12,155 research outputs found
Cosmological Constant and Gravitational Repulsion Effect: 1. Homogeneous models with radiation
Within the framework of the minimum quadratic Poincare gauge theory of
gravity in the Riemann-Cartan spacetime we study the influence of gravitational
vacuum energy density (a cosmological constant) on the dynamics of various
gravitating systems. It is shown that the inclusion of the cosmological term
can lead to gravitational repulsion. For some simple cases of spatially
homogeneous cosmological models with radiation we obtain non-singular solutions
in form of elementary functions and elliptic integrals.Comment: REVTEX, 11 pages, Syracuse University preprint SU-GP-93/5-
Was the Higgs boson discovered?
The standard model has postulated the existence of a scalar boson, named the
Higgs boson. This boson plays a central role in a symmetry breaking scheme
called the Brout-Englert-Higgs mechanism (or the
Brout-Englert-Higgs-Guralnik-Hagen-Kibble mechanism, for completeness) making
the standard model realistic. However, until recently at least, the
50-year-long-sought Higgs boson had remained the only particle in the standard
model not yet discovered experimentally. It is the last but very important
missing ingredient of the standard model. Therefore, searching for the Higgs
boson is a crucial task and an important mission of particle physics. For this
purpose, many theoretical works have been done and different experiments have
been organized. It may be said in particular that to search for the Higgs boson
has been one of the ultimate goals of building and running the LHC, the world's
largest and most powerful particle accelerator, at CERN, which is a great
combination of science and technology. Recently, in the summer of 2012, ATLAS
and CMS, the two biggest and general-purpose LHC collaborations, announced the
discovery of a new boson with a mass around 125 GeV. Since then, for over two
years, ATLAS, CMS and other collaborations have carried out intensive
investigations on the newly discovered boson to confirm that this new boson is
really the Higgs boson (of the standard model). It is a triumph of science and
technology and international cooperation. Here, we will review the main results
of these investigations following a brief introduction to the Higgs boson
within the theoretical framework of the standard model and Brout-Englert-Higgs
mechanism as well as a theoretical and experimental background of its search.
This paper may attract interest of not only particle physicists but also a
broader audience.Comment: LateX, 23 pages, 01 table, 9 figures. To appear in Commun. Phys.
Version 2: Minor changes, two references adde
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