Vitaly Beylin

Possible compensation of the QCD vacuum contribution to the dark energy

We suggest one of the possible ways to compensate the large negative quantum-topological QCD contribution to the vacuum energy density of the Universe by means of a positive constant contribution from a cosmological Yang-Mills field. An important role of the exact particular solution for the Yang-Mills field corresponding to the finite-time instantons is discussed. An interesting connection of the compensation mechanism to the color confinement in the framework of instanton { � �

Chiral-symmetric technicolor with standard model Higgs boson

Most of the traditional technicolor-based models are known to be in a strong tension with the electroweak precision tests. We show that this serious issue is naturally cured in strongly coupled sectors with chiral-symmetric vectorlike gauge interactions in the framework of the gauged linear sigma model. We discuss possible phenomenological implications of such a nonstandard chiral-symmetric technicolor scenario in its simplest formulation preserving the standard model (SM) Higgs mechanism. For this purpose, we assume the existence of an extra technifermion sector confined under extra SU(3)(TC) at the energy scales reachable at the LHC, Lambda(TC) similar to 0: 1-1 TeV and interacting with the SM gauge bosons in a chiral-symmetric (vectorlike) way. In the framework of this scenario, the SM Higgs vacuum expectation value acquires a natural interpretation in terms of the condensate of technifermions in confinement in the nearly conformal limit. We study the influence of the lowest-lying composite physical states, namely, technipions, technisigma, and constituent technifermions, on the Higgs sector properties in the SM and other observables at the LHC. We find that the predicted Higgs boson signal strengths in gamma gamma, vector-boson VV*, and fermion f (f) over bar decay channels can be sensitive to the new strongly coupled dynamics and are consistent with the current SM-like Higgs boson observations in the limit of relatively small Higgs-technisigma mixing. At the same time, the chiral-symmetric technicolor provides us with rich technipion phenomenology at the LHC, and its major implications are discussed in detail. (Less)

Dark Energy from graviton-mediated interactions in the QCD vacuum

Adopting the hypothesis about the exact cancellation of vacuum condensates contributions to the ground state energy in particle physics to the leading order in graviton-mediated interactions, we argue that the observable cosmological constant can be dynamically induced by an uncompensated quantum gravity correction to them after the QCD phase transition epoch. To start with, we demonstrate a possible cancellation of the quark-gluon condensate contribution to the total vacuum energy density of the Universe at temperatures T < 100 MeV without taking into account the graviton-mediated effects. In order to incorporate the latter, we then calculate the leading-order quantum correction to the classical Einstein equations due to metric fluctuations induced by the non-perturbative vacuum fluctuations of the gluon and quark fields in the quasiclassical approximation. It has been demonstrated that such a correction to the vacuum energy density has a form eΛ ~ GΛQCD6, where G is the gravitational constant, and ΛQCD is the QCD scale parameter. We analyze capabilities of this approach based on the synthesis between quantum gravity in quasiclassical approximation and theory of non-perturbative QCD vacuum for quantitative explanation of the observed Dark Energy density.

Vector-like technineutron Dark Matter: is a QCD-type Technicolor ruled out by XENON100?

One of the specific predictions of a new strongly coupled dynamics at a TeV scale is the existence of stable vector-like technibaryon states so that the lightest neutral one could serve as a Dark Matter candidate. We study the latter hypothesis in the QCD-type technicolor with

Diagonalization of the neutralino mass matrix and boson-neutralino interaction

\mathrm{SU}(3)_\mathrm{TC}

Composite scalar dark matter from vector-like SU (2) confinement

SU(3)TC confined group and one

Scalar technibaryon Dark Matter from vector-like SU(2) Technicolor

\mathrm{SU}(2)_\mathrm{W}