COSMIC RAY'S DATA OF MEAN LIVES OF D MESONS AND ∑_c⁺ BARYON

Abstract: A sieve-comparison method is proposed according to the accelerator's data ofcharmed particles to identify the properties of the X-particles observed in high energycosmic ray interactions. The principles of the sieve-comparison method are as follows: 1. The cross section σ_{x<span style="border-top: 1px solid; padding-top: 0px;">x</span>} of these X-particles produced in pair should be appro-ximately equal to the cross section σ_DD of D meson produced in pair. 2. The empirical selection rules of the decay in weak interaction from the experi-ments using accelerators should be suitable to these X-particles: charmed number|Δc|=1, strangeness ΔS=Δc=1, isospin |ΔI₃| =1→|ΔI|=1, (nonlepton). 3. The charge and the decay channel should be in coincidence with the empiricalselection rule, Q=I₃+(B+C)/2 for each X particle and it's transverse momentumshould be large (P_⊥=400-1000MeV/c). 4. For the same kind of the particles, their width-mass ratio (г/M) should beof the same order of magnitude. All the X particles observed so far in emulsion chambers have been analyzedaccording to this method, it is found that they are possibly D, <span style="border-top: 1px solid; padding-top: 0px;">D</span>, Σ_c⁺, Λ_c⁺, E_cc⁺, (seetable I). Inversely, we may estimate the mean lives and masses of new charmed parti-cles observed in accelerator's experiments according to cosmic ray's data. The resultsare shown in table II.