Determination of the average lifetime of bottom hadrons

We have determined the average lifetime of hadrons containing b quarks produced in e⁺e^? annihilation to be

$\text{τ}\text{B}\text{=}\text{1.83}\text{+0.83}\text{+0.37}\text{?}\text{?0.34}\text{×10}{}^{\mathrm{?12}}\text{s}$

. Our method uses charged decay products from both non-leptonic and semileptonic decay modes.     

On the Bullwhip Avoidance Phase: The Synchronised Supply Chain

The aim of this paper is to analyse the operational response of a Synchronised Supply Chain (SSC). To do so, first a new mathematical model of a SSC is presented. An exhaustive Latin Square design of experiments is adopted in order to perform a boundary variation analysis of the main three parameters of the periodic review smoothing (S, R) order-up-to policy: i.e., lead time, demand smoothing forecasting factor, and proportional controller of the replenishment rule. The model is then evaluated under a variety of performance measures based on internal process benefits and customer benefits. The main results of the analysis are: (I) SSC responds to violent changes in demand by resolving bullwhip effect and by creating stability in inventories under different parameter settings and (II) in a SSC, long production–distribution lead times could significantly affect customer service level. Both results have important consequences for the design and operation of supply chains.     

The problem of the relation between double pomeron exchange in inclusive and exclusive experiments

The pionization region of the inclusive single-particle spectrum is accounted for by double pomeron exchange in the absorptive part of a six-point amplitude. In this paper a multiperipheral model for the six-point amplitude with double pomeron exchange is used for continuation by crossing and analyticity to the physical region of the exclusive two particle → four particle production process. The cross section for π^? p → π^?(π⁺π^?)p in the double-Regge region is then calculated and compared with the experimental analysis of Lipes, Zweig and Robertson which sets an upper bound to the strength of the double pomeron exchange coupling. This upper bound, coupled with the model for continuation to the inclusive cross section, is shown to give too small a magnitude for the double pomeron exchange in the pionization region. Further avenues for investigation are discussed.     

Off-shell NN annihilation studied in π+p interactions at 8 and 16 GeV/c

Interactions in which the baryon is emitted forwards in the c.m.s. are studied in 8 and 16 GeV/cπ⁺p collisions. These interactions are interpreted as representing baryon exchange. The properties of such off-shell $\text{N}$N annihilation events are studied. It is found that the multiplicity distribution of the multi-pion system as a function of the effective mass for events with |u_pp| < 1 GeV² is the same as for real $\text{N}\text{N}$ annihilations.     

Rapidity density distributions in antiproton-proton collisions

Data on the density of charged particles in rapidity space for annihilation and non-annihilation p?p interactions at 7.3 and 12 GeV/c are reported. It is shown that the central rapidity density for non-annihilation processes is a simple linear function of $\text{ln}\text{(}\text{s}\text{)}$ from these low energies up to p?p collider energies ($\text{s}\text{=540}\text{GeV}$). Significant differences in density distributions for p?p and e^?e⁺ annihilations at comparable energies are found.     

Partial-wave analysis of the low-mass (π+π−p) system produced in K−p interactions at 4.2 GeV/c

A partial-wave analysis of the low-mass (π⁺π^?p) system produced in the reaction K^?p → K^?(π⁺π^?p) at 4.2 GeV/c incident momentum is performed in order to study the two (π⁺π^?p) enhancements around 1500 and 1700 MeV. It is found that the low-mass (π⁺π^?p) system can be described using the spin-parity states $\text{J}{}^{\mathrm{P}}\text{=}\text{1}\text{2}{}^{\mathrm{+}}\text{,}\text{3}\text{2}{}^{\mathrm{?}}$ and $\text{5}\text{2}{}^{\mathrm{+}}$ only. In the 1500 MeV region contributions are observed from the $\text{1}\text{2}{}^{\mathrm{+}}$ wave decaying into p? and the $\text{3}\text{2}{}^{\mathrm{?}}$ wave decaying into Δ⁺⁺π^?; in the 1700 MeV region contributions are found from the $\text{1}\text{2}{}^{\mathrm{+}}$ wave decaying into Δ⁺⁺π^?, the $\text{3}\text{2}{}^{\mathrm{?}}$ wave decaying into p?, and the $\text{5}\text{2}{}^{\mathrm{+}}$ wave decaying into p?.     

First direct observation of the decay of neutral charmed particles produced by neutrinos in emulsion

Three examples of the production in emulsion by neutrinos and subsequent decay of neutral short-lived particles are reported. The flight times are ≈ 10^?13s, similar in order of magnitude to those previously determined for charged charmed particles in the same experiment.     

A study of the reactions π−p → K1X, K1Σ and K1Y11(1385) at 3.93 GeV/c

We have investigated the final states K¹⁰(890)Σ, $\text{K}{}^{10}\text{(890)Σ}{}^0$ and K¹⁰(890) Y₁¹⁰(1385) produced in π^?p interactions at 3.93 GeV/c. We present the differential cross sections and spin density matrix elements for the resonances as functions of momentum transfer, as well as the gL and Σ⁰ polarizations. The Σ⁰ polarization is found to be positive and maximal. An amplitude analysis is performed for the K¹ Λ and $\text{K}{}^1\text{Σ}{}^0$ reactions, and it is found that one natural parity transversity amplitude is dominant for the latter.     

Inclusive production of muon pairs and vector mesons in π−N collisions at momenta 27 and 40 GeV/c

Experimental results on the investigation of inclusive production of muon pairs and vector mesons (J/ψ, ?⁰(ω)) in π^?N collisions at 27 and 40 GeV/c momenta are presented.     

Observation of the decay τ → πv

The decay of the heavy lepton τ into πv has been established using the magnetic detector PLUTO. The branching ratio is determined to be BR(τ→πv)=(9.0 ± 2.9)% with an additional systematic uncertainty of 2.5%. This value is in good agreement with the theoretical prediction.