Lifetime measurement of charm mesons produced in π⁻p and pp interactions at 360 GeV/c

Abstract

Results are presented on charm meson lifetimes. The sample of charm particle decays was obtained by exposing the high resolution rapid cycling hydrogen bubble chamber (LEBC) coupled with the European Hybrid Spectrometer to π⁻ and p beams at 360 GeV/c ffrom the CERN SPS. The analysis of ∼850 k pictures has yielded 77 events containing a total of 60 charm decays. From these, an unbiased sample of 31 D decays (15± and 16 D⁰) is issued in the lifetime analysis. The measured mean lifetimes for D^± and D⁰ are (where the symbol D⁰ means D⁰ and $\text{D}$⁰):τ(D^±)=8.4^+3.5_−2.2 × 10⁻¹³sτ(D⁰)=4.1^+1.3_−0.9 ×10−13s. Three unambiguous examples of F^± decay have also been observed and the corresponding lifetime, based on 2 decays, is τ(F^±)=2.1 ^+3.6_−0.8 × 10 ⁻¹³s