
Abbas, G. (2016). Rightrightleft extension of the Standard Model. Mod. Phys. Lett. A, 31(19), 1650117–10pp.
Abstract: A rightrightleft extension of the Standard Model is proposed. In this model, SM gauge group SU(2)(L) circle times U(1)(Y) is extended to SU(2)(L) circle times SU(2)(R) circle times SU(2)'(R) circle times SU(2)'(L) circle times U(1)(Y). The gauge symmetries SU(2)'(R), SU(2)'(L) are the mirror counterparts of the SU(2)(L) and SU(2)(R), respectively. Parity is spontaneously broken when the scalar Higgs fields acquire vacuum expectation values (VEVs) in a certain pattern. Parity is restored at the scale of SU(2)'(L). The gauge sector has a unique pattern. The scalar sector of the model is optimum, elegant and unique.



Centelles Chulia, S., & Trautner, A. (2020). Asymmetric tribimaximal mixing and residual symmetries. Mod. Phys. Lett. A, 35(35), 2050292–15pp.
Abstract: Asymmetric tribimaximal mixing is a recently proposed, grand unified theory (GUT) based, flavor mixing scheme. In it, the charged lepton mixing is fixed by the GUT connection to downtype quarks and a T13 flavor symmetry, while neutrino mixing is assumed to be tribimaximal (TBM) with one additional free phase. Here we show that this additional free phase can be fixed by the residual flavor and CP symmetries of the effective neutrino mass matrix. We discuss how those residual symmetries can be unified with T13 and identify the smallest possible unified flavor symmetries, namely (Z(13)xZ(13))(sic)D12 and (Z(13)xZ(13))(sic)S4. Sharp predictions are obtained for lepton mixing angles, CP violating phases and neutrinoless double beta decay.



Han, X. F., Wang, L., & Yang, J. M. (2016). Higgs pair signal enhanced in the 2HDM with two degenerate 125 GeV Higgs bosons. Mod. Phys. Lett. A, 31(31), 1650178–14pp.
Abstract: We discuss a scenario of the typeII twoHiggs doublet model (2HDM) in which the b (b) over bar gamma gamma rate of the Higgs pair production is enhanced due to the two nearly degenerate 125 GeV Higgs bosons ( h, H). Considering various theoretical and experimental constraints, we figure out the allowed ranges of the trilinear couplings of these two Higgs bosons and calculate the signal rate of b (b) over bar gamma gamma from the productions of Higgs pairs (hh, hH, HH) at the large hadron collider (LHC). We find that in the allowed parameter space some trilinear Higgs couplings can be larger than the Standard Model (SM) value by an order and the production rate of b _ b.. can be greatly enhanced. We also consider a “decoupling” benchmark point where the light CPeven Higgs has a SMlike cubic selfcoupling while other trilinear couplings are very small. With a detailed simulation on the b (b) over bar gamma gamma signal and backgrounds, we find that in such a “decoupling” scenario the hh and hH channels can jointly enhance the statistical significance to 5 sigma at 14 TeV LHC with an integrated luminosity of 3000 fb(1).



Peinado, E., Reig, M., Srivastava, R., & Valle, J. W. F. (2020). Dirac neutrinos from PecceiQuinn symmetry: A fresh look at the axion. Mod. Phys. Lett. A, 35(21), 2050176–9pp.
Abstract: We show that a very simple solution to the strong CP problem naturally leads to Dirac neutrinos. Small effective neutrino masses emerge from a typeI Dirac seesaw mechanism. Neutrino mass limits probe the axion parameters in regions currently inaccessible to conventional searches.



Pich, A., & RodriguezSanchez, A. (2016). Updated determination of alpha(s)(m(tau)(2)) from tau decays. Mod. Phys. Lett. A, 31(30), 1630032–15pp.
Abstract: Using the most recent release of the ALEPH tau decay data, we present a very detailed phenomenological update of the alpha(s)(m(tau)(2)) determination. We have exploited the sensitivity to the strong coupling in many different ways, exploring several complementary methodologies. All determinations turn out to be in excellent agreement, allowing us to extract a very reliable value of the strong coupling. We find alpha((nf =3))(s)(m(tau)(2)) = 0.328 +/ 0.012 which implies alpha((nf=5))(s)(MZ(2)) = 0.1197 +/ 0.0014. We critically revise previous work, and point out the problems flawing some recent analyses which claim slightly smaller values.

