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3 pages, 177 KiB

Open AccessEditorial

Italian Research Facilities for Fundamental Physics

by Marco Selvi and Francesco Terranova

Universe 2022, 8(2), 82; https://doi.org/10.3390/universe8020082 - 27 Jan 2022

Viewed by 1463

Abstract

This Special Issue of Universe addresses the international community working at the Italian Research Facilities for Fundamental Physics, Italian labs and facilities playing a pivotal role in the core fields of this journal, such as gravitational waves, dark matter and rare event searches, [...] Read more.

This Special Issue of Universe addresses the international community working at the Italian Research Facilities for Fundamental Physics, Italian labs and facilities playing a pivotal role in the core fields of this journal, such as gravitational waves, dark matter and rare event searches, neutrino astronomy, and underground physics [...] Full article

(This article belongs to the Special Issue Italian Research Facilities for Fundamental Physics)

Research

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15 pages, 5271 KiB

Open AccessArticle

Dark Matter Searches at LNF

by Claudio Gatti, Paola Gianotti, Carlo Ligi, Mauro Raggi and Paolo Valente

Universe 2021, 7(7), 236; https://doi.org/10.3390/universe7070236 - 9 Jul 2021

Cited by 11 | Viewed by 2367

Abstract

In recent years, the absence of experimental evidence for searches dedicated to dark matter has triggered the development of new ideas on the nature of this entity, which manifests at the cosmological level. Some of these can be explored by small experiments with [...] Read more.

In recent years, the absence of experimental evidence for searches dedicated to dark matter has triggered the development of new ideas on the nature of this entity, which manifests at the cosmological level. Some of these can be explored by small experiments with a short timescale and an investment that can be afforded by national laboratories, such as the Frascati one. This is the main reason why a laboratory that, traditionally, was focused in particle physics studies with accelerators has begun intense activity in this field of research. Full article

(This article belongs to the Special Issue Italian Research Facilities for Fundamental Physics)

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Review

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45 pages, 9582 KiB

Open AccessReview

Advanced Virgo: Status of the Detector, Latest Results and Future Prospects

by Diego Bersanetti, Barbara Patricelli, Ornella Juliana Piccinni, Francesco Piergiovanni, Francesco Salemi and Valeria Sequino

Universe 2021, 7(9), 322; https://doi.org/10.3390/universe7090322 - 30 Aug 2021

Cited by 23 | Viewed by 4236

Abstract

The Virgo detector, based at the EGO (European Gravitational Observatory) and located in Cascina (Pisa), played a significant role in the development of the gravitational-wave astronomy. From its first scientific run in 2007, the Virgo detector has constantly been upgraded over the years; [...] Read more.

The Virgo detector, based at the EGO (European Gravitational Observatory) and located in Cascina (Pisa), played a significant role in the development of the gravitational-wave astronomy. From its first scientific run in 2007, the Virgo detector has constantly been upgraded over the years; since 2017, with the Advanced Virgo project, the detector reached a high sensitivity that allowed the detection of several classes of sources and to investigate new physics. This work reports the main hardware upgrades of the detector and the main astrophysical results from the latest five years; future prospects for the Virgo detector are also presented. Full article

(This article belongs to the Special Issue Italian Research Facilities for Fundamental Physics)

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31 pages, 8764 KiB

Open AccessReview

GERDA and LEGEND: Probing the Neutrino Nature and Mass at 100 meV and beyond

by Carla Maria Cattadori and Francesco Salamida

Universe 2021, 7(9), 314; https://doi.org/10.3390/universe7090314 - 25 Aug 2021

Cited by 9 | Viewed by 2857

Abstract

The Gerda (GERmanium Detector Array) project, located at Laboratori Nazionali del Gran Sasso (LNGS), was started in 2005, a few years after the claim of evidence for the neutrinoless double beta decay (

0 ν β β

) of

^{76}

Ge to the [...] Read more.

The Gerda (GERmanium Detector Array) project, located at Laboratori Nazionali del Gran Sasso (LNGS), was started in 2005, a few years after the claim of evidence for the neutrinoless double beta decay (

0 ν β β

) of

^{76}

Ge to the ground state of

^{76}

Se: it is an ultra-rare process whose detection would directly establish the Majorana nature of the neutrino and provide a measurement of its mass and mass hierarchy. The aim of Gerda was to confirm or disprove the claim by an increased sensitivity experiment. After establishing the new technology of Ge detectors operated bare in liquid Argon and since 2011, Gerda efficiently collected data searching for

