Constraining the minimal supergravity model parameter tan(beta) by measuring the dilepton mass distribution at LHC

Denegri, D.; Majerotto, W.; Rurua, L.

Constraining the minimal supergravity model parameter tan(beta) by measuring the dilepton mass distribution at LHC

Authors

Denegri, D.

Majerotto, W.

Rurua, L.

Description

We study the dependence on $\tanβ$ of the event kinematics of final states with $e^+e^- /μ^+μ^- /e^{\pm}μ^{\mp} + E_T^{\rm miss} + jets$, as expected in $pp$ collisions at CERN LHC, within the framework of the minimal supergravity model. With increase of $\tanβ$, the third generation sparticle masses $m_{\tildeτ_1}$ and $m_{\tilde{b}_1}$ decrease due to the increase of the tau and bottom Yukawa couplings. As a result, gluino, stop, sbottom, chargino and neutralino decays to third generation particles and sparticles are enhanced. With $\tanβ$ rising, we observe a characteristic change in the shape of the dilepton mass spectra in $e^+e^- /μ^+μ^- +E_T^{\rm miss} + jets$ versus $e^{\pm}μ^{\mp} + E_T^{\rm miss} + jets$ final states, reflecting the presence of the decays $\tildeχ_2^0\to \tilde{\ell}_{L,R}^{\pm}\ell^{\mp}\to \tildeχ_1^0 \ell^+\ell^-, \tildeχ_2^0\to \tildeχ_1^0 \ell^+\ell^-$ and $\tildeχ_2^0\to \tildeτ^{\pm}_1τ^{\mp}\to \tildeχ_1^0 τ^+ τ^-$, $\tildeχ_2^0\to τ^+ τ^- \tildeχ_1^0$, respectively. We exploit this effect for constraining the value of $\tanβ$.
16 page latex file including 5 eps figures