Subscribe to the gold package and get unlimited access to Shamra Academy
Register a new userDark matter, lepton and baryon number, and left-right symmetric theories
64
0
0.0
(
0
)
Authors
Sudhanwa Patra
Ask ChatGPT about the research
No Arabic abstract
A lepto-baryonic left-right symmetric theory is considered along with pointing out stable dark matter candidates whose stability is ensured automatically where leptons and baryons are defined as local gauge symmetries. These theories are generally anomalous and the possible gauge anomaly free solutions for these theories are presented. It is found that the neutral component of fermion triplets can be a viable dark matter candidate originally introduced for gauge anomaly cancellation. The other dark matter possibilities within this lepto-baryonic left-right symmetric theory are also presented.
rate research
Read More
We did a model independent phenomenological study of baryogenesis via leptogenesis, neutrinoless double beta decay (NDBD) and charged lepton flavour violation (CLFV) in a generic left-right symmetric model (LRSM) where neutrino mass originates from the type I + type II seesaw mechanism. We studied the new physics contributions to NDBD coming from the left-right gauge boson mixing and the heavy neutrino contribution within the framework of LRSM. We have considered the mass of the RH gauge boson to be specifically 5 TeV, 10 TeV and 18 TeV and studied the effects of the new physics contributions on the effective mass and baryogenesis and compared with the current experimental limit. We tried to correlate the cosmological BAU from resonant leptogenesis with the low energy observables, notably, NDBD and LFV with a view to finding a common parameter space where they coexists.
$SU(2)_L times SU(2)_R$ gauge symmetry requires three right-handed neutrinos ($ N _i $), one of which, $N_1$, can be sufficiently stable to be dark matter. In the early universe, $ W _R $ exchange with the Standard Model thermal bath keeps the right-handed neutrinos in thermal equilibrium at high temperatures. $N_1$ can make up all of dark matter if they freeze-out while relativistic and are mildly diluted by subsequent decays of a long-lived and heavier right-handed neutrino, $N_2$. We systematically study this parameter space, constraining the symmetry breaking scale of $SU(2)_R$ and the mass of $N_1$ to a triangle in the $(v_R,M_1)$ plane, with $v_R = (10^6 - 3 times 10^{12})$ GeV and $M_1 = (2, {rm keV} - 1 , {rm MeV)}$. Much of this triangle can be probed by signals of warm dark matter, especially if leptogenesis from $N_2$ decay yields the observed baryon asymmetry. The minimal value of $v_R$ is increased to $10^8 , {rm GeV}$ for doublet breaking of $SU(2)_R$, and further to $10^9 , {rm GeV}$ if leptogenesis occurs via $N_2$ decay, while the upper bound on $M_1$ is reduced to 100 keV. In addition, there is a component of hot $N_1$ dark matter resulting from the late decay of $N_2 rightarrow N_1 ell^+ ell^-$ that can be probed by future cosmic microwave background observations. Interestingly, the range of $v_R$ allows both precision gauge coupling unification and the Higgs Parity understanding of the vanishing of the Standard Model Higgs quartic at scale $v_R$. Finally, we study freeze-in production of $N_1$ dark matter via the $W_R$ interaction, which allows a much wider range of $(v_R,M_1)$.
In this work, we studied baryogenesis via leptogenesis, neutrinoless double beta decay (NDBD) in the framework of LRSM where type I and type II seesaw terms arises naturally. The type I seesaw mass term is considered to be favouring $mu-tau$ symmetry, taking into account the widely studied realizations of $mu-tau$ symmetric neutrino mass models, viz. Tribimaximal Mixing (TBM), Hexagonal Mixing (HM) and Golden Ratio Mixing (GRM) respectively. The required correction to generate a non vanishing reactor mixing angle $theta_{13}$ is obtained from the perturbation matrix, type II seesaw mass term in our case. We studied the new physics contributions to NDBD and baryogenesis ignoring the left-right gauge boson mixing and the heavy-light neutrino mixing, keeping mass of the gauge bosons and scalars to be around TeV and studied the effects of the new physics contributions on the effective mass, NDBD half life and cosmological BAU and compared with the values imposed by experiments. We basically tried to find the leading order contributions to NDBD and BAU, coming from type I or type II seesaw in our work.
We propose a model to explain tiny masses of neutrinos with the lepton number conservation, where neither too heavy particles beyond the TeV-scale nor tiny coupling constants are required. Assignments of conserving lepton numbers to new fields result in an unbroken $Z_2$ symmetry that stabilizes the dark matter candidate (the lightest $Z_2$-odd particle). In this model, $Z_2$-odd particles play an important role to generate the mass of neutrinos. The scalar dark matter in our model can satisfy constraints on the dark matter abundance and those from direct searches. It is also shown that the strong first-order phase transition, which is required for the electroweak baryogenesis, can be realized in our model. In addition, the scalar potential can in principle contain CP-violating phases, which can also be utilized for the baryogenesis. Therefore, three problems in the standard model, namely absence of neutrino masses, the dark matter candidate, and the mechanism to generate baryon asymmetry of the Universe, may be simultaneously resolved at the TeV-scale. Phenomenology of this model is also discussed briefly.
We argue that dark matter can automatically arise from a gauge theory that possesses a non-minimal left-right gauge symmetry, SU(3)_C otimes SU(M)_L otimes SU(N)_R otimes U(1)_X, for (M,N) = (2,3), (3,2), (3,3), cdots, and (5,5).
Log in to be able to interact and post comments
comments
Fetching comments
Sign in to be able to follow your search criteria
