An unquenched lattice QCD calculation of the mass of the bottom quark
  We compute the b quark mass from dynamical lattice QCD with clover quarks. The calculation is done at a fixed lattice spacing with sea quark masses as low as half the strange quark mass. Our final result is m_b(m_b} = 4.25(2)(11) GeV, where the first error is statistical and the last error is the systematic uncertainty. 
UKQCD Collaboration:C. McNeile, C.Michael, and Gavin Thompson