A microscopic NN to NN*(1440) potential

By means of a NN to NN*(1440) transition potential derived in a parameter-free way from a quark-model based NN potential, we determine simultaneously the $\pi NN^*(1440)$ and $\sigma NN^*(1440)$ coupling constants. We also present a study of the target Roper excitation diagram contributing to the $p(d,d')$ reaction.Comment: Talk presented at the Fourth International Conference on Perspectives in Hadronic Physics (ICTP, Trieste, Italy, May 2003). To appear in EPJA. 6 pages, 9 figures, needs svepj.clo and svjour.cl

Quark model derivation of a NN* (1440) potential

We derive a $NN^*$(1440) potential from a non-relativistic quark-quark interaction and a chiral quark cluster model for the baryons. By making use of the Born-Oppenheimer approximation we examine the most important features of this interaction in comparison to those obtained from meson-exchange models.Comment: 4 pages, 1 fig. Contribution to the XVII European Conference in Few-Body problems in physics. September 2000, Evora (Portugal). To appear in the proceedings in Nucl. Phys.

Spin-driven spatial symmetry breaking of spinor condensates in a double-well

The properties of an F=1 spinor Bose-Einstein condensate trapped in a double-well potential are discussed using both a mean-field two-mode approach and a simplified two-site Bose-Hubbard Hamiltonian. We focus in the region of phase space in which spin effects lead to a symmetry breaking of the system, favoring the spatial localization of the condensate in one well. To model this transition we derive, using perturbation theory, an effective Hamiltonian that describes N/2 spin singlets confined in a double-well potential.Comment: 12 pages, 5 figure

Dynamical coupled-channel approach to hadronic and electromagnetic production of kaon-hyperon on the proton

A dynamical coupled-channel formalism for processes $\pi N \to KY$ and $\gamma N \to KY$ is presented which provides a comprehensive investigation of recent data on the $\gamma p \to K^+ \Lambda$ reaction. The non-resonant interactions within the subspace $KY\oplus\pi N$ are derived from effective Lagrangians, using a unitary transformation method. The calculations of photoproduction amplitudes are simplified by casting the coupled-channel equations into a form such that the empirical $\gamma N \to \pi N$ amplitudes are input and only the parameters associated with the $KY$ channel are determined by performing $\chi^2$-fits to all of the available data for $\pi^- p \to K^\circ\Lambda, K^\circ\Sigma^\circ$ and $\gamma p \to K^+\Lambda$. Good agreement between our models and those data are obtained. In the fits to $\pi N \to KY$ channels, most of the parameters are constrained within $\pm 20$ of the values given by the Particle Data Group and/or quark model predictions, while for $\gamma p \to K^+ \Lambda$ parameters, ranges compatible with broken $SU(6)\otimes O(3)$ symmetry are imposed. The main reaction mechanisms in $K^+ \Lambda$ photoproduction are singled out and issues related to newly suggested resonances $S_{11}$, $P_{13}$, and $D_{13}$ are studied. Results illustrating the importance of using a coupled-channel treatment are reported. Meson cloud effects on the $\gamma N \to N^*$ transitions are also discussed.Comment: Accepted Physical Review

Microscopic NN→NN∗(1440)NN\to NN^{\ast}(1440) transition potential: Determination of πNN∗(1440)\pi NN^{\ast}(1440) and σNN∗(1440)\sigma NN^{\ast}(1440) coupling constants

A $NN\to NN^{\ast}(1440)$ transition potential, based on an effective quark-quark interaction and a constituent quark cluster model for baryons, is derived in the Born-Oppenheimer approach. The potential shows significant differences with respect to those obtained by a direct scaling of the nucleon-nucleon interaction. From its asymptotic behavior we extract the values of $\pi NN^{\ast}(1440)$ and $\sigma NN^{\ast}(1440)$ coupling constants in a particular coupling schemeComment: 15 eps figures, Accepted for publication in Phys. Rev.

Ru-Catalyzed C-H Arylation of Fluoroarenes with Aryl Halides

We gratefully acknowledge the Engineering and Physical Sciences Research Council (EPSRC, EP/I038578/1 and EP/ K039547/1) for funding and the European Research Council for a Starting Grant (to I.L.).

The contribution of Real Madrid’s first five European Cups to the emergence of a common football space

Real Madrid won the first five editions of the European Champion Clubs’ Cup (now formally known as the UEFA Champions League, and to which we will refer hereon as the European Cup) between 1956 and 1960, contributing decisively to the competition’s consolidation. The tournament’s history started towards the end of 1954, when a journalist of the French sports daily L’Équipe, Gabriel Hanot, published an article arguing the need to organise a competition that could bring together the champions of every European league. However, this was not an original proposal. Thirty years before Hanot’s article proposals for such a football competition were circulated among the game’s ruling elite. Unfortunately, at that time the lack of a good transport infrastructure to travel through Europe discouraged the proposers which, instead, turned their attention to regional supranational competitions, such as the Mitropa Cup or the Latin Cup. The first five editions of the European Cup witnessed as many victories of Real Madrid, thus forging an indissoluble bond between the competition and the Spanish club. These five European titles did not only cement the supremacy of Real Madrid on the pitch as a great football team, but they also contributed to the consolidation of the European Cup itself in the public’s imaginary. We also argue that given the expectations raised by Real Madrid’s triumphs across Europe those matches might have contributed as well to the emergence of a European football space. Since 1955 Real Madrid occupied an ever increasing space in the press across Europe. Real Madrid was then considered as the best expression of modernity in football. This chapter aims to analyse the meaning of these five European Cup titles for the emergence and definition of a nascent European football space. We, of course, also question whether such a common space can be found. The chapter explores in depth the reasons behind Real Madrid’s enthusiasm with the new European competition. We also examine the social impact that Real Madrid’s hegemony in the European Cup had in the context of Spain’s international isolation during General Franco’s dictatorship (1939-1975). In order to achieve the above mentioned objectives, the chapter relies on thematic analysis of selected publications in the Spanish and British press during those years. Moreover, we have also relied on a review of academic literature on the role of Real Madrid during the Franco dictatorship years, mainly the 1950s and 60s. This chapter is part of wider on-going research. In this research we examine the content of two Spanish dailies (ABC and Marca) and three British newspapers (The Guardian, The Times and the Daily Mirror). We searched these newspapers for content related to Real Madrid on specific dates: The semifinal games (two legs) and the final of each one of the five years where Real Madrid won the European Cup. We searched for content the day of each match, the day before and two days after each one of the matches. This chapter is a presentation of the findings obtained through thematic analysis of the data obtained through those searches

Electroproduction of kaons from the proton in a Regge-plus-resonance approach

We present a Regge-plus-resonance (RPR) description of the p(e,e'K^+)Y processes (Y=\Lambda,\Sigma^0) in the resonance region. The background contributions to the RPR amplitude are constrained by the high-energy p(\gamma, K^+)Y data. As a result, the number of free model parameters in the resonance region is considerably reduced compared to typical effective-Lagrangian approaches. We compare a selection of RPR model variants, originally constructed to describe $KY$ photoproduction, with the world electroproduction database. The electromagnetic form factors of the intermediate N^*s and $\Delta^*s are computed in the Bonn constituent-quark model. With this input, we find a reasonable description of the p(e,e'K^+)Y data without adding or readjusting any parameters. It is demonstrated that the electroproduction response functions are extremely useful for fine-tuning both the background and resonant contributions to the reaction dynamics.Comment: 14 pages, 7 figures; added discussion on double counting in the RPR model; accepted for publication in Phys. Lett.