117937444
Textures of Yukawa coupling matrices in the 2HDM type III
The quark mass matrices ansatze proposed by Fritzsch, Du‐Xing and Fukuyama‐Nishiura in the framework of the general two Higgs doublet model are studied. The corresponding Cabbibo‐Kobayashi‐Maskawa matrix elements are computed in all cases and compared with their experimental values. The complex phases of the anstaze are taken into account and the CP violating phase δ is computed. Finally some phenomenology is discussed.
122784148
Anomalous top magnetic couplings
The real and imaginary parts of the one-loop electroweak contributions to the left and right tensorial anomalous couplings of the tbW vertex in the Standard Model (SM) are computed.
119271341
Quark mass hierarchy in 3-3-1 models
We study the mass spectrum of the quark sector in an special type I-like model with gauge symmetry $SU(3)_c \otimes SU(3)_L \otimes U(1)_X$. By considering couplings with scalar triplets at large ($\sim TeV$) and small ($\sim GeV$) scales, we obtain specific zero-texture mass matrices for the quarks which predict three massless quarks ($u,d,s$) and three massive quarks ($c,b,t$) at the electroweak scale ($\sim$ GeV). Taking into account mixing couplings with three heavy quarks at large scales predicted by the model, the three massless quarks obtain masses at small order that depends on the inverse of the large scale. Thus, masses of the form $m_u \lesssim m_d < m_s \sim MeV$ and $ m_{c,b,t} \sim GeV$ can be obtained naturally from the gauge structure of the model.
53625847
Top quark tensor couplings
We compute the real and imaginary parts of the one-loop electroweak contributions to the left and right tensorial anomalous couplings of the tbW vertex in the Standard Model (SM). For both tensorial couplings we find that the real part of the electroweak SM correction is close to 10% of the leading contribution given by the QCD gluon exchange. We also find that the electroweak real and imaginary parts for the anomalous right coupling are almost of the same order of magnitude. The one loop SM prediction for the real part of the left coupling is close to the 3σ discovery limit derived from b → sγ. Besides, taking into account that the predictions of new physics interactions are also at the level of a few percents when compared with the one loop QCD gluon exchange, these electroweak corrections should be taken into account in order to disentangle new physics effects from the standard ones. These anomalous tensorial couplings of the top quark will be investigated at the LHC in the near future where sensitivity to these contributions may be achieved.
46694686
Light Higgs Boson Production in Two Higgs Doublets Models Type III
By using the Cheng, Sher and Yuan's anzats, we study the light Higgs Boson production associated with b quark production at TEVATRON using the 2HDM type III. We compare the simulations with experimental results coming from TEVATRON, finding valid ranges for the bb coupling. By using these results, we calculate the cross section for the process pp → bbh(bb) for the LHC collider.
16563203
The Higgs decay in the large N limit
The Equivalence Theorem is commonly used to calculate perturbatively amplitudes with gauge boson at higher energies than gauge boson masses. However, when the scalar sector is strongly interacting the theory is nonperturbative. We show that the Equivalence Theorem hold in the large N limit at next-to-leading order by calculating the width of the decays h → W+W− and h → π+π−. We also show, in the same scheme of calculations, that for the process h → π+π− unitarity is fulfilled.
119563879
Loop-induced radiative decays of neutral scalars and neutral vector bosons in left-right symmetric theories
Abstract We compute the decay widths of the radiative modes h 0 (H 0 , δ L 0r ) → γγ , γ Z and Z′→ γ h 0 (H 0 , δ L 0r ), where h 0 , H 0 and δ L 0r are the light neutral Higgs scalars of left-right symmetric (LR) models with a minimal Higgs potential. We use a nonlinear R -gauge to compute these one-loop induced decays. We find that only the decay modes which involve the scalar h 0 , the LR analogue of the standard model Higgs boson, are not suppressed by LR mixing angles.