25,660 research outputs found
Phase Transition Couplings in the Higgsed Monopole Model
Using a one-loop approximation for the effective potential in the Higgs model
of electrodynamics for a charged scalar field, we argue for the existence of a
triple point for the renormalized (running) values of the selfinteraction
and the "charge" g given by . Considering the
beta-function as a typical quantity we estimate that the one-loop approximation
is valid with accuracy of deviations not more than 30% in the region of the
parameters: The phase diagram given in the present paper
corresponds to the above-mentioned region of . Under the
point of view that the Higgs particle is a monopole with a magnetic charge g,
the obtained electric fine structure constant turns out to be
by the Dirac relation. This value is very close
to the which in a U(1) lattice gauge theory
corresponds to the phase transition between the "Coulomb" and confinement
phases. Such a result is very encouraging for the idea of an approximate
"universality" (regularization independence) of gauge couplings at the phase
transition point. This idea was suggested by the authors in their earlier
papers.Comment: 27 pages, 3 figure
Standard Model and Graviweak Unification with (Super)Renormalizable Gravity. Part I: Visible and Invisible Sectors of the Universe
We develop a self-consistent -invariant model of the unification
of gravity with weak gauge and Higgs fields in the visible and
invisible sectors of our Universe. We consider a general case of the graviweak
unification, including the higher-derivative super-renormalizable theory of
gravity, which is a unitary, asymptotically-free and perturbatively consistent
theory of the quantum gravity.Comment: 27 page
Generalized dual symmetry of nonabelian theories, monopoles and dyons
In the present talk we present an investigation of nonabelian SU(N) gauge
theories, describing a system of fields with non--dual g and dual \tilde g
charges and revealing the generalized dual symmetry. The Zwanziger type action
is suggested. The renormalization group equations for pure nonabelian theories,
in particular for pure SU(3)\times\widetilde{SU(3)} gauge theory (as an
example) are analysed. We consider not only monopoles, but also dyons. The
behaviour of the QCD total beta--function is investigated. It was shown that
this beta--function is antisymmetric under the interchange
\alpha\leftrightarrow\frac 1\alpha (here \alpha\equiv\alpha_s), and has zero
("fixed point") at \alpha = 1. Monopoles, or dyons, are responsible for the
phase transition. Considering critical points at \alpha_1\approx 0.4 and
\alpha_2\approx 2.5, we give an explanation of the freezing of \alpha_s.Comment: 15 pages, 5 figures, Presented at the 12th Lomonosov Conference on
Elementary Particle Physics, Moscow State University, Moscow, 25-31 August,
200
The Fundamental-Weak Scale Hierarchy in the Standard Model
The multiple point principle, according to which several vacuum states with
the same energy density exist, is put forward as a fine-tuning mechanism
predicting the ratio between the fundamental and electroweak scales in the
Standard Model (SM). It is shown that this ratio is exponentially huge: . Using renormalisation group equations for the SM, we obtain the
effective potential in the 2-loop approximation and investigate the existence
of its postulated second minimum at the fundamental scale. The investigation of
the evolution of the top quark Yukawa coupling constant in the 2-loop
approximation shows that, with initial values of the top Yukawa coupling in the
interval (here is the top quark pole mass), a
second minimum of the SM effective potential can exist in the region
GeV. A prediction is made of the existence
of a new bound state of 6 top quarks and 6 anti-top quarks, formed due to Higgs
boson exchanges between pairs of quarks/anti-quarks. This bound state is
supposed to condense in a new phase of the SM vacuum. This gives rise to the
possibility of having a phase transition between vacua with and without such a
condensate. The existence of three vacuum states (new, electroweak and
fundamental) solves the hierarchy problem in the SM.Comment: 30 pages, 7 figures; to be published in Phys. Atom. Nuc
- …