Higgs boson width and couplings at high energy muon colliders with forward muon detection
Peiran Li, Zhen Liu, Kun-Feng Lyu
Abstract
We propose a novel method using the <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" display="inline"><a:mi>Z</a:mi><a:mi>Z</a:mi></a:math>-fusion channel and forward muon detection at high energy muon colliders to address the challenge of the Higgs coupling-width degeneracy. Our approach enables inclusive Higgs rate measurement to 0.75% at 10 TeV muon collider, breaking the coupling-width degeneracy. Results indicate the potential to refine Higgs coupling to subpercent levels and estimate its total width within (<c:math xmlns:c="http://www.w3.org/1998/Math/MathML" display="inline"><c:mrow><c:mrow><c:mo>−</c:mo><c:mn>0.41</c:mn><c:mo>%</c:mo></c:mrow></c:mrow></c:math>, <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" display="inline"><e:mrow><e:mo>+</e:mo><e:mn>2.1</e:mn><e:mo>%</e:mo></e:mrow></e:math>). Key insights include the effectiveness of forward muon tagging in signal-background separation despite broad recoil mass distribution due to muon energy reconstruction and beam energy spread. The study emphasizes the significance of muon rapidity coverage up to <g:math xmlns:g="http://www.w3.org/1998/Math/MathML" display="inline"><g:mrow><g:mo stretchy="false">|</g:mo><g:mi>η</g:mi><g:mo stretchy="false">(</g:mo><g:mi>μ</g:mi><g:mo stretchy="false">)</g:mo><g:mo stretchy="false">|</g:mo><g:mo><</g:mo><g:mn>6</g:mn></g:mrow></g:math>, enhancing measurement precision. Our findings highlight the unique capabilities of high energy lepton colliders for model-independent Higgs coupling determination and lay the groundwork for future advancements in muon collider technology and Higgs physics research. Published by the American Physical Society 2024