标题： 强子Z衰变中Σ和Λ(1520)的产生 显示英文标题

标题： Inclusive Sigma- and Lambda(1520) production in hadronic Z decays

摘要： 在强子Z玻色子衰变中Sigma-和Lambda(1520)的产生已被LEP上的DELPHI探测器测量。 Sigma-直接在DELPHI微顶点探测器中作为带电轨迹被重建，并通过其Sigma→n pi衰变导致Sigma-和pi轨迹之间的拐点来识别。 Lambda(1520)共振的重建很大程度上依赖于圆柱形环形成像切连科夫探测器的粒子识别能力和TPC的电离损失测量。 对这两种粒子都测量了其包含产生谱。 测量得到的产生率分别为 <N_{西格玛}/N_{Z}^{有}> = 0.081 +/- 0.002 +/- 0.010, <N_{Lambda(1520)}/N_{Z}^{有}> = 0.029 +/- 0.005 +/- 0.005. Lambda(1520)的产生率表明，大量稳定重子可能来自轨道激发的重子态。 结果表明，Z玻色子衰变中的重子产生率遵循与同位旋、奇异数和粒子质量相关的普遍现象学规律。 显示英文摘要

摘要： Production of Sigma- and Lambda(1520) in hadronic Z decays has been measured using the DELPHI detector at LEP. The Sigma- is directly reconstructed as a charged track in the DELPHI microvertex detector and is identified by its Sigma -> n pi decay leading to a kink between the Sigma- and pi-track. The reconstruction of the Lambda(1520) resonance relies strongly on the particle identification capabilities of the barrel Ring Imaging Cherenkov detector and on the ionisation loss measurement of the TPC. Inclusive production spectra are measured for both particles. The production rates are measured to be <N_{Sigma-}/N_{Z}^{had}> = 0.081 +/- 0.002 +/- 0.010, <N_{Lambda(1520)}/N_{Z}^{had}> = 0.029 +/- 0.005 +/- 0.005. The production rate of the Lambda(1520) suggests that a large fraction of the stable baryons descend from orbitally excited baryonic states. It is shown that the baryon production rates in Z decays follow a universal phenomenological law related to isospin, strangeness and mass of the particles.