Search for massive rare particles with the SLIM experiment

The search for magnetic monopoles in the cosmic radiation remains one of the main aims of non-accelerator particle astrophysics. Experiments at high altitude allow lower mass thresholds with respect to detectors at sea level or underground. The SLIM experiment is a large array of nuclear track detectors at the Chacaltaya High Altitude Laboratory (5290 m a.s.l.). The results from the analysis of 171 m$^2$ exposed for more than 3.5 y are here reported. The completion of the analysis of the whole detector will allow to set the lowest flux upper limit for Magnetic Monopoles in the mass range 10$^5$ - 10$^{12}$ GeV. The experiment is also sensitive to SQM nuggets and Q-balls, which are possible Dark Matter candidates.Comment: Presented at the 29-th ICRC, Pune, India (2005

Synthesis of high ion exchange zeolites from coal fly ash

This study focuses on the synthesis at a pilot plant scale of zeolitic material obtained from the coal fly ashes of the Teruel and Narcea power plants in Spain. After the optimisation of the synthesis parameters at laboratory scale, the Teruel and Narcea fly ashes were selected as low and high glass fly ashes. The pilot plant scale experiments were carried out in a 10 m3 reactor of Clariant SA (Barcelona, Spain). The results allowed obtaining 1.1 and 2.2 tonnes of zeolitic material with 40 and 55% of NaP1 content, in two single batch experiments of 24 and 8 hours, for Teruel and Narcea fly ashes, respectively. The cation exchange capacities (CEC) of the final product reached 2.0 and 2.7 meq g-1 for Teruel and Narcea zeolitic material, respectively, which are very close to the usual values reached by the high quality natural zeolitic products. Finally, with the aim of testing possible applications of the commercial NaP1-IQE and pilot plant NaP1-Narcea zeolitic products in water decontamination, efficiency for metal uptake from waste waters from electroplating baths was investigate

Search for Intermediate Mass Magnetic Monopoles and Nuclearites with the SLIM experiment

SLIM is a large area experiment (440 m2) installed at the Chacaltaya cosmic ray laboratory since 2001, and about 100 m2 at Koksil, Himalaya, since 2003. It is devoted to the search for intermediate mass magnetic monopoles (107-1013 GeV/c2) and nuclearites in the cosmic radiation using stacks of CR39 and Makrofol nuclear track detectors. In four years of operation it will reach a sensitivity to a flux of about 10-15 cm-2 s-1 sr-1. We present the results of the calibration of CR39 and Makrofol and the analysis of a first sample of the exposed detector.Comment: Presented at the 22nd ICNTS, Barcelona 200

Search for strange quark matter and Q-balls with the SLIM experiment

We report on the search for Strange Quark Matter (SQM) and charged Q-balls with the SLIM experiment at the Chacaltaya High Altitude Laboratory (5230 m a.s.l.) from 2001 to 2005. The SLIM experiment was a 427 m$^{2}$ array of Nuclear Track Detectors (NTDs) arranged in modules of $24 \times 24$ cm$^{2}$ area. SLIM NTDs were exposed to the cosmic radiation for 4.22 years after which they were brought back to the Bologna Laboratory where they were etched and analyzed. We estimate the properties and energy losses in matter of nuclearites (large SQM nuggets), strangelets (small charged SQM nuggets) and Q-balls; and discuss their detection with the SLIM experiment. The flux upper limits in the CR of such downgoing particles are at the level of $1.3 10^{-15}$/cm$^{2}$/s/sr (90% CL).Comment: 4 pages, 7 eps figures. Talk given at the 24th International Conference on Nuclear Tracks in Solids, Bologna, Italy, 1-5 September 200

Bulk Etch Rate Measurements and Calibrations of Plastic Nuclear Track Detectors

New calibrations of CR39 and Makrofol nuclear track detectors have been obtained using 158 A GeV Pb (82+) and In (49+) ions; a new method for the bulk etch rate determination, using both cone height and base diameter measurements was developed. The CR39 charge resolution based on the etch-pit base area measurement is adequate to identify nuclear fragments in the interval 7 <= Z/beta <= 49. For CR39 the detection threshold is at REL~50 MeV cm^2/g, corresponding to a nuclear fragment with Z/beta~7. Base cone area distributions for Makrofol foils exposed to Pb (82+) ions have shown for the first time all peaks due to nuclear fragments with Z > 50; the distribution of the etched cone heights shows well separated individual peaks for Z/beta = 78 - 83 (charge pickup). The Makrofol detection threshold is at REL 2700 MeV cm^2/g, corresponding to a nuclear fragment with Z/beta~50.Comment: 11 pages, 5 EPS figures. Submitted to Nucl. Instr. Meth.

Prospect for Charge Current Neutrino Interactions Measurements at the CERN-PS

Tensions in several phenomenological models grew with experimental results on neutrino/antineutrino oscillations at Short-Baseline (SBL) and with the recent, carefully recomputed, antineutrino fluxes from nuclear reactors. At a refurbished SBL CERN-PS facility an experiment aimed to address the open issues has been proposed [1], based on the technology of imaging in ultra-pure cryogenic Liquid Argon (LAr). Motivated by this scenario a detailed study of the physics case was performed. We tackled specific physics models and we optimized the neutrino beam through a full simulation. Experimental aspects not fully covered by the LAr detection, i.e. the measurements of the lepton charge on event-by-event basis and their energy over a wide range, were also investigated. Indeed the muon leptons from Charged Current (CC) (anti-)neutrino interactions play an important role in disentangling different phenomenological scenarios provided their charge state is determined. Also, the study of muon appearance/disappearance can benefit of the large statistics of CC muon events from the primary neutrino beam. Results of our study are reported in detail in this proposal. We aim to design, construct and install two Spectrometers at "NEAR" and "FAR" sites of the SBL CERN-PS, compatible with the already proposed LAr detectors. Profiting of the large mass of the two Spectrometers their stand-alone performances have also been exploited.Comment: 70 pages, 38 figures. Proposal submitted to SPS-C, CER

