Simple gravitational arguments imply that most of the mass in the Universe is some (unknown) non-luminous matter. In the same way, one can calculate the rotation velocity of isolated stars or hydrogen clouds in the outer parts of Galaxies. The disc is thought to be flat, as light matter can emit photons and thus gravitationally collapse into a pancake-like structure.
In principle, the dark matter halo could be round, elliptical, or even oblate, like the disk. But it was not until the 1970s, with the precise measurements of galactic rotation curves by Vera Rubin (1928-) and others, that the existence of dark matter began to be seriously considered. Today, this phenomenon of anomalous rotation curves has been observed in detail in thousands of galaxies, and in particular in our galaxy, the Milky Way.
The white arrows show the path of the light from the true position of the source. The analysis reveals that the cluster's dark matter (shown in blue) is not evenly distributed, but closely follows the clumps of luminous matter.
Another evidence: Bullet Cluster 1E 0657-56
Bullet Cluster: dark matter observed through gravitational lensing
Globular cluster: As in all clusters, the vast majority of the normal matter in the globular is not in the galaxies themselves, but in the hot, X-ray-emitting intergalactic gas.
Bullet Cluster: supersimposing the lensing and X-ray maps
Recently, in July 2012, for the first time, a DM filament was detected between two galaxy clusters through gravitational lensing. Its mass appears to be too small, m ~ eV to calculate WDM h2 0.1 This type of DM (hot) cannot accurately reproduce the observed one.
PARTICLE CANDIDATES
The only possible candidate for DM within the Standard Model of Particle Physics, the neutrino, is ruled out. Neutral Otherwise it would bind to nuclei and be excluded from unsuccessful searches for exotic heavy isotopes produced after the Big Bang and still present today. Reproduce the observed quantity DM WDM h2 0.1 A particle with weak interactions and a mass GeV-TeV.
In the early universe, when the temperature was greater than the mass of the DM particle, it annihilated with its own antiparticle into lighter particles and vice versa. However, when the temperature dropped below the mass of the DM particle, there was not enough kinetic energy to create it (T< mWIMPc2). However, when the annihilation rate fell below the expansion rate of the universe, the DM particles could not annihilate and their density has been the same ever since.
Key question: the relic density
DETECTION
A complete confirmation can only arise from experiments where the particle is detected as part of the galactic halo.
Direct and Indirect Detection
These three detection strategies are ideal because they make it possible to explore many different particle dark matter models in an exhaustive way. Besides, in case of a redundant detection. in two or more different experiments) combining their data can provide good insight into the nature of dark matter.
Direct Detection
Experiments must be placed in the deep subsurface to greatly reduce the number of these background events. WIMPs are expected to produce less or about 10-2 nuclear recoils/kg day with energies of a few keV.
The background problem
Background events still remain, and experiments must have extremely good background discrimination to distinguish nuclear shocks due to WIMPs. In addition, neutrons are created by the radioactivity of the environment, and rays and particles are also produced, which cause electron bounce. Unlike WIMPs, neutrons will often produce double-scattering signatures, so the detector must be able to identify (and reject) multi-interaction events.
DIRECT DARK MATTER EXPERIMENTS
Type of experiments
DAMA/LIBRA
Recent experimental results
The DM hints are in a low energy region where the background makes analyzes very complicated. Assuming that this effect is due to a non-Maxwellian local halo velocity distribution, the DAMA/LIBRA ROI can be moved.
Crucial Moment for SUSY in 2015
MSSM
What is the origin of µ, and why its value is so small?
And therefore a good candidate for DM
The scalar part recently discovered at the LHC is compatible with a Higgs boson with a mass of 126 GeV and rat ios with SM-like branching [DC: cit on ion needed]. In fact, the presence of an extra scalar Higgs field gives rise to new Higgs rebut ions in the Higgs mass from λSHuHd t erm to the superpot ent, which allows to obtain a fairly heavy Higgs boson by reducing the small one . tuning regarding position in MSSM. The Higgs or NMSSM sect is very rich, and the presence of a lighter scalar Higgs is also allowed, provided it is at most a singlet.
