Measurement of D0 Azimuthal Anisotropy at Midrapidity in Au + Au Collisions at √ s N N = 200 GeV

We report the first measurement of the elliptic anisotropy (v2) of the charm meson D0 at midrapidity (|y

Measurement of the 7Be(p, γ)8B reaction cross section at low energies

The absolute total cross section for the reaction 7Be(p, γ)8B has been measured for Ec.m.=117-1230 keV by detecting the delayed α particles following the 8B β decay. Two independent methods have been used to determine the areal density of the 7Be target. The inferred zero-energy S factor from the present experiment is S17(0)=0.0216±0.0025 keV b. This value reduces the predicted 37Cl solar-neutrino capture rate by ∼25%

Absolute cross section for 7Li(d,p)8Li and solar neutrino capture rates

The absolute total cross section for the 7Li(d,p)8Li reaction has been measured between 0.60 and 1.2 MeV by counting the beta-delayed alpha particles from 8Be*. The cross section at the peak of the 0.77-MeV resonance was measured to be 148±12 mb in good agreement with the new measurement of Elwyn et al. but disagreeing with several previous experiments. The effects of changes in this cross section on the calculation of solar neutrino captures rates is discussed

Proton capture cross section of 7Be and the flux of high energy solar neutrinos

The low energy cross section for the 7Be(p, γ)8B reaction has been measured by detecting the delayed α particles from the 8B beta decay. Detailed discussion is presented of the analysis of the radioactive 7Be target including the use of two independent methods to determine the 7Be areal density. The direct capture part of the cross section is subtracted from the total cross section to deduce resonance parameters for the 1+ first excited state in 8B. The zero-energy astrophysical S factor inferred from the present experiment is compared with previous values. The effect on the 37Cl solar neutrino capture rate, predicted by the standard solar model, is also discussed

Measurement of D0 Azimuthal Anisotropy at Midrapidity in Au + Au Collisions at √ s N N = 200 GeV

We report the first measurement of the elliptic anisotropy (v2) of the charm meson D0 at midrapidity (|y

A search for two body muon decay signals

Lepton family number violation is tested by searching for $\mu^+\to e^+X^0$ decays among the 5.8$\times 10^8$ positive muon decay events analyzed by the TWIST collaboration. Limits are set on the production of both massless and massive $X^0$ bosons. The large angular acceptance of this experiment allows limits to be placed on anisotropic $\mu^+\to e^+X^0$ decays, which can arise from interactions violating both lepton flavor and parity conservation. Branching ratio limits of order $10^{-5}$ are obtained for bosons with masses of 13 - 80 MeV/c$^2$ and with different decay asymmetries. For bosons with masses less than 13 MeV/c$^{2}$ the asymmetry dependence is much stronger and the 90% limit on the branching ratio varies up to $5.8 \times 10^{-5}$. This is the first study that explicitly evaluates the limits for anisotropic two body muon decays.Comment: 7 pages, 5 figures, 2 tables, accepted by PR

Parton energy loss limits and shadowing in Drell-Yan dimuon production

A precise measurement of the ratios of the Drell-Yan cross section per nucleon for an 800 GeV/c proton beam incident on Be, Fe and W targets is reported. The behavior of the Drell-Yan ratios at small target parton momentum fraction is well described by an existing fit to the shadowing observed in deep-inelastic scattering. The cross section ratios as a function of the incident parton momentum fraction set tight limits on the energy loss of quarks passing through a cold nucleus

Measurement of Inverse Pion Photoproduction at Energies Spanning the N(1440) Resonance

Differential cross sections for the process pi^- p -> gamma n have been measured at Brookhaven National Laboratory's Alternating Gradient Synchrotron with the Crystal Ball multiphoton spectrometer. Measurements were made at 18 pion momenta from 238 to 748 MeV/c, corresponding to E_gamma for the inverse reaction from 285 to 769 MeV. The data have been used to evaluate the gamma n multipoles in the vicinity of the N(1440) resonance. We compare our data and multipoles to previous determinations. A new three-parameter SAID fit yields 36 +/- 7 (GeV)^-1/2 X 10^-3 for the A^n_1/2 amplitude of the P_11.Comment: 14 pages, 8 figures, submitted to PR