Related papers: CP asymmetry factor in decays at finite temperatur…
If massive neutrinos are Majorana particles, then the lepton number should be violated in nature and neutrino-antineutrino oscillations $\nu^{}_\alpha \leftrightarrow \overline{\nu}^{}_\beta$ (for $\alpha, \beta = e, \mu, \tau$) will…
The current laws of physics do not explain the observed imbalance of matter and antimatter in the universe. Sakharov proposed that an explanation would require the violation of CP symmetry between matter and antimatter. The only CP…
Leptogenesis is an appealing framework to account for the baryon asymmetry in the universe. To this end physics beyond the Standard Model is demanded. In this paper we investigate the possibility to attain successful leptogenesis with…
If the baryon asymmetry of the Universe is produced by leptogenesis, CP violation is required in the lepton sector. In the seesaw extension of the Standard Model with three hierarchical right-handed neutrinos, we show that the baryon…
In this paper, we carry out a systematic study of the sufficient and necessary conditions for CP conservation in the leptonic sector with massive Majorana neutrinos. In particular, the emphasis is placed on the number of CP-violating phases…
The rates for generating a matter-antimatter asymmetry in extensions of the Standard Model (SM) containing right-handed neutrinos are the most interesting and least trivial coefficients in the rate equations for baryogenesis through thermal…
Within the extension of MSSM by two right handed neutrinos, which masses are degenerate at tree level, we address the issue of leptogenesis. Investigating the quantum corrections in details, we show that the lepton asymmetry is induced at…
Leptogenesis is studied within the seesaw neutrino mass model in a regime where all sterile neutrinos have prompt rather than delayed decays. It is shown that during neutrino thermal production lepton asymmetries are generated in both…
Assuming 3-neutrino mixing and massive Majorana neutrinos, we analyze the possibility of establishing the existence of CP-violation associated with Majorana neutrinos in the lepton sector i) by measuring of the effective Majorana mass |<m>|…
We study the freeze-in scenario of leptogenesis via oscillations within the type-I seesaw model with two quasi-degenerate heavy Majorana neutrinos $N_{1,\,2}$ having masses $M_2 > M_1 \sim (0.1-100)\,\text{GeV}$, $(M_2-M_1)/M_1 \ll 1$,…
The consequences of CP- and CPT-invariance for production and subsequent decay of Majorana fermions are analytically studied. We derive general symmetry relations for the spin density matrix for production of Majorana fermions by polarized…
We propose a lepto-baryogenesis mechanism in which the non-zero B-L of the universe is produced in out-of-equilibrium, lepton number and CP violating scattering processes that convert ordinary particles into particles of some hidden sector.…
Properties of neutrinos may be the origin of the matter-antimatter asymmetry of the universe. In the seesaw model for neutrino masses this leads to important constraints on the properties of light and heavy neutrinos. In particular, an…
We analyse the interplay of generalised CP transformations and the non-Abelian discrete group $T^{\prime}$ and use the semi-direct product $G_f= T^{\prime}\rtimes H_{\text{CP}}$, as family symmetry acting in the lepton sector. The family…
We propose that the observed large leptonic mixing may just reflect a quasidegeneracy of three Majorana neutrinos. The limit of exact degeneracy of Majorana neutrinos is not trivial, as leptonic mixing and even CP violation may occur. We…
Recent developments in thermal leptogenesis are reviewed. Neutrino mixing data favor a simple picture where the matter-anti matter asymmetry is generated by the decays of the heavy RH neutrinos mildly close to thermal equilibrium and,…
Small neutrino masses confirmed in the neutrino oscillation experiments indicate the need for new physics beyond the standard model. Seesaw mechanism is an interesting way to extend the standard model for explaining the neutrino masses. In…
We study leptonic CP violation from a new perspective. For Majorana neutrinos, a new parametrization for leptonic mixing of the form $V=O_{23} O_{12} K_{a}^{i}\cdot O$ reveals interesting aspects that are less clear in the standard…
Discovery of the CP-violation in the lepton sector is one of the challenges of the particle physics. We search for possible principles, symmetries and phenomenological relations that can lead to particular values of the CP-violating Dirac…
The behaviour of the broken CP symmetry at finite temperature is examined. This is achieved through the investigation of the neutron electric dipole moment $d_n$ induced by $\theta$-term. By using thermal QCD sum rules, we find that below…