878 research outputs found
Indicators of Electoral Victory
We study a two-party contest where candidates strategically allocate their campaign resources between two salient issues. We analyze to what extent the following indicators of a party's success predict the electoral victory: (1) the pre-campaign advantage, (2) the advantage on every salient issue, and (3) the advantage on campaign resources. We show that the electoral victory is guaranteed only when a party has a "sufficiently large" advantage on every salient issue. Otherwise no combination of these indicators ensures the electoral victory.Election campaign, salient issues, majority voting
Dialogue or issue divergence in the political campaign?
We incorporate the media priming effects to explain how politicians can affect voters preferences on issues during the political campaign. We adapt well-known terms of international trade, such as absolute advantage and comparative advantage, to the context of parties' competition in political issues. We show that when either each party has an absolute advantage on a different issue or when parties have high comparative advantage on a different issue, the political campaign will consist of issue-emphasis divergence. However, when a party has an absolute advantage on both issues but the parties' comparative advantage is not high enough, the political campaign will consist of issue engagement or dialogue. Our results conciliate two separated theories concerning whether there must be dialogue or issue-emphasis divergence in the political campaign.political campaign, media priming, political issues, spatial model
Two-loop hybrid renormalization of local dimension-4 heavy-light operators
The renormalization of local dimension-4 operators containing a heavy and a
light quark field at scales below the heavy-quark mass is discussed, using the
formalism of the heavy-quark effective theory. The anomalous dimensions of
these operators and their mixing are calculated to two-loop order. Some
phenomenological applications are briefly discussed.Comment: 11 pages, 2 figure
The chiral logs of the K -> pi pi amplitude
I calculate the leading logarithmic contributions up to two-loop order of the
octet part of the K -> pi pi amplitude. This sector of the weak chiral
Lagrangian is believed to be the main source of the enhancement of the I=0
relative to the I=2 K -> pi pi amplitude, the so-called Delta I = 1/2 rule. I
discuss the procedure of chiral extrapolations of lattice data specific to K ->
pi pi decays and study the implication of the present calculation on these
numerically. The latter reinforces the fact that one has to expect a large
enhancement of the I=0 part of the amplitude due to re-scattering effects
between the three mesons.Comment: 20 pages, 4 figures, uses axodra
Sudden singularities in semiclassical gravity
It has been claimed in a recent paper \cite{bbfhd12} that sudden
singularities will survive in semiclassical gravity. This issue is here
carefully reviewed, pointing out that such conclusion, even if valid under some
specific conditions, does not stand in other cases. An explicit example is
studied in detail to support our statement, stemming from these other
situations, that quantum effects may in fact drastically modify the behavior of
sudden singularities.Comment: Accepted for publication in PR
An example of resonance saturation at one loop
We argue that the large-Nc expansion of QCD can be used to treat a Lagrangian
of resonances in a perturbative way. As an illustration of this we compute the
L_10 coupling of the Chiral Lagrangian by integrating out resonance fields at
one loop. Given a Lagrangian and a renormalization scheme, this is how in
principle one can answer in a concrete and unambiguous manner questions such as
at what scale resonance saturation takes place.Comment: 9 pages, 5 figures. Enlarged discussion, results unchanged. To be
published in Phys. Rev.
Meson resonances, large N_c and chiral symmetry
We investigate the implications of large N_c and chiral symmetry for the mass
spectra of meson resonances. Unlike for most other mesons, the mass matrix of
the light scalars deviates strongly from its large-N_c limit. We discuss the
possible assignments for the lightest scalar nonet that survives in the
large-N_c limit.Comment: 14 page
Integrating out strange quarks in ChPT
We study three flavour chiral perturbation theory in a limit where the
strange quark mass is much larger than the external momenta and the up and down
quark masses, and where the external fields are those of two-flavour chiral
perturbation theory. In this case, the theory reduces to the one of SU(2)_L x
SU(2)_R. Through this reduction, one can work out the strange quark mass
dependence of the LECs in the two-flavour case. We present the pertinent
relations at two-loop order for F,B and l_i.Comment: 14 pages, 3 figures, References added. Due to a typo in a form
program, we missed a finite, scale independent part in l_7. Is now included.
Version to appear in Phys.Lett.
The Inverse Amplitude Method in Scattering in Chiral Perturbation Theory to Two Loops
The inverse amplitude method is used to unitarize the two loop
scattering amplitudes of SU(2) Chiral Perturbation Theory in the ,
and channels. An error analysis in terms of the low energy
one-loop parameters and existing experimental data is
undertaken. A comparison to standard resonance saturation values for the two
loop coefficients is also carried out. Crossing
violations are quantified and the convergence of the expansion is discussed.Comment: (Latex, epsfig) 30 pages, 13 figures, 8 table
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