 ± 0.33) × 10(-4) for E(γ) >1.8 GeV and the direct CP(More)
A precise measurement of the cross section of the process e(+)e(-) --> pi(+)pi(-)(gamma) from threshold to an energy of 3 GeV is obtained with the initial state radiation (ISR) method using 232 fb(-1) of data collected with the BABAR detector at e(+)e(-) center-of-mass energies near 10.6 GeV. The ISR luminosity is determined from a study of the leptonic(More)
In 1992, L.G. Levchuk noted that the asymmetries measured in MMller scattering polarimeters could be signiicantly aaected by the intrinsic momenta of the target electrons. This eeect is largest in devices with very small acceptance or very high resolution in laboratory scattering angle. We use a high resolution po-larimeter in the linac of the polarized(More)
Radiative beam polarization has been measured in the SPEAR storage ring to determine experimentally the strengths of depolarization phenomena. With single beams, the expected linear depolarization resonances and additional nonlinear and satellite resonances were observed. Data are also presented on polarization with colliding beams.
We search for the rare flavor-changing neutral current process B^{+}→K^{+}τ^{+}τ^{-} using data from the BABAR experiment. The data sample, collected at the center-of-mass energy of the ϒ(4S) resonance, corresponds to a total integrated luminosity of 424  fb^{-1} and to 471×10^{6}  BB[over ¯] pairs. We reconstruct one B meson, produced in the(More)