1,906 research outputs found
Optimal Districting with Endogenous Party Platforms
This paper proposes a theory of socially optimal districting in a legislative-election model with endogenous party platforms. We generalize the model of Coate and Knight (2007), allowing parties to strategically condition their platforms on the districting. The socially optimal districting re ects the ideological leaning of the population, so that parties internalize voters' preferences in their policy platforms. The optimal seat-vote curve is unbiased when voters are risk-neutral, and -contrary to previous findings-biased against the largest partisan group when voters are risk-averse. The model is then calibrated by an econometric analysis of the elections of U.S. State legislators during the 1990s.
Investigating the tetraquark structure of the new mesons
Using the QCD sum rule approach we investigate the possible four-quark
structure of the recently observed mesons , firstly observed
by BaBaR, X(3872), firstly observed by BELLE and observed by
BELLE. We use diquark-antidiquark currents and work in full QCD, without
relying on expansion. Our results indicate that a four-quark structure
is acceptable for these mesons.Comment: 4 pages 1 eps figure, proceedings of the XVIII Workshop on Hadronic
Interactions (RETINHA-18) Sao Paulo-S
An inspection on the Borel masses relation used in QCD sum rules
In this work, we studied the Borel masses relation used in QCDSR
calculations. These masses are the parameters of the Borel transform used when
the three point function is calculated. We analised an usual and a more general
linear relations. We concluded that a general linear relation between these
masses provides the best results regarding the standard deviation.Comment: 6 pages, 2 figures, Prepared for 11th Hadron Physic
Analysis of the vertex with the light-cone QCD sum rules
In this article, we analyze the vertex with the light-cone QCD
sum rules. The strong coupling constant is an important
parameter in evaluating the charmonium absorption cross sections in searching
for the quark-gluon plasmas. Our numerical value for the is
consistent with the prediction of the effective SU(4) symmetry and vector meson
dominance theory.Comment: 6 pages, 1 figure, revised versio
A QCD sum rules calculation of the strong coupling constant
In this work, we calculate the form factors and the coupling constant of the
strange-charmed vertex in the framework of the QCD sum rules
by studying their three-point correlation functions. All the possible off-shell
cases are considered, , and , resulting in three different
form factors. These form factors are extrapolated to the pole of their
respective off-shell mesons, giving the same coupling constant for the process.
Our final result for the coupling constant is .Comment: 17 pages, 4 figure
- …