Theoretical predictions for inclusive <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>B</mml:mi><mml:mo stretchy="false">→</mml:mo><mml:msub><mml:mi>X</mml:mi><mml:mi>u</mml:mi></mml:msub><mml:mi>τ</mml:mi><mml:mover accent="true"><mml:mi>ν</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover></mml:math> decay

With the expected large increase in datasets, previously not measured decays will be studied at Belle II. We derive standard model predictions for $B\ensuremath{\rightarrow}{X}_{u}\ensuremath{\tau}\overline{\ensuremath{\nu}}$ decay rate and distributions. The region lepton energy spectrum where higher-dimension operators local operator product expansion need to resummed into $b$-quark light-cone distribution function is a significantly greater fraction of phase space than massless leptons. finite $\ensuremath{\tau}$ mass has novel effect shifting squeezing how enters spectrum. also new polarization.