Non-ideal particle distributions from kinetic freeze out models

In fluid dynamical models the freeze out of particles across a three dimensional space-time hypersurface is discussed. The calculation of final momentum distribution of emitted particles is described for freeze out surfaces, with both space-like and time-like normals, taking into account conservation laws across the freeze out discontinuity

Entropy development in ideal relativistic fluid dynamics with the Bag Model equation of state

We consider an idealized situation where the Quark-Gluon Plasma (QGP) is described by a perfect, (3 + 1)-dimensional fluid dynamic model starting from an initial state and expanding until a final state where freeze-out and/or hadronization takes place. We study the entropy production with attention to effects of (i) numerical viscosity, (ii) late stages of flow where the Bag Constant and the partonic pressure are becoming similar, (iii) and the consequences of final freeze-out and constituent quark matter formation.Peer reviewe

Freeze-out in hydrodynamical models in relativistic heavy ion collisions

In continuum and fluid dynamical models, particles, which leave the system and reach the detectors, can be taken into account via freeze-out (FO) or final break-up schemes, where the frozen out particles are formed on a 3-dimensional hypersurface in space-time. Such FO descriptions are important ingredients of evaluations of two-particle correlation data, transverse-, longitudinal-, radial- and cylindrical- flow analyses, transverse momentum and transverse mass spectra and many other observables. The FO on a hypersurface is a discontinuity, where the pre FO equilibrated and interacting matter abruptly changes to non-interacting particles, showing an ideal gas type of behavior

Kinetic freeze out models

Freeze out of particles across a space-time hypersurface is discussed in kinetic models. The calculation of final momentum distribution of emitted particles is described for freeze out surfaces, with spacelike normals. The resulting non-equilibrium distribution does not resemble, the previously proposed, cut Jüttner distribution, and shows non-exponential pt-spectra similar to the ones observed in experiments. PACS: 24.10.Nz, 25.75.-

Freeze out in hydrodynamical models

We study the effects of strict conservation laws and the problem of negative contributions to final momentum distribution during the freeze out through 3-dimensional hypersurfaces with space-like normal. We study some suggested solutions for this problem, and demonstrate it on one example. PACS: 24.10.Nz, 25.75.-

Large p(t) enhancement from freeze out

Freeze out of particles across three dimensional space-time hypersurface is discussed in a simple kinetic model. The final momentum distribution of emitted particles, for freeze out surfaces with space-like normal, shows a non-exponential transverse momentum spectrum. The slope parameter of the pt distribution increases with increasing pt, in agreement with recently measured SPS pion and h spectra

Explicit Model Realizing Parton-Hadron Duality

We present a model that realizes both resonance-Regge (Veneziano) and parton-hadron (Bloom-Gilman) duality. We first review the features of the Veneziano model and we discuss how parton-hadron duality appears in the Bloom-Gilman model. Then we review limitations of the Veneziano model, namely that the zero-width resonances in the Veneziano model violate unitarity and Mandelstam analyticity. We discuss how such problems are alleviated in models that construct dual amplitudes with Mandelstam analyticity (so-called DAMA models). We then introduce a modified DAMA model, and we discuss its properties. We present a pedagogical model for dual amplitudes and we construct the nucleon structure function F2(x,Q2). We explicitly show that the resulting structure function realizes both Veneziano and Bloom-Gilman duality.Comment: 11 pages, 8 figure

Weak decays of heavy hadrons into dynamically generated resonances

In this paper, we present a review of recent works on weak decay of heavy mesons and baryons with two mesons, or a meson and a baryon, interacting strongly in the final state. The aim is to learn about the interaction of hadrons and how some particular resonances are produced in the reactions. It is shown that these reactions have peculiar features and act as filters for some quantum numbers which allow to identify easily some resonances and learn about their nature. The combination of basic elements of the weak interaction with the framework of the chiral unitary approach allow for an interpretation of results of many reactions and add a novel information to different aspects of the hadron interaction and the properties of dynamically generated resonances.We would like to thank C. Hanhart and S. Stone for valuable comments on the manuscript. One of us, E. O., wishes to acknowledge support from the Chinese Academy of Science in the Program of Visiting Professorship for Senior International Scientists (Grant No. 2013T2J0012). This work is partly supported by the Spanish Ministerio de Economia y Competitividad and European FEDER funds under the contract numbers FIS2011-28853-C02-01, FIS2011-28853-C02-02, FIS2014-57026-REDT, FIS2014-51948-C2-1-P, and FIS2014-51948-C2-2-P, and the Generalitat Valenciana in the program Prometeo II-2014/068. This work is also partly supported by the National Natural Science Foundation of China under Grant Nos. 11165005, 11565007, 11475227, 11375080 and 11575076. We acknowledge the support of the European Community-Research Infrastructure Integrating Activity Study of Strongly Interacting Matter (acronym HadronPhysics3, Grant Agreement n. 283286) under the Seventh Framework Programme of EU. It is also supported by the Open Project Program of State Key Laboratory of Theoretical Physics, Institute of Theoretical Physics, Chinese Academy of Sciences, China (No. Y5KF151CJ1). M. D. gratefully acknowledges support from the NSF/PIF Grant No. PHY 1415459 and the NSF/Career grant No. 1452055.Peer reviewe