SNO+

Abstract:

The evidence for supersymmetric dark matter annihilations presented by Strausz is based on both an analysis of data from the JACEE balloon-borne emulsion experiment which ignores systematic uncertainties and on a flawed analysis of background data from the Whipple gamma-ray observatory. When the latter analysis is corrected, it is found that there is no evidence for a peak in the 3.5–4.0 TeV regime in the Whipple data. Furthermore, were any such excess seen in the Whipple data, it would indicate a flux in gross conflict with the JACEE upper limits. It is therefore concluded that no evidence exists for an annihilation line due to supersymmetric dark matter. © 1998 The American Physical Society.

Abstract:

The average bottom-hadron and individual (Formula presented), (Formula presented), and (Formula presented) meson lifetimes have been determined using decays with a (Formula presented) in the final state. The data sample consists of 110 pb(Formula presented) of (Formula presented) collisions at (Formula presented) TeV collected by the CDF detector at the Fermilab Tevatron collider during 1992–1995. For the average lifetime of (Formula presented) hadrons decaying into (Formula presented)+X, we obtain (Formula presented) For the (Formula presented) and (Formula presented) meson lifetimes, we determine (Formula presented) (Formula presented) and (Formula presented) For the (Formula presented) meson lifetime, we find (Formula presented) ps. © 1998 The American Physical Society.

Abstract:

The lifetimes of the B- and B̄0 mesons are measured using the partially reconstructed semileptonic decays B̄ → Dl- v̄X, where D0 is either a D0 or D*+ meson. The data were collected by the CDF detector at the Fermilab Tevatron collider during 1992-1995 and correspond to about 110 pb-1 of pp collisions at √s = 1.8 TeV. We measure decay lengths and extract the lifetimes to be τ(B-) = 1.637±0.058-0.043+0.045 ps and τ(B̄0) = 1.474±0.039-0.051+0.052 ps, and the ratio of the lifetimes to be τ(B-)/τ(B̄0) = 1.110±0.056-0.030+0.033, where the first uncertainties are statistical and the second are systematic.

Abstract:

We present a measurement of the B⁰ ↔ B^-0 oscillation frequency using a flavor tagging method based on correlations of B meson flavor with the charge of other particles produced in pp collisions at √ s = 1.8 TeV. Such correlations are expected to arise from b quark hadronization and from B** decays. We partially reconstruct B mesons using the semileptonic decays B⁰ → l⁺D^(*)-X and B⁺ → l⁺D^-0X. From the oscillation frequency, we obtain the mass difference between the two B⁰ mass eigenstates, Δmd = 0.471^+0.078 -0.068(stat) ± 0.034(syst) ħps^-1, and measure the efficiency and purity of this flavor tagging method for both charged and neutral B mesons. © 1998 The American Physical Society.

Abstract:

From considering the effect of γ-γ interactions on recently observed TeV gamma-ray spectra, improved limits are set to the density of extragalactic infrared photons which are robust and essentially model independent. The resulting limits are more than an order of magnitude more restrictive than direct observations in the 0.025‒0.3 eV regime. These limits are used to improve constraints on radiative neutrino decay in the mass range above 0.05 eV and to rule out very massive objects as providing the dark matter needed to explain galaxy rotation curves. Lower bounds on the maximum distance which TeV gamma rays may probe are also derived. © 1998 The American Physical Society.