No Arabic abstract
NEXT is an experiment dedicated to neutrinoless double beta decay searches in xenon. The detector is a TPC, holding 100 kg of high-pressure xenon enriched in the $^{136}$Xe isotope. It is under construction in the Laboratorio Subterraneo de Canfranc in Spain, and it will begin operations in 2015. The NEXT detector concept provides an energy resolution better than 1% FWHM and a topological signal that can be used to reduce the background. Furthermore, the NEXT technology can be extrapolated to a 1-ton scale experiment.
The determination of the neutrino mass hierarchy, whether the $ u _3$ neutrino mass eigenstate is heavier or lighter than the $ u _1$ and $ u _2$ mass eigenstates, is one of the remaining undetermined fundamental aspects of the Standard Model in the lepton sector. Furthermore the mass hierarchy determination will have an impact in the quest of the neutrino nature (Dirac or Majorana mass terms) towards the formulation of a theory of flavour. The Jiangmen Underground Neutrino Observatory (JUNO) is a reactor neutrino experiment under construction at Kaiping, Jiangmen in Southern China composed by a large liquid scintillator detector (sphere of 35.4 m of diameter) surronding by 18000 large PMTs and 25000 small PMTs, a water cherenkov detector and a top tracker detector. The large active mass (20 kton) and the unprecedented energy resolution (3% at 1 MeV) will allow to determine the neutrino mass hierarchy with good sensitivity and to precisely measure the neutrino mixing parameters, $theta _{12}$, $Delta m^2_{21} $, and $Delta m^2_{ee}$ below the 1% level. Moreover, a large liquid scintillator detector will allow to explore physics beyond mass hierarchy determination, in particular on many oyher topics such as in astroparticle physics, like supernova burst and diffuse supernova neutrinos, solar neutrinos, atmospheric neutrinos, geo-neutrinos, nucleon decay, indirect dark matter searches and a number of additional exotic searches. In this work the status and the perspectives of the JUNO experiment will be described, focusing also on the main physics aims and the other possible physics cases.
SNO+ is a large liquid scintillator-based experiment located 2km underground at SNOLAB, Sudbury, Canada. It reuses the Sudbury Neutrino Observatory detector, consisting of a 12m diameter acrylic vessel which will be filled with about 780 tonnes of ultra-pure liquid scintillator. Designed as a multipurpose neutrino experiment, the primary goal of SNO+ is a search for the neutrinoless double-beta decay (0$ ubetabeta$) of 130Te. In Phase I, the detector will be loaded with 0.3% natural tellurium, corresponding to nearly 800 kg of 130Te, with an expected effective Majorana neutrino mass sensitivity in the region of 55-133 meV, just above the inverted mass hierarchy. Recently, the possibility of deploying up to ten times more natural tellurium has been investigated, which would enable SNO+ to achieve sensitivity deep into the parameter space for the inverted neutrino mass hierarchy in the future. Additionally, SNO+ aims to measure reactor antineutrino oscillations, low-energy solar neutrinos, and geoneutrinos, to be sensitive to supernova neutrinos, and to search for exotic physics. A first phase with the detector filled with water will begin soon, with the scintillator phase expected to start after a few months of water data taking. The 0$ ubetabeta$ Phase I is foreseen for 2017.
Precise measurements of semileptonic kaon decay rates at KLOE provide the measurement of the CKM mixing matrix element vus and information about lepton universality. Leptonic kaon decays provide an independent measurement of $abs{vus}^2/abs{vud}^2$, through the ratio $Gamma(Ktomu u)/Gamma(pitomu u)$. These measurements, together with the result of $|vud|$ from nuclear $beta$ transitions, provide the most precise test of CKM unitarity, allowing the universality of lepton and quark weak couplings to be tested. After the completion of the KLOE data taking, the proposal of a new run with an upgraded KLOE detector, KLOE-2, at an upgraded Dafne machine has been accepted by INFN and it is now starting. Present results from KLOE and future perspectives from KLOE-2 are reported.
Recently some of the authors proposed a search for galactic axions with mass about 0.2~$mu$eV using a large volume resonant cavity, tens of cubic meters, cooled down to 4~K and immersed in a magnetic field of about 0.6~T generated inside the superconducting magnet of the KLOE experiment located at the National Laboratory of Frascati of INFN. This experiment, called KLASH (KLoe magnet for Axion SearcH), has a potential sensitivity on the axion-to-photon coupling, $g_{agammagamma}$, of about $6times10^{-17}$ $mbox{GeV}^{-1}$, reaching the region predicted by KSVZcite{KSVZ} and DFSZcite{DFSZ} models of QCD axions. We report here the status of the project.
In the past years the spotlight of the search for dark matter particles widened to the low mass region, both from theoretical and experimental side. We discuss results from data obtained in 2013 with a single detector TUM40. This detector is equipped with a new upgraded holding scheme to efficiently veto backgrounds induced by surface alpha decays. This veto, the low threshold of 0.6keV and an unprecedented background level for CaWO$_4$ target crystals render TUM40 the detector with the best overall performance of CRESST-II phase 2 (July 2013 - August 2015). A low-threshold analysis allowed to investigate light dark matter particles (<3GeV/c$^2$), previously not accessible for other direct detection experiments.