Neutral Minimal Supersymmetric Standard Model Research Articles

Hadronic production of a MSSM Higgs boson with a pair of stops at the LHC

We present the next-to-leading order supersymmetric-QCD corrections to the production of a light neutral minimal supersymmetric standard model Higgs boson with a pair of supersymmetric scalar partners of the top quark at next-to-leading order at the LHC. We study the dependence of the lowest order total cross section on both the renormalization/factorization scale and the Higgs mass in the framework of minimal supergravity, taking the point SPS1a as a benchmark, for the numerical calculations. The renormalization/factorization scale dependence of the lowest order total cross section is strong. Including the next-to-leading order supersymmetric-QCD corrections significantly reduces and stabilizes the dependence of the lowest order total cross section on the renormalization/factorization scale.

Study of charged and neutral minimal supersymmetric standard model Higgs boson decays and measurement of tan β at the compact linear collider

The minimal supersymmetric extension of the standard model (MSSM) predicts the existence of new charged and neutral Higgs bosons. The pair creation of these new particles at the multi-TeV e + e − compact linear collider (CLIC), followed by decays into standard model particles, were simulated along with the corresponding background. High-energy beam-beam effects such as ISR, beamstrahlung and hadronic background were included. We have investigated the possibility of using the ratio between the number of events found in various decay channels to determine the MSSM parameter tan β and we have derived the corresponding statistical error from the uncertainties on the measured cross-sections and Higgs boson masses.

Charged and neutral minimal supersymmetric standard model Higgs boson decays and measurement of tan β at the compact linear collider

Charged and neutral minimal supersymmetric standard model Higgs boson decays and measurement of tan β at the compact linear collider

Determining supersymmetric parameters with dark matter experiments

In this paper, we explore the ability of direct and indirect dark matter experimentsto not only detect neutralino dark matter, but to constrain and measure theparameters of supersymmetry. In particular, we explore the relationship betweenthe phenomenological quantities relevant to dark matter experiments, suchas the neutralino annihilation and elastic scattering cross sections, and theunderlying characteristics of the supersymmetric model, such as the values ofμ (and the composition of the lightest neutralino),mA and tanβ. We explore a broad range of supersymmetric models and then focus on a smaller set of benchmarkmodels. We find that by combining astrophysical observations with collider measurements,μ could plausibly be constrained more tightly than it can be fromLarge Hadron Collider (LHC) data alone. In models in theA-funnel region of parameter space, we find that dark matter experiments could potentially determinemA toroughly ± 100 GeV, even when heavy neutral minimal supersymmetric standard model (MSSM) Higgs bosons(A,H1) cannot be observed at the LHC. The information provided by astrophysicalexperiments is often highly complementary to the information most easily ascertained atcolliders.

Implications of Direct Dark Matter Constraints for Minimal Supersymmetric Standard Model Higgs Boson Searches at the Tevatron

In regions of large tanbeta and small mAlpha, searches for heavy neutral minimal supersymmetric standard model (MSSM) Higgs bosons at the Tevatron are promising. At the same time, rates in direct dark matter experiments, such as CDMS, are enhanced in the case of large tanbeta and small mAlpha. As a result, there is a natural interplay between the heavy, neutral Higgs searches at the Tevatron and the region of parameter space explored by CDMS. We show that if the lightest neutralino makes up the dark matter of our universe, current limits from CDMS strongly constrain the prospects of heavy, neutral MSSM Higgs discovery at the Tevatron unless |mu| greater or approximately 400 GeV. The limits of CDMS projected for 2007 will increase this constraint to |mu| greater or approximately 800 GeV. If CDMS does observe neutralinos in the near future, however, it will make the discovery of Higgs bosons at the Tevatron far more likely.

Can there be a heavy sbottom hidden in three-jet data at CERN LEP?

A low-energy supersymmetry scenario with a light gluino of mass 12--16 GeV and light sbottom $({b}_{1})$ of mass 2--6 GeV has been used to explain the apparent overproduction of b quarks at the fermilab Tevatron. In this scenario the other mass eigenstate of the sbottom, i.e., ${b}_{2},$ is favored to be lighter than 180 GeV due to constraints from electroweak precision data. We survey its decay modes in this scenario and show that decay into a b quark and gluino should be dominant. Associated sbottom production at CERN LEP via ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{Z}^{*}\ensuremath{\rightarrow}{b}_{1}{b}_{2}^{*}+{b}_{1}^{*}{b}_{2}$ is studied and we show that it is naturally a three-jet process with a small cross section, increasingly obscured by a large standard model background for heavier ${b}_{2}.$ However we find that direct observation of a ${b}_{2}$ at the $5\ensuremath{\sigma}$ level is possible if it is lighter than 110--129 GeV, depending on the sbottom mixing angle $|\mathrm{cos}{\ensuremath{\theta}}_{b}|=0.30--0.45.$ We also show that ${b}_{2}$-pair production can be mistaken for production of neutral minimal supersymmetric standard model Higgs bosons in the channel ${e}^{+}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{h}^{0}{A}^{0}\ensuremath{\rightarrow}b\overline{b}b\overline{b}.$ Using searches for the latter we place a lower mass limit of 90 GeV on ${b}_{2}.$