Neutralino

Neutralino
Status	Hypothetical
Symbol	N͂0; 1, N͂0; 2, N͂0; 3, N͂0; 4
Antiparticle	self (truly 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^: 71–74 is a hypothetical particle. In the Minimal Supersymmetric Standard Model (MSSM), a popular model of realization of supersymmetry at a low energy, there are four neutralinos that are fermions and are electrically neutral, the lightest of which is stable in an R-parity conserved scenario of MSSM. They are typically labeled $N ͂ 01$ (the lightest), $N ͂ 02$ , $N ͂ 03$ and $N ͂ 04$ (the heaviest) although sometimes ${\tilde {\chi }}_{1}^{0},\ldots ,{\tilde {\chi }}_{4}^{0}$ is also used when ${\tilde {\chi }}_{i}^{\pm }$ is used to refer to charginos.

(In this article,

C ͂ \pm 1

is used for chargino #1, etc.)

These four states are composites 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.