Using Micromegas detectors for direct dark matter searches: challenges and perspectives

International audienceGas time projection chambers (TPCs) with Micromegas pixelated readouts are being used in dark matter searches and other rare event searches, due to their potential in terms of low background levels, energy and spatial resolution, gain, and operational stability. Moreover, these detectors can provide precious features,such as topological information, allowing for event directionality and powerful signal-background discrimination. The Micromegas technology of the microbulk type is particularly suited to low-background applications and is being exploited by detectors for CAST and IAXO (solar axions) and TREX-DM (low-mass WIMPs) experiments. Challenges for the future include reducing intrinsic background levels, reaching lower energy detection levels, and technical issues such as robustness of detector, new design choices, novel gas mixtures and operation points, scaling up to larger detector sizes, handling large readout granularity, etc. We report on the status and prospects of the development ongoing in the context of IAXO and TREX-DM experiments, pointing to promising perspectives for the use of Micromegas detectors in directdark matter searche

Solar neutrinos spectroscopy with borexino phase-II

Solar neutrinos have played a central role in the discovery of the neutrino oscillation mechanism. They still are proving to be a unique tool to help investigate the fusion reactions that power stars and further probe basic neutrino properties. The Borexino neutrino observatory has been operationally acquiring data at Laboratori Nazionali del Gran Sasso in Italy since 2007. Its main goal is the real-time study of low energy neutrinos (solar or originated elsewhere, such as geo-neutrinos). The latest analysis of experimental data, taken during the so-called Borexino Phase-II (2011-present), will be showcased in this talk-yielding new high-precision, simultaneous wide band flux measurements of the four main solar neutrino components belonging to the \u201cpp\u201d fusion chain (pp, pep, 7 Be, 8 B), as well as upper limits on the remaining two solar neutrino fluxes (CNO and hep)

Limiting neutrino magnetic moments with Borexino Phase-II solar neutrino data

A search for the solar neutrino effective magnetic moment has been performed using data from 1291.5 days exposure during the second phase of the Borexino experiment. No significant deviations from the expected shape of the electron recoil spectrum from solar neutrinos have been found, and a new upper limit on the effective neutrino magnetic moment of mu(eff)(nu) < 2.8 x 10(-11) mu(B) at 90% C.L. has been set using constraints on the sum of the solar neutrino fluxes implied by the radiochemical gallium experiments. Using the limit for the effective neutrino moment, new limits for the magnetic moments of the neutrino flavor states, and for the elements of the neutrino magnetic moments matrix for Dirac and Majorana neutrinos, are derived

Solar neutrinos spectroscopy with borexino phase-II

Solar neutrinos have played a central role in the discovery of the neutrino oscillation mechanism. They still are proving to be a unique tool to help investigate the fusion reactions that power stars and further probe basic neutrino properties. The Borexino neutrino observatory has been operationally acquiring data at Laboratori Nazionali del Gran Sasso in Italy since 2007. Its main goal is the real-time study of low energy neutrinos (solar or originated elsewhere, such as geo-neutrinos). The latest analysis of experimental data, taken during the so-called Borexino Phase-II (2011-present), will be showcased in this talk-yielding new high-precision, simultaneous wide band flux measurements of the four main solar neutrino components belonging to the “pp” fusion chain (pp, pep, 7 Be, 8 B), as well as upper limits on the remaining two solar neutrino fluxes (CNO and hep)

Radioactive source experiments in Borexino

Most of the neutrino oscillation results can be explained by the three-neutrino paradigm. However several anomalies in short baseline oscillation data (L/E of about 1 m/MeV) could be interpreted by invoking a light sterile neutrino. This new state would be separated from the standard neutrinos by a squared mass difference \u394m2new 3c 0.1-1 eV2 and would have mixing angles of sin2 2\u3b8ee 73 0.01 in the electron disappearance channel. This new neutrino, often called sterile, would not feel standard model interactions but mix with the others. We present the CeSOX and CrSOX projects to constrain the existence of eV-scale sterile neutrinos by deploying an intense radioactive \u3b2-source next to the Borexino detector

Search for sterile neutrinos with the SOX experiment

In the recent years, the Borexino detector has proven its outstanding performances in detecting neutrinos and antineutrinos in the low energy regime. Consequently, it is an ideal tool to investigate the existence of sterile neutrinos, whose presence has been suggested by several anomalies over the past two decades. The SOX (Short distance neutrino Oscillations with boreXino) project will investigate the presence of sterile neutrinos placing a neutrino and an antineutrino sources in a location under the detector foreseen for this purpose since the construction of Borexino. Interacting in the detector active volume, each beam would create a well detectable spatial wave pattern in case of oscillation of neutrino or antineutrino in a sterile state. Otherwise, the experiment will set a very stringent limit on the existence of a sterile state

Radioactive source experiments in Borexino

© Copyright owned by the author(s) under the terms of the Creative Commons Attribution-NonCommercial-ShareAlike Licence. Most of the neutrino oscillation results can be explained by the three-neutrino paradigm. However several anomalies in short baseline oscillation data (L/E of about 1 m/MeV) could be interpreted by invoking a light sterile neutrino. This new state would be separated from the standard neutrinos by a squared mass difference Δm 2new ∼ 0.1-1 eV 2 and would have mixing angles of sin 2 2θ ee ≳ 0.01 in the electron disappearance channel. This new neutrino, often called sterile, would not feel standard model interactions but mix with the others. We present the CeSOX and CrSOX projects to constrain the existence of eV-scale sterile neutrinos by deploying an intense radioactive β-source next to the Borexino detector