174,531 research outputs found
Challenges for early discovery in ATLAS and CMS
The challenges for a discovery of new physics with 1 fb^-1 of LHC data for
ATLAS and CMS are discussed. Four specific examples are chosen: a deviation of
QCD jet distributions at high E_T, high-mass dilepton pairs, Higgs search in
the WW decay channel, and low mass supersymmetry.Comment: 6 pages, 17 figure
Exact Space-Time Gauge Symmetry of Gravity, Its Couplings and Approximate Internal Symmetries in a Total-Unified Model
Gravitational field is the manifestation of space-time translational ()
gauge symmetry, which enables gravitational interaction to be unified with the
strong and the electroweak interactions. Such a total-unified model is based on
a generalized Yang-Mills framework in flat space-time. Following the idea of
Glashow-Salam-Ward-Weinberg, we gauge the groups on equal-footing, so that we have the
total-unified gauge covariant derivative {\bf \d}_{\mu} = \p_{\mu} -
ig\phi_{\mu}^{\nu} p_{\nu}+ig_{s}{G_{\mu}^{a}}(\ld^a/2) +if{W_{\mu}^{k}}{t^k} +
if' U_{\mu}t_{o} + ig_{b}B_{\mu}. The generators of the external group
have the representation p_{\mu}=i\p_{\mu}, which differs from other
generators of all internal groups, which have constant matrix representations.
Consequently, the total-unified model leads to the following new results: (a)
All internal and baryonic gauge symmetries
have extremely small violations due to the gravitational interaction. (b) The
gauge symmetry remains exact and dictates the universal coupling of
gravitons. (c) Such a gravitational violation of internal gauge symmetries
leads to modified eikonal and Hamilton-Jacobi type equations, which are
obtained in the geometric-optics limit and involve effective Riemann metric
tensors. (d) The rules for Feynman diagrams involving new couplings of
photon-graviton, gluon-graviton and quark-gaviton are obtained.Comment: 19 pages, to be published in the Chinese Journal of Physics, 201
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