0000000000161537

AUTHOR

M. I. Adamovich

Spectra and correlations of Λ andΛ¯produced in 340-GeV/cΣ−+Cand 260-GeV/cn+Cinteractions

We have measured the production of strange baryons and antibaryons in 340-GeV/c Sigma /sup -/+C and 260-GeV/c n+C interactions. The single x/sub F/ distributions show the expected leading particle effect, and the single p/sub t//sup 2/ distributions show a distinct nonthermal behavior. The x/sub F/ distributions of Lambda - Lambda pairs indicate two different phase space distributions for the two coincident baryons. On the other hand two Lambda 's show identical distributions. Momentum conservation during the formation process may represent a significant source for the observed behavior.

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Search for the exoticΞ−−(1860)resonance in340GeV∕cΣ−-nucleus interactions

We report on a high statistics search for the ${\ensuremath{\Xi}}^{\ensuremath{-}\ensuremath{-}}(1860)$ resonance in ${\ensuremath{\Sigma}}^{\ensuremath{-}}$-nucleus collisions at $340\phantom{\rule{0.3em}{0ex}}\mathrm{GeV}∕c$. No evidence for this resonance is found in our data sample which contains 676000 ${\ensuremath{\Xi}}^{\ensuremath{-}}$ candidates above background. For the decay channel ${\ensuremath{\Xi}}^{\ensuremath{-}\ensuremath{-}}(1860)\ensuremath{\rightarrow}{\ensuremath{\Xi}}^{\ensuremath{-}}{\ensuremath{\pi}}^{\ensuremath{-}}$ and the kinematic range $0.15l{x}_{F}l0.9$ we find a $3\ensuremath{\sigma}$ upper limit for the production cross section of 3.1 and $3.5\phantom{\rul…

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Measurement of charmed-particle lifetimes and decay branching ratios

The lifetimes of charmed hadrons photoproduced in nuclear emulsion have been computed from a practically background-free sample of 44 neutral particle decays and 42 charged-particle decays including 27D±, 11Λc+, 1Ds+ and 3 ambiguous decays. The values obtained are τ(D0, bar D0) = (3.6-0.8+1.2 ± 0.7) 10-13 s, τ(D±) = (5.0-1.0+1.5 ± 1.9) 10-13 s, τ(Λc+) = = (2.3-0.6+0.9 ± 0.4) 10-13 s. Branching ratios of various decay topologies were also obtained.

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Associated Photoproduction Of Charmed Lambda(c)+ Baryons And Anti-d Mesons And Weak Decays Of The Lambda(c)+ Baryon

Data on associated photoproduction.

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Cross sections and some features of charm photoproduction at gamma energies of 20-70 GeV

Abstract We report some results on charm photoproduction at γ energies ranging from 20 to 70 GeV. 36 events with pairs of charmed particles have been found in emulsions. The computed total cross section is (230±57)nb/nucleon. Frequencies of different production channels and some distributions are presented and compared with the predictions from a photon-gluon fusion model with string fragmentation.

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Measurement of the Lifetime of Neutral Charmed Mesons

Abstract The lifetime of neutral charmed particles photoproduced in emulsion has been measured. The lifetime value presented here was obtained from a sample of 22D 0 mesons, 18 of which have their charmed partner seen in emulsion. The sample is essentially background-free. The result obtained is τ D 0 =(2.11 +1.21 -0.63 )×10 13 s The D 0 mass derived from 8 3C events is m D 0 = 1856 ± 36 MeV/ c 2 .

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Charged charmed particle lifetime

Abstract We present the lifetime values obtained for D ± and Λ c + , photoproduced in nuclear emulsion in the WA58 experiment. In photohadronic interactions, pairs of charmed particles are produced. Out of 20 charged charmed particles used for lifetime evaluation, 17 have their charmed partner seen emulsion, being then essentially free from any background. The values of the lifetime are τ D ± = (3.91 −1.25 +2.35 ) × 10 −13 s, τ Λ c + = (2.22 −0.75 +1.34 ) × 10 −13 s.

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Measurement of the polarization of $$\Lambda ^0 , \overline \Lambda ^0 , \Sigma ^ + $$ and ?? produced in a ?? beam of 330 GeV/c

The polarization of Lambda0 , AntiLambda0 , Sigma+ and Xi- inclusively produced in Sigma- induced interactions at 330 GeV has been measured in the experiment WA89 at CERN. This is the first measurement of polarization of baryons produced by a hyperon beam. No polarization of AntiLambda is observed, as was also the case in proton beam data. At transverse momenta of about 1~GeV/c Lambda0 and Sigma+ show little polarization, significantly lower than in the proton beam data, while Xi- have a polarization comparable to the polarization of Lambda0 produced in proton beams. The polarization of Lambda0, AntiLambda0, Sigma+ and Xi- inclusively produced in Sigma- induced interactions at 330 GeV has b…

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