arXiv subjects

F. Terranova

Publications and source records attributed to F. Terranova.

At least 73 records · Page 4Linked to original sources

arXiv2016

A compact light readout system for longitudinally segmented shashlik calorimeters

The longitudinal segmentation of shashlik calorimeters is challenged by dead zones and non-uniformities introduced by the light collection and readout system. This limitation can be overcome by direct fiber-photosensor coupling, avoiding routing and bundling of the wavelength shifter fibers and embedding ultra-compact photosensors (SiPMs) in the bulk of the calorimeter. We present the first experimental test of this readout scheme performed at the CERN PS-T9 beamline in 2015 with negative particles in the 1-5~GeV energy range. In this paper, we demonstrate that the scheme does not compromise the energy resolution and linearity compared with standard light collection and readout systems. In addition, we study the performance of the calorimeter for partially contained charged hadrons to assess the $e/π$ separation capability and the response of the photosensors to direct ionization.

physics.ins-det↗

arXiv2016

The CUORE Cryostat: A 1-Ton Scale Setup for Bolometric Detectors

The cryogenic underground observatory for rare events (CUORE) is a 1-ton scale bolometric experiment whose detector consists of an array of 988 TeO2 crystals arranged in a cylindrical compact structure of 19 towers. This will be the largest bolometric mass ever operated. The experiment will work at a temperature around or below 10 mK. CUORE cryostat consists of a cryogen-free system based on pulse tubes and a custom high power dilution refrigerator, designed to match these specifications. The cryostat has been commissioned in 2014 at the Gran Sasso National Laboratories and reached a record temperature of 6 mK on a cubic meter scale. In this paper, we present results of CUORE commissioning runs. Details on the thermal characteristics and cryogenic performances of the system will be also given.

physics.ins-det↗

arXiv2015

A non-conventional neutrino beamline for the measurement of the electron neutrino cross section

Absolute neutrino cross section measurements at the GeV scale are ultimately limited by the knowledge of the initial $ν$ flux. In order to evade such limitation and reach the accuracy that is needed for precision oscillation physics ($\sim 1$%), substantial advances in flux measurement techniques are requested. We discuss here the possibility of instrumenting the decay tunnel to identify large-angle positrons and monitor $ν_e$ production from $K^+ \rightarrow e^+ ν_e π^0$ decays. This non conventional technique opens up opportunities to measure the $ν_e$ CC cross section at the per cent level in the energy range of interest for DUNE/HK. We discuss the progress in the simulation of the facility (beamline and instrumentation) and the ongoing R&D.

hep-ex↗

arXiv2015

Large area Si low-temperature light detectors with Neganov-Luke effect

Next generation calorimetric experiments for the search of rare events rely on the detection of tiny amounts of light (of the order of 20 optical photons) to discriminate and reduce background sources and improve sensitivity. Calorimetric detectors are the simplest solution for photon detection at cryogenic (mK) temperatures. The development of silicon based light detectors with enhanced performance thanks to the use of the Neganov-Luke effect is described. The aim of this research line is the production of high performance detectors with industrial-grade reproducibility and reliability.

physics.ins-det↗

arXiv2015

A novel technique for the measurement of the electron neutrino cross section

Absolute neutrino cross section measurements are presently limited by uncertainties on $ν$ fluxes. In this paper, we propose a technique that is based on the reconstruction of large angle positrons in the decay tunnel to identify three-body semileptonic $K^+ \rightarrow e^+ π^0 ν_e$ decays. This tagging facility operated in positron counting mode ("event count mode") can be employed to determine the absolute $ν_e$ flux at the neutrino detector with ${\cal O}(1\%)$ precision. Facilities operated in "event by event tag mode" i.e. tagged neutrino beams that exploit the time coincidence of the positron at source and the $ν_e$ interaction at the detector, are also discussed.

hep-ex↗

arXiv2015

HOLMES - The Electron Capture Decay of 163Ho to Measure the Electron Neutrino Mass with sub-eV sensitivity

The European Research Council has recently funded HOLMES, a new experiment to directly measure the neutrino mass. HOLMES will perform a calorimetric measurement of the energy released in the decay of 163Ho. The calorimetric measurement eliminates systematic uncertainties arising from the use of external beta sources, as in experiments with beta spectrometers. This measurement was proposed in 1982 by A. De Rujula and M. Lusignoli, but only recently the detector technological progress allowed to design a sensitive experiment. HOLMES will deploy a large array of low temperature microcalorimeters with implanted 163Ho nuclei. The resulting mass sensitivity will be as low as 0.4 eV. HOLMES will be an important step forward in the direct neutrino mass measurement with a calorimetric approach as an alternative to spectrometry. It will also establish the potential of this approach to extend the sensitivity down to 0.1 eV. We outline here the project with its technical challenges and perspectives.

