Analysis of the neutralino system in supersymmetric theories

Abstract

Charginosχ ± and neutralinosχ 0 in supersymmetric theories can be produced copiously at e + e − colliders and their properties can be measured with high accuracy. Consecutively to the chargino system, in which the SU(2) gaugino parameter M 2 , the higgsino mass parameter µ and tan β can be determined, the remaining fundamental supersymmetry parameter in the gaugino/higgsino sector of the minimal supersymmetric extension of the Standard Model, the U(1) gaugino mass M 1 , can be analyzed in the neutralino system, including its modulus and its phase in CP-noninvariant theories. The CP properties of the neutralino system are characterized by unitarity quadrangles. Analytical solutions for the neutralino mass eigenvalues and for the mixing matrix are presented for CP-noninvariant theories in general. They can be written in compact form for large supersymmetric mass parameters. The closure of the neutralino and chargino systems can be studied by exploiting sum rules for the pair-production processes in e + e − collisions. Thus the picture of the non-colored gaugino and higgsino complex in supersymmetric theories can comprehensively be reconstructed in these experiments.

The soft supersymmetry-breaking Lagrangian: theory and applications

“…[749,750,751,752,753,754,755,756,757] and references therein for further details. In this section, we will illustrate the general issues and complications, such as nontrivial phases and large tan β, involved in this reconstruction process.…”

Neutralino projector formalism for complex supersymmetry parameters

“…Diagonalizing the neutralino mass matrix is then more complicated; but nevertheless, explicit analytic solutions have already been constructed in [12].…”

“…Under these conditions, the only (generally complex) parameter to be determined from the neutralino studies is M 1 . Explicit formulae for determining M 1 , and suggestions on the neutralino information needed to lift the inherent ambiguities, have appeared in [15,16,12].…”

“…As an example, it was assumed that only the lightest chargino and its mixing angles are determined from Linear Collider (LC), together with the masses of one or two of the lightest neutralinos. Then, relations for determining the generally complex M 1 and µ parameters were suggested, in which information from e − e + →χ 0 1χ 0 2 was used [12]. The second aim of this paper is to present the formalism for extracting the SUSY parameters, in the context of scenarios concerning the neutralino and chargino measurements.…”

“…They will be determined below using (27). The expressions (29 -32), together with (28, 16), guarantee that all projector and pseudo-projector properties (11)(12)(13)(24)(25)(26), and the unitarity of U N , are automatically satisfied, for any complex symmetric neutralino mass matrix. It is very important to remark that all these expressions, can be directly generalized to any neutralino number, and any complex symmetric mass matrix.…”