scholarly journals The Search for μ+ → e+γ with 10–14 Sensitivity: The Upgrade of the MEG Experiment

Symmetry ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1591
Author(s):  
Alessandro M. Baldini ◽  
Vladimir Baranov ◽  
Michele Biasotti ◽  
Gianluigi Boca ◽  
Paolo W. Cattaneo ◽  
...  
Keyword(s):  
Particle Physics ◽  
Rate Capability ◽  
Muon Beam ◽  
Paul Scherrer Institute ◽  
Current Status ◽  
Elementary Particle Physics ◽  
Lepton Flavor ◽  
The Standard Model ◽  
Stringent Limit ◽  
Paul Scherrer

The MEG experiment took data at the Paul Scherrer Institute in the years 2009–2013 to test the violation of the lepton flavor conservation law, which originates from an accidental symmetry that the Standard Model of elementary particle physics has, and published the most stringent limit on the charged lepton flavor violating decay μ+→e+γ: BR(μ+→e+γ) <4.2×10−13 at 90% confidence level. The MEG detector has been upgraded in order to reach a sensitivity of 6×10−14. The basic principle of MEG II is to achieve the highest possible sensitivity using the full muon beam intensity at the Paul Scherrer Institute (7×107 muons/s) with an upgraded detector. The main improvements are better rate capability of all sub-detectors and improved resolutions while keeping the same detector concept. In this paper, we present the current status of the preparation, integration and commissioning of the MEG II detector in the recent engineering runs.

scholarly journals COMET, an Experiment to Search for mu-e Conversion in a Nuclear Field

2018 ◽  
Vol 46 ◽  
pp. 1860065
Author(s):  
Hiroaki Natori
Keyword(s):  
Elementary Particle ◽  
Particle Physics ◽  
New Physics ◽  
Experimental Limit ◽  
Elementary Particle Physics ◽  
Lepton Flavor ◽  
Nuclear Field ◽  
Past Experiment ◽  
The Standard Model ◽  
Current Experimental Limit

Charged lepton flavor violating (CLFV) process is predicted to be out of experimental reach by the Standard Model of elementary particle physics (SM). However, many models of the new physics beyond the SM predicts that it is just below the current experimental limit. COMET searches for one of the CLFV process, mu-e conversion in a nuclear field, improving the sensitivity by a factor of approximately [Formula: see text] for Phase-I and [Formula: see text] for Phase-II experiment from a past experiment.

scholarly journals Towards a New μ→eγ Search with the MEG II Experiment: From Design to Commissioning

Universe ◽  
2021 ◽  
Vol 7 (12) ◽  
pp. 466
Author(s):  
Marco Chiappini ◽  
Marco Francesconi ◽  
Satoru Kobayashi ◽  
Manuel Meucci ◽  
Rina Onda ◽  
...  
Keyword(s):  
State Of The Art ◽  
New Physics ◽  
Muon Beam ◽  
Current Status ◽  
Beyond The Standard Model ◽  
Experimental Apparatus ◽  
The Standard Model ◽  
Sensitivity Level ◽  
Paul Scherrer ◽  
Lepton Flavour

The MEG experiment represents the state of the art in the search for the Charged Lepton Flavour Violating μ+→e+γ decay. With its first phase of operations at the Paul Scherrer Institut (PSI), MEG set the most stringent upper limit on the BR (μ+→e+γ)≤4.2×10−13 at 90% confidence level, imposing one of the tightest constraints on models predicting LFV-enhancements through new physics beyond the Standard Model. An upgrade of the MEG experiment, MEG II, was designed and it is presently in the commissioning phase, aiming at a sensitivity level of 6×10−14. The MEG II experiment relies on a series of upgrades, which include an improvement of the photon detector resolutions, brand new detectors on the positron side with better acceptance, efficiency and performances and new and optimized trigger and DAQ electronics to exploit a muon beam intensity twice as high as that of MEG (7×107 μ+/s). This paper presents a complete overview of the MEG II experimental apparatus and the current status of the detector commissioning in view of the physics data taking in the upcoming three years.

scholarly journals Probing μτ flavor-violating solutions for the muon g − 2 anomaly at Belle II

2020 ◽  
Vol 2020 (9) ◽  
Author(s):  
Syuhei Iguro ◽  
Yuji Omura ◽  
Michihisa Takeuchi
Keyword(s):  
Particle Physics ◽  
Standard Model Prediction ◽  
Mass Range ◽  
Loop Correction ◽  
Lepton Flavor ◽  
Highly Sensitive ◽  
The Standard Model ◽  
Belle Ii ◽  
The One ◽  
Mass Enhancement

