Determination of the α parameter for the decay Ξ− → Λπ−

The α parameter for Ξ^? → Λπ^? decay has been determined to be α_Ξ^?=?0.462 ± 0.015, from a sample of 1.5 × 10⁵ events recorded in the CERN SPS hyperon beam. This value is 2.5 standard deviations higher than the current world average.     

First observation ofΩ * resonances

In a experiment at the CERN SPS charged hyperon beam using incident Ξ^?, we have obtained evidence for the production of two Ω^* resonances decaying into Ξ^?π⁺ K ^?, with the following parameters:M ₁=2251±12,Γ ₁=48±20 MeV/c², 78 ±23 events, andM ₂=2284±12,Γ ₂=26±23 MeV/c² 45±10 events. The first state is also observed as a 4.2σ effect in a subsample which contains an additionalK ⁺ orK ⁰ in the final state. Production cross sections and branching ratios to Ξ^* K ^? and Ξ^? K ^* are presented.     

Structure of final states with a high transverse momentum π0 in proton-proton collisions

We present a study of the final state structure in proton-proton collisions (√s = 53 GeV) where a large transverse momentum π⁰ (p_t > 2 GeV/c) is produced at an angle of 90°. Charged secondaries have been detected and momentum analysed in the split field magnet detector at the CERN Intersecting Storage Rings. The large angular coverage of this detector extends over ±2.5 units of rapidity and ±30° of azimuth with respect to the trigger π⁰, both towards and away from it. In each of these directions, where we observe similar strong correlations, we present charged particle distributions, in rapidity and momentum. In the hemisphere containing the trigger π⁰ we have measured the cross section for inclusive production of large transverse momentum ?^± mesons. In the opposite hemisphere the data exhibit several features predicted by hard scattering quark-parton models: coplanarity and short-range rapidity correlation for the large transverse momentum secondaries as well as a transverse momentum sharing distribution similar to that observed in deep inelastic electro-production and in e⁺e^? collisions.     

A new upper limit for the branching ratio (Ξ− → nπ−)(Ξ− → Λπ−)

From a sample of 735 000 Ξ^? decays, we have obtained a new upper limit for the branching ratio $\text{(Ξ}{}^{\mathrm{?}}\text{→}\text{n}\text{π}{}^{\mathrm{?}}\text{)}\text{(Ξ}{}^{\mathrm{?}}\text{→ Λπ}{}^{\mathrm{?}}\text{)}$. The result is 1.9 × 10^?5 at the 90% confidence level.     

Large transverse momentum jets in high-energy proton-proton collisions

We present a study of pp collisions producing large transverse momentum π⁰'s. The data collected at c.m. energies √s=52.4 and 62.7 GeV, give evidence for a two-jet structure. The fragmentation of the jets is studied and correlations between the two jets are investigated. Results are compared with e⁺e^? and νp data.     

Measurement of single electron production up to 45 GeV/c transverse momentum at the CERN ISR

The production of single electrons of transverse momentum between 1.8 and 45 GeV/c is measured in pp collisions at √s=53 and 63 GeV. Contributions from ?,ω,?,ψ, ?, DD? and Drell-Yan pairs are deduced from measurements in the same apparatus.     

Peroxiredoxin-1 from the Human Hookworm Ancylostoma ceylanicum Forms a Stable Oxidized Decamer and Is Covalently Inhibited by Conoidin A

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Regeneration amplitude of KS0 from KL0 in carbon

We have measured the transmission regeneration amplitude for carbon. The invariant amplitude $\text{[?(0) ?}\text{?}\text{(0)]/P}$ varies from 5.909 ± 0.066 mb at 4.5 GeV/c to 3.933 ± 0.152 mb at 9.5 GeV/c. The results agree with optical model calculations using measured kaon-nucleon total cross sections. The data also provide a value for the ω trajectory intercept α_ω(0) = 0.42 ± 0.04.     

A measurement of the branching ratio∑ +→pγ/∑ +→pπ 0⋆

In an experiment performed in the CERN SPS hyperon beam we have obtained a value for the branching ratio $${{\Sigma ^ + \to p\gamma } \mathord{\left/ {\vphantom {{\Sigma ^ + \to p\gamma } {\Sigma ^ + \to p\pi }}} \right. \kern-\nulldelimiterspace} {\Sigma ^ + \to p\pi }}^0 of\left( {2.46_{ - 0.35}^{ + 0.30} } \right) \times 10^{ - 3} ,$$ corresponding to a branching ratio $${{\Sigma ^ + \to p\gamma } \mathord{\left/ {\vphantom {{\Sigma ^ + \to p\gamma } {\Sigma ^ + \to all}}} \right. \kern-\nulldelimiterspace} {\Sigma ^ + \to all}}of\left( {1.27_{ - 0.18}^{ + 0.16} } \right) \times 10^{ - 3} .$$ This result is discussed in the context of present understanding of hyperon radiative decays.