53,255 research outputs found
Do the gravitational corrections to the beta functions of the quartic and Yukawa couplings have an intrinsic physical meaning?
We study the beta functions of the quartic and Yukawa couplings of General
Relativity and Unimodular Gravity coupled to the and Yukawa
theories with masses. We show that the General Relativity corrections to those
beta functions as obtained from the 1PI functional by using the standard MS
multiplicative renormalization scheme of Dimensional Regularization are gauge
dependent and, further, that they can be removed by a non-multiplicative,
though local, field redefinition. An analogous analysis is carried out when
General Relativity is replaced with Unimodular Gravity. Thus we show that any
claim made about the change in the asymptotic behaviour of the quartic and
Yukawa couplings made by General Relativity and Unimodular Gravity lack
intrinsic physical meaning.Comment: 6 pages, 7 figure
Present Bounds on New Neutral Vector Resonances from Electroweak Gauge Boson Pair Production at the LHC
Several extensions of the Standard Model predict the existence of new neutral
spin-1 resonances associated to the electroweak symmetry breaking sector. Using
the data from ATLAS (with integrated luminosity of L=1.02 fb^{-1}) and CMS
(with integrated luminosity of L=1.55 fb^{-1}) on the production of W+W- pairs
through the process pp -> l^+ l^{\prime -} \sla{E}_T, we place model
independent bounds on these new vector resonances masses, couplings and widths.
Our analyses show that the present data excludes new neutral vector resonances
with masses up to 1-2.3 TeV depending on their couplings and widths. We also
demonstrate how to extend our analysis framework to different models working a
specific example.Comment: 10 pages, 6 figure
Constraining anomalous Higgs interactions
The recently announced Higgs discovery marks the dawn of the direct probing
of the electroweak symmetry breaking sector. Sorting out the dynamics
responsible for electroweak symmetry breaking now requires probing the Higgs
interactions and searching for additional states connected to this sector. In
this work we analyze the constraints on Higgs couplings to the standard model
gauge bosons using the available data from Tevatron and LHC. We work in a
model--independent framework expressing the departure of the Higgs couplings to
gauge bosons by dimension--six operators. This allows for independent
modifications of its couplings to gluons, photons and weak gauge bosons while
still preserving the Standard Model (SM) gauge invariance. Our results indicate
that best overall agreement with data is obtained if the cross section of Higgs
production via gluon fusion is suppressed with respect to its SM value and the
Higgs branching ratio into two photons is enhanced, while keeping the
production and decays associated to couplings to weak gauge bosons close to
their SM prediction.Comment: v3: Added acknowledgment to FP7 ITN INVISIBLES (Marie Curie Actions
PITN-GA-2011-289442). Nothing else changed with respect to v
Model of mobile agents for sexual interactions networks
We present a novel model to simulate real social networks of complex
interactions, based in a granular system of colliding particles (agents). The
network is build by keeping track of the collisions and evolves in time with
correlations which emerge due to the mobility of the agents. Therefore,
statistical features are a consequence only of local collisions among its
individual agents. Agent dynamics is realized by an event-driven algorithm of
collisions where energy is gained as opposed to granular systems which have
dissipation. The model reproduces empirical data from networks of sexual
interactions, not previously obtained with other approaches.Comment: 6 pages, 8 figure
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