# how to modify NMIX in param_card for a binolike LSP and winolike NLSP

hello , I am a beginner . I am a bit confused about neutralino mixing matrix in param_card . I am generating process :

import model mssm

generate p p > x1+ n2 , x1+ > w+ > n1 l+ vl , n2 > z > n1 l+ l-

add process p p > x1- n2 , x1- > w- > n1 l- vl~ , n2 > z > n1 l+ l-

In my model , I assume pMSSM models with a bino-like LSP(60%-99%) and wino-like NLSP(80%-99%) and wino-like chargino1(\chi_1) . So I modify NMIX ,UMIX,VMIX . my param_card is like this:

NMIX:

1 1 0.6 # rnn1x1

1 2 0.1 # rnn1x2

1 3 0.1 # rnn1x3

1 4 0.2 # rnn1x4

2 1 0.06 # rnn2x1

2 2 0.8 # rnn2x2

2 3 0.06 # rnn2x3

2 4 0.08 # rnn2x4

3 1 -6.033880e-02 # rnn3x1

3 2 8.770049e-02 # rnn3x2

3 3 6.958775e-01 # rnn3x3

3 4 7.102270e-01 # rnn3x4

4 1 -1.165071e-01 # rnn4x1

4 2 3.107390e-01 # rnn4x2

4 3 6.492260e-01 # rnn4x3

4 4 -6.843778e-01 # rnn4x4

BLOCK UMIX #

1 1 0.8 # ruu1x1

1 2 0.2 # ruu1x2

2 1 3.992666e-01 # ruu2x1

2 2 9.168349e-01 # ruu2x2

BLOCK VMIX #

1 1 0.8 # rvv1x1

1 2 0.2 # rvv1x2

2 1 2.326612e-01 # rvv2x1

2 2 9.725578e-01 # rvv2x2

In NMIX matrix , I only modified elements (1,1) (1,2) (1,3) (1,4) (2,1) (2,2) (2,3) (2,4) while leaving others the default values. Similarly in UMIX and VMIX , I also modified (1,1) (2,2) .

Am I doing right or wrong? It seems strange to modify param_card like this.

What makes me more confused is that it seems changing mixing matrix element has no effect on my events .So I am doubting there 's something wrong . I know in MSSM neutralinos are mixtures of the bino , wino, higgsinos . The mass matrix M can be diagonalized by a unitary matrix N . I don't know which matrix( N or M ) corresponds to NMIX ? Similarly for charginos there are U matrix and V matrix which diagonalize chargino mass matrix . So how to modify chargino matrix so that chargino1 is wino-like?

My problems may seems stupid because I am a beginner . But I am really confused because modifying NMIX , UMIX ,VMIX has no effect on my final event analsis . Can anyone help me?

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- Solved by:
- Olivier Mattelaer

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