The Reach of Fermilab Tevatron Upgrades for SU(5) Supergravity Models with Non-universal Gaugino Masses

Abstract

We explore the reach of luminosity upgrades of the Fermilab Tevatron collider for SU(5) supergravity models in which non-universal GUT-scale gaugino masses arise via a vacuum expectation value for the auxiliary component of a superfield that transforms as a 24, 75 or 200 dimensional representation of SU(5). This results in a different pattern of sparticle masses and mixing angles from what is expected in the minimal supergravity model (mSUGRA) with universal GUT scale gaugino masses. We find that the resulting signal cross sections, and hence the reach of the Tevatron, are sensitive to the gaugino masses at the GUT scale. In the 24 model, the large splitting amongst the two lightest neutralinos leads to SUSY events containing many isolated leptons, including events with a real leptonic Z boson plus jets plus missing energy signal which is visible over much of parameter space. In contrast, in the 75 and 200 models, the reach via leptonic SUSY signals is greatly reduced relative to mSUGRA, and the signal is usually visible only via the canonical $\eslt +$jets channel.

Figures (21)

• Figure 1: Gaugino mass ratios for the four special cases where the field $\Phi$ transforms as the 1, 24, 75 or 200 dimensional representation of $SU(5)$, or as an arbitrary linear combination of the singlet and adjoint representations (solid line).
• Figure 2: A plot of the evolution of soft SUSY breaking parameters versus renormalization scale $Q$ from $M_{GUT}$ to $M_{weak}$ for SUGRA model parameters $m_0=100$ GeV, $M_3^0=125$ GeV, $A_0=0$, $\tan\beta =5$ and $\mu >0$, for the a) $F_\Phi \sim 1$, b) $F_\Phi\sim 24$, c) $F_\Phi\sim 75$ and d) $F_\Phi\sim 200$ models. We take $m_t=175$ GeV. Notice the different scale in frame d)
• Figure 3: A plot of various physical sparticle masses and the magnitude of the $\mu$ parameter versus $\tan\beta$ for SUGRA model parameters $m_0=100$ GeV, $M_3^0=125$ GeV, $A_0=0$ and $\mu >0$, for the a) $F_\Phi\sim 1$, b) $F_\Phi\sim 24$, c) $F_\Phi\sim 75$ and d) $F_\Phi\sim 200$ models. The squark mass is averaged over the first two generations.
• Figure 4: A plot of gluino and squark mass contours in the $m_0\ vs.\ M_3^0$ plane for SUGRA model parameters $A_0=0$, $\tan\beta =5$ and $\mu >0$ for the a) $F_\Phi \sim 1$, b) $F_\Phi\sim 24$, c) $F_\Phi\sim 75$ and d) $F_\Phi\sim 200$ models. The squark mass is averaged over the first generation.
• Figure 5: Same as Fig. \ref{['FIG3']} except for $\tan\beta =25$.