One-loop effects in supergravity models with an additional U(1)

Abstract

For an Abelian extended supergravity model, we investigate some important low-energy parameters: tan ␤, the Z-ZЈ mixing angle, lightest CP-even Higgs mass bound, ZЈ mass, and effective parameter. By integrating the renormalization group equations from the string scale down to the weak scale we constuct the scalar potential and analyze the quantities above at the tree-and one-loop levels by including the contributions of top squarks and top quark in the effective potential. ͓S0556-2821͑98͒02211-5͔ PACS number͑s͒: 04.65.ϩe, 12.60.Jv

MinimalU(1)′extension of the minimal supersymmetric standard model

“…(44). The one-loop piece is an approximate result (note it does not depend on h s ) that holds when (i) the loop contributions are renormalized at Q ∼ m t , (ii) all terms involving the gauge couplings are neglected, and (iii) stop LR mixing is much smaller than the diagonal terms such that the two physical stops are nearly degenerate with mass m t (see [6,23] for exact results). The radiatively corrected upper bound (45) can be used to place a lower bound on the stop mass…”

“…The physical Higgs bosons are given by H i = R ij B j where the mixing matrix R necessarily satisfies RR T = 1, and it has already been computed up to one loop order in [5,6,7,23]. In the CP-conserving limit the theory contains three CP-even, one CP-odd, and a charged Higgs boson.…”

“…On the other hand, the second option restricts muon mass to follow from non-holomorphic terms only. From (23)(24)(25)(26)(27)(28)(29), one can check that the first option leads to…”

Higgs sector in extensions of the minimal supersymmetric standard model

“…The UMSSM and sMSSM each contains a U1 0 gauge symmetry and its gauge boson, Z 0 , that can mix with the SM after symmetries are broken Z [12,27]. While the continuous U1 0 symmetry is free from domain wall constraints, the UMSSM may require exotic fields [28][29][30] to cancel chiral anomalies related to the U1 0 symmetry 2 .…”

FAMILY NONUNIVERSAL Z′ AND b → sγ DECAY

“…The Z ′ models form a viable candidate model to extend the MSSM in order to solve the µ problem [1]. The vacua that suppress the Z − Z ′ mixing have been found in [2] with further improvements concerning the radiative effects [3]. The effects of such extra Z bosons on precision observables have been analyzed in detail in [4].…”