Regular Article - Experimental Physics

The European Physical Journal C

, Volume 56, Issue 3, pp 333-355

Open Access This content is freely available online to anyone, anywhere at any time.

First results from DAMA/LIBRA and the combined results with DAMA/NaI

  • R. BernabeiAffiliated withDipartimento di Fisica, Università di Roma “Tor Vergata”INFN, Sezione Roma “Tor Vergata” Email author 
  • , P. BelliAffiliated withINFN, Sezione Roma “Tor Vergata”
  • , F. CappellaAffiliated withDipartimento di Fisica, Università di Roma “La Sapienza”INFN, Sezione Roma
  • , R. CerulliAffiliated withLaboratori Nazionali del Gran Sasso, INFN
  • , C. J. DaiAffiliated withIHEP, Chinese Academy
  • , A. d’AngeloAffiliated withDipartimento di Fisica, Università di Roma “La Sapienza”INFN, Sezione Roma
  • , H. L. HeAffiliated withIHEP, Chinese Academy
  • , A. IncicchittiAffiliated withINFN, Sezione Roma
  • , H. H. KuangAffiliated withIHEP, Chinese Academy
    • , J. M. MaAffiliated withIHEP, Chinese Academy
    • , F. MontecchiaAffiliated withDipartimento di Fisica, Università di Roma “Tor Vergata”INFN, Sezione Roma “Tor Vergata”
    • , F. NozzoliAffiliated withDipartimento di Fisica, Università di Roma “Tor Vergata”INFN, Sezione Roma “Tor Vergata”
    • , D. ProsperiAffiliated withDipartimento di Fisica, Università di Roma “La Sapienza”INFN, Sezione Roma
    • , X. D. ShengAffiliated withIHEP, Chinese Academy
    • , Z. P. YeAffiliated withIHEP, Chinese AcademyUniversity of Jing Gangshan

Abstract

The highly radiopure ≃ 250 kg NaI(Tl) DAMA/LIBRA set-up is running at the Gran Sasso National Laboratory of the INFN. In this paper the first result obtained by exploiting the model independent annual modulation signature for Dark Matter (DM) particles is presented. It refers to an exposure of 0.53 ton×yr. The collected DAMA/LIBRA data satisfy all the many peculiarities of the DM annual modulation signature. Neither systematic effects nor side reactions able to account for the observed modulation amplitude and to contemporaneously satisfy all the several requirements of this DM signature are available. Considering the former DAMA/NaI and the present DAMA/LIBRA data all together (total exposure 0.82 ton×yr), the presence of Dark Matter particles in the galactic halo is supported, on the basis of the DM annual modulation signature, at 8.2 σ C.L.; in particular, in the energy interval (2–6) keV, the modulation amplitude is (0.0131±0.0016) cpd/kg/keV and the phase and the period are well compatible with June 2 nd and one year, respectively.