Higgsino

This article needs additional citations for verification. Please help improve this article by adding citations to reliable sources. Unsourced material may be challenged and removed. Find sources: "Higgsino" – news · newspapers · books · scholar · JSTOR (January 2011) (Learn how and when to remove this message)

Standard Model of particle physics
Elementary particles of the Standard Model
Background Particle physics Standard Model Quantum field theory Gauge theory Spontaneous symmetry breaking Higgs mechanism
Constituents Electroweak interaction Quantum chromodynamics CKM matrix Standard Model mathematics
Limitations Strong CP problem Hierarchy problem Neutrino oscillations Physics beyond the Standard Model
Scientists Rutherford Thomson Chadwick Bose Sudarshan Davis Jr Anderson Fermi Dirac Feynman Rubbia Gell-Mann Kendall Taylor Friedman Powell Anderson Glashow Iliopoulos Lederman Maiani Meer Cowan Nambu Chamberlain Cabibbo Schwartz Perl Majorana Weinberg Lee Ward Salam Kobayashi Maskawa Mills Yang Yukawa 't Hooft Veltman Gross Pais Pauli Politzer Reines Schwinger Wilczek Cronin Fitch Vleck Higgs Englert Brout Hagen Guralnik Kibble de Mayolo Lattes Zweig
v t e

In particle physics, for models with N = 1 supersymmetry, a higgsino, symbol
H͂
, is the superpartner of the Higgs field. A higgsino is a Dirac fermionic field with spin ⁠1/2⁠ and it refers to a weak isodoublet with hypercharge half under the Standard Model gauge symmetries. After electroweak symmetry breaking higgsino fields linearly mix with U(1) and SU(2) gauginos leading to four neutralinos and two charginos^[1] that refer to physical particles. While the two charginos are charged Dirac fermions (plus and minus each), the neutralinos are electrically neutral Majorana fermions. In an R-parity-conserving version of the Minimal Supersymmetric Standard Model, the lightest neutralino typically becomes the lightest supersymmetric particle (LSP). The LSP is a particle physics candidate for the dark matter of the universe since it cannot decay to particles with lighter mass. A neutralino LSP, depending on its composition can be bino, wino or higgsino dominated in nature^[2] and can have different zones of mass values in order to satisfy the estimated dark matter relic density. Commonly, a higgsino dominated LSP is often referred as a higgsino, in spite of the fact that a higgsino is not a physical state in the true sense.

In natural scenarios of SUSY, top squarks, bottom squarks, gluinos, and higgsino-enriched neutralinos and charginos are expected to be relatively light, enhancing their production cross sections. Higgsino searches have been performed by both the ATLAS and CMS experiments at the Large Hadron Collider at CERN, where physicists have searched for the direct electroweak pair production of Higgsinos. As of 2017, no experimental evidence for Higgsinos has been reported.^[3][4]

If dark matter is composed only of Higgsinos, then the Higgsino mass is 1.1 TeV. On the other hand, if dark matter has multiple components, then the Higgsino mass depends on the relevant multiverse distribution functions, making the mass of the Higgsino lighter.

m_ħ ≈ 1.1 (Ω_ħ/Ω_DM)^1/2 TeV^[5]