You only live twice (a story of dark and ghost matters)

From weakly interacting massive particles to a mimetic scalar field
If I may divert a famous quote of Jean Iliopoulos at the 1979 Einstein Symposion I would say:

Several people believe, and I share this view, that dark matter is a convenient parametrisation of our ignorance concerning the dynamics of gravitation beyond the solar system and elementary dark matter particles might not exist... 

Indeed since we have learned that scalar particles do exists and the naturalness problem of the standard model-like 125 GeV Higgs stays as acute today as its older brother the gravitational constant, one may envision to take seriously the geometric insight from the spectral standard model and its Pati-Salam extension discussed in yesterday's post. It anticipates indeed the possible absence of new elementary particles beyond the intermediate see-saw scale in the approximate ZeV range leaves little hope for wimps (except possibly some wimpzillas or other ultra-heavy dark matter fermions?). 

Furthermore the most advanced results from the spectral geometrisation endeavour provide a new operator theoretic equation to express a condition of volume quantisation for connected Riemannian Spin 4-manifolds with Euclidean signature. Then any 4D ...

... manifold can be reconstructed as a composition of the pullback maps from two separate four spheres with coordinates defined over two Clifford algebras. The phase space of coordinates and Dirac operator defines a noncommutative space of KO dimension 10. The symmetries of the algebras defining the noncommutative space turn out to be those of ... the Pati-Salam models. Connections along discrete directions are the Higgs fields

And last but not least:

There are many consequences of the volume quantization condition which could be investigated. For example imposing the quantization condition through a Lagrange multiplier would imply that the cosmological constant will arise as an integrating constant in the equations of motion. One can also look at the possibility that only the three volume (space-like) is quantized. This can be achieved provided that the four-dimensional manifold arise due to the motion of three dimensional hypersurfaces, which is equivalent to the 3 + 1 splitting of a four-dimensional Lorentzian manifold. Then three dimensional space volume will be quantized, provided that the field X that maps the real line have a gradient of unit norm g_µν∂_µX∂_νX = 1. It is known that this condition when satisfied gives a modified version of Einstein gravity with integrating functions giving rise to mimetic dark matter [21] [22].

Quanta of Geometry and Unification

Ali H. Chamseddine

(Submitted on 3 Jun 2016)

From dark matter to ghost particles 
Now the question is : if nothing more than the standard model up to the see-saw scale then what?
Neutrinos of course!

Dark matter detectors that utilize liquid xenon have now achieved tonne-scale targets, giving them sensitivity to all flavours of supernova neutrinos via coherent elastic neutrino-nucleus scattering. Considering for the first time a realistic detector model, we simulate the expected supernova neutrino signal for different progenitor masses and nuclear equations of state in existing and upcoming dual-phase liquid xenon experiments. We show that the proportional scintillation signal (S2) of a dual-phase detector allows for a clear observation of the neutrino signal and guarantees a particularly low energy threshold, while the backgrounds are rendered negligible during the supernova burst. XENON1T (XENONnT and LZ; DARWIN) experiments will be sensitive to a supernova burst up to 25 (35; 65) kpc from Earth at a significance of more than 5σ, observing approximately 35 (123; 704) events from a 27 solar mass supernova progenitor at 10 kpc. Moreover, it will be possible to measure the average neutrino energy of all flavours, to constrain the total explosion energy, and to reconstruct the supernova neutrino light curve. Our results suggest that a large xenon detector such as DARWIN will be competitive with dedicated neutrino telescopes, while providing complementary information that is not otherwise accessible. 

The detection significance is given as a function of the supernova (SN) distance for a 27 solar mass progenitor with the Lattimer and Swesty equation of state for dense nuclear matter. The SN signal has been integrated over [0, 7] s. The different bands refer to XENON1T (red), XENONnT and LZ (blue), and DARWIN (green). The band width reflects uncertainties from our estimates for the background rate, discussed in section IV. The vertical dotted lines mark the centre and edge of the Milky Way as well as the Large and Small Magellanic Clouds (LMC and SMC, respectively). For this SN progenitor, XENONnT/LZ could make at least a 5σ discovery of the neutrinos from a SN explosion anywhere in the Milky Way. DARWIN extends the sensitivity beyond the SMC.

Supernova neutrino physics with xenon dark matter detectors: A timely perspective

Rafael F. Lang, Christopher McCabe, Shayne Reichard, Marco Selvi, Irene Tamborra

(Submitted on 28 Jun 2016)

//Last edit 14 August 2016