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 Searches for extra spatial dimensions with the CMS detector at the LHC

2015 ◽  
Vol 30 (15) ◽  
pp. 1540017 ◽  
Author(s):  
Greg Landsberg
Keyword(s):  
Hadron Collider ◽  
Center Of Mass ◽  
New Physics ◽  
Current Status ◽  
Beyond The Standard Model ◽  
Cern Large Hadron Collider ◽  
The Standard Model ◽  
Cms Detector ◽  
Spatial Dimensions ◽  
8 Tev

The success of the first three years of operations of the CERN Large Hadron Collider (LHC) at center-of-mass energies of 7 TeV and 8 TeV radically changed the landscape of searches for new physics beyond the Standard Model (BSM) and our very way of thinking about its possible origin and its hiding place. Among the paradigms of new physics that have been probed quite extensively at the LHC, are various models that predict the existence of extra spatial dimensions. In this review, the current status of searches for extra dimensions with the Compact Muon Solenoid (CMS) detector is presented, along with prospects for future searches at the full energy of the LHC, expected to be reached in the next few years.

scholarly journals The rare and forbidden: Testing physics beyond the standard model with Mu3e

2019 ◽  
Author(s):  
Ann-Kathrin Perrevoort
Keyword(s):  
Standard Model ◽  
Muon Beam ◽  
Effective Field ◽  
Beyond The Standard Model ◽  
Theory Approach ◽  
Pixel Sensors ◽  
The Standard Model ◽  
Detailed Simulation ◽  
Momentum Acceptance ◽  
Lepton Flavour

The upcoming Mu3e experiment aims to search for the lepton flavour violating decay \boldsymbol{\muposeeemath} with an unprecedented final sensitivity of one signal decay in \boldsymbol{\num{e16}} observed muon decays by making use of an innovative experimental design based on novel ultra-thin silicon pixel sensors. In a first phase, the experiment is operated at an existing muon beam line with rates of up to \boldsymbol{\num{e8}} muons per second. Detailed simulation studies confirm the feasibility of background-free operation and project single event sensitivities in the order of \boldsymbol{\num{e-15}} for signal decays modelled in an effective field theory approach. The precise tracking of the decay electrons and large geometric and momentum acceptance of Mu3e enable searches for physics beyond the Standard Model in further signatures. Examples of which are searches for lepton flavour violating two-body decays of the muon into an electron and an undetected boson as well as for electron-positron resonances in \boldsymbol{\muposeeenunumath} which could result for instance from a dark photon decay. The Mu3e experiment is expected to be competitive in all of these channels already in phase I.

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 Mapping out the space for new physics with leptonic and semileptonic $$B_{(c)}$$ decays

2021 ◽  
Vol 81 (7) ◽  
Author(s):  
Robert Fleischer ◽  
Ruben Jaarsma ◽  
Gilberto Tetlalmatzi-Xolocotzi
Keyword(s):  
New Physics ◽  
Tensor Operator ◽  
Beyond The Standard Model ◽  
Final State ◽  
Ckm Matrix ◽  
The Standard Model ◽  
The Individual ◽  
Pseudo Scalar ◽  
Additional Constraints ◽  
Lepton Flavour

AbstractDecays of B mesons with leptons in the final state offer an interesting laboratory to search for possible effects of physics from beyond the Standard Model. In view of puzzling patterns in experimental data, the violation of lepton flavour universality is an interesting option. We present a strategy, utilising ratios of leptonic and semileptonic B decays, where the elements $$|V_{ub}|$$ | V ub | and $$|V_{cb}|$$ | V cb | of the Cabibbo–Kobayashi–Maskawa (CKM) matrix cancel, to constrain the short-distance coefficients of (pseudo)-scalar, vector and tensor operator contributions. The individual branching ratios allow us then to extract also the CKM matrix elements, even in the presence of new-physics contributions. Bounds on unmeasured leptonic and semileptonic decays offer important additional constraints. In our comprehensive analysis, we give also predictions for decays which have not yet been measured in a variety of scenarios.

scholarly journals B decay anomalies at LHCb

2018 ◽  
Vol 175 ◽  
pp. 01004
Author(s):  
Arantza Oyanguren
Keyword(s):  
Standard Model ◽  
B Meson ◽  
Neutral Current ◽  
New Physics ◽  
Lhcb Collaboration ◽  
Beyond The Standard Model ◽  
Clear Tendency ◽  
The Standard Model ◽  
Model Predictions ◽  
Lepton Flavour

The LHCb collaboration has provided a plethora of precise measurements of flavour observables in the last years. In the B meson sector some of these results show consistent deviations from Standard Model predictions with a clear tendency to specific New Physics scenarios. B decay anomalies are found in particular related to lepton flavour universality tests and angular observables in Flavour-Changing-Neutral-Current transitions. I review here the LHCb measurements and their experimental caveats. Results from Lattice are crucial in the coming years to verify if these anomalies are explained by QCD effects or if they are unambiguous hints of physics beyond the Standard Model.