physics.ins-det↗

arXiv2014

Initial performance of the CUORE-0 experiment

CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide bolometers to search for neutrinoless double-beta decay of ^{130}Te. We present the first data analysis with 7.1 kg y of total TeO_2 exposure focusing on background measurements and energy resolution. The background rates in the neutrinoless double-beta decay region of interest (2.47 to 2.57 MeV) and in the α background-dominated region (2.70 to 3.90 MeV) have been measured to be 0.071 \pm 0.011 and 0.019 \pm 0.002 counts/keV/kg/y, respectively. The latter result represents a factor of 6 improvement from a predecessor experiment, Cuoricino. The results verify our understanding of the background sources in CUORE-0, which is the basis of extrapolations to the full CUORE detector. The obtained energy resolution (full width at half maximum) in the region of interest is 5.7 keV. Based on the measured background rate and energy resolution in the region of interest, CUORE-0 half-life sensitivity is expected to surpass the observed lower bound of Cuoricino with one year of live time.

physics.ins-det↗

arXiv2014

Particle acceleration in sub-cycle optical cells

A single laser pulse with spot size smaller than half its wavelength ($w_0 < λ/2$) can provide a net energy gain to ultra-relativistic particles. In this paper, we discuss the properties of an optical cell consisting of $N$ sub-cycle pulses that propagate in the direction perpendicular to the electron motion. We show that the energy gain produced by the cell is proportional to $N$ and it is sizable even for $\mathcal{O}(1\mathrm{~TW})$ pulses.

physics.optics↗

arXiv2014

Testing the $a_μ$ anomaly in the electron sector through a precise measurement of $h/M$

The persistent $a_μ\equiv (g-2)/2$ anomaly in the muon sector could be due to new physics visible in the electron sector through a sub-ppb measurement of the anomalous magnetic moment of the electron $a_e$. Driven by recent results on the electron mass (S. Sturm et al., Nature 506 (2014) 467), we reconsider the sources of uncertainties that limit our knowledge of $a_e$ including current advances in atom interferometry. We demonstrate that it is possible to attain the level of precision needed to test $a_μ$ in the naive scaling hypothesis on a timescale similar to next generation $g-2$ muon experiments at Fermilab and JPARC. In order to achieve such level of precision, the knowledge of the quotient $h/M$, i.e. the ratio between the Planck constant and the mass of the atom employed in the interferometer, will play a crucial role. We identify the most favorable isotopes to achieve an overall relative precision below $10^{-10}$.

hep-ex↗

arXiv2013

The Future of Neutrino Mass Measurements: Terrestrial, Astrophysical, and Cosmological Measurements in the Next Decade. Highlights of the NuMass 2013 Workshop. Milano, Italy, February 4 - 7, 2013

The third Workshop of the NuMass series ("The Future of Neutrino Mass Measurements: Terrestrial, Astrophysical, and Cosmological Measurements in the Next Decade: NuMass 2013") was held at Dipartimento di Fisica "G. Occhialini, University of Milano-Bicocca in Milano, Italy, on 4-7 February 2013. The goal of this international workshop was to review the status and future of direct and indirect neutrino mass measurements in the laboratory as well as from astrophysical and cosmological observations. This paper collects most of the contributions presented during the Workshop.

hep-ex↗

arXiv2013

The 4 K outer cryostat for the CUORE experiment: construction and quality control

The external shell of the CUORE cryostat is a large cryogen-free system designed to host the dilution refrigerator and the bolometers of the CUORE experiment in a low radioactivity environment. The three vessels that form the outer shell were produced and delivered to the Gran Sasso underground Laboratories in July 2012. In this paper, we describe the production techniques and the validation tests done at the production site in 2012.

physics.ins-det↗

arXiv2013

CP violation and mass hierarchy at medium baselines in the large theta(13) era

The large value of theta(13) recently measured by rector and accelerator experiments opens unprecedented opportunities for precision oscillation physics. In this paper, we reconsider the physics reach of medium baseline superbeams. For theta(13) ~ 9 degree we show that facilities at medium baselines -- i.e. L ~ O(1000 km) -- remain optimal for the study of CP violation in the leptonic sector, although their ultimate precision strongly depends on experimental systematics. This is demonstrated in particular for facilities of practical interest in Europe: a CERN to Gran Sasso and CERN to Phyasalmi nu_mu beam based on the present SPS and on new high power 50 GeV proton driver. Due to the large value of theta(13), spectral information can be employed at medium baselines to resolve the sign ambiguity and determine the neutrino mass hierarchy. However, longer baselines, where matter effects dominate the nu_mu->nu_e transition, can achieve much stronger sensitivity to sign(Delta m^2) even at moderate exposures.

hep-ph↗

arXiv2012

EUROnu-WP6 2010 Report

This is a summary of the work done by the Working Package 6 (Physics) of the EU project "EUROnu" during the second year of activity of the project.

hep-ph↗

arXiv2012

Determination of a time-shift in the OPERA set-up using high energy horizontal muons in the LVD and OPERA detectors

