The results from experiments to determine the density and surface tension of zinc-molybdenum (0.597 wt %)-aluminium (0.560 wt %)-magnesium (0.249 wt %) alloy are presented. The obtained results are ...discussed.
The balance function is a new observable based on the principle that charge is locally conserved when particles are pair produced. Balance functions have been measured for charged particle pairs and ...identified charged pion pairs in Au + Au collisions at √(sNN) = 130 GeV at the Relativistic Heavy Ion Collider using STAR. Balance functions for peripheral collisions have widths consistent with model predictions based on a superposition of nucleon-nucleon scattering. Widths in central collisions are smaller, consistent with trends predicted by models incorporating late hadronization.
The STAR Collaboration reports the first observation of exclusive ρ⁰ photoproduction, AuAu→AuAuρ⁰, and ρ⁰ production accompanied by mutual nuclear Coulomb excitation, AuAu→Au*Au*ρ⁰, in ...ultraperipheral heavy-ion collisions. The ρ0 have low transverse momenta, consistent with coherent coupling to both nuclei. The cross sections at √(sNN)=130 GeV agree with theoretical predictions treating ρ⁰ production and Coulomb excitation as independent processes.
Inclusive transverse momentum distributions of charged hadrons within 0.2<pT <6.0 GeV/c have been measured over a broad range of centrality for Au+Au collisions at √(sNN)=130 GeV. Hadron yields are ...suppressed at high pT in central collisions relative to peripheral collisions and to a nucleon-nucleon reference scaled for collision geometry. Peripheral collisions are not suppressed relative to the nucleon-nucleon reference. The suppression varies continuously at intermediate centralities. The results indicate significant nuclear medium effects on high-pT hadron production in heavy-ion collisions at high energy.
We report STAR results on the azimuthal anisotropy parameter v₂ for strange particles K0s, Λ, and Λ⁻ at midrapidity in Au+Au collisions at √(sNN)=130 GeV at the Relativistic Heavy Ion Collider. The ...value of v₂ as a function of transverse momentum, pt, of the produced particle and collision centrality is presented for both particles up to pt~3.0 GeV/c. A strong pt dependence in v₂ is observed up to 2.0 GeV/c. The v₂ measurement is compared with hydrodynamic model calculations. The physics implications of the pt integrated v₂ magnitude as a function of particle mass are also discussed.
We report the first measurement of strange (Λ) and antistrange (Λ¯¯¯) baryon production from √(sNN)=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and ...transverse mass distributions at midrapidity are presented as a function of centrality. The yield of Λ and Λ¯¯¯ hyperons is found to be approximately proportional to the number of negative hadrons. The production of Λ¯¯¯ hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models alone.
We report the first measurement of strange (Λ) and antistrange (Λ¯¯¯) baryon production from √(sNN)=130 GeV Au+Au collisions at the Relativistic Heavy Ion Collider (RHIC). Rapidity density and ...transverse mass distributions at midrapidity are presented as a function of centrality. The yield of Λ and Λ¯¯¯ hyperons is found to be approximately proportional to the number of negative hadrons. The production of Λ¯¯¯ hyperons relative to negative hadrons increases very rapidly with transverse momentum. The magnitude of the increase cannot be described by existing hadronic string fragmentation models alone.
The large droplet method (in a graphite cup) was used to study the temperature dependences of density ρ and surface tension σ of bismuth lead (∼10% Bi) in the temperature range from its melting point ...to ∼1050 K in a helium atmosphere. It was found that the ρ(
T
) and σ(
T
) dependences are close to linear and decrease with temperature. The sessile drop method (on a substrate) was used to study temperature dependences of the angle θ of wetting new high-nickel and ferritic-martensitic pressure-vessel steels by bismuth lead in the above temperature range in a vacuum (0.01 Pa). It is shown that the steel substrates alloyed with aluminum are not wetted in the temperature range studied.
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