A5067881038- Particle physics theoretical and experimental studies
- Particle Detector Development and Performance
- Dark Matter and Cosmic Phenomena
- Neutrino Physics Research
- Radiation Detection and Scintillator Technologies
- Particle Accelerators and Free-Electron Lasers
- Quantum Chromodynamics and Particle Interactions
- Distributed and Parallel Computing Systems
- High-Energy Particle Collisions Research
- Particle accelerators and beam dynamics
- Superconducting Materials and Applications
- Atomic and Subatomic Physics Research
- Medical Imaging Techniques and Applications
- Magnetic confinement fusion research
- Scientific Research and Discoveries
- Graphite, nuclear technology, radiation studies
- Nuclear reactor physics and engineering
- Sarcoma Diagnosis and Treatment
- Muon and positron interactions and applications
- Radiation Therapy and Dosimetry
- Bone Tumor Diagnosis and Treatments
- Nuclear Physics and Applications
- Soft tissue tumors and treatment
Istituto Nazionale di Fisica Nucleare, Sezione di Roma I
2018-2024
Sapienza University of Rome
2018-2023
The University of Tokyo
2021
Paul Scherrer Institute
2021
Istituto Nazionale di Fisica Nucleare
2019
Abstract The MEG II experiment, based at the Paul Scherrer Institut in Switzerland, reports result of a search for decay $$\upmu ^+ \rightarrow {\textrm{e}}^+ \upgamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:mtext>e</mml:mtext> </mml:mrow> <mml:mi>γ</mml:mi> </mml:math> from data taken first physics run 2021. No excess events over expected background is observed, yielding an...
Abstract The workshop “Shedding light on X17” brings together scientists looking for the existence of a possible new particle, often referred to as X17. This hypothetical particle can explain resonant structure observed at $$\sim $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mo>∼</mml:mo> </mml:math> 17 MeV in invariant mass electron-positron pairs, produced after excitation nuclei such $$^8\hbox {Be}$$ <mml:mrow> <mml:msup> <mml:mrow /> <mml:mn>8</mml:mn> </mml:msup>...
Abstract The MEG II experiment, located at the Paul Scherrer Institut (PSI) in Switzerland, is successor to which completed data taking 2013. started fully operational 2021, with goal of improving sensitivity $$\upmu ^+ \rightarrow {\textrm{e}}^+ \upgamma $$ <mml:math...
The MEG experiment took data at the Paul Scherrer Institute in years 2009–2013 to test violation of lepton flavor conservation law, which originates from an accidental symmetry that Standard Model elementary particle physics has, and published most stringent limit on charged violating decay μ+→e+γ: BR(μ+→e+γ) <4.2×10−13 90% confidence level. detector has been upgraded order reach a sensitivity 6×10−14. basic principle II is achieve highest possible using full muon beam intensity (7×107...
Abstract The cylindrical drift chamber is the most innovative part of MEG II detector, upgraded version experiment. differs from one because it a single volume structure, instead segmented one, chosen to improve its resolutions and efficiency in detecting low energy positrons muon decays at rest. In this paper, we show characteristics performances fundamental apparatus discuss impact higher resolution on sensitivity Because structure high quality will be cornerstone development an ideal...
Abstract We present the first direct search for lepton flavour violating muon decay mediated by a new light particle X, $$\upmu ^+ \rightarrow \mathrm {e}^+\mathrm {X}, {X} \upgamma \ $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:msup> <mml:mi>μ</mml:mi> <mml:mo>+</mml:mo> </mml:msup> <mml:mo>→</mml:mo> <mml:mi>e</mml:mi> </mml:mrow> <mml:mi>X</mml:mi> <mml:mo>,</mml:mo> <mml:mi>γ</mml:mi> <mml:mspace /> </mml:math> . This uses dataset resulting from...
The MEG~II experiment at Paul Scherrer Institute (PSI) in Switzerland aims to achieve a sensitivity of $6\times10^{-14}$ on the charged lepton flavor violating decay $\mu^+\to e^+\gamma$. current upper limit this is $4.2\times10^{-13}$ 90% Confidence Level (CL), set by first phase MEG. This result was achieved using PSI muon beam reduced intensity, $3\times10^7~\mu^+/$s, keep background manageable level. upgraded detectors can cope with higher thus expected run $7\times10^7~\mu^+/$s...
