Measuring hadronic Higgs boson branching ratios at future lepton colliders
Max Knobbe, Frank Krauss, Daniel Reichelt, S. Schumann
Abstract
Abstract We present a novel strategy for the simultaneous measurement of Higgs-boson branching ratios into gluons and light quarks at a future lepton collider operating in the Higgs-factory mode. Our method is based on template fits to global event-shape observables, and in particular fractional energy correlations, thereby exploiting differences in the QCD radiation patterns of quarks and gluons. In a constrained fit of the deviations of the light-flavour hadronic Higgs-boson branching ratios from their Standard Model expectations, based on an integrated luminosity of $$5\,\text {ab}^{-1}$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>5</mml:mn> <mml:mspace/> <mml:msup> <mml:mtext>ab</mml:mtext> <mml:mrow> <mml:mo>-</mml:mo> <mml:mn>1</mml:mn> </mml:mrow> </mml:msup> </mml:mrow> </mml:math> , we obtain $$68\%$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mn>68</mml:mn> <mml:mo>%</mml:mo> </mml:mrow> </mml:math> confidence level limits of $$\mu _{gg}=1 \pm 0.05$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>μ</mml:mi> <mml:mrow> <mml:mi>gg</mml:mi> </mml:mrow> </mml:msub> <mml:mo>=</mml:mo> <mml:mn>1</mml:mn> <mml:mo>±</mml:mo> <mml:mn>0.05</mml:mn> </mml:mrow> </mml:math> and $$\mu _{q\bar{q}}<21$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msub> <mml:mi>μ</mml:mi> <mml:mrow> <mml:mi>q</mml:mi> <mml:mover> <mml:mrow> <mml:mi>q</mml:mi> </mml:mrow> <mml:mrow> <mml:mo>¯</mml:mo> </mml:mrow> </mml:mover> </mml:mrow> </mml:msub> <mml:mo><</mml:mo> <mml:mn>21</mml:mn> </mml:mrow> </mml:math> .