0 ν β β

of

^{76}

Ge, first deploying the

^{76}

Ge-enriched detectors from two former experiments and later new detectors with enhanced signal-to-background rejection, produced from freshly

^{76}

Ge-enriched material. Since then, the Gerda setup has been upgraded twice, first in 2013–2015 and later in 2018. The period before 2013 is Phase I and that after 2015 is Phase II. Both the Gerda setup and the analysis tools evolved along the project lifetime, allowing to achieve the remarkable average energy resolution of ∼3.6 and ∼2.6 keV for Coaxial Germanium (Coax) detectors and for Broad Energy Germanium (BEGe), respectively, and the background index of

5 . 2_{- 1.3}^{+ 1.6}

·

10^{- 4}

cts/(keV·kg·yr) in a 230 keV net range centered at

Q_{β β}

. No evidence of the

0 ν β β

decay at

Q_{β β}

= 2039.1 keV has been found, hence the limit of

1.8 \cdot 10^{26}

yr on the half-life (

T_{1 / 2}^{0 ν}

) at 90% C.L. was set with the exposure of 127.2 kg·yr. The corresponding limit range for the effective Majorana neutrino mass

m_{e e}

has been set to 79–180 meV. The Gerda performances in terms of background index, energy resolution and exposure are the best achieved so far by

^{76}

Ge double beta decay experiments. In Phase II, Gerda succeeded in operating in a background free regime and set a world record. In 2017, the Legend Collaboration was born from the merging of the Gerda and Majorana Collaborations and resources with the aim to further improve the Gerda sensitivity. First, the Legend200 project, with a mass of up to 200 kg of

^{76}

Ge-enriched detectors, aims to further improve the background index down to <0.6 ·

10^{- 3}

cts/(keV·kg·yr) to explore the Inverted Hierarchy region of the neutrino mass ordering, then the Legend1000 (1 ton of

^{76}

Ge-enriched) will probe the Normal Hierarchy. In this paper, we describe the Gerda experiment, its evolution, the data analysis flow, a selection of its results and technological achievements, and finally the design, features and challenges of Legend, the Gerda prosecutor. Full article

(This article belongs to the Special Issue Italian Research Facilities for Fundamental Physics)

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27 pages, 15000 KiB

Open AccessReview

The Xenon Road to Direct Detection of Dark Matter at LNGS: The XENON Project

by Pietro Di Gangi

Universe 2021, 7(8), 313; https://doi.org/10.3390/universe7080313 - 23 Aug 2021

Cited by 5 | Viewed by 4162

Abstract

Dark matter is a milestone in the understanding of the Universe and a portal to the discovery of new physics beyond the Standard Model of particles. The direct search for dark matter has become one of the most active fields of experimental physics [...] Read more.

Dark matter is a milestone in the understanding of the Universe and a portal to the discovery of new physics beyond the Standard Model of particles. The direct search for dark matter has become one of the most active fields of experimental physics in the last few decades. Liquid Xenon (LXe) detectors demonstrated the highest sensitivities to the main dark matter candidates (Weakly Interactive Massive Particles, WIMP). The experiments of the XENON project, located in the underground INFN Laboratori Nazionali del Gran Sasso (LNGS) in Italy, are leading the field thanks to the dual-phase LXe time projection chamber (TPC) technology. Since the first prototype XENON10 built in 2005, each detector of the XENON project achieved the highest sensitivity to WIMP dark matter. XENON increased the LXe target mass by nearly a factor 400, up to the 5.9 t of the current XENONnT detector installed at LNGS in 2020. Thanks to an unprecedentedly low background level, XENON1T (predecessor of XENONnT) set the world best limits on WIMP dark matter to date, for an overall boost of more than 3 orders of magnitude to the experimental sensitivity since the XENON project started. In this work, we review the principles of direct dark matter detection with LXe TPCs, the detectors of the XENON project, the challenges posed by background mitigation to ultra-low levels, and the main results achieved by the XENON project in the search for dark matter. Full article

(This article belongs to the Special Issue Italian Research Facilities for Fundamental Physics)

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31 pages, 4153 KiB

Open AccessReview

Optical Polarimetry for Fundamental Physics

by Guido Zavattini and Federico Della Valle

Universe 2021, 7(7), 252; https://doi.org/10.3390/universe7070252 - 20 Jul 2021

Cited by 4 | Viewed by 3069

Abstract

Sensitive magneto-optical polarimetry was proposed by E. Iacopini and E. Zavattini in 1979 to detect vacuum electrodynamic non-linearity, in particular Vacuum Magnetic Birefringence (VMB). This process is predicted in QED via the fluctuation of electron–positron virtual pairs but can also be due to [...] Read more.

