Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userLeft-handed and right-handed U(1) gauge symmetry
74
0
0.0
(
0
)
Ask ChatGPT about the research
No Arabic abstract
We propose a model with the left-handed and right-handed continuous Abelian gauge symmetry; $U(1)_Ltimes U(1)_R$. Then three right-handed neutrinos are naturally required to achieve $U(1)_R$ anomaly cancellations, while several mirror fermions are also needed to do $U(1)_L$ anomaly cancellations. Then we formulate the model, and discuss its testability of the new gauge interactions at collider physics such as the large hadron collider (LHC) and the international linear collider (ILC). In particular, we can investigate chiral structure of the interactions by the analysis of forward-backward asymmetry based on polarized beam at the ILC.
rate research
Read More
In this letter we consider that assuming: a) that the only left-handed neutral fermions are the active neutrinos, b) that $B-L$ is a gauge symmetry, and c) that the $L$ assignment is restricted to the integer numbers, the anomaly cancellation imply that at least three right-handed neutrinos must be added to the minimal representation content of the electroweak standard model. However, two types of models arise: i) the usual one where each of the three identical right-handed neutrinos has total lepton number L=1; ii) and the other one in which two of them carry L=4 while the third one carries $L=-5$.
The breaking of parity, a fundamental symmetry between left and right is best understood in the framework of left-right symmetric extension of the standard model. We show that the production of a heavy right-handed neutrino at the proposed Large Hadron-Electron Collider (LHeC) could give us the most simple and direct hint of the scale of this breaking in left-right symmetric theories. This production mode gives a lepton number violating signal with $Delta L=2$ which is very clean and has practically no standard model background. We highlight that the right-handed nature of $W_R$ exchange which defines the left-right symmetric theories can be confirmed by using a polarized electron beam and also enhance the production rates with relatively lower beam energy.
Several models of neutrino masses predict the existence of neutral heavy leptons. Here, we review current constraints on heavy neutrinos and apply a new formalism separating new physics from Standard Model. We discuss also the indirect effect of extra heavy neutrinos in oscillation experiments.
Recent lattice determinations of direct CP violation in kaon decays, parametrized by $epsilon$, suggest a discrepancy of several sigma between experiment and the standard model. Assuming that this situation is due to new physics, we investigate a solution in terms of right-handed charged currents. Chiral perturbation theory, in combination with lattice QCD results, allows one to accurately determine the effect of right-handed interactions on $epsilon$. In addition, similar techniques provide a direct link between the right-handed contributions to $epsilon$ and hadronic electric dipole moments. We demonstrate that the $epsilon$ discrepancy can be resolved with right-handed charged currents, and that this scenario can be falsified by next-generation hadronic electric dipole moment experiments.
We point out that the recent excess observed in searches for a right-handed gauge boson W_R at CMS can be explained in a left-right symmetric model with D parity violation. In a class of SO(10) models, in which D parity is broken at a high scale, the left-right gauge symmetry breaking scale is naturally small, and at a few TeV the gauge coupling constants satisfy g_R ~ 0.6 g_L. Such models therefore predict a right-handed charged gauge boson W_R in the TeV range with a suppressed gauge coupling as compared to the usually assumed manifest left-right symmetry case g_R = g_L. The recent CMS data show excess events which are consistent with the cross section predicted in the D parity breaking model for 1.9 TeV < M_{W_R} < 2.4 TeV. If the excess is confirmed, it would in general be a direct signal of new physics beyond the Standard Model at the LHC. A TeV scale W_R would for example not only rule out SU(5) grand unified theory models. It would also imply B-L violation at the TeV scale, which would be the first evidence for baryon or lepton number violation in nature and it has strong implications on the generation of neutrino masses and the baryon asymmetry in the Universe.
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
