Fent ones amb un llençol

Amb un simple llençol és possible observar tant les variables que caracteritzen una ona bidimensional, com els fenòmens típics associats a les ones

Càlcul casolà de la velocitat del so

Es proposa un mètode senzill per determinar amb pocs mitjans la velocitat del so a l’aire

El Racó obscur . Fer l'animal a sobre d'una cadira giratòria

Fent l'animal sobre una cadira giratòria arribem al moll de l'os de conceptesque, més enllà de la conservació del moment angular, ens fan rodar el cap

El Diccionari de física: els termes de la física, en línia

En aquest article es presenta el Diccionari de física, elaborat conjuntament per la Universitat Politècnica de Catalunya, Enciclopèdia Catalana i el TERMCAT. S’hi descriuen les característiques principals (contingut, opcions de cerca, destinataris) de l’obra i les estratègies de difusió que es van seguir per a donar-la a conèixer, i se’n destaca el valor com a eina de consulta de terminologia bàsica i com a recurs didàctic

Pseudoscalar decays into two photons in chiral perturbation theory

We study the one-loop corrections in chiral perturbation theory to the γγ and γγ∗ decays of the pseudoscalar mesons. The latter are divergent, thus requiring the existence of dimension-six terms contributing to the anomalous Lagrangian. Some examples of such terms are given. We also discuss the experimental consequences of the next-to-leading terms

Past-Future Interference in Φ\Phi-Decays into Entangled Kaon Pairs

Quantum interference effects between past and future events (neutral kaon transitions, including CP violating decays) are discussed for entangled kaon pairs produced through $\phi \to K^0 \bar{K^0}$ in $\phi$-factories. Contrasting with the exciting conclusions of other recent analyses, we predict the inexistence of such an observable effect.Comment: 8 pages, LaTeX file, A postscript version can be obtained via anonymous ftp at ftp://ftp.ifae.es/preprint.ft/

A test of Local Realism with entangled kaon pairs and without inequalities

We propose the use of entangled pairs of neutral kaons, considered as a promising tool to close the well known loopholes affecting generic Bell's inequality tests, in a specific Hardy-type experiment. Hardy's contradiction without inequalities between Local Realism and Quantum Mechanics can be translated into a feasible experiment by requiring ideal detection efficiencies for only one of the observables to be alternatively measured. Neutral kaons are near to fulfil this requirement and therefore to close the efficiency loophole.Comment: 4 RevTeX page

Scalar meson dynamics in Chiral Perturbation Theory

A comparison of the linear sigma model (L$\sigma$M) and Chiral Perturbation Theory (ChPT) predictions for pion and kaon dynamics is presented. Lowest and next-to-leading order terms in the ChPT amplitudes are reproduced if one restricts to scalar resonance exchange. Some low energy constants of the order $p^4$ ChPT Lagrangian are fixed in terms of scalar meson masses. Present values of these low energy constants are compatible with the L$\sigma$M dynamics. We conclude that more accurate values would be most useful either to falsify the L$\sigma$M or to show its capability to shed some light on the controversial scalar physics.Comment: 9 pages, REVTeX 4.0. Final version accepted for publicatio