scholarly journals Studying background processes of the exotic neutrino-nucleus reactions

2019 ◽  
Vol 21 ◽  
pp. 11
Author(s):  
D. K. Papoulias ◽  
T. S. Kosmas
Keyword(s):  
Charged Lepton ◽  
Neutral Current ◽  
New Physics ◽  
Quasi Particle ◽  
Leptonic Sector ◽  
Charged Leptons ◽  
Nuclear Structure Calculations ◽  
Structure Calculations ◽  
Lepton Flavour

The background processes of the flavour changing neutral current (FCNC) processes, predicted by various new-physics models to occur in the presence of nuclei, are examined by computing the relevant nuclear matrix elements within the context of the quasi-particle RPA using realistic strong two-body forces. Our main goal is to explore the role of the non-standard interactions (NSI) in the leptonic sector and specifically: (i) in lepton flavour violating (LFV) processes involving neutrinos νl and ν ̃l, l = e, μ, τ and (ii) in charged lepton flavour violating (cLFV) processes involving the charged leptons l− or l+. As concrete nuclear system we have chosen the stopping target of μ− → e− conversion experiment, i.e. the 48Ti nucleus of the PRIME/PRISM experiment at J-PARC. This experiment has been designed to reduce the single event sensitivity down to 10−16–10−18 in searching for charged lepton mixing events. We also present, stringent constraints on the flavour violating parameters entering the NSI Lagrangians that have been obtained by taking advantage of our detailed nuclear structure calculations and exploiting the present limits or the sensitivity of the proposed exotic μ− → e− experiments.

scholarly journals Search for Charged Lepton Flavour Violation at CMS

2018 ◽  
Vol 182 ◽  
pp. 02090
Author(s):  
Swagata Mukherjee
Keyword(s):  
Gauge Symmetry ◽  
Standard Model ◽  
Particle Physics ◽  
Charged Lepton ◽  
New Physics ◽  
Lepton Sector ◽  
Lepton Flavour Violation ◽  
The Standard Model ◽  
Flavour Violation ◽  
Lepton Flavour

Lepton flavour is a conserved quantity in the standard model of particle physics, but it does not follow from an underlying gauge symmetry. After the discovery of neutrino oscillation, it has been established that lepton flavour is not conserved in the neutral sector. Thus the lepton sector is an excellent place to look for New Physics, and in this perspective the Charged Lepton Flavour Violation is interesting. Various extensions of the standard model predict lepton flavour violating decays that can be observed at LHC. This report summarises several searches for lepton flavour violation with data collected by the CMS detector.

scholarly journals Implications of the Muon g-2 result on the flavour structure of the lepton mass matrix

2021 ◽  
Vol 81 (10) ◽  
Author(s):  
Lorenzo Calibbi ◽  
M. L. López-Ibáñez ◽  
Aurora Melis ◽  
Oscar Vives
Keyword(s):  
Mass Matrix ◽  
New Physics ◽  
Flavor Symmetry ◽  
Moment Matrix ◽  
Leptonic Sector ◽  
Mass Matrices ◽  
The Standard Model ◽  
Model Predictions ◽  
Low Energies ◽  
Lepton Flavour

AbstractThe confirmation of the discrepancy with the Standard Model predictions in the anomalous magnetic moment by the Muon g-2 experiment at Fermilab points to a low scale of new physics. Flavour symmetries broken at low energies can account for this discrepancy but these models are much more restricted, as they would also generate off-diagonal entries in the dipole moment matrix. Therefore, if we assume that the observed discrepancy in the muon $$g-2$$ g - 2 is explained by the contributions of a low-energy flavor symmetry, lepton flavour violating processes can constrain the structure of the lepton mass matrices and therefore the flavour symmetries themselves predicting these structures. We apply these ideas to several discrete flavour symmetries popular in the leptonic sector, such as $$\Delta (27)$$ Δ ( 27 ) , $$A_4$$ A 4 , and $$A_5 < imes \mathrm{CP}$$ A 5 ⋉ CP .

scholarly journals Electron-capture and beta-decay modes with realistic nuclear structure calculations

2012 ◽  
Vol 20 ◽  
pp. 112
Author(s):  
P. G. Giannaka ◽  
T. S. Kosmas
Keyword(s):  
Excited States ◽  
Meson Exchange ◽  
Exchange Potential ◽  
Β Decay ◽  
Decay Modes ◽  
Nuclear Structure Calculations ◽  
Analytical Expressions ◽  
Structure Calculations ◽  
Gamow Teller

In this work, we concentrate on the e-capture and β-decay processes in isotopes that are important for searching the explosive nucleosynthesis in massive stars. To this aim, we improved our codes which use compact analytical expressions for the required reduced matrix elements of all basic multipole operators (isospin repre- sentation). The ground state of the nuclear isotopes chosen, is constructed in the context of the BCS method while their excited states are calculated by solving the QRPA equations, using as residual two-body interactions that of the Bonn C-D one-meson exchange potential. We focus on the role of the charged Gamow-Teller and Fermi transitions in Fe group nuclei that are the main constituents of the core in presupernovae formation.

