Precision Measurement of the Mass and Lifetime of the Ξ[0 over b] Baryon
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Aaij-2014-Precision measurement.pdf
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Author(s)
Counts, Ian Thomas Hunt
LHCb collaboration
Ilten, Philip J
Williams, Michael
Alternative Title
Precision Measurement of the Mass and Lifetime of the Ξ0b Baryon
Date Issued
July 2014
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Aaij, R., B. Adeva, M. Adinolfi, A. Affolder, Z. Ajaltouni, S. Akar, J. Albrecht, et al. “Precision Measurement of the Mass and Lifetime of the Ξ[0 over b] Baryon.” Physical Review Letters 113, no. 3 (July 2014).
Version
Final published version
Abstract
Using a proton-proton collision data sample corresponding to an integrated luminosity of 3 fb[superscript −1] collected by LHCb at center-of-mass energies of 7 and 8 TeV, about 3800 Ξ0b→Ξ+cπ−, Ξ+c→pK−π+ signal decays are reconstructed. From this sample, the first measurement of the Ξ0b baryon lifetime is made, relative to that of the Λ0b baryon. The mass differences M(Ξ0b)−M(Λ0b) and M(Ξ+c)−M(Λ+c) are also measured with precision more than 4 times better than the current world averages. The resulting values are
τΞ0bτΛ0b=1.006±0.018±0.010,M(Ξ0b)−M(Λ0b)=172.44±0.39±0.17 MeV/c2,M(Ξ+c)−M(Λ+c)=181.51±0.14±0.10 MeV/c2,
where the first uncertainty is statistical and the second is systematic. The relative rate of Ξ0b to Λ0b baryon production is measured to be
fΞ0bfΛ0bB(Ξ0b→Ξ+cπ−)B(Λ0b→Λ+cπ−)B(Ξ+c→pK−π+)B(Λ+c→pK−π+)=(1.88±0.04±0.03)×10−2,
where the first factor is the ratio of fragmentation fractions, b→Ξ0b relative to b→Λ0b. Relative production rates as functions of transverse momentum and pseudorapidity are also presented.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.113.032001
