arXiv subjects

D. Montanino

Publications and source records attributed to D. Montanino.

At least 19 recordsLinked to original sources

arXiv2026

Application of zone refining to the development of NaI(Tl) detectors for SABRE North

The SABRE North experiment is developing ultra-high radiopurity NaI(Tl) detectors to investigate dark matter. To achieve this, SABRE North utilizes the technique called zone refining for NaI purification. This work details the mathematical model developed to describe the purification process. By comparing this model to the results of the commissioning and production runs conducted prior to crystal growth, the distribution coefficients were determined for various impurities, contained in the powder at the parts-per-billion (ppb) level. Furthermore, the synthesis of data from both zone refining and normal freezing is discussed. These findings can be used to predict the SABRE North detectors background level in the energy region-of-interest for dark matter search and to optimize the production of ultra-high purity crystals through multiple purification strategies.

physics.ins-det↗

arXiv2022

Snowmass 2021 White Paper: The Selena Neutrino Experiment

Imaging devices made from an ionization target layer of amorphous selenium (aSe) coupled to a silicon complementary metal-oxide-semiconductor (CMOS) active pixel array for charge readout are a promising technology for neutrino physics. The high spatial resolution in a solid-state target provides unparalleled rejection of backgrounds from natural radioactivity in the search for neutrinoless $ββ$ decay and for electron neutrino ($ν_e$) spectroscopy with $^{82}$Se. In this white paper, we summarize the broad scientific program of a large imaging detector with a 10-ton target of $^{82}$Se. We review the detector technology, and outline the ongoing research program to realize this experiment.

physics.ins-det↗

arXiv2021

Coded masks for imaging of neutrino events

The capture of scintillation light emitted by liquid Argon and Xenon under molecular excitations by charged particles is still a challenging task. Here we present a first attempt to design a device able to grab sufficiently high luminosity in order to reconstruct the path of ionizing particles. This preliminary study is based on the use of masks to encode the light signal combined with single-photon detectors. In this respect, the proposed system is able to detect tracks over focal distances of about tens of centimeters. From numerical simulations it emerges that it is possible to successfully decode and recognize signals, even complex, with a relatively limited number of acquisition channels. Such innovative technique can be very fruitful in a new generation of detectors devoted to neutrino physics and dark matter search. Indeed the introduction of coded masks combined with SiPM detectors is proposed for a liquid-Argon target in the Near Detector of the DUNE experiment.

physics.ins-det↗

arXiv2019

KLASH Conceptual Design Report

The last decade witnessed an increasing interest in axions and axion-like particles with many theoretical works published and many new experimental proposals that started a real race towards their discovery. This paper is the Conceptual Design Report of the KLASH (KLoe magnet for Axion SearcH) experiment at the Laboratori Nazionali di Frascati (LNF). The idea of this experiment has been stimulated by the availability of the large volume superconducting magnet, with a moderate magnetic field of 0.6 T, used in the KLOE detector at the DAFNE collider. The main conclusion we draw from this report is the possibility to build and put in operation at LNF in 2-3 years a large haloscope with the sensitivity to KSVZ axions in the low mass range between 0.2 and 1 $μ$eV, complementary to that of other experiments. Timeline and cost are competitive with respect to other proposals in the same mass region thanks to the availability of most of the infrastructure, in particular the superconducting magnet and the cryogenics plant.

physics.ins-det↗

arXiv2016

Neutrino masses and mixings: Status of known and unknown $3ν$ parameters

Within the standard 3nu mass-mixing framework, we present an up-to-date global analysis of neutrino oscillation data (as of January 2016), including the latest available results from experiments with atmospheric neutrinos (Super-Kamiokande and IceCube DeepCore), at accelerators (first T2K anti-nu and NOvA nu runs in both appearance and disappearance mode), and at short-baseline reactors (Daya Bay and RENO far/near spectral ratios), as well as a reanalysis of older KamLAND data in the light of the "bump" feature recently observed in reactor spectra. We discuss improved constraints on the five known oscillation parameters (delta m^2, |Delta m^2|, sin^2theta_12, sin^2theta_13, sin^2theta_23), and the status of the three remaining unknown parameters: the mass hierarchy, the theta_23 octant, and the possible CP-violating phase delta. With respect to previous global fits, we find that the reanalysis of KamLAND data induces a slight decrease of both delta m^2 and sin^2theta_12, while the latest accelerator and atmospheric data induce a slight increase of |Delta m^2|. Concerning the unknown parameters, we confirm the previous intriguing preference for negative values of sin(delta) [with best-fit values around sin(delta) ~ -0.9], but we find no statistically significant indication about the theta_23 octant or the mass hierarchy (normal or inverted). Assuming an alternative (so-called LEM) analysis of NOvA data, some delta ranges can be excluded at >3 sigma, and the normal mass hierarchy appears to be slightly favored at 90% C.L. We also describe in detail the covariances of selected pairs of oscillation parameters. Finally, we briefly discuss the implications of the above results on the three non-oscillation observables sensitive to the (unknown) absolute nu mass scale: the sum of nu masses, the effective nu_e mass, and the effective Majorana mass.

