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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