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 Studying supernova neutrinos through nuclear structure calculations

2019 ◽  
Vol 18 ◽  
pp. 193
Author(s):  
V. Tsakstara ◽  
T. S. Kosmas ◽  
J. Sinatkas
Keyword(s):  
Cross Sections ◽  
Random Phase ◽  
Neutrino Energy ◽  
Double Beta Decay ◽  
Quasi Particle ◽  
Supernova Neutrinos ◽  
Nuclear Structure Calculations ◽  
Structure Calculations ◽  
Two Parameter ◽  
Astrophysical Neutrino

Differential and integrated cross section calculations are performed in the context of the quasi particle random phase approximation (QRPA) by utilizing realistic two- nucleon forces, for the 64,66 Zn isotopes, contents of the COBRA double beta decay detector. For these isotopes the response to supernova neutrinos is of current inter- est. The response of the 66 Zn isotope to the energy-spectra of supernova neutrinos is also explored by convoluting the original results for the differential cross sections by employing: (i) a two-parameter Fermi-Dirac (FD) and (ii) a Power-Law (PL) neutrino energy distribution. Such folded cross sections are useful in low-energy astrophysical-neutrino detection in underground terrestrial experiments.

scholarly journals On the role of leptonic CPV phases in cLFV observables

2021 ◽  
Vol 81 (11) ◽  
Author(s):  
A. Abada ◽  
J. Kriewald ◽  
A. M. Teixeira
Keyword(s):  
Standard Model ◽  
Crucial Role ◽  
Charged Lepton ◽  
Lepton Number ◽  
Majorana Fermions ◽  
Future Observation ◽  
The Standard Model ◽  
Lepton Flavour ◽  
Lepton Number Violating

AbstractIn extensions of the standard model by Majorana fermions, the presence of additional CP violating phases has been shown to play a crucial role in lepton number violating processes. In this work we show that (Dirac and Majorana) CP violating phases can also lead to important effects in charged lepton flavour violating (cLFV) transitions and decays, in some cases with a significant impact for the predicted rates of cLFV observables. We conduct a thorough exploration of these effects in several cLFV observables, and discuss the implications for future observation. We emphasise how the presence of leptonic CP violating phases might lead to modified cLFV rates, and to a possible loss of correlation between cLFV observables.

scholarly journals Signatures of $$A_4$$ symmetry in the charged lepton flavour violating decays in a neutrino mass model

2021 ◽  
Vol 81 (5) ◽  
Author(s):  
Rambabu Korrapati ◽  
Jai More ◽  
Ushak Rahaman ◽  
S. Uma Sankar
Keyword(s):  
Neutrino Mass ◽  
Top Quark ◽  
Charged Lepton ◽  
Discrete Symmetry ◽  
Tree Level ◽  
Mass Model ◽  
Neutral Mesons ◽  
Flavour Violation ◽  
Charged Leptons ◽  
Lepton Flavour

AbstractWe study the charged lepton flavour violation in a popular neutrino mass model with $$A_4$$ A 4 discrete symmetry. This symmetry requires the presence of multiple Higgs doublets in the model and it also dictates the flavour violating Yukawa couplings of the additional neutral scalars of the model. Such couplings lead to the decays of the neutral mesons, the top quark and the $$\tau $$ τ lepton into charged leptons of different flavours at tree level. The $$A_4$$ A 4 symmetry of the model leads to certain characteristic signatures in these decays. We discuss these signatures and predict the rates for the most favourable charged lepton flavour violating modes.

scholarly journals SEMILEPTONIC $\Lambda_b\to\Lambda\nu\bar\nu$ DECAY IN THE LEPTOPHOBIC Z′ MODEL

2008 ◽  
Vol 23 (05) ◽  
pp. 347-358 ◽  
Author(s):  
B. B. ŞIRVANLI
Keyword(s):  
Z Boson ◽  
Neutral Current ◽  
Branching Ratio ◽  
New Physics ◽  
Experimental Measurements ◽  
Beyond The Standard Model ◽  
Flavor Changing ◽  
The Standard Model ◽  
Flavor Changing Neutral Current ◽  
Charged Leptons

We study the exclusive flavor changing neutral current process [Formula: see text] in the leptophobic Z′ model, where charged leptons do not couple to the extra Z′ boson. The branching ratio, as well as, the longitudinal, transversal and normal polarizations are calculated. It has been shown that all these physical observables are very sensitive to the existence of new physics beyond the standard model and their experimental measurements can give valuable information about it.

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