Sensitive magneto-optical polarimetry was proposed by E. Iacopini and E. Zavattini in 1979 to detect vacuum electrodynamic non-linearity, in particular Vacuum Magnetic Birefringence (VMB). This process is predicted in QED via the fluctuation of electron–positron virtual pairs but can also be due to hypothetical Axion-Like Particles (ALPs) and/or MilliCharged Particles (MCP). Today ALPs are considered a strong candidate for Dark Matter. Starting in 1992 the PVLAS collaboration, financed by INFN, Italy, attempted to measure VMB conceptually following the original 1979 scheme based on an optical cavity permeated by a time-dependent magnetic field and heterodyne detection. Two setups followed differing basically in the magnet: the first using a rotating superconducting 5.5 T dipole magnet at the Laboratori Nazionali di Legnaro, Legnaro, Italy and the second using two rotating permanent 2.5 T dipole magnets at the INFN section of Ferrara. At present PVLAS is the experiment which has set the best limit in VMB reaching a noise floor within a factor 7 of the predicted QED signal:

Δ n^{(QED)} = 2.5 \times 10^{- 23}

@ 2.5 T. It was also shown that the noise floor was due to the optical cavity and a larger magnet is the only solution to increase the signal to noise ratio. The PVLAS experiment ended at the end of 2018. A new effort, VMB@CERN, which plans to use a spare LHC dipole magnet at CERN with a new modified optical scheme, is now being proposed. In this review, a detailed description of the PVLAS effort and the comprehension of its limits leading to a new proposal will be given. Full article

(This article belongs to the Special Issue Italian Research Facilities for Fundamental Physics)

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58 pages, 10202 KiB

Open AccessReview

Borexino Results on Neutrinos from the Sun and Earth

by Sindhujha Kumaran, Livia Ludhova, Ömer Penek and Giulio Settanta

Universe 2021, 7(7), 231; https://doi.org/10.3390/universe7070231 - 6 Jul 2021

Cited by 15 | Viewed by 3976

Abstract

Borexino is a 280-ton liquid scintillator detector located at the Laboratori Nazionali del Gran Sasso in Italy. Since the start of its data-taking in May 2007, it has provided several measurements of low-energy neutrinos from various sources. At the base of its success [...] Read more.

Borexino is a 280-ton liquid scintillator detector located at the Laboratori Nazionali del Gran Sasso in Italy. Since the start of its data-taking in May 2007, it has provided several measurements of low-energy neutrinos from various sources. At the base of its success lie unprecedented levels of radio-purity and extensive thermal stabilization, both resulting from a years-long effort of the collaboration. Solar neutrinos, emitted in the Hydrogen-to-Helium fusion in the solar core, are important for the understanding of our star, as well as neutrino properties. Borexino is the only experiment that has performed a complete spectroscopy of the pp chain solar neutrinos (with the exception of the hep neutrinos contributing to the total flux at

10^{- 5}

level), through the detection of pp,

^{7}

Be, pep, and

^{8}

B solar neutrinos and has experimentally confirmed the existence of the CNO fusion cycle in the Sun. Borexino has also detected geoneutrinos, antineutrinos from the decays of long-lived radioactive elements inside the Earth, that can be exploited as a new and unique tool to study our planet. This paper reviews the most recent Borexino results on solar and geoneutrinos, from highlighting the key elements of the analyses up to the discussion and interpretation of the results for neutrino, solar, and geophysics. Full article

(This article belongs to the Special Issue Italian Research Facilities for Fundamental Physics)

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9 pages, 194 KiB

Open AccessReview

Astro-Particle Physics at INFN

by Oliviero Cremonesi

Universe 2021, 7(7), 224; https://doi.org/10.3390/universe7070224 - 4 Jul 2021

Cited by 1 | Viewed by 1600

Abstract

In Italy, INFN coordinates the research in the field of astro-particle physics. The supported experimental activities include the study of the cosmic radiation, the search of gravitational waves, the study of dark universe, general and quantum physics, and the study of the neutrino [...] Read more.

In Italy, INFN coordinates the research in the field of astro-particle physics. The supported experimental activities include the study of the cosmic radiation, the search of gravitational waves, the study of dark universe, general and quantum physics, and the study of the neutrino properties. A rich program of experiments installed on the earth, in the space, and underground or underwater is being supported to provide a possible answer to some of the most relevant open questions of particle physics, astrophysics, and cosmology. A short overview of the ongoing effort is presented. Full article

(This article belongs to the Special Issue Italian Research Facilities for Fundamental Physics)

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