hep-ph↗

arXiv2014

Status of three-neutrino oscillation parameters, circa 2013

The standard three-neutrino (3nu) oscillation framework is being increasingly refined by results coming from different sets of experiments, using neutrinos from solar, atmospheric, accelerator and reactor sources. At present, each of the known oscillation parameters [the two squared mass gaps (delta m^2, Delta m^2) and the three mixing angles (theta_12}, theta_13, theta_23)] is dominantly determined by a single class of experiments. Conversely, the unknown parameters [the mass hierarchy, the theta_23 octant and the CP-violating phase delta] can be currently constrained only through a combined analysis of various (eventually all) classes of experiments. In the light of recent new results coming from reactor and accelerator experiments, and of their interplay with solar and atmospheric data, we update the estimated N-sigma ranges of the known 3nu parameters, and revisit the status of the unknown ones. Concerning the hierarchy, no significant difference emerges between normal and inverted mass ordering. A slight overall preference is found for theta_23 in the first octant and for nonzero CP violation with sin delta < 0; however, for both parameters, such preference exceeds 1 sigma only for normal hierarchy. We also discuss the correlations and stability of the oscillation parameters within different combinations of data sets.

hep-ph↗

arXiv2012

Global analysis of neutrino masses, mixings and phases: entering the era of leptonic CP violation searches

We perform a global analysis of neutrino oscillation data, including high-precision measurements of the neutrino mixing angle theta_13 at reactor experiments, which have confirmed previous indications in favor of theta_13>0. Recent data presented at the Neutrino 2012 Conference are also included. We focus on the correlations between theta_13 and the mixing angle theta_23, as well as between theta_13 and the neutrino CP-violation phase delta. We find interesting indications for theta_23< pi/4 and possible hints for delta ~ pi, with no significant difference between normal and inverted mass hierarchy.

hep-ph↗

arXiv2009

Neutrino Dipole Moments and Solar Experiments

First we investigate the possibility of detecting solar antineutrinos with the KamLAND experiment. Then we analyze the first Borexino data release to constrain the neutrino magnetic moment. Finally we investigate the resonant spin flavour conversion of solar neutrinos to sterile ones, a mechanism which is added to the well known LMA one. In this last condition, we show that the data from all solar neutrino experiments except Borexino exhibit a clear preference for a sizable magnetic field. We argue that the solar neutrino experiments are capable of tracing the possible modulation of the solar magnetic field. In this way Borexino alone may play an essential role although experimental redundancy from other experiments will be most important.

hep-ph↗

arXiv2008

Probing neutrino magnetic moment and unparticle interactions with Borexino

We discuss the limits on the neutrino magnetic moment and hypothetical interactions with a hidden unparticle sector, coming from the first neutrino data release of the Borexino experiment. The observed spectrum in Borexino depends weakly on the solar model used in the analysis, since most of the signal comes from the mono-energetic 7Be neutrinos. This fact allows us to calibrate the nu-e scattering cross section through the spectral shape. In this way, we have derived a limit on the magnetic moment for the neutrinos coming from the Sun (in which a nu_mu and nu_tau component is present): mu_nu<8.4E-11 mu_B (90%CL) which is comparable with those obtained from low energy reactor experiments. Moreover, we improve the previous upper limit on magnetic moment of the nu_tau by three orders of magnitude and the limit on the coupling constant of the neutrino with a hidden unparticle sector.

