Indirect searches of Galactic diffuse dark matter in INO-MagICAL
  detector
  The signatures for the existence of dark matter are revealed only through its
gravitational interaction. Theoretical arguments support that the Weakly
Interacting Massive Particle (WIMP) can be a class of dark matter and it can
annihilate and/or decay to Standard Model particles, among which neutrino is a
favorable candidate. We show that the proposed 50 kt Magnetized Iron
CALorimeter (MagICAL) detector under the India-based Neutrino Observatory (INO)
project can play an important role in the indirect searches of Galactic diffuse
dark matter in the neutrino and antineutrino mode separately. We present the
sensitivity of 500 kt$\cdot$yr MagICAL detector to set limits on the
velocity-averaged self-annihilation cross-section ($\langle\sigma v\rangle$)
and decay lifetime ($\tau$) of dark matter having mass in the range of 2 GeV
$\leq m_\chi \leq $ 90 GeV and 4 GeV $\leq m_\chi \leq $ 180 GeV respectively,
assuming no excess over the conventional atmospheric neutrino and antineutrino
fluxes at the INO site. Our limits for low mass dark matter constrain the
parameter space which has not been explored before. We show that MagICAL will
be able to set competitive constraints, $\langle\sigma v\rangle\leq
1.87\,\times\,10^{-24}$ cm$^3$ s$^{-1}$ for $\chi\chi\rightarrow\nu\bar\nu$ and
$\tau\geq 4.8\,\times\,10^{24}$ s for $\chi\rightarrow\nu\bar\nu$ at 90$\%$
C.L. (1 d.o.f.) for $m_\chi$ = 10 GeV assuming the NFW as dark matter density
profile.
