[Hps] Planck results.

[Rouven Essig]

Hi Maurik, All,

Just adding a few things to Natalia's email.

There is no paper yet that combines all the available CMB data (Planck,
WMAP, ACT, and SPT), although I imagine that one will appear soon.

A recent paper that uses all the available CMB data *pre-Planck* to
constrain DM annihilation (WMAP-9 temperature+polarization, ACT
temperature, and SPT temperature) is arxiv:1303.5094.  They disfavor the
thermal WIMP annihilation cross section (3*10^-26 cm^3/s) for DM
annihilating to e+e- and mu+mu- for DM masses below 30 and 15 GeV,
respectively.  Annihilation through A's to electrons and muons will be
similarly constrained.  The DM explanation with annihilation to A's of the
PAMELA/Fermi data requires larger DM masses but also larger cross sections,
so should be "right on the edge" of detectability.

Planck did analyze their data for DM annihilation signals and showed the
results in their paper 16 (Sec. 6.6 in 1303.5076).  They only combine their
data with WMAP polarization data and find a weaker constraint than the one
mentioned in the previous paragraph.  They did not combine their data with
all other available data (ACT and SPT temperature), but someone will do
this most likely soon.  And the improvement will be minimal compared to the
results in the previous paragraph, as Natalia mentioned.

What is next?  As Natalia mentioned, the big leverage will be from the
Planck, ACT, and SPT polarization data.  The timescales for these are 6
months to ~1 year.  Whether Neelima does the analysis with the ACT
polarization data will depend on the availability of the ACT data in
comparison to Planck's.  If Planck publishes their polarization data first,
they will evaluate how much adding the available ACT polarization data will
further improve the constraints.

Rouven


On Fri, Mar 22, 2013 at 10:28 AM, Natalia Toro
<ntoro at perimeterinstitute.ca>wrote:

> Hi Maurik,
>
> I had an email exchange yesterday with Tracy Slatyer who's done a lot of
> the work on CMB constraints (on dark matter annihilating to heavy
> photons).  According to her, the big sensitivity gains from PLANCK come
> from the polarization data, which wasn't included in this year's release.
> She estimated only a 10-20% increase in expected sensitivity relative to
> WMAP...
>
> (Tracy also tells me that ACT polarization + Planck temperature data could
> be very sensitive even without Planck's polarization data, and that Neelima
> Seghal is looking into this.  I don't know the timescale for this result,
> but Rouven probably does...)
>
> There is also a recent paper constraining heavy photons that decay to
> light fermions based on the number of relativistic d.o.f. arXiv:1303.5379<http://arxiv.org/abs/1303.5379>.
> But this constraint doesn't apply to dark photons that decay to ordinary
> matter (whether directly or through a dark-sector cascade).
>
> Best regards,
> Natalia
>
>
> On Fri, Mar 22, 2013 at 6:51 AM, Maurik Holtrop <maurik at physics.unh.edu>
> wrote:
>
>> Dear HPS,
>>
>> The Planck collaboration has just released a large amount of new
>> information. See:
>>
>>
>> http://www.sciops.esa.int/index.php?project=PLANCK&page=Planck_Published_Papers
>> And for the main summary paper: http://arxiv.org/abs/1303.5062
>>
>> I would be very interested in learning more about how these new results
>> impact the search for heavy photons.
>>
>> Cheers,
>>         Maurik
>>
>>
>>
>>
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