scholarly journals Developments in Rare Kaon Decay Physics

2000 ◽  
Vol 50 (1) ◽  
pp. 249-297 ◽  
Author(s):  
A.R. Barker ◽  
S.H. Kettell
Keyword(s):  
Standard Model ◽  
New Physics ◽  
High Mass ◽  
Current Status ◽  
Model Parameters ◽  
Beyond The Standard Model ◽  
Kaon Decay ◽  
Kaon Decays ◽  
The Standard Model

▪ Abstract  We review the current status of the field of rare kaon decays. The study of rare kaon decays has played a key role in the development of the standard model, and the field continues to have significant impact. The two areas of greatest import are the search for physics beyond the standard model and the determination of fundamental standard-model parameters. Due to the exquisite sensitivity of rare kaon decay experiments, searches for new physics can probe very high mass scales. Studies of the K → π ν[Formula: see text] modes in particular, where the first event has recently been seen, will permit tests of the standard-model picture of quark mixing and CP violation.

scholarly journals LHC Signatures of Vector-Like Quarks

2013 ◽  
Vol 2013 ◽  
pp. 1-17 ◽  
Author(s):  
Yasuhiro Okada ◽  
Luca Panizzi
Keyword(s):  
New Physics ◽  
Short Description ◽  
Current Status ◽  
Beyond The Standard Model ◽  
Final States ◽  
Final State ◽  
Mixing Parameters ◽  
The Standard Model ◽  
Model Independent

This work provides an overview on the current status of phenomenology and searches for heavy vector-like quarks, which are predicted in many models of new physics beyond the Standard Model. Searches at Tevatron and at the LHC, here listed and shortly described, have not found any evidence for new heavy fermionic states (either chiral or vector-like) and have therefore posed strong bounds on their masses: depending on specific assumptions on the interactions and on the observed final state, vector-like quarks with masses up to roughly 400–600 GeV have been excluded by all experiments. In order to be as simple and model independent as possible, the chosen framework for the phenomenological analysis is an effective model with the addition of a vector-like quark representation (singlet, doublet, or triplet underSU(2)L) which couples through Yukawa interactions with all SM families. The relevance of different observables for the determination of bounds on mixing parameters is then discussed and a complete overview of possible two body final states for every vector-like quark is provided, including their subsequent decay into SM particles. A list and short description of phenomenological analyses present in the literature are also provided for reference purposes.

scholarly journals Diphoton resonances at the LHC

2017 ◽  
Vol 32 (27) ◽  
pp. 1730024 ◽  
Author(s):  
Emiliano Molinaro ◽  
Natascia Vignaroli
Keyword(s):  
Effective Field Theory ◽  
New Physics ◽  
Effective Field ◽  
Current Status ◽  
Beyond The Standard Model ◽  
Theory Approach ◽  
Independent Analysis ◽  
The Standard Model ◽  
Model Independent ◽  
Production Mechanisms

We review the current status of searches for new physics beyond the Standard Model in the diphoton channel at the LHC and estimate the reach with future collected data. We perform a model independent analysis based on an effective field theory approach and different production mechanisms. As an illustrative example, we apply our results to a scenario of minimal composite dynamics.

scholarly journals Disentangling QCD and new physics in D → πℓ+ℓ−

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Aoife Bharucha ◽  
Diogo Boito ◽  
Cédric Méaux
Keyword(s):  
Standard Model ◽  
Branching Ratio ◽  
Branching Ratios ◽  
New Physics ◽  
Operator Product ◽  
Beyond The Standard Model ◽  
Spectral Functions ◽  
The Standard Model ◽  
Model Independent ◽  
Weak Annihilation

Abstract In this paper we consider the decay D+ → π+ℓ+ℓ−, addressing in particular the resonance contributions as well as the relatively large contributions from the weak annihilation diagrams. For the weak annihilation diagrams we include known results from QCD factorisation at low q2 and at high q2, adapting the existing calculation for B decays in the Operator Product Expansion. The hadronic resonance contributions are obtained through a dispersion relation, modelling the spectral functions as towers of Regge-like resonances in each channel, as suggested by Shifman, imposing the partonic behaviour in the deep Euclidean. The parameters of the model are extracted using e+e− → (hadrons) and τ → (hadrons) + ντ data as well as the branching ratios for the resonant decays D+ → π+R(R → ℓ+ℓ−), with R = ρ, ω, and ϕ. We perform a thorough error analysis, and present our results for the Standard Model differential branching ratio as a function of q2. Focusing then on the observables FH and AFB, we consider the sensitivity of this channel to effects of physics beyond the Standard Model, both in a model independent way and for the case of leptoquarks.

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