Linear Collider Physics Resource Book for Snowmass 2001 - Part 2: Higgs and Supersymmetry Studies

TL;DR

The paper surveys how a next-generation e+e- linear collider can illuminate the Higgs sector, focusing on SM-like and MSSM Higgs phenomenology with high luminosity and multiple center-of-mass energies. It argues that tens of thousands of Higgs events per year enable precision measurements of couplings, widths, branching ratios, and production mechanisms, while also probing non-standard Higgs scenarios and the MSSM Higgs spectrum, including decoupling and non-decoupling regimes. By linking precision electroweak constraints, naturalness considerations, and collider capabilities, the work outlines how LC measurements can discriminate SM-like Higgs behavior from extended Higgs sectors and test electroweak symmetry breaking dynamics. The study highlights the impact of LC options such as Giga-Z and gamma-gamma collisions in sharpening indirect probes of the Higgs sector and in exploring beyond-SM scenarios with high sensitivity.

Abstract

This Resource Book reviews the physics opportunities of a next-generation e+e- linear collider and discusses options for the experimental program. Part 2 reviews the possible experiments on Higgs bosons and supersymmetric particles that can be done at a linear collider.

Figures (6)

• Figure 3.1: The upper hambye and the lower quiros Higgs mass bounds as a function of the energy scale $\Lambda$ at which the Standard Model breaks down, assuming $m_t=175$ GeV and $\alpha_s(m_Z)=0.118$. The shaded areas above reflect the theoretical uncertainties in the calculations of the Higgs mass bounds. This figure is taken from Riesselmann.
• Figure 3.2: Branching ratios of the dominant decay modes of the Standard Model Higgs boson. These results have been obtained with the program HDECAY hdecay, and include QCD corrections beyond the leading order.
• Figure 3.3: Main production processes for Higgs production in $e^+e^-$ annihilation. (a) Higgsstrahlung. (b) $WW$ fusion.
• Figure 3.4: Cross sections for Higgsstrahlung ($e^+e^-\to Zh_{\rm SM}$) and Higgs production via $W^+W^-$ fusion ($e^+e^-\to \nu\overline{\nu} h_{\rm SM}$) and $ZZ$ fusion ($e^+e^-\to e^+e^-h_{\rm SM}$) as a function of $m_{h_{\rm SM}}$ for two center-of-mass energies, $\sqrt{s}=500$ and 800 GeV Accomando:1998wt.
• Figure :