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lambda-b baryon

American  
[lam-duh-bee bar-ee-on] / ˈlæm dəˈbi ˈbær iˌɒn /

noun

Physics.
  1. a protonlike baryon containing a b quark; a neutral baryon with a mass 11,000 times that of the electron and a mean lifetime of approximately 1.1 X 10 -12 seconds.