We present a new result based on an analysis of the data collected by the MEG detector at the Paul Scherrer Institut in 2009 and 2010, in search of the lepton-flavor-violating decay μ(+)e(+)γ. The ...likelihood analysis of the combined data sample, which corresponds to a total of 1.8×10(14) muon decays, gives a 90% C.L. upper limit of 2.4×10(-12) on the branching ratio of the μ(+)→e(+)γ decay, constituting the most stringent limit on the existence of this decay to date.
The MEG detector for μ+→e+γ decay search Adam, J.; Bai, X.; Baldini, A. M. ...
The European physical journal. C, Particles and fields,
04/2013, Letnik:
73, Številka:
4
Journal Article
Recenzirano
Odprti dostop
The MEG (Mu to Electron Gamma) experiment has been running at the Paul Scherrer Institut (PSI), Switzerland since 2008 to search for the decay
μ
+
→e
+
γ
by using one of the most intense continuous
μ
...+
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.
An FPGA-based trigger for the phase II of the MEG experiment Baldini, A.; Bemporad, C.; Cei, F. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
07/2016, Letnik:
824
Journal Article
Recenzirano
For the phase II of MEG, we are going to develop a combined trigger and DAQ system. Here we focus on the former side, which operates an on-line reconstruction of detector signals and event selection ...within 450μs from event occurrence. Trigger concentrator boards (TCB) are under development to gather data from different crates, each connected to a set of detector channels, to accomplish higher-level algorithms to issue a trigger in the case of a candidate signal event. We describe the major features of the new system, in comparison with phase I, as well as its performances in terms of selection efficiency and background rejection.
•A new, two-level trigger scheme for the phase-II of the MEG experiment is presented.•Improvements with respect to phase-I are underlined.•The role of detector upgrades and the use of a new generation of FPGA as well are emphasized.
A precise measurement of the thermal neutron flux (and an approximate measurement of the non-thermal neutron flux), associated with the high intensity stopping
μ
+
beam (
≈
1.5
×
10
8
μ
+
s
-
1
) of ...the MEG experiment, was studied by measuring the delayed radioactivity of an activated NaI detector. This passive method provides a high sensitivity and allows the neutron flux determination at all locations, even in regions of high magnetic field. We present and discuss the results.
The final results of the search for the lepton flavour violating decay Formula omitted based on the full dataset collected by the MEG experiment at the Paul Scherrer Institut in the period 2009-2013 ...and totalling Formula omitted stopped muons on target are presented. No significant excess of events is observed in the dataset with respect to the expected background and a new upper limit on the branching ratio of this decay of Formula omitted (90 % confidence level) is established, which represents the most stringent limit on the existence of this decay to date.
Large underground experiments Bemporad, C.
Nuclear physics. Section B, Proceedings supplement,
05/1996, Letnik:
48, Številka:
1
Journal Article
Recenzirano
Large underground detectors are discussed in connection with low energy neutrino physics and astrophysics; a special emphasis is given to the search for neutrinos from stellar gravitational collapse.
A search for the decay
μ
+
→
e
+
γ
, performed at PSI and based on data from the initial three months of operation of the MEG experiment, yields an upper limit on the branching ratio of
BR
(
μ
+
→
e
...+
γ
)
⩽
2.8
×
10
−
11
(90% C.L.). This corresponds to the measurement of positrons and photons from
∼
10
14
stopped
μ
+
-decays by means of a superconducting positron spectrometer and a 900 litre liquid xenon photon detector.
We designed, built and operated a liquid hydrogen target for the calibration of the liquid xenon calorimeter of the MEG experiment. The target was used throughout the entire data taking period, from ...2008 to 2013 and it is being refurbished and partly re-designed to be integrated and used in the MEG-II experiment.
We present the design, implementation and first tests of the superconducting LC filters for the frequency domain readout of spiderweb TES bolometers of the SWIPE experiment on the balloon-borne LSPE ...mission which aims at measuring the linear polarization of the Cosmic Microwave Background at large angular scales to find the imprint of inflation on the B-mode CMB polarization. LC filters are designed, produced and tested at the INFN sections of Pisa and Genoa where thin film deposition and cryogenic test facilities are present, and where also the TES spiderweb bolometers are being produced.
PDF