All these features are still valid in our construction, but when implementing constraints on the resulting Higgs phenomenology one must be aware that the presence of light RH neutrinos or sneutrinos can contribute significantly to the invisible decay width of the scalar Higgses . The decay width of a scalar Higgs in an RH neutrino pair or a RH neutrino pair is [?], ΓH0. where the Higgs sneut rhino-sneut rino link reads [?]. 2.11).
Predictions for its distribution cross section still extend over many orders of magnitude (excellent motivation for more sensitive detectors). Very light neutrals are viable (albeit quite well-ordered) in the Minimal Supersymmetric Standard Model.
NMSSM
Overview of the NMSSM
Neutralino in the NMSSM
Right-handed sneutrinos can also be the dark matter in extensions of the NMSSM
The Lagrangian effect describing the four-field interaction is just a scalar coupling that reads. There is no Lagrangian continuation effect, no axial weight or coupling since the nose jet is a scalar field, thus implying a vanishing contribution to the rotation-dependent cross section. The spin-independent rino-prot sneut in the ion of a diffuse cross section gives σN pSI˜ = 1 .
The quantity it is fT qp. i and fT Gp are the hadronic matrix elements that parametrize the quark content of the prot op. causing a significant correction to the theoretical predictions for σSI˜. In our analysis, we will consider the most recent values for this quantity, as explained in [69]. It is clear from the previous formulas that the snout rhino detection cross section is extremely dependent on the characteristics of the Higgs sect or of the model.
Neutrinos as light as mN=6 GeV can be obtained consistent with LHC data and with a LARGE scattering cross section. Not ice, as the effective Lagrangian contains no axial weight or coupling, since snow rino is a scalar field, which therefore implies a vanishing contribution to the spin-dependent cross section. The t ot al spin-independent sneut rino prot on scattering cross section ion gives σN pSI˜ = 1.
In our analysis, we will consider the most recent values for these quantities, as discussed in [69]. Neutrinos as light as mN=6 GeV can be obtained according to LHC data and have a LARGE scattering cross section.
INDIRECT DETECTION
Its destruction will produce neutrinos that can be detected with neutrino telescopes, especially through the muons produced by their interactions in the rock. Underwater experiments (ANTARES with a size of 104 m2. In the future KM3NeT with a size of 106 m2) Experiments under ice. Contributions of e– and e+ from Geminga pulsar, assuming different distances, age and energy of the pulsar.
An excess may be due to the modeling of the diffuse emission, unresolved sources, etc. An interesting possibility might be to look for DM around the Galactic Center where the density is very high. Assuming an excess, and that the DM density in the inner galaxy is r(r) ~ r0/r, one can derive possible DM samples that reproduce the observations.
In regions close to the galactic center, he found an indication of a gamma-ray line at an energy. If interpreted in terms of DM particles annihilating into a photon pair, the observations would imply mDM 130 GeV , σannv ~10–27 cm3 s–1 using Einasto profile. Implies limits on the annihilation cross section between σannv ~10-23 to 10-22 cm3 s-1 for a 1 TeV mass neutralino, assuming an NFW dwarf density profile.
Nearby clusters of galaxies are also attractive targets
YES in the likely case that the collapse of baryons to the Galactic Center is accompanied by the contraction of the DM. Because these are DM-only simulations, but central regions of galaxies like the Milky Way are dominated by baryons. Cerdeño, Huh, Klypin, Mambrini, C.M., Peiró, Prada, MultiDark + Gómez-Vargas, Morselli, Sánchez-Conde Fermi-LAT arXiv:1308.3515.
From observational data of the Milky Way, the parameters of the DM profiles are constrained.
Caution
The value of sv in the galactic halo can also be less than 3 x 10-26 cm3 s-1 - e.g. in SUSY, in the early universe coannihilation channels can also contribute to sv. In this sense, the results for pure annihilation channels can be interpreted as limiting cases that give an idea of what can happen in realistic scenarios. So we now update the neutralino MSSM case and study NMSSM and sneutrino in extension of NMSSM.
Decaying Dark Matter
SUSY
Also strict selection rules: particles are attached to different sectors in the compact space, or they have extra U(1) charges.
But the LSP can still be a candidate for dark matter
Gravitino as decaying dark matter
FERMI might in principle detect these gamma rays
CONCLUSIONS
