Neutrinos from supernovae: experimental status and perspectives

I discuss the state of the art in the search for neutrinos from galactic stellar collapses and the future perspectives of this field. The implications for the neutrino physics of a high statistics supernova neutrino burst detection by the network of detectors operating around the world are also reviewed.Comment: 19 pages, 12 figures. Extended version of talk given at IInd International Workshop on Matter, Anti-Matter and Dark Matter, Trento (Italy), 29-30 October 2001. A reduced version will appear in Int. J. of Mod. Phys.

The WaveDAQ integrated Trigger and Data Acquisition System for the MEG II experiment

The WaveDAQ is a newly-designed digitization Trigger and Data AcQuisition system (TDAQ) allowing Multi-gigasample waveform recording on a large amount of channels (up to 16384) by using the DRS4 analog switched capacitor array as downconverting ASIC. A high bandwidth, programmable input stage has been coupled with a bias generator to allow SiPM operation without need of any other external apparatus. The trigger generation is tightly coupled within the system to limit the required depth of the analog memory, allowing faster digitization speeds. This system has been designed for the MEG experiment upgrade but also proved to be highly scalable and already found other applications.Comment: This manuscript is for conference record of the 21st IEEE Real Time conference onl

Initial Results from the CHOOZ Long Baseline Reactor Neutrino Oscillation Experiment

Initial results are presented from CHOOZ, a long-baseline reactor-neutrino vacuum-oscillation experiment. Electron antineutrinos were detected by a liquid scintillation calorimeter located at a distance of about 1 km. The detector was constructed in a tunnel protected from cosmic rays by a 300 MWE rock overburden. This massive shielding strongly reduced potentially troublesome backgrounds due to cosmic-ray muons, leading to a background rate of about one event per day, more than an order of magnitude smaller than the observed neutrino signal. From the statistical agreement between detected and expected neutrino event rates, we find (at 90% confidence level) no evidence for neutrino oscillations in the electron antineutrino disappearance mode for the parameter region given approximately by deltam**2 > 0.9 10**(-3) eV**2 for maximum mixing and (sin(2 theta)**2) > 0.18 for large deltam**2.Comment: 13 pages, Latex, submitted to Physics Letters

Final results of magnetic monopole searches with the MACRO experiment

We present the final results obtained by the MACRO experiment in the search for GUT magnetic monopoles in the penetrating cosmic radiation, for the range $4\times 10^{-5}< \beta < 1$. Several searches with all the MACRO sub-detectors (i.e. scintillation counters, limited streamer tubes and nuclear track detectors) were performed, both in stand alone and combined ways. No candidates were detected and a 90% Confidence Level (C.L.) upper limit to the local magnetic monopole flux was set at the level of $1.4\times 10^{-16}$ cm$^{-2}$ s$^{-1}$ sr$^{-1}$. This result is the first experimental limit obtained in direct searches which is well below the Parker bound in the whole $\beta$ range in which GUT magnetic monopoles are expected.Comment: 12 pages, Latex, 9 figures and 2 Table

The MEG detector for μ+→e+γ decay search

The MEG (Mu to Electron Gamma) experiment has been running at the Paul Scherrer Institut (PSI), Switzerland since 2008 to search for the decay mu(+) -> e(+)gamma by using one of the most intense continuous mu(+) beams in the world. This paper presents the MEG components: the positron spectrometer, including a thin target, a superconducting magnet, a set of drift chambers for measuring the muon decay vertex and the positron momentum, a timing counter for measuring the positron time, and a liquid xenon detector for measuring the photon energy, position and time. The trigger system, the read-out electronics and the data acquisition system are also presented in detail. The paper is completed with a description of the equipment and techniques developed for the calibration in time and energy and the simulation of the whole apparatus

SEARCH FOR SLOWLY MOVING MAGNETIC MONOPOLES WITH THE MACRO DETECTOR

A search for slowly moving magnetic monopoles in the cosmic radiation was conducted from October 1989 to November 1991 using the large liquid scintillator detector subsystem of the first supermodule of the MACRO detector at the Gran Sasso underground laboratory. The absence of candidates established an upper limit on the monopole flux of 5.6 x 10(-15) cm-2 sr-1 s-1 at 90% confidence level in the velocity range of 10(-4) less than or similar to beta < 4 x 10(-3). This result places a new constraint on the abundance of monopoles trapped in our solar system

Status and perspectives of the MEG experiment

The MEG experiment is searching for the Lepton Flavour violating decay mu+ --> e+ gamma since several years. Using the data collected in 2009 and 2010 the experiment set a 90 % C.L. upper bound on the branching ratio of this process of 2.4 x 10^(-12), which is the best limit in the world and updates the previous one by a factor of 5. The experiment continues its data-taking and is expected to reach a sensitivity on the mu+ --> e+ gamma branching ratio of a few times 10^(-13) in the next few years

Latest results from MEG

We present the status and the perspectives of the MEG experiment which searched for the Lepton Flavour Violating decay µ+→ e+γ for several years. In the full dataset corresponding to 7.4× 1014positive muons stopped on target we didn’t find any evidence for this decay and we set an upper bound on the µ+→ e+γ branching ratio of 4.2×10−13at 90% C.L., with a sensitivity of 5.3×10−13, which improves our previous world best limit by a factor of 1.5 and the best limit set by past experiments by a factor of 30. On the basis of the experience gained in MEG phase I we elaborated an upgrade plan of our detector, which was approved by the host laboratory and is presently in setting-up stage. We discuss here the status of the MEG upgrade (MEG II), which aims to improve the experimental sensitivity by a further order of magnitude

Latest results of the MEG experiment

We present recent results of the MEG experiment, which has been searching for the Lepton Flavour Violating decay μ+ → e+ γ since several years. In a combined dataset corresponding to 3.6×10^14 stopped muons on target we didn’t find any evidence for this decay and we established an upper bound on the μ+ → e+ γ branching ratio of 5.7×10^−13 at 90% C.L., which improves our world best limit by a factor four. We discuss also the expected final sensitivity of the MEG experiment

Status and perspectives of the MEG experiment

We present the status and the perspectives of the MEG experiment which has been searching for the Lepton Flavour Violating decay μ+ → e+γ for several years. In a dataset corresponding to 3.6 × 1014 positive muons stopped on target we didn't find any evidence for this decay and established an upper bound on the μ+ → e+γ branching ratio of 5.7 × 10-13 at 90% C.L., with a sensitivity of 7.7 × 10-13, which improves our world best limit by a factor of 4 and the best previous limit by a factor of 20. Our final dataset is about twice as large than the analyzed sample and the expected final sensitivity of the experiment is ∼ 5 × 10-13. We also discuss the status of the upgrade of the experiment (MEGII) which aims to improve the sensitivity by a further order of magnitude