The purpose of this work is to report the measurement of a time-shift in the OPERA set-up in a totally independent way from Time Of Flight (TOF) measurements of CNGS neutrino events. The LVD and OPERA experiments are both installed in the same laboratory: LNGS. The relative position of the two detectors, separated by an average distance of ~ 160 m, allows the use of very high energy horizontal muons to cross-calibrate the timing systems of the two detectors, using a TOF technique which is totally independent from TOF of CNGS neutrino events. Indeed, the OPERA-LVD direction lies along the so-called "Teramo anomaly", a region in the Gran Sasso massif where LVD has established, many years ago, the existence of an anomaly in the mountain structure, which exhibits a low m. w. e. thickness for horizontal directions. The "abundant" high-energy horizontal muons (nearly 100 per year) going through LVD and OPERA exist because of this anomaly in the mountain orography. The total live time of the data in coincidence correspond to 1200 days from mid 2007 until March 2012. The time coincidence study of LVD and OPERA detectors is based on 306 cosmic horizontal muon events and shows the existence of a negative time shift in the OPERA set-up of the order of deltaT(AB) = - (73 \pm 9) ns when two calendar periods, A and B, are compared. This result shows a systematic effect in the OPERA timing system from August 2008 until December 2011. The size of the effect is comparable with the neutrino velocity excess recently measured by OPERA. It is probably interesting not to forget that with the MRPC technology developed by the ALICE Bologna group the TOF world record accuracy of 20 ps was reached. That technology can be implemented at LNGS for a high precision determination of TOF with the CNGS neutrino beams of an order of magnitude smaller than the value of the OPERA systematic effect.

hep-ex↗

arXiv2011

An infrared origin of leptonic mixing and its test at DeepCore

Fermion mixing is generally believed to be a low-energy manifestation of an underlying theory whose energy scale is much larger than the electroweak scale. In this paper we investigate the possibility that the parameters describing lepton mixing actually arise from the low-energy behavior of the neutrino interacting fields. In particular, we conjecture that the measured value of the mixing angles for a given process depends on the number of unobservable flavor states at the energy of the process. We provide a covariant implementation of such conjecture, draw its consequences in a two neutrino family approximation and compare these findings with current experimental data. Finally we show that this infrared origin of mixing will be manifest at the Ice Cube DeepCore array, which measures atmospheric oscillations at energies much larger than the tau lepton mass; it will hence be experimentally tested in a short time scale.

hep-ph↗

arXiv2011

Learning from tau appearance

The study of numu->nutau oscillation and the explicit observation of the nutau through the identification of the final-state tau lepton ("direct appearance search") represent the most straightforward test of the oscillation phenomenon. It is, nonetheless, the most challenging from the experimental point of view. In this paper we discuss the current empirical evidence for direct appearance of tau neutrinos at the atmospheric scale and the perspectives for the next few years, up to the completion of the CNGS physics programme. We investigate the relevance of this specific oscillation channel to gain insight into neutrino physics within the standard three-family framework. Finally, we discuss the opportunities offered by precision studies of numu->nutau transitions in the occurrence of more exotic scenarios emerging from additional sterile neutrinos or non-standard interactions.

hep-ex↗

arXiv2010

Electron neutrino tagging through tertiary lepton detection

We discuss an experimental technique aimed at tagging electron neutrinos in multi-GeV artificial sources on an event-by-event basis. It exploits in a novel manner calorimetric and tracking technologies developed in the framework of the LHC experiments and of rare kaon decay searches. The setup is suited for slow-extraction, moderate power beams and it is based on an instrumented decay tunnel equipped with tagging units that intercept secondary and tertiary leptons from the bulk of undecayed π^+ and protons. We show that the taggers are able to reduce the \nue contamination originating from K_e3 decays by about one order of magnitude. Only a limited suppression (~60%) is achieved for \nue produced by the decay-in-flight of muons; for low beam powers, similar performance as for K_e3 can be reached supplementing the tagging system with an instrumented beam dump.

hep-ex↗

arXiv2010

A minimal Beta Beam with high-Q ions to address CP violation in the leptonic sector

In this paper we consider a Beta Beam setup that tries to leverage at most existing European facilities: i.e. a setup that takes advantage of facilities at CERN to boost high-Q ions (8Li and 8B) aiming at a far detector located at L = 732 Km in the Gran Sasso Underground Laboratory. The average neutrino energy for 8Li and 8B ions boosted at γ~ 100 is in the range E_ν= [1,2] GeV, high enough to use a large iron detector of the MINOS type at the far site. We perform, then, a study of the neutrino and antineutrino fluxes needed to measure a CP-violating phase delta in a significant part of the parameter space. In particular, for theta_13 > 3 deg, if an antineutrino flux of 3 10^19 useful 8Li decays per year is achievable, we find that delta can be measured in 60% of the parameter space with 6 10^18 useful 8B decays per year.

hep-ph↗