GPS-based CERN-LNGS time link for Borexino

We describe the design, the equipment, and the calibration of a new GPS based time link between CERN and the Borexino experiment at the Gran Sasso Laboratory in Italy. This system has been installed and operated in Borexino since March 2012, and used for a precise measurement of CNGS muon neutrinos speed in May 2012. The result of the measurement will be reported in a different letter.Comment: 13 pages, 11 figure

Unveiling the parent population of beamed narrow-line Seyfert 1s

Narrow-line Seyfert 1 galaxies (NLS1s) are active galactic nuclei (AGN) recently identified as a new class of $\gamma$-ray sources. The high energy emission is explained by the presence of a relativistic jet observed at small angles, just like in the case of blazars. When the latter are observed at larger angles they appear as radio-galaxies, but an analogue parent population for beamed NLS1s has not yet been determined. In this work we analyze this problem by studying the physical properties of three different samples of parent sources candidates: steep-spectrum radio-loud NLS1s, radio-quiet NLS1s, and disk-hosted radio-galaxies, along with compact steep-spectrum sources. In our approach, we first derived black hole mass and Eddington ratio from the optical spectra, then we investigated the interaction between the jet and the narrow-line region from the [O III] $\lambda\lambda$4959,5007 lines. Finally, the radio luminosity function allowed us to compare their jet luminosity and hence determine the relations between the samples.Comment: 6 pages, no figures. Proceedings of the 28th Texas Symposium, Geneva, December 13-18, 201

High sensitivity double beta decay study of 116-Cd and 100-Mo with the BOREXINO Counting Test Facility (CAMEO project)

The unique features (super-low background and large sensitive volume) of the CTF and BOREXINO set ups are used in the CAMEO project for a high sensitivity study of 100-Mo and 116-Cd neutrinoless double beta decay. Pilot measurements with 116-Cd and Monte Carlo simulations show that the sensitivity of the CAMEO experiment (in terms of the half-life limit for neutrinoless double beta decay) is (3-5) 10^24 yr with a 1 kg source of 100-Mo (116-Cd, 82-Se, and 150-Nd) and about 10^26 yr with 65 kg of enriched 116-CdWO_4 crystals placed in the liquid scintillator of the CTF. The last value corresponds to a limit on the neutrino mass of less than 0.06 eV. Similarly with 1000 kg of 116-CdWO_4 crystals located in the BOREXINO apparatus the neutrino mass limit can be pushed down to m_nu<0.02 eV.Comment: 29 pages, LaTex, 9 eps figure

Exploring the parent population of beamed NLS1s: from the black hole to the jet

The aim of this work is to understand the nature of the parent population of beamed narrow-line Seyfert 1 galaxies (NLS1s), by studying the physical properties of three parent candidates samples: steep-spectrum radio-loud NLS1s, radio-quiet NLS1s and disk-hosted radio-galaxies. In particular, we focused on the black hole mass and Eddington ratio distribution and on the interactions between the jet and the narrow-line region.Comment: 6 pages, 2 figures, to appear in Proceedings of High Energy Phenomena in Relativistic Outflows (HEPRO) V, Workshop Series of the Argentinian Astronomical Societ

Broad-band properties of flat-spectrum radio-loud narrow-line Seyfert 1 galaxies

We report about recent updates of broad-band properties of radio-loud narrow-line Seyfert 1 galaxies.Comment: 5 pages, no figures. Proceedings 28th Texas Symposium on Relativistic Astrophysics, Geneva (Switzerland), 13-18 December 201

Double Beta Decay, Majorana Neutrinos, and Neutrino Mass

The theoretical and experimental issues relevant to neutrinoless double-beta decay are reviewed. The impact that a direct observation of this exotic process would have on elementary particle physics, nuclear physics, astrophysics and cosmology is profound. Now that neutrinos are known to have mass and experiments are becoming more sensitive, even the non-observation of neutrinoless double-beta decay will be useful. If the process is actually observed, we will immediately learn much about the neutrino. The status and discovery potential of proposed experiments are reviewed in this context, with significant emphasis on proposals favored by recent panel reviews. The importance of and challenges in the calculation of nuclear matrix elements that govern the decay are considered in detail. The increasing sensitivity of experiments and improvements in nuclear theory make the future exciting for this field at the interface of nuclear and particle physics.Comment: invited submission to Reviews of Modern Physics, higher resolution figures available upon request from authors, Version 2 has fixed typos and some changes after referee report

Measurement of CNGS muon neutrino speed with Borexino

We have measured the speed of muon neutrinos with the Borexino detector using short-bunch CNGS beams. The final result for the difference in time-of-flight between a =17 GeV muon neutrino and a particle moving at the speed of light in vacuum is {\delta}t = 0.8 \pm 0.7stat \pm 2.9sys ns, well consistent with zero.Comment: 6 pages, 5 figure

Solar neutrino with Borexino: results and perspectives

Borexino is a unique detector able to perform measurement of solar neutrinos fluxes in the energy region around 1 MeV or below due to its low level of radioactive background. It was constructed at the LNGS underground laboratory with a goal of solar $^{7}$Be neutrino flux measurement with 5\% precision. The goal has been successfully achieved marking the end of the first stage of the experiment. A number of other important measurements of solar neutrino fluxes have been performed during the first stage. Recently the collaboration conducted successful liquid scintillator repurification campaign aiming to reduce main contaminants in the sub-MeV energy range. With the new levels of radiopurity Borexino can improve existing and challenge a number of new measurements including: improvement of the results on the Solar and terrestrial neutrino fluxes measurements; measurement of pp and CNO solar neutrino fluxes; search for non-standard interactions of neutrino; study of the neutrino oscillations on the short baseline with an artificial neutrino source (search for sterile neutrino) in context of SOX project.Comment: 15 pages, 4 figure

Recent Borexino results and prospects for the near future

The Borexino experiment, located in the Gran Sasso National Laboratory, is an organic liquid scintillator detector conceived for the real time spectroscopy of low energy solar neutrinos. The data taking campaign phase I (2007 - 2010) has allowed the first independent measurements of 7Be, 8B and pep fluxes as well as the first measurement of anti-neutrinos from the earth. After a purification of the scintillator, Borexino is now in phase II since 2011. We review here the recent results achieved during 2013, concerning the seasonal modulation in the 7Be signal, the study of cosmogenic backgrounds and the updated measurement of geo-neutrinos. We also review the upcoming measurements from phase II data (pp, pep, CNO) and the project SOX devoted to the study of sterile neutrinos via the use of a 51Cr neutrino source and a 144Ce-144Pr antineutrino source placed in close proximity of the active material.Comment: 8 pages, 11 figures. To be published as proceedings of Rencontres de Moriond EW 201