Abstract The discrepancy between the measured value and the Standard Model prediction of the muon anomalous magnetic moment is one of the most important issues in the particle physics. It is known that introducing a mediator boson X with the μτ lepton flavor violating (LFV) couplings is one good solution to explain the discrepancy, due to the τ mass enhancement in the one-loop correction. In this paper, we study the signal of this model, i.e. the same-sign leptons, in the Belle II experiment, assuming the flavor-diagonal couplings are suppressed. We show that the Belle II experiment is highly sensitive to the scenario in the mediator mass range of O(1–10) GeV, using the e+e−→ μ±τ∓X → μ±μ±τ∓τ∓ process induced by the X .

scholarly journals Neutron’s dark secret

2020 ◽  
Vol 35 (31) ◽  
pp. 2030019
Author(s):  
Bartosz Fornal ◽  
Benjamín Grinstein
Keyword(s):  
Standard Model ◽  
Particle Physics ◽  
Current Status ◽  
Neutron Lifetime ◽  
Dark Sector ◽  
Lifetime Measurements ◽  
The Standard Model ◽  
Dark Decay ◽  
Theoretical Developments

The existing discrepancy between neutron lifetime measurements in bottle and beam experiments has been interpreted as a sign of the neutron decaying to dark particles. We summarize the current status of this proposal, including a discussion of particle physics models involving such a portal between the Standard Model and a baryonic dark sector. We also review further theoretical developments around this idea and elaborate on the prospects for verifying the neutron dark decay hypothesis in current and upcoming experiments.

scholarly journals Neutrino Oscillations

2014 ◽  
Vol 2014 ◽  
pp. 1-28 ◽  
Author(s):  
G. Bellini ◽  
L. Ludhova ◽  
G. Ranucci ◽  
F. L. Villante
Keyword(s):  
Particle Physics ◽  
Neutrino Oscillations ◽  
Theoretical Background ◽  
Beyond The Standard Model ◽  
Full Understanding ◽  
Elementary Particle Physics ◽  
Oscillation Phenomenon ◽  
The Standard Model ◽  
Near Future ◽  
Different Sources

In the last decades, a very important breakthrough has been brought about in the elementary particle physics by the discovery of the phenomenon of the neutrino oscillations, which has shown neutrino properties beyond the Standard Model. But a full understanding of the various aspects of the neutrino oscillations is far to be achieved. In this paper the theoretical background of the neutrino oscillation phenomenon is described, referring in particular to the paradigmatic models. Then the various techniques and detectors which studied neutrinos from different sources are discussed, starting from the pioneering ones up to the detectors still in operation and to those in preparation. The physics results are finally presented adopting the same research path which has been crossed by this long saga. The problems not yet fixed in this field are discussed, together with the perspectives of their solutions in the near future.

scholarly journals External Resources: Clouds and HPCs for the expansion of the ATLAS production system at the Tokyo regional analysis center

2020 ◽  
Vol 245 ◽  
pp. 07034
Author(s):  
Michiru Kaneda
Keyword(s):  
Production System ◽  
Particle Physics ◽  
Current System ◽  
Regional Analysis ◽  
Current Status ◽  
External Resources ◽  
Elementary Particle Physics ◽  
Cloud Resource ◽  
Analysis Center ◽  
The University

The Tokyo regional analysis center at the International Center for Elementary Particle Physics, the University of Tokyo, is one of the Tier 2 sites for the ATLAS experiment in the Worldwide LHC Computing Grid. The current system has 10,752 CPU cores and 16 PB disk storage. CERN plans the HighLuminosity LHC starting from 2026, which increases the peak luminosity by 5 times compared to the present value at the LHC. A shortage of computing resources for the high-luminosity LHC is expected with the current system. Therefore new ideas to expand the system are necessary. To expand the ATLAS production system at the Tokyo regional analysis center, R&D using external resources has been launched. One kind of external resources is a commercial cloud resource, such as Google Cloud Platform. Another resource is the HighPerformance Computer (HPC) at the University of Tokyo. In this contribution, the current status of the R&D, the systems for these resources, and comparisons of the cost are reported.

scholarly journals Die topkwark

1998 ◽  
Vol 17 (2) ◽  
pp. 68-71
Author(s):  
R. Tegen
Keyword(s):  
Elementary Particle ◽  
Standard Model ◽  
Top Quark ◽  
Particle Physics ◽  
Relevant Literature ◽  
Big Bang ◽  
Elementary Particle Physics ◽  
The Standard Model ◽  
Technical Article

The importance of the recent discovery of the top-quark at Fermilab in Chicago is reviewed. It is shown that the top-quark is important for Big-Bang physics as well as for the Standard Model of Elementary Particle Physics. Relevant literature for further reading can be traced from the list of references given in this short, non-technical article.

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