[Shape-univ] INTEGRAL/SPI: first 511keV-photograph of dark matter halo?

[Boud Roukema]

hi all,

On Fri, 9 Jun 2006, Bartosz Lew wrote:

> > In other words: the QH and g-2 experiments give different results for alpha.
> > The difference is not (yet) statistically significant, but a light scalar coupled to
> > a heavy particle, needed for the LDM hypothesis, would give this difference
> > for m_LDM \sim 3-9 MeV.  (The real mass might be higher since this assumes
> > smooth distribution of matter in the DM halo, ignores the fact that some part
> > of the emission might be from point sources, etc.)
>
> still it's elusive to me, but if I understand correctly you say only about
> two different , and possibly giving different results, methods of
> measuring alpha.
> where is the part about it's evolution ?

The LDM article says nothing at all about evolution of alpha.

> and the alpha is made of three fundamental physical constants:
> due to change of which one is the hypotetised evolution ascribed to ?

It's not about evolution. It's about using two different experiments
and different sets of physics assumptions. From what i understand,
the QH experiment requires less physical assumptions than the g-2
experiment, but (at the moment) is less precise. The g-2 experiment
is more precise, but requires assumptions of QED (standard model of pp).

If we add in the hypothesised pp explanation for LDM, which goes beyond
the standard model of pp, then the two experiments come into agreement
because the derived value of alpha from g-2 is modified by the difference
from the standard model.


> > So improvements in the QH effect experiments could support the LDM hypothesis
> > and explain the present possible discrepancy in alpha estimates.
> >
> > This is, coincidentally(?), roughly on the same order of magnitude as
> > the alpha evolution claims in quasar absorption systems, since the QSO
> > claims were of order 10^{-6} or over \sim 5 billion yr or
> > so, and if convert this to 8kpc = 3000yr then we get
> >
> > delta(alpha)/alpha \sim 10^{-12} between the Sun and the GC.
>
> hmm, so this is about the evolution but, this is a different experiment.

i'm not so convinced by alpha evolution, see the following paragraph:

> > However, the last i remember of the QSO abs sys alpha evolution claims they
> > were no longer looking interesting (one of Srianand's papers is pretty
> > convincing - look in shape-univ and/or cosmo-torun archives... :). In any case,
> > a more precise calculation would be needed to see if these really are on
> > the same scale or whether i've rounded off too many orders of magnitude.
> >
>
> well, anyway it's interesting enough to read more about over a morning
> coffee :))

Well, there was also something which came up during discussions at the
cosm-pl meeting a few weeks ago. Just as a century ago, particle
physics seemed to be nearly complete with everything made of protons,
electrons, neutrons and four fundamental forces, and there was just a
few minor problems such as the infrared catastrophe and the
Michelson-Morley experiment, it could be that the explanation for nbDM
is a whole bunch of different particles - so maybe both DAMA/NaI and
INTEGRAL/SPI correctly reveal two of the main constituents of nbDM.
And from what i understand from Ascasibar 2005, the \sim 6-7 MeV
particle would have to interact with both a light Z' boson and a heavy
particle, implying at least 3 particles present in significant
densities in the DM halo.

So we might end up with a whole new zoo of astronomically significant
particle populations... ;)

pozdr
boud