相关论文: Why the Four SM Families
Results are presented from a search for a fourth generation of quarks produced singly or in pairs in a data set corresponding to an integrated luminosity of 5 inverse femtobarns recorded by the CMS experiment at the LHC in 2011. A novel…
We propose a tri-hypercharge (TH) embedding of the Standard Model (SM) in which a separate gauged weak hypercharge is associated with each fermion family. In this way, every quark and lepton multiplet carries unique gauge quantum numbers…
In the spin-charge-family theory four massless families of quarks and leptons before the electroweak break are predicted. Mass matrices of all the family members demonstrate in this proposal the same symmetry, determined by the family…
A scenario is presented where the $s$, $c$, and $b$ quark fusion Higgs production cross sections are enhanced with respect to those of the Standard Model. In particular the $c$ quark fusion production is very important and can account for a…
We propose a Three Higgs Doublet Model (3HDM) that goes beyond natural flavor conservation and in which each of the three Higgs doublets couples mainly to a single generation of fermions via non-standard Yukawa structures. A hierarchy in…
We reanalyze constraints on the mass spectrum of the chiral fourth generation fermions and the Higgs bosons for the standard model (SM4) and the two Higgs doublet model (THDM). We find that the Higgs mass in the SM4 should be larger than…
A common lore has arisen that beyond the Standard Model (BSM) particles, which can be searched for at current and proposed experiments, should have flavorless or mostly third-generation interactions with Standard Model quarks. This…
Two vector-like families with masses of order 1 TeV, one of which is a doublet of $SU(2)_L$ and the other a doublet of $SU(2)_R$, have been predicted to exist in the context of a viable and economical SUSY composite model. One of the many…
We summarise the analyses that search for fourth generation quarks at the Central Muon Solenoid (CMS) experiment. Such particles provide a natural extension to the Standard Model (SM) and are still consistent with precision electroweak…
We study the observability for a Higgs boson at upgraded Tevatron via the modes gg->h->ZZ->4l (l=e,mu). We find that the signal can be observed at an integrated luminosity of 30 fb^(-1) if the fourth SM family exists.
We study the possibilty to produce single fourth SM family fermions at electron-positron colliders via anomalous gamma-f4-f interactions.
We analyse relevant signals expected at the LHC for a squark of the first two families as the lightest supersymmetric particle (LSP). The discussion is established in the framework of the $\mu\nu$SSM, where the presence of $R$-parity…
In this talk, I present a new framework to understand the long-standing fermion mass hierarchy puzzle. We extend the Standard Model gauge symmetry by an extra local U(1)_S symmetry, broken spontaneously at the electroweak scale. All the SM…
The standard model extended with the pairs of the vector-like families is studied. The model independent analysis for an arbitrary case and an explicit realization for the case with one pair of the heavy vector-like families are considered.…
The heaviness of the third family fermions and the experimental absence of large flavor violating processes suggest, in supersymmetric theories, that the three families belong to a $2+1$ representation of a horizontal symmetry $G_H$. In…
We investigate the possible enhancement to the discovery of the heavy Higgs boson through the possible fourth SM family heavy neutrino. Using the channel h-> v4 v4->mu W mu W-> mu j j mu j j, it is found that for certain ranges of Higgs…
With the aim of linking natural supersymmetry to flavour physics, a model is proposed based on a family symmetry G \times U(1), where G is a discrete nonabelian subgroup of SU(2), with both F-term and (abelian) D-term supersymmetry…
We propose that the electroweak and flavour quantum numbers of the Standard Model (SM) could be unified at high energies in an $SU(4)\times Sp(6)_L \times Sp(6)_R$ anomaly-free gauge model. All the SM fermions are packaged into two…
The LHC is a promising machine to discover new physics in the top sector. There are several models that predict the existence of heavy colored resonances decaying to top quarks in the TeV energy range. The production of such resonances…
The pseudoscalar quarkonium state, eta_4 1^S_0, formed by the Standard Model (SM) fourth generation quarks, is the best candidate among the fourth generation quarkonia to be produced at the LHC and VLHC. The production of this J^{PC} =…