Model-independent measurement of the e+^{{+}} e^{-} \rightarrow HZ cross section at a future e+^{{+}} e^{-} linear collider using hadronic Z decays

Sep 9, 2015
14 pages
Published in:
  • Eur.Phys.J.C 76 (2016) 2, 72
  • Published: Feb 13, 2016
e-Print:
Report number:
  • CH-HEP-2015-07

Citations per year

201520182021202420250246810
Abstract: (Springer)
A future e+e\mathrm{e}^{+} \mathrm{e}^{-} collider, such as the ILC or CLIC, would allow the Higgs sector to be probed with a precision significantly beyond that achievable at the High-Luminosity LHC. A central part of the Higgs programme at an e+e\mathrm{e}^{+} \mathrm{e}^{-} collider is the model-independent determination of the absolute Higgs couplings to fermions and to gauge bosons. Here the measurement of the e+eHZ\mathrm{e}^{+} \mathrm{e}^{-} \rightarrow \mathrm{H} \mathrm{Z} Higgsstrahlung cross section, using the recoil mass technique, sets the absolute scale for all Higgs coupling measurements. Previous studies have considered \upsigma (\mathrm{e}^{+} \mathrm{e}^{-} \rightarrow \mathrm{H} \mathrm{Z}) with Z+\mathrm{Z} \rightarrow {\ell } ^{+} {\ell } ^{-} , where {\ell } = \mathrm{e},\,{\upmu } . In this paper it is shown for the first time that a near model-independent recoil mass technique can be extended to the hadronic decays of the Z\mathrm{Z} boson. Because the branching ratio for Zqq\mathrm{Z} \rightarrow \mathrm{q} {\overline{\mathrm{q}}} is approximately ten times greater than for Z+\mathrm{Z} \rightarrow {\ell } ^{+} {\ell } ^{-} , this method is statistically more powerful than using the leptonic decays. For an integrated luminosity of 500  fb1\text {fb}^{-1} at a centre-of-mass energy of s=350 GeV\sqrt{s} =350~\text {GeV} at CLIC, \upsigma (\mathrm{e}^{+} \mathrm{e}^{-} \rightarrow \mathrm{H} \mathrm{Z}) can be measured to ±1.8 %{\pm }1.8~\% using the hadronic recoil mass technique. A similar precision is found for the ILC operating at s=350 GeV\sqrt{s} =350~\text {GeV} . The centre-of-mass dependence of this measurement technique is discussed, arguing for the initial operation of a future linear collider at just above the top-pair production threshold.
Note:
  • 14 pages, 10 figures
  • electron positron: annihilation
  • Higgs particle: electroproduction
  • Z0: associated production
  • mass: recoil
  • coupling: Higgs
  • Higgs particle: coupling
  • coupling: Yukawa
  • recoil: hadronic
  • threshold: production
  • Z0: hadronic decay