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Charged dark matter particle

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It is generally assumed that the particle of dark matter has to be electrically neutral, so that it doesn't interact with the electromagnetic field and stays "dark".

But cannot the lightest superpartner or WIMP or dark matter particle be charged, e.g. a chargino? I think that in order to neutralize, such a chargino would create bound states with electrons or positrons which would behave as "very heavy" (150 times heavier, for example) hydrogen atoms whose spectrum would be otherwise indistinguishable from the hydrogen spectrum, including the -13.6 electronvolts of the ground state (up to tiny differences from the reduced mass' not being the electron mass).

We would still see some "hydrogen" in the galaxy but the actual mass that this "hydrogen" carries would be e.g. 150 times higher, so this excessively heavy atoms could account for the extra mass needed as dark matter. Does this scenario contradict some facts?

asked Jun 5, 2014 in Phenomenology by Luboš Motl (10,248 points) [ no revision ]

is this paper on "dark atoms" relevant? http://arxiv.org/abs/1009.3523

Nice, it is at least relevant! And Jay Wacker is a co-author, too. ;-)

1 Answer

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There will be a shift of less than 2% in the lines, but spectroscopy from the cosmos is fairly good, they can see 1% shifts.  Now if normal hydrogen would coexist in the region, this might  be a handle to check experimentally as the two spectra from the same region would be shifted .

It opens a new window for lab experiments if such stable exotics exist. As they have dipole etc moments they will bind up in matter.  Weighing stuff and counting molecules once more would become important  " what if some uranium mass has a hydrogen spectrum ?". On the other hand wouldn't 5% exotic in heavy ores have been found until now?  With centrifuges  used in separating uranium isotopes for example?

answered Jun 5, 2014 by anna v (1,785 points) [ no revision ]

Thanks, Anna. Can you distinguish the shifts to the hydrogen spectrum from the omnipresent redshift or blueshift? Concerning the labs, is that obvious that such exotic heavy atoms would have to exist on Earth? That would probably exclude the idea because there aren't any "very heavy hydrogen atoms" here.

They would not look like heavy hydrogen atoms because you are postulating something heavy, order TeV?. They would probably be accumulated in the iron and less atomic number ores, because the heavier ones are generated in supernovas, and the exotics must be primordial, when first the stars were made. These strata go by weight/ gravitation , and your hypothesis is that they are heavy. They cannot be a gas once solids are made, they will probably be in the interstitial locations of the lattices as their moments  and wan der waals forces will be different than 95% of the host.

The shift in the redshift will only be identifiable if there are real hydrogen atoms around a galaxy with some reasonable percent  of these exotics mixed, as I said above. They will look like two clouds moving oppositely. It would take a careful experiment but I think it might be doable: measure spectra from the galaxy as in the link I gave above, search for a hydrogen spectrum where you then know the velocity from the associated galaxy and check if there exists a faster shadow/ echo  to the hydrogen lines. It needs an experimental astrophysicist to answer how well they see hydrogen lines etc.

As the ratio of matter to dark matter is 1 to five, one might find out that what was thought a hydrogen cloud  not correlated with a galaxy in effect it is because there exists a shadow  cloud in the same region that moves with the galaxy. Astrophysical modeling has to be attempted.

There exists the mass spectrometry that one would expect they would have seen unusual charge to mass ratio. On the other hand a TeV ion is not expected, they might just put it down to experimental error, as it would be practically a straight line. And the 5% I am quoting might be very overvalued, since most of them might have fallen to the center of the earth!  It is different 25% overall percentage of dark matter  excess from trajectory calculations, and my assuming   5% uniformly distributed within a planetary mass.

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