Do solar neutrinos impact light dark matter searches?

By Colin Adcock on May 27, 2016 • ( 1 )

That’s the question researchers Anthony W Thomas (University of Adelaide) and J Vergados (University of Ioannina) sought to uncover in their latest Letter in Journal of Physics G: Nuclear and Particle Physics.

We asked first author and JPhysG Editorial Board Member Thomas what it is all about.

The origin and nature of dark matter constitutes one of the major challenges for modern physics. The famous Standard Model, which we understand so well, accounts for less than 5% of the stuff of the Universe, while there is almost 5 times as much dark matter.

There are currently many underground experiments looking for evidence of weakly interacting massive particles (WIMPs) through the small recoil energy after such a dark matter candidate strikes an atomic nucleus. Over the past few years most of those experiments have found null results, pushing the regions where such particles might live to ever more unlikely regions. The few hints of a dark matter signal, such as that from DAMA, appear to contradict other limits and will, in any case, soon be tested by much improved, simultaneous measurements in both the Northern and Southern hemispheres.

Constraints from the Large Hadron Collider have also dampened the enthusiasm for supersymmetry, which until recently offered the most promising theoretical dark matter candidate, the neutralino.

In view of all of these developments interest is moving towards the search for lighter weakly interacting particles, perhaps with masses in the MeV region. Such light particles cannot transfer significant energy to atomic nuclei and hence, in order to detect them underground, one needs to look for experiments capable of detecting recoiling electrons.

These authors consider the background for such experiments posed by the all-pervasive solar neutrinos. Paying attention to the binding of typical atomic electrons, it is found that Boron neutrinos do not constitute a significant background for such experiments.

On the other hand, pp neutrinos are found to provide a very serious background once one looks for dark matter candidates in the MeV region. They will provide a serious challenge to experimental searches in this promising region.

Read the Letter in JPhysG:

Solar neutrinos as background in dark matter searches involving electron detection

Read more in JPhys+ on dark matter:

Laura Baudis on the detection of dark matter and XENON

Did dark matter kill the dinosaurs?

Is there dark matter in our neighborhood?

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