A. Di Marco

DARK MATTER INVESTIGATION BY DAMA AT GRAN SASSO

Experimental observations and theoretical arguments at Galaxy and larger scales have suggested that a large fraction of the Universe is composed by Dark Matter particles. This has motivated the DAMA experimental efforts to investigate the presence of such particles in the galactic halo by exploiting a model independent signature and very highly radiopure setup in deep underground. Few introductory arguments are summarized before presenting a review of the present model independent positive results obtained by the DAMA/NaI and DAMA/LIBRA setups at the Gran Sasso National Laboratory of the INFN. Implications and model dependent comparisons with other different kinds of results will be shortly addressed. Some arguments put forward in literature will be confuted.

Performances of the new high quantum efficiency PMTs in DAMA/LIBRA

New dedicated high quantum efficiency (Q.E.) photomultipliers (PMTs) have been produced by HAMAMATSU company, tested, selected and installed in the DAMA/LIBRA set-up at the Gran Sasso National Laboratory (LNGS) of the I.N.F.N.. In this paper the results obtained in the measurements of various features of these high Q.E. PMTs are reported, and some performances of DAMA/LIBRA in this new configuration are shown.

No role for muons in the DAMA annual modulation results

This paper gathers arguments and reasons why muons surviving the Gran Sasso mountain cannot mimic the Dark Matter annual modulation signature exploited by the DAMA/NaI and DAMA/LIBRA experiments. A number of these items have already been presented in individual papers. Further arguments have been addressed here in order to present a comprehensive collection and to enable a wider community to correctly approach this point.

New search for correlated e+e- pairs in the \( \alpha\) decay of 241Am

Abstract.A new search for production of correlated

No role for neutrons, muons and solar neutrinos in the DAMA annual modulation results

e^{+}e^{-}

Investigating Earth shadowing effect with DAMA/LIBRA-phase1

pairs in the

Search for 2β decay of cerium isotopes with CeCl3 scintillator

\alpha

First search for double-

decay of 241Am has been carried out deep underground at the Gran Sasso National Laboratory of the INFN by using pairs of NaI(Tl) detectors of the DAMA/LIBRA set-up. The experimental data show an excess of double coincidences of events with energy around 511keV in faced pairs of detectors, which are not explained by known side reactions. This measured excess gives a relative activity

\beta

\lambda=(4.70\pm 0.63)\times 10^{-9}

decay of platinum by ultra-low background HP Ge

for the Internal Pair Production (IPP) with respect to the alpha decay of 241Am; this value is of the same order of magnitude as previous determinations. In a conservative approach the upper limit