Neutralino

Neutralino

Status	Hypothetical
Symbol	N͂0 1, N͂0 2, N͂0 3, N͂0 4
Antiparticle	Real neutral particle
Types	4
Mass	> 300 GeV
Electric charge	0
Spin	1/2
Lepton number	0
Baryon number	0
R parity	−1

In supersymmetry, the neutralino is a hypothetical particle. There are four neutralinos that are fermions and are electrically neutral, the lightest of which is typically stable. They are typically labeled
N͂0
1 (the lightest),
N͂0
2,
N͂0
3 and
N͂0
4 (the heaviest) although sometimes ${\displaystyle {\tilde {\chi }}_{1}^{0},\ldots ,{\tilde {\chi }}_{4}^{0}}$ is also used when ${\displaystyle {\tilde {\chi }}_{i}^{\pm }}$ is used to refer to charginos. These four states are mixtures of the bino and the neutral wino (which are the neutral electroweak gauginos), and the neutral higgsinos. As the neutralinos are Majorana fermions, each of them is identical to its antiparticle. Because these particles only interact with the weak vector bosons, they are not directly produced at hadron colliders in copious numbers. They would primarily appear as particles in cascade decays of heavier particles (decays that happen in multiple steps) usually originating from colored supersymmetric particles such as squarks or gluinos.

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