The only particles of the MSSM that are electrically and color-neutral are the neutrinos, their scalar superpartners, called sneutrinos, and, finally, the
neutralinos.
Neutralinos, [[chi].sub.i=1,..,4], are Majorana fermion mass eigenstates emerging, after EWSB, from the diagonalization of the mass matrix of four electrically and color-neutral SUSY states (see [24-27] for early studies and [3] for a comprehensive, classic review).
It's been disappointing that the LHC has not yet seen copious
neutralinos and other superpartners pouring out of its detectors.
Neutralinos would also be WIMPs and are favored by models invoking a special type of dark matter: cold dark matter, which moves relatively slowly.
Nath, "Event rates in dark matter detectors for
neutralinos including constraints from b->s gamma decay," Physical Review Letters, vol.
The lowest-mass supersymmetric particles, called
neutralinos, would annihilate when they encounter each other, producing high-energy electrons and positrons that would seem to pop out of nothing.
WIMPs may be
neutralinos, the lightest of these supersymmetric partners.
Particular CDM candidates, like
neutralinos (which are stable and can be produced thermally in the early Universe) and other WIMPs originating in supersymmetric extensions of the Standard Model were severely constrained by recent LHC results, rendering them into the range 200 GeV [??] [m.sub.n] [??] 500 GeV [33].
But according to Dan Hooper (Fermi National Accelerator Laboratory) and two colleagues, a nearby clump of
neutralinos could also do the trick.
Most are as exotic as the names their inventors have given them: massive compact halo objects (MACHOs), weakly interacting massive particles (WIMPs), axions,
neutralinos, and wimpzillas.
Abajyan et al., "Search for direct production of charginos and
neutralinos in events with three leptons and missing transverse momentum in [square root of s] = 7 TeV pp collisions with the ATLAS detector," Physics Letters B, vol.
Regarding dark matter, scientists have at least managed to round up a couple of suspects,
neutralinos and axions, hypothetical particles that would solve some problems with the Standard Model of particle physics (S&T: August 2008, page 30).