相关论文: May Heavy hadrons of the 4th generation be hidden …
Existence of metastable quarks of new generation can be embedded into phenomenology of heterotic string together with new long range interaction, which only this new generation possesses. We discuss primordial quark production in the early…
Stable neutrino and U quark of 4th generation are excluded neither by experimental data, nor by astrophysical constraints. Moreover, excess of stable $\bar U$ quarks in the Universe can lead to an exciting composite nuclear-interacting form…
The 4th generation of fermions predicted by the phenomenology of heterotic string models can possess new strictly conserved charge, which leads, in particular, to the hypothesis of the existence of the 4th generation massive stable…
We consider the phenomenology of the fourth generation heavy quarks which would be pair produced at the LHC. We show that if such a quark with a mass in the phenomenologically interesting range of 400 GeV--600 GeV decays to a light quark…
The nonbaryonic dark matter of the Universe can consist of new stable charged species, bound in heavy neutral "atoms" by ordinary Coulomb interaction. Stable $\bar U$ (anti-$U$)quarks of 4th generation, bound in stable colorless ($\bar U…
Hypothesis of heavy stable quark of 4th family can provide a nontrivial solution for cosmological dark matter if baryon asymmetry in 4th family has negative sign and the excess of anti-U quarks with charge (-2/3) is generated in early…
Recent studies of precision electroweak observables have led to the conclusion that a fourth generation is highly constrained. However, we point out that a long-lived fourth generation can reopen a large portion of the parameter space. In…
The existence of fourth family follows from the basics of the Standard Model. Because of the high masses of the fourth family quarks, their anomalous decays could be dominant, if certain criteria are met. This will drastically change the…
The Standard Model has three generations of fermions and although it does not contain any explicit reason for this, the existence of additional generations is now very constrained by experiment. Present measurements are saturating…
The nonbaryonic dark matter of the Universe is assumed to consist of new stable forms of matter. Their stability reflects symmetry of micro world and particle candidates for cosmological dark matter are the lightest particles that bear new…
The general character of 4-quark (mesonic) and strange 6-quark (baryonic) quark systems is very briefly reviewed a la Jaffe, i.e. in the MIT bag, and so far still possibly viable candidates are indicated. Concentration is on S=-2 systems.…
We review the theoretical and experimental situation for long-lived heavy quarks, or bound states thereof, arising in simple extensions of the Standard Model. If these particles propagate large distances before their decay, they give rise…
Primordial Heavy neutrinos of 4th generation might explain different astrophysical puzzles: indeed the simplest 4th neutrino scenario may be still consistent with known 4th neutrino physics, cosmic ray anti-matter and gamma fluxes and…
We propose a simple extension of the standard model by adding a fourth generation vector-like lepton doublet and show that if the fourth neutrino is a massive pseudo-Dirac fermion with mass in the few hundred GeV range and mass splitting of…
The strange-anticharmed Pentaquark is a $uud\bar{c}s$ or $udd\bar{c}s$ five-quark baryon that is expected to be either a narrow resonance, or possibly even stable against strong and electromagnetic decay. We describe this hyperon here, its…
The nonbaryonic dark matter of the Universe can consist of new stable charged leptons and quarks, if they are hidden in elusive "dark atoms" of composite dark matter. Such possibility can be compatible with the severe constraints on…
During the last three years strong experimental evidence from $B$ and charm factories has been accumulating for the existence of exotic hadronic quarkonia, narrow resonances which cannot be made from a quark and an antiquark. Their masses…
The mechanism of string creation for light quarks developed earlier is considered for nonzero quark chemical potential. A strong modification of the confining string due to finite quark density (chemical quark potential $\mu$) is observed.…
Cryptons are metastable bound states of fractionally-charged particles that arise generically in the hidden sectors of models derived from heterotic string. We study their properties and decay modes in a specific flipped SU(5) model with…
Dark sector particles at the GeV scale carrying baryon number provide an attractive framework for understanding the origin of dark matter and the matter-antimatter asymmetry of the universe. We demonstrate that dark decays of hadronic…