A comparative study of flavour-sensitive observables in hadronic Higgs decays

Jet production from hadronic Higgs decays at future lepton colliders will have significantly different phenomenological implications than jet production via off-shell photon and <i>Z</i>-boson decays, owing to the fact that Higgs bosons decay to both pairs of quarks and gluons. We compute observables involving flavoured jets in hadronic Higgs decays to three partons at Born level including next-to-leading order corrections in QCD (i.e., up to <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:mrow><mml:mi>O</mml:mi> <mml:mo>(</mml:mo> <mml:msubsup><mml:mi>α</mml:mi> <mml:mtext>s</mml:mtext> <mml:mn>2</mml:mn></mml:msubsup> <mml:mo>)</mml:mo> <mml:mo>)</mml:mo></mml:mrow> </mml:math> . The calculation is performed in the framework of an effective theory in which the Higgs boson couples directly to gluons and massless <i>b</i>-quarks retaining a non-vanishing Yukawa coupling. For the energy of the leading and subleading flavoured jet, the angular separation and the invariant mass of the leading <i>b</i>- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mover><mml:mrow><mml:mi>b</mml:mi></mml:mrow> <mml:mrow><mml:mo>¯</mml:mo></mml:mrow> </mml:mover> </mml:math> pair, we contrast the results obtained in both Higgs-decay categories and using either of the infrared-safe flavoured jet algorithms flavour- <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"><mml:msub><mml:mi>k</mml:mi> <mml:mtext>T</mml:mtext></mml:msub> </mml:math> and flavour-dressing.