[416] | 1 | \section{Indirect Search for Dark Matter} |
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| 2 | \label{sec:DM} |
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| 3 | %\REDBLA{Version 0 by AB 23/03/06} |
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| 4 | %\REDBLA{update by JEC 16/10/06: this is a section now} |
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| 5 | WIMPs that constitute the halo of the Milky Way can occasionally interact with massive objects, |
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| 6 | such as stars or planets. When they scatter off of such an object, |
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| 7 | they can potentially lose enough energy that they become gravitationally bound and |
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| 8 | eventually will settle in the center of the celestial body. In |
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| 9 | particular, WIMPs can be captured by and accumulate in the core of the Sun. |
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| 10 | % |
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| 11 | \begin{figure} |
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| 12 | \includegraphics[width=\columnwidth]{./figures/wimp_senal_fondo_10gev.eps} |
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| 13 | \caption{\label{fig:GLACIERdm1} |
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| 14 | Expected number of signal and background events as a function of the |
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| 15 | WIMP elastic scattering production cross section in the Sun, with a cut |
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| 16 | of 10 GeV on the minimum neutrino energy.} |
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| 17 | %The three lines correspond |
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| 18 | % to three values of the WIMP mass.} |
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| 19 | \end{figure} |
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| 20 | |
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| 21 | |
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| 22 | \begin{figure} |
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| 23 | \includegraphics[width=\columnwidth]{./figures/jasp_dislimit_10gev.eps} |
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| 24 | \caption{\label{fig:GLACIERdm2} Minimum number of years required to claim a discovery WIMP signal |
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| 25 | from the Sun in a 100~kton LAr detector as function of $\sigma_{\rm{elastic}}$ |
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| 26 | for three values of the WIMP mass.} |
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| 27 | \end{figure} |
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| 28 | % |
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| 29 | |
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| 30 | We have assessed, in a model-independent way, the capabilities that |
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| 31 | GLACIER offers for identifying |
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| 32 | neutrino signatures coming from the products of WIMP annihilations in the core |
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| 33 | of the Sun \cite{Bueno:2004dv}. |
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| 34 | Signal events will consist |
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| 35 | of energetic electron (anti)neutrinos coming from the decay |
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| 36 | of $\tau$ leptons and $b$ quarks produced in WIMP annihilation in |
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| 37 | the core of the Sun. Background contamination from |
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| 38 | atmospheric neutrinos is expected to be low. |
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| 39 | We do not consider the possibility of observing neutrinos from WIMPs accumulated in the Earth. |
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| 40 | Given the smaller mass of the Earth and the fact that only scalar interactions contribute, |
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| 41 | the capture rates for our planet are not |
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| 42 | enough to produce, in our experimental set-up, a statistically |
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| 43 | significant signal. |
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| 44 | |
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| 45 | Our search method takes advantage of the excellent angular reconstruction and |
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| 46 | superb electron identification capabilities GLACIER |
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| 47 | offers to look for an excess of |
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| 48 | energetic electron (anti)neutrinos pointing in the direction of the |
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| 49 | Sun. The expected signal and background event rates have been evaluated, in |
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| 50 | a model independent way, as a function of the WIMP's elastic scatter cross |
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| 51 | section for a range of masses up to 100~GeV. |
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| 52 | |
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| 53 | The detector discovery potential, i.e. the number of years needed to |
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| 54 | claim a WIMP signal has been discovered, is shown in Figs.~\ref{fig:GLACIERdm1} |
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| 55 | and \ref{fig:GLACIERdm2}. With the assumed set-up and thanks to the low background environment |
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| 56 | offered by the LAr TPC, a clear WIMP signal would be detected |
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| 57 | provided the elastic scattering cross section in the Sun is above |
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| 58 | $\sim 10^{-4}$~pb. |
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| 59 | |
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