Prospects for the measurement of muon-neutrino disappearance at the FNAL-Booster

Neutrino physics is nowadays receiving more and more attention as a possible source of information for the long-standing problem of new physics beyond the Standard Model. The recent measurement of the mixing angle $\theta_{13}$ in the standard mixing oscillation scenario encourages us to pursue the still missing results on leptonic CP violation and absolute neutrino masses. However, puzzling measurements exist that deserve an exhaustive evaluation. The NESSiE Collaboration has been setup to undertake conclusive experiments to clarify the muon-neutrino disappearance measurements at small $L/E$, which will be able to put severe constraints to models with more than the three-standard neutrinos, or even to robustly measure the presence of a new kind of neutrino oscillation for the first time. To this aim the use of the current FNAL-Booster neutrino beam for a Short-Baseline experiment has been carefully evaluated. This proposal refers to the use of magnetic spectrometers at two different sites, Near and Far. Their positions have been extensively studied, together with the possible performances of two OPERA-like spectrometers. The proposal is constrained by availability of existing hardware and a time-schedule compatible with the CERN project for a new more performant neutrino beam, which will nicely extend the physics results achievable at the Booster. The possible FNAL experiment will allow to clarify the current $\nu_{\mu}$ disappearance tension with $\nu_e$ appearance and disappearance at the eV mass scale. Instead, a new CERN neutrino beam would allow a further span in the parameter space together with a refined control of systematics and, more relevant, the measurement of the antineutrino sector, by upgrading the spectrometer with detectors currently under R&D study.Comment: 76 pages, 52 figure

Flux Modulations seen by the Muon Veto of the GERDA Experiment

The GERDA experiment at LNGS of INFN is equipped with an active muon veto. The main part of the system is a water Cherenkov veto with 66~PMTs in the water tank surrounding the GERDA cryostat. The muon flux recorded by this veto shows a seasonal modulation. Two effects have been identified which are caused by secondary muons from the CNGS neutrino beam (2.2 %) and a temperature modulation of the atmosphere (1.4 %). A mean cosmic muon rate of $I^0_{\mu} = (3.477 \pm 0.002_{\textrm{stat}} \pm 0.067_{\textrm{sys}}) \times 10^{-4}$/(s$\cdot$m$^2$) was found in good agreement with other experiments at LNGS at a depth of 3500~meter water equivalent.Comment: 7 pages, 6 figure

Search for anomalies in the neutrino sector with muon spectrometers and large LArTPC imaging detectors at CERN

A new experiment with an intense ~2 GeV neutrino beam at CERN SPS is proposed in order to definitely clarify the possible existence of additional neutrino states, as pointed out by neutrino calibration source experiments, reactor and accelerator experiments and measure the corresponding oscillation parameters. The experiment is based on two identical LAr-TPCs complemented by magnetized spectrometers detecting electron and muon neutrino events at Far and Near positions, 1600 m and 300 m from the proton target, respectively. The ICARUS T600 detector, the largest LAr-TPC ever built with a size of about 600 ton of imaging mass, now running in the LNGS underground laboratory, will be moved at the CERN Far position. An additional 1/4 of the T600 detector (T150) will be constructed and located in the Near position. Two large area spectrometers will be placed downstream of the two LAr-TPC detectors to perform charge identification and muon momentum measurements from sub-GeV to several GeV energy range, greatly complementing the physics capabilities. This experiment will offer remarkable discovery potentialities, collecting a very large number of unbiased events both in the neutrino and antineutrino channels, largely adequate to definitely settle the origin of the observed neutrino-related anomalies.Comment: Contribution to the European Strategy for Particle Physics - Open Symposium Preparatory Group, Kracow 10-12 September 201

Background free search for neutrinoless double beta decay with GERDA Phase II

The Standard Model of particle physics cannot explain the dominance of matter over anti-matter in our Universe. In many model extensions this is a very natural consequence of neutrinos being their own anti-particles (Majorana particles) which implies that a lepton number violating radioactive decay named neutrinoless double beta ($0\nu\beta\beta$) decay should exist. The detection of this extremely rare hypothetical process requires utmost suppression of any kind of backgrounds. The GERDA collaboration searches for $0\nu\beta\beta$ decay of $^{76}$Ge (^{76}\rm{Ge} \rightarrow\,^{76}\rm{Se} + 2e^-) by operating bare detectors made from germanium with enriched $^{76}$Ge fraction in liquid argon. Here, we report on first data of GERDA Phase II. A background level of $\approx10^{-3}$ cts/(keV$\cdot$kg$\cdot$yr) has been achieved which is the world-best if weighted by the narrow energy-signal region of germanium detectors. Combining Phase I and II data we find no signal and deduce a new lower limit for the half-life of $5.3\cdot10^{25}$ yr at 90 % C.L. Our sensitivity of $4.0\cdot10^{25}$ yr is competitive with the one of experiments with significantly larger isotope mass. GERDA is the first $0\nu\beta\beta$ experiment that will be background-free up to its design exposure. This progress relies on a novel active veto system, the superior germanium detector energy resolution and the improved background recognition of our new detectors. The unique discovery potential of an essentially background-free search for $0\nu\beta\beta$ decay motivates a larger germanium experiment with higher sensitivity.Comment: 14 pages, 9 figures, 1 table; ; data, figures and images available at http://www.mpi-hd.mpg/gerda/publi