Hadron widths in mixed-phase matter

We derive classically an expression for a hadron width in a two-phase region of hadron gas and quark-gluon plasma (QGP). The presence of QGP gives hadrons larger widths than they would have in a pure hadron gas. We find that the $\phi$ width observed in a central Au+Au collision at $\sqrt{s}=200$ GeV/nucleon is a few MeV greater than the width in a pure hadron gas. The part of observed hadron widths due to QGP is approximately proportional to $(dN/dy)^{-1/3}$.Comment: 8 pages, latex, no figures, KSUCNR-002-9

RPA-Approach to the Excitations of the Nucleon, Part II: Phenomenology

The tensor-RPA approach developed previously in part I is applied to the Nambu-Jona-Lasinio (NJL) model. As a first step we investigate the structure of Dirac-Hartree-Fock solutions for a rotationally and isospin invariant ground-state density. Whereas vacuum properties can be reproduced, no solitonic configuration for a system with unit baryon number is found. We then solve the tensor-RPA equation employing simple models of the nucleon ground state. In general the ph interaction effects a decrease of the excited states to lower energies. Due to an enhanced level density at low energies the obtained spectra cannot be matched with the experimental data when a standard MIT-bag configuration is used. However, when the size of the nucleon quark core is reduced to approximately 0.3 fm a fair description of the baryon spectrum in the positive-parity channel is achieved. For this purpose the residual interaction turns out to be crucial and leads to a significant improvement compared with the mean-field spectra.Comment: 33 pages, Latex, 9 Postscpript figures, section on the excited states has been completely rewritten after error was detected, results are now much more encouragin

Effective Chiral Meson Lagrangian For The Extended Nambu-Jona-Lasinio Model

We present a derivation of the low-energy effective meson Lagrangian of the extended Nambu -- Jona-Lasinio (ENJL) model. The case with linear realization of broken $SU(2)\times SU(2)$ chiral symmetry is considered. There are two crucial points why this revision is needed. Firstly it is the explicit chiral symmetry breaking effect. On the basis of symmetry arguments we show that relevant contributions related with the current quark mass terms are absent from the effective Lagrangians derived so far in the literature. Secondly we suggest a chiral covariant way to avoid non-diagonal terms responsible for the pseudoscalar -- axial-vector mixing from the effective meson Lagrangian. In the framework of the linear approach this diagonalization has not been done correctly. We discuss as well the $SU(2)\times SU(2)/SU(2)$ coset space parametrization for the revised Lagrangian (nonlinear ansatz). Our Lagrangian differs in an essential way from those that have been derived till now on the basis of both linear and nonlinear realizations of chiral symmetry.Comment: 23 pages, plain LaTex, no figure

Pion light-cone wave function and pion distribution amplitude in the Nambu-Jona-Lasinio model

We compute the pion light-cone wave function and the pion quark distribution amplitude in the Nambu-Jona-Lasinio model. We use the Pauli-Villars regularization method and as a result the distribution amplitude satisfies proper normalization and crossing properties. In the chiral limit we obtain the simple results, namely phi_pi(x)=1 for the pion distribution amplitude, and = -M / f_pi^2 for the second moment of the pion light-cone wave function, where M is the constituent quark mass and f_pi is the pion decay constant. After the QCD Gegenbauer evolution of the pion distribution amplitude good end-point behavior is recovered, and a satisfactory agreement with the analysis of the experimental data from CLEO is achieved. This allows us to determine the momentum scale corresponding to our model calculation, which is close to the value Q_0 = 313 MeV obtained earlier from the analogous analysis of the pion parton distribution function. The value of is, after the QCD evolution, around (400 MeV)^2. In addition, the model predicts a linear integral relation between the pion distribution amplitude and the parton distribution function of the pion, which holds at the leading-order QCD evolution.Comment: mistake in Eq.(38) correcte

Varieties of localization: international norms and the commodification of knowledge in India and Brazil

Contains fulltext : 157237.pdf (publisher's version ) (Closed access)The legal implementation of internationally agreed norms on a domestic level gives momentum to a substantial reinterpretation. Based on this insight, this article develops an ideal-typology of possible ‘localization’ outcomes. Apart from a literal adoption of an international norm, we show that the domestic implementation may change its emphasis (accentuation), amend it by supplementary purposes (addition), or imply a deviation which nevertheless sticks to the letter of the international wording (subversion). We argue that the specific form of localization depends on the interaction between international pressure politics and its congruence with the prevailing domestic public and private preferences. International power constellations explain why an international norm is implemented, but the specific character of its localization is mainly determined by domestic actor constellations. To substantiate our claims, we analyze the implementation of two interconnected international agreements in India and Brazil. While both the Convention on Biodiversity and the Agreement on Trade Related Aspects of Intellectual Property Rights introduce the norm of property rights for intellectual knowledge in previously (at least internationally) unregulated fields, the particular characteristics of their respective implementation in both countries display the interaction between international pressure and domestic preferences in our four case studies.16 februari 201