Charm Lifetime

Discovery of naked charm particles and lifetime differences among charm species using nuclear emulsion techniques innovated in Japan

This is a historical review of the discovery of naked charm particles and lifetime differences among charm species. These discoveries in the field of cosmic-ray physics were made by the innovation of nuclear emulsion techniques in Japan. A pair of naked charm particles was discovered in 1971 in a cosmic-ray interaction, three years prior to the discovery of the hidden charm particle, J/Psi, in ...

Review of Charm Lifetimes

A review of the latest experimental results on charm particle lifetimes is presented. The most significant update is that the D s lifetime is conclusively larger than the D 0 lifetime and signifies that W-exchange/W-annihilation contributions are large. Using new high statistics data on D → Kππ together with the D s lifetime and some assumptions, one can phenomenologically extract the strength ...

Perturbative QCD analysis of B ( B → Xlν̄ ) , charm yield 〈 n c 〉 in B decay

Perturbative QCD analysis of B(B → Xl¯ ν), charm yield n c in B decay, and τ (Λ b)/τ (B d) Abstract We apply perturbative QCD factorization theorems to inclusive heavy hadron decays, and obtain simultaneously a low semileptonic branching ratio B(B → Xl¯ ν) = 10.16%, the average charm yield n c = 1.17 per B decay, a small lifetime ratio τ (Λ b)/τ (B d) = 0.78, and the correct absolute decay widt...

6 v 1 1 0 N ov 1 99 8 Measurement of the D s Lifetime

We report the results of a precise measurement of the Ds meson lifetime based on 1662± 56 fully reconstructed Ds → φπ decays, from the charm hadroproduction experiment E791 at Fermilab. Using an unbinned maximum likelihood fit, we measure the Ds lifetime to be 0.518 ± 0.014 ± 0.007 ps. The ratio of the measured Ds lifetime to the world average D0 lifetime [1] is 1.25 ± 0.04. This result differs...

Charm Counting and Lifetime Differences in Inclusive Bottom Hadron Decays

SELEX: Recent Progress in the Analysis of Charm-Strange and Double-Charm Baryons

SELEX observes the Ω0c in three decay modes, namely Ω 0 c → Ω π, Ω0c → Ω πππ, and Ω0c → Ξ Kππ. The invariant mass distributions for these modes are shown in fig. 1. The total sample contains 107 ± 22 events, nearly half of them in Ω3π. At this moment we are working on the systematics of the mass and branching ratio measurements of these modes [2]. We use the Ωπ and Ω3π channels to determine the...