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Two types of large grain YBCO samples doped with tungsten oxide, one with platinum and the other without, were produced using a slow cooling process. Observations of the trapped magnetic flux density showed that the flux density of the W-doped, Pt-free samples did not change with W doping levels of up to 2.1 mol%. In contrast, the (W+Pt)-doped samples resulted in a monotonic improvement in trapped magnetic flux density as a function of W doping. Microstructure studies indicate that both types of samples contain profuse sub-micrometer deposits of a W-rich compound. The Pt-free samples contain (W{sub 0.4}Y{sub 0.6})BaO{sub 3} deposits while the (W+Pt)-doped samples contain deposits of a (W{sub 0.5}Pt{sub 0.5})YBa{sub 2}O{sub 6} compound. Both types of deposits are of essentially the same size and have comparable number density. The results are strikingly similar to an earlier experiment in which uranium doped, Pt-free, large grain YBCO also did not show any improvement in trapped magnetic flux density. The U-doped, Pt-free samples contain profuse sub-micrometer deposits of a (U{sub 0.4}Y{sub 0.6})BaO{sub 3} compound, which have been shown to be ferromagnetic. The inability of both the (W{sub 0.4}Y{sub 0.6})BaO{sub 3} and (U{sub 0.4}Y{sub 0.6})BaO{sub 3} sub-micrometer deposits to act as pinning centersmore » in self-field, suggest that this behavior is systematic.« less

The LVD particle astrophysics detector at Gran Sasso Laboratory is described and the status of the detector is presented.

The mass spectrum of dimuons produced by 400 GeV/c protons in Tungsten has been measured for masses greater than 7 GeV. A clear resonant signal of 2700 upsilons has been seen. The dependence of dimuon production on xF and pT has been determined for dimuon masses in the range 7.0 to 8.25 GeV as well as for masses in the upsilon region 8.25 to 9.75 GeV.

Measurements of missing mass (MM) spectra from π−p ⇒ (MM)−p at 8, 11, 13.5, and 16 GeV are reported. The MM mass range examined is 0 ≤ M2 ≤ 7.3 GeV2 with t (the proton four momentum transfer squared) in the interval 0.2 ≤ ∣t∣ ≤ 0.3 GeV2. Narrow resonances (R1, R2, R3, S, T, and U) with cross sections and widths reported by the CERN missing mass group are ruled out by the data. The cross sections d2σ/dtdM2 show evidence for triple factorizability of the form d2σdtdM2 ≃ D(PB)A(M2)G(P⊥2) where PB is the incident beam momentum,and P⊥2 is the perpendicular component of the detected proton's momentum with respect to the beam direction.