[Paper Review] Combining Supersymmetric Dark Matter with Recent Accelerator Data

A.B. Lahanas, D.V. Nanopoulos+1 more|ArXiv.org|Dec 10, 2001

Particle physics theoretical and experimental studies3 citations

TL;DR

This paper combines constraints from the E821 muon g-2 experiment, LEP Higgs mass bounds, and cosmological dark matter data within the Constrained Minimal Supersymmetric Standard Model (CMSSM). It shows that the g-μ-2 discrepancy limits the lightest neutralino (LSP) mass to ≤200 GeV (1σ) or ≤350 GeV (2σ), while the spin-independent neutralino-nucleon cross section is constrained to 10⁻¹⁰–10⁻⁸ pb, making CMSSM a viable target for direct dark matter detection and future colliders like the LHC or 1.2 TeV e⁺e⁻ linear colliders.

ABSTRACT

In the framework of the Constrained Minimal Supersymmetric Standard Model we discuss the impact of the recent experimental information, especially from the E821 Brookhaven experiment on $g_μ-2$ along with the light Higgs boson mass bound from LEP, in delineating regions of the parameters which are consistent with cosmological data. The effect of these to the Dark Matter direct searches is also discussed.

Motivation & Objective

• To assess the viability of the Constrained Minimal Supersymmetric Standard Model (CMSSM) as a dark matter candidate by combining recent high-energy and cosmological data.
• To determine how the E821 muon g-2 anomaly and LEP Higgs mass bound constrain the CMSSM parameter space.
• To evaluate the detectability of supersymmetric dark matter in direct detection experiments and future colliders.
• To identify the regions of parameter space where the neutralino relic density matches cosmological observations (ΩDMh² = 0.13 ± 0.05).

Proposed method

• Uses the Constrained Minimal Supersymmetric Standard Model (CMSSM) as the theoretical framework for parameter space scanning.
• Applies the E821 Brookhaven experiment's measurement of the anomalous magnetic moment of the muon (δαμ = 43(16)×10⁻¹⁰) as a key constraint.
• Incorporates the LEP lower bound on the light Higgs boson mass (mh > 113.5 GeV) to exclude unphysical regions.
• Imposes cosmological constraints on the neutralino relic density (Ωχh² = 0.13 ± 0.05) to identify viable dark matter candidates.
• Calculates the spin-independent neutralino-nucleon scattering cross section (σscalar) using a random sample of CMSSM points.
• Performs Monte Carlo sampling to map the parameter space and assess compatibility with experimental bounds from CDMS and DAMA.

Experimental results

Research questions

• RQ1 What regions of the CMSSM parameter space are consistent with the E821 muon g-2 measurement and cosmological dark matter density?
• RQ2 How do the LEP Higgs mass bound and the g-μ-2 anomaly jointly constrain the mass and composition of the lightest neutralino (LSP)?
• RQ3 What is the predicted range of the spin-independent neutralino-nucleon scattering cross section in CMSSM, and how does it compare to direct detection sensitivities?
• RQ4 Can the CMSSM be discovered at the LHC or future e⁺e⁻ linear colliders, and what energy thresholds are required?

Key findings

• The E821 g-μ-2 result restricts the lightest neutralino mass to a maximum of 200 GeV at 1σ confidence level and up to 350 GeV at 2σ confidence level.
• The spin-independent neutralino-nucleon cross section is constrained to a range of 10⁻¹⁰ pb to 10⁻⁸ pb, with the lower bound increased by one order of magnitude due to g-μ-2 constraints.
• The maximum cross section of 10⁻⁸ pb occurs in the large tanβ regime, where pseudo-scalar Higgs exchange dominates annihilation and enhances direct detection signals.
• Coannihilation processes allow cosmologically viable LSP masses up to 500 GeV when g-μ-2 constraints are relaxed, but the E821 data strongly suppress such high masses.
• The LHC can discover CMSSM signals, but a 1.2 TeV center-of-mass energy is required for e⁺e⁻ linear colliders to detect CMSSM in chargino or tau sneutrino final states.
• The combination of g-μ-2, Higgs mass, and cosmological data significantly reduces the viable CMSSM parameter space, enhancing testability at future experiments.