Related papers: Neutrino Cosmology after WMAP and LHC7

We calculate the effects of a light, very weakly-coupled boson $X$ arising from a spontaneously broken $U(1)_{B-L}$ symmetry on $\Delta N_{\rm eff}$ as measured by the CMB and $Y_p$ from BBN. Our focus is the mass range $1 \; {\rm eV}…

In this note I mainly focus on the neutrino physics part in my talk and report the most recent progress made in \cite{YLW0}. It is seen that the Majorana features of neutrinos and SO(3) gauge flavor symmetry can simultaneously explain the…

We propose a supersymmetric extension of the minimal $B-L$ model where we consider a new $Z_2$-parity under which one right-handed neutrino is assigned odd parity. When the Majorana Yukawa coupling of a $Z_2$-even right-handed neutrino is…

The three electroweak doublet neutrinos $\nu_{e,\mu,\tau}$ of the Standard Model may acquire small seesaw masses, using either three Majorana fermion singlets $N$ or three Majorana fermion triplets $(\Sigma^+,\Sigma^0,\Sigma^-)$. It is…

We study the type-I seesaw model with three right-handed neutrinos and Majorana masses below the pion mass. In this mass range, the model parameter space is not only strongly constrained by the requirement to explain the light neutrino…

We propose a minimal gauged U(1)$_X$ extension of the MSSM with R-parity conservation. In this model, U(1)$_X$ is a generalization of the well-known U(1) $B-L$. Apart from the MSSM particle content, the model includes three right-handed…

We propose an alternative formulation of a Left-Right Symmetric Model (LRSM) where the difference between baryon number ($B$) and lepton number ($L$) remains an unbroken symmetry. This is unlike the conventional formulation, where $B-L$ is…

We reexamine lepton mixing in gauge models by considering two theories within the type I seesaw mechanism, the Extended Standard Model, i.e. SU(2)_L \times U(1)_Y with singlet right-handed heavy neutrinos, and the Left-Right Model SU(2)_L x…

I suggest a minimal extension of the SM with $U(1)_{B-L}\otimes Z_{2}$. It can simultaneously accommodate the tiny neutrino mass, cold dark mater and baryon asymmetry besides the SM. All of the new physics arise from the $U(1)_{B-L}$…

This paper includes two main parts. In the first part, we present generalized gauge models based on SU(3)_C x SU(4)_L x U(1)_X (3-4-1) gauge group with arbitrary electric charge of leptons. The mixing matrix of neutral gauge bosons is…

Lepton number is promoted to an $U(1)_L$ gauge symmetry in a simple extension of the standard model. The spontaneous breaking of $U(1)_L$ by three units allows a conserved $Z_3^L$ lepton symmetry to remain, guaranteeing that neutrinos are…

The tensor-to-scalar ratio (r = 0.20^{+0.07}_{-0.05}) inferred from the excess B-mode power observed by the Background Imaging of Cosmic Extragalactic Polarization (BICEP2) experiment is almost twice as large as the 95% CL upper limits…

We study the decay $K_L -> e\mu$ in minimal extensions of the Standard Model based on the gauge groups $SU(2)_L x U(1)_Y$ and $SU(2)_R x SU(2)_L x U(1)_{B-L}$, in which heavy Majorana neutrinos are present. In $SU(2)_L x U(1)_Y$ models with…

We propose a new leptogenesis scenario in a gauged $B-L$ model with supersymmetry at the TeV energy scale. Instead of relying on the very small Yukawa couplings of the singlet neutrinos $N^c$ to generate the observed baryon asymmetry of the…

We revisit a supersymmetric flavor model based on the symmetries $SU(2)_L \times A_4 \times Z_3 \times U(1)_R$, which extends the original Altarelli and Feruglio construction by introducing flavon and driving superfields responsible for the…

A new era in particle physics is being spurred on by new data from the Large Hadron Collider. Non-vanishing neutrino masses represent firm observational evidence of new physics beyond the Standard Model. An extension of the latter, based on…

If neutrinos are Dirac particles, their right-handed partners must be present in the theory. Once introduced in the Standard Model (SM), the difference between the baryon number $B$ and the lepton number $L$ can be promoted to a local…

We perform a detailed study of a variety of LHC signals in supersymmetric models where lepton number is promoted to an (approximate) U(1)_R symmetry. Such a symmetry has interesting implications for naturalness, as well as flavor- and…

We explain the electron-positron excess reported by the DAMPE collaboration recently in a radiative Dirac seesaw model where a dark $U(1)_X$ gauge symmetry can (i) forbid the tree-level Yukawa couplings of three right-handed neutrinos to…

We study thermal leptogenesis in realistic supersymmetric flipped $SU(5)\times U(1)$ unification. As up-type quarks and neutrinos are arranged in the same multiplets, they exhibit strong correlations, and it is commonly believed that the…