source: Backup NB/Talks/MEMPHYSetal/LAGUNA/EU I3/PhysicsLatex/Laguna-before-xarchiv/darkmatter_det.tex @ 416

\section{Indirect Search for Dark Matter}
\label{sec:DM}
%\REDBLA{Version 0 by AB 23/03/06}
%\REDBLA{update by JEC 16/10/06: this is a section now}
WIMPs that constitute the halo of the Milky Way can occasionally interact with massive objects, 
such as stars or planets. When they scatter off of such an object, 
they can potentially lose enough energy that they become gravitationally bound and 
eventually will settle in the center of the celestial body. In
particular, WIMPs can be captured by and accumulate in the core of the Sun. 
%
\begin{figure}
\includegraphics[width=\columnwidth]{./figures/wimp_senal_fondo_10gev.eps}
\caption{\label{fig:GLACIERdm1} 
Expected number of signal and background events as a function of the
 WIMP elastic scattering production cross section in the Sun, with a cut 
of 10 GeV on the minimum neutrino energy.} 
%The three lines correspond
% to three values of the WIMP mass.}
\end{figure}


\begin{figure}
\includegraphics[width=\columnwidth]{./figures/jasp_dislimit_10gev.eps}
\caption{\label{fig:GLACIERdm2} Minimum number of years required to claim a discovery WIMP signal
 from the Sun in a 100~kton LAr detector as function of $\sigma_{\rm{elastic}}$
 for three values of the WIMP mass.}
\end{figure}
%

We have assessed, in a model-independent way, the capabilities that
GLACIER offers for identifying
neutrino signatures coming from the products of WIMP annihilations in the core 
of the Sun \cite{Bueno:2004dv}. 
Signal events will consist
of energetic electron (anti)neutrinos coming from the decay
of $\tau$ leptons and $b$ quarks produced in WIMP annihilation in 
the core of the Sun. Background contamination from
atmospheric neutrinos is expected to be low. 
We do not consider the possibility of observing neutrinos from WIMPs accumulated in the Earth. 
Given the smaller mass of the Earth and the fact that only scalar interactions contribute, 
the capture rates for our planet are not
enough to produce, in our experimental set-up, a statistically
significant signal.

Our search method takes advantage of the excellent angular reconstruction and 
superb electron identification capabilities GLACIER 
offers to look for an excess of 
energetic electron (anti)neutrinos pointing in the direction of the
Sun. The expected signal and background event rates have been evaluated, in
a model independent way, as a function of the WIMP's elastic scatter cross
section for a range of masses up to 100~GeV.

The detector discovery potential, i.e. the number of years needed to
claim a WIMP signal has been discovered, is shown in Figs.~\ref{fig:GLACIERdm1} 
and \ref{fig:GLACIERdm2}. With the assumed set-up and thanks to the low background environment 
offered by the LAr TPC, a clear WIMP signal would be detected
provided the elastic scattering cross section in the Sun is above
$\sim 10^{-4}$~pb.