hep-ph↗

arXiv2007

Revisiting cosmological bounds on radiative neutrino lifetime

Neutrino oscillation experiments and direct bounds on absolute masses constrain neutrino mass differences to fall into the microwave energy range, for most of the allowed parameter space. As a consequence of these recent phenomenological advances, older constraints on radiative neutrino decays based on diffuse background radiations and assuming strongly hierarchical masses in the eV range are now outdated. We thus derive new bounds on the radiative neutrino lifetime using the high precision cosmic microwave background spectral data collected by the Far Infrared Absolute Spectrophotometer instrument on board of Cosmic Background Explorer. The lower bound on the lifetime is between a few x 10^19 s and 5 x 10^20 s, depending on the neutrino mass ordering and on the absolute mass scale. However, due to phase space limitations, the upper bound in terms of the effective magnetic moment mediating the decay is not better than ~ 10^-8 Bohr magnetons. We also comment about possible improvements of these limits, by means of recent diffuse infrared photon background data. We compare these bounds with pre-existing limits coming from laboratory or astrophysical arguments. We emphasize the complementarity of our results with others available in the literature.

hep-ph↗

arXiv2007

Probing non-standard decoherence effects with solar and KamLAND neutrinos

It has been speculated that quantum gravity might induce a "foamy" space-time structure at small scales, randomly perturbing the propagation phases of free-streaming particles (such as kaons, neutrons, or neutrinos). Particle interferometry might then reveal non-standard decoherence effects, in addition to standard ones (due to, e.g., finite source size and detector resolution.) In this work we discuss the phenomenology of such non-standard effects in the propagation of electron neutrinos in the Sun and in the long-baseline reactor experiment KamLAND, which jointly provide us with the best available probes of decoherence at neutrino energies E ~ few MeV. In the solar neutrino case, by means of a perturbative approach, decoherence is shown to modify the standard (adiabatic) propagation in matter through a calculable damping factor. By assuming a power-law dependence of decoherence effects in the energy domain (E^n with n = 0,+/-1,+/-2), theoretical predictions for two-family neutrino mixing are compared with the data and discussed. We find that neither solar nor KamLAND data show evidence in favor of non-standard decoherence effects, whose characteristic parameter gamma_0 can thus be significantly constrained. In the "Lorentz-invariant" case n=-1, we obtain the upper limit gamma_0<0.78 x 10^-26 GeV at 95% C.L. In the specific case n=-2, the constraints can also be interpreted as bounds on possible matter density fluctuations in the Sun, which we improve by a factor of ~ 2 with respect to previous analyses.

hep-ph↗

arXiv2006

Oscillations of solar atmosphere neutrinos

The Sun is a source of high energy neutrinos (E > 10 GeV) produced by cosmic ray interactions in the solar atmosphere. We study the impact of three-flavor oscillations (in vacuum and in matter) on solar atmosphere neutrinos, and calculate their observable fluxes at Earth, as well as their event rates in a kilometer-scale detector in water or ice. We find that peculiar three-flavor oscillation effects in matter, which can occur in the energy range probed by solar atmosphere neutrinos, are significantly suppressed by averaging over the production region and over the neutrino and antineutrino components. In particular, we find that the relation between the neutrino fluxes at the Sun and at the Earth can be approximately expressed in terms of phase-averaged ``vacuum'' oscillations, dominated by a single mixing parameter (the angle theta_23).

hep-ph↗

arXiv2006

Damping of supernova neutrino transitions in stochastic shock-wave density profiles

Supernova neutrino flavor transitions during the shock wave propagation are known to encode relevant information not only about the matter density profile but also about unknown neutrino properties, such as the mass hierarchy (normal or inverted) and the mixing angle theta_13. While previous studies have focussed on "deterministic" density profiles, we investigate the effect of possible stochastic matter density fluctuations in the wake of supernova shock waves. In particular, we study the impact of small-scale fluctuations on the electron (anti)neutrino survival probability, and on the observable spectra of inverse-beta-decay events in future water-Cherenkov detectors. We find that such fluctuations, even with relatively small amplitudes, can have significant damping effects on the flavor transition pattern, and can partly erase the shock-wave imprint on the observable time spectra, especially for sin^2(theta_13) > O(10^-3).

