scholarly journals Flavor-changing Majoron interactions with leptons

2021 ◽  
Vol 104 (1) ◽  
Author(s):  
Yu Cheng ◽  
Cheng-Wei Chiang ◽  
Xiao-Gang He ◽  
Jin Sun
Keyword(s):  
Flavor Changing

scholarly journals The low-energy effective theory of axions and ALPs

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Martin Bauer ◽  
Matthias Neubert ◽  
Sophie Renner ◽  
Marvin Schnubel ◽  
Andrea Thamm
Keyword(s):  
High Energy ◽  
New Physics ◽  
Mass Scale ◽  
Low Energy ◽  
Effective Theory ◽  
Loop Order ◽  
Flavor Changing ◽  
Effective Lagrangian ◽  
Anomalous Dimensions ◽  
Pseudoscalar Mesons

Abstract Axions and axion-like particles (ALPs) are well-motivated low-energy relics of high-energy extensions of the Standard Model, which interact with the known particles through higher-dimensional operators suppressed by the mass scale Λ of the new-physics sector. Starting from the most general dimension-5 interactions, we discuss in detail the evolution of the ALP couplings from the new-physics scale to energies at and below the scale of electroweak symmetry breaking. We derive the relevant anomalous dimensions at two-loop order in gauge couplings and one-loop order in Yukawa interactions, carefully considering the treatment of a redundant operator involving an ALP coupling to the Higgs current. We account for one-loop (and partially two-loop) matching contributions at the weak scale, including in particular flavor-changing effects. The relations between different equivalent forms of the effective Lagrangian are discussed in detail. We also construct the effective chiral Lagrangian for an ALP interacting with photons and light pseudoscalar mesons, pointing out important differences with the corresponding Lagrangian for the QCD axion.

scholarly journals Structure of flavor changing Goldstone boson interactions

2021 ◽  
Vol 2021 (4) ◽  
Author(s):  
Jin Sun ◽  
Yu Cheng ◽  
Xiao-Gang He
Keyword(s):  
Symmetry Breaking ◽  
Model Building ◽  
Neutral Current ◽  
Goldstone Boson ◽  
New Physics ◽  
Majorana Neutrino ◽  
Neutrino Masses ◽  
Type I ◽  
Flavor Changing ◽  
Flavor Changing Neutral Current

Abstract General flavor changing Goldstone boson (GB) interactions with fermions from a spontaneous global U(1)G symmetry breaking are discussed. This GB may be the Axion, solving the strong QCD CP problem, if there is a QCD anomaly for the assignments of quarks U(1)G charge. Or it may be the Majoron, producing seesaw Majorana neutrino masses by lepton number violation, if the symmetry breaking scale is much higher than the electroweak scale. It may also, in principle, play the roles of Axion and Majoron simultaneously as far as providing solution for the strong CP problem and generating a small Majorana neutrino masses are concerned. Great attentions have been focused on flavor conserving GB interactions. Recently flavor changing Axion and Majoron models have been studied in the hope to find new physics from rare decays in the intensity frontier. In this work, we will provide a systematic model building aspect study for flavor changing neutral current (FCNC) GB interactions in the fermion sectors, or separately in the quark, charged lepton and neutrino sectors and will identify in detail the sources of FCNC interactions in a class of beyond standard model with a spontaneous global U(1)G symmetry breaking. We also provide a general proof of the equivalence of using physical GB components and GB broken generators for calculating GB couplings to two gluons and two photons, and discuss some issues related to spontaneous CP violation models. Besides, we will also provide some details for obtaining FCNC GB interactions in several popular models, such as the Type-I, -II, -III seesaw and Left-Right symmetric models, and point out some special features in these models.

THE SINGLE NEUTRAL TOP-HIGGS PRODUCTION AT ILC IN THE TC2 MODEL

2011 ◽  
Vol 26 (09) ◽  
pp. 1629-1637 ◽  
Author(s):  
YAO-BEI LIU ◽  
HUI YE ◽  
YONG-HUA CAO
Keyword(s):  
Linear Collider ◽  
International Linear Collider ◽  
Higgs Production ◽  
Production Rates ◽  
Flavor Changing ◽  
Text Production ◽  
Production Processes ◽  
Parameter Values

In the framework of the topcolor-assisted technicolor (TC2) model, we study the neutral top-Higgs [Formula: see text] production processes [Formula: see text], [Formula: see text] and [Formula: see text]. The results show that the production rates can reach the level of a few fb with reasonable parameter values. With the clean background of the flavor-changing [Formula: see text] channel, the top-Higgs events can possibly be detected at the International Linear Collider (ILC) experiments. Therefore, such neutral top-Higgs production processes offer a useful way to probe for neutral top-Higgs and test the TC2 model directly.

SOLAR NEUTRINOS WITH EXOTIC SCATTERING

1993 ◽  
Vol 08 (14) ◽  
pp. 1273-1284 ◽  
Author(s):  
JOÃO PULIDO
Keyword(s):  
Elastic Scattering ◽  
Solar Neutrino ◽  
Solar Neutrinos ◽  
The Sun ◽  
Neutral Currents ◽  
Neutrino Scattering ◽  
Flavor Changing ◽  
Lepton Decays ◽  
Neutrino Experiments ◽  
Vacuum Mixing

The possibility of unconventional neutrino scattering in the Sun via flavor changing neutral currents as a possible source of the solar neutrino deficit is investigated. If the effect is really significant, a resonant process will occur. Taking into account the neutrino deficit reported by the solar neutrino experiments (Kamiokande II, SAGE Gallex), one finds Δ2m21 = (0.6–1.4) × 10−5 eV 2 with no vacuum mixing and 0.16 ≤ fex ≤ 0.34 where fex is the lepton violating coupling. Our understanding of the neutrino phenomenon in the Sun may be improved through accuracy improvements in experiments measuring νee− elastic scattering or others searching for exotic lepton decays.

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