The MEG II experiment, based at the Paul Scherrer Institut in Switzerland, reports result of a search for decay $\mu^+\to e^+\gamma$ from data taken first physics run 2021. No excess events over expected background is observed, yielding an upper limit on branching ratio B($\mu^+\to e^+\gamma$) < $7.5 \times 10^{-13}$ (90% C.L.). combination this and obtained by gives $3.1 C.L.), which most stringent to date. A ten-fold larger sample being collected during years 2022-2023, data-taking will...
The reconstruction of the positron trajectory in MEG-II experiment searching for $\mu^+ \to e^+ \gamma$ decay uses a cylindrical drift chamber operated with helium-isobutane gas mixture. A stable performance detector terms its electron properties, avalanche multiplication, and mixture controlled composition purity has to be provided continuously monitored. In this paper we describe strategies adopted meet requirements imposed by target sensitivity MEG-II, including construction commissioning...
Abstract Ultra-thin metallic anode and cathode wires are frequently employed in low-mass gaseous detectors for precision experiments, where the amount of material crossed by charged particles must be minimised. We present here results an analysis mechanical stress chemical corrosion effects observed 40 50 μm diameter silver plated aluminum mounted within volume MEG II drift chamber, which caused breakage about one hundred (over a total ≈ 12000). This is based on careful inspection broken...
The MEG experiment represents the state of art in search for Charged Lepton Flavour Violating μ+→e+γ decay. With its first phase operations at Paul Scherrer Institut (PSI), set most stringent upper limit on BR (μ+→e+γ)≤4.2×10−13 90% confidence level, imposing one tightest constraints models predicting LFV-enhancements through new physics beyond Standard Model. An upgrade experiment, II, was designed and it is presently commissioning phase, aiming a sensitivity level 6×10−14. II relies series...
The MEG II experiment, located at the Paul Scherrer Institut (PSI) in Switzerland, is successor to which completed data taking 2013. started fully operational 2021, with goal of improving sensitivity mu+ -> e+ gamma decay down 6e-14 almost an order magnitude better than current limit. In this paper, we describe operation and performance experiment give a new estimate its versus acquisition time.
The cylindrical drift chamber is the most innovative part of MEG~II detector, upgraded version MEG experiment. differs from one because it a single volume structure, instead segmented one, chosen to improve its resolutions and efficiency in detecting low energy positrons muon decays at rest. In this paper, we show characteristics performances fundamental apparatus discuss impact higher resolution on sensitivity Because structure high quality will be cornerstone development an ideal tracking...
Tracking systems for modern particle physics experiments, both the search of extremely rare processes, which require high momentum resolutions in ranges dominated by multiple scattering, and next generation luminosity lepton colliders, large active volumes granularity, make use light drift chambers able to withstand rates and, therefore, made numbers closely spaced wires. For such chambers, classical feed-through technique, as wire anchoring system, cannot be implemented it is necessary...
An automatic target monitoring method based on photographs taken by a CMOS photo-camera has been developed for the MEG II detector. The technique could be adapted other fixed-target experiments requiring good knowledge of their position to avoid biases and systematic errors in measuring trajectories outcoming particles. A CMOS-based, high resolution, radiation tolerant magnetic field resistant was mounted inside detector at Paul Scherrer Institute (Switzerland). is used search lepton flavour...
The MEG experiment at the Paul Scherrer Institut searches for charged-Lepton-Flavor-Violating mu+ -> e+ gamma decay. has already set world best upper limit on branching ratio: BR<4.2x10^-13 @ 90% C.l. An upgrade (MEG II) of whole detector been approved to obtain a substantial increase sensitivity. Currently II is completing various detectors, an engineering run and pre-commissioning were carried out during 2018 2019. new positron tracker unique volume, ultra-light He based cylindrical drift...
The observation of a resonance structure in the opening angle electron-positron pairs $^{7}$Li(p,\ee) $^{8}$Be reaction was claimed and interpreted as production subsequent decay hypothetical particle (X17). Similar excesses, consistent with this particle, were later observed processes involving $^{4}$He $^{12}$C nuclei same experimental technique. MEG II apparatus at PSI, designed to search for $\mu^+ \rightarrow \mathrm{e}^+ \gamma$ decay, can be exploited investigate existence study its...
The MEG experiment at the Paul Scherrer Institut (PSI) represents state of art in search for charged Lepton Flavour Violating (cLFV) μ+→ e+ γ decay. With phase 1, set new world best upper limit on BR(μ+→ γ) < 4.2 × 10−13 (90% C.L.). 2, II, aims reaching a sensitivity enhancement about one order magnitude compared to previous result. Cylindrical Drift CHamber (CDCH) is key detector II. CDCH low-mass single volume with high granularity: 9 layers 192 drift cells, few mm wide, defined by ∼ 12000...