hep-ph↗

arXiv2005

How to observe 8B solar neutrinos in liquid scintillator detectors

We show that liquid organic scintillator detectors (e.g., KamLAND and Borexino) can measure the 8B solar neutrino flux by means of the nu_e charged current interaction with the 13C nuclei naturally contained in the scintillators. The neutrino events can be identified by exploiting the time and space coincidence with the subsequent decay of the produced 13N nuclei. We perform a detailed analysis of the background in KamLAND, Borexino and in a possible liquid scintillator detector at SNOLab, showing that the 8B solar neutrino signal can be extracted with a reasonable uncertainty in a few years of data taking. KamLAND should be able to extract about 18 solar neutrino events from the already collected data. Prospects for gigantic scintillator detectors (such as LENA) are also studied.

physics.ins-det↗

arXiv2005

Probing supernova shock waves and neutrino flavor transitions in next-generation water-Cherenkov detectors

Several current projects aim at building a large water-Cherenkov detector, with a fiducial volume about 20 times larger than in the current Super-Kamiokande experiment. These projects include the Underground nucleon decay and Neutrino Observatory (UNO) in the Henderson Mine (Colorado), the Hyper-Kamiokande (HK) detector in the Tochibora Mine (Japan), and the MEgaton class PHYSics (MEMPHYS) detector in the Frejus site (Europe). We study the physics potential of a reference next-generation detector (0.4 Mton of fiducial mass) in providing information on supernova neutrino flavor transitions with unprecedented statistics. After discussing the ingredients of our calculations, we compute neutrino event rates from inverse beta decay ($\barν_e p\to e^+ n $), elastic scattering on electrons, and scattering on oxygen, with emphasis on their time spectra, which may encode combined information on neutrino oscillation parameters and on supernova forward (and possibly reverse) shock waves. In particular, we show that an appropriate ratio of low-to-high energy events can faithfully monitor the time evolution of the neutrino crossing probability along the shock-wave profile. We also discuss some background issues related to the detection of supernova relic neutrinos, with and without the addition of gadolinium.

hep-ph↗

arXiv2004

Decays of supernova relic neutrinos

We propose that future observations of supernova relic neutrinos (SRN) can be used to probe neutrino decay models. We focus on invisible (e.g. Majoron) decays, and work out the general solution of SRN kinetic equations in the presence of oscillations plus decay. We then apply the general solution to specific decay scenario, and show that the predicted SRN event rate can span the whole range below the current experimental bounds. Therefore, future SRN observations will surely have an impact on the neutrino decay parameter space.

hep-ph↗

arXiv2004

Three-generation flavor transitions and decays of supernova relic neutrinos

If neutrinos have mass, they can also decay. Decay lifetimes of cosmological interest can be probed, in principle, through the detection of the redshifted, diffuse neutrino flux produced by all past supernovae--the so-called supernova relic neutrino (SRN) flux. In this work, we solve the SRN kinetic equations in the general case of three-generation flavor transitions followed by invisible (nonradiative) two-body decays. We then use the general solution to calculate observable SRN spectra in some representative decay scenarios. It is shown that, in the presence of decay, the SRN event rate can basically span the whole range below the current experimental upper bound--a range accessible to future experimental projects. Radiative SRN decays are also briefly discussed.

hep-ph↗

arXiv2003

Neutrino Oscillations: A Global Analysis

We review the status of the neutrino oscillation physics (as of June 2003), with a particular emphasis on the present knowledge of the neutrino mass-mixing parameters in a three generation approach. We consider first the nu_mu-->nu_tau flavor transitions of atmospheric neutrinos. It is found that standard oscillations provide the best description of the SK+K2K data, and that the associated mass-mixing parameters are determined at 1 sigma (and dof=1) as: Delta m^2=(2.6 +-0.4) x 10^-3 eV^2 and sin^2(2theta)=1.00+0.00-0.05. Such indications, presently dominated by SK, could be strengthened by further K2K data. Then we analyze the energy spectrum of reactor neutrino events recently observed at KamLAND and combine them with solar and terrestrial neutrino data. We find that the solution to the solar neutrino problem at large mixing angle (LMA) is basically split into two sub-regions, that we denote as LMA-I and LMA-II. The LMA-I solution, characterized by lower values of the squared neutrino mass gap, is favored by the global data fit. Finally, we briefly illustrate how prospective data from the SNO and KamLAND can increase our confidence in the occurrence of standard matter effects in the Sun, which are starting to emerge from current data.

hep-ph↗