SUBLUMINAL OPERA NEUTRINOS

Superluminal neutrinos at OPERA confront pion decay kinematics.

Violation of Lorentz invariance (VLI) has been suggested as an explanation of the superluminal velocities of muon neutrinos reported by OPERA. In this Letter, we show that the amount of VLI required to explain this result poses severe difficulties with the kinematics of the pion decay, extending its lifetime and reducing the momentum carried away by the neutrinos. We show that the OPERA experim...

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Coherent Phonon-Polaritons and Subluminal Čerenkov Radiation

Impulsive stimulated Raman scattering can be used to generate a wide range of coherent low-lying excitations [1] and, in particular, phonon-polaritons which are hybrid modes resulting from the coupling of infrared-active transverse optical phonons to infrared photons. In most cases reported in the literature, phase matching is achieved by using the so-called traveling grating geometry involving...

Opera postuma

It seems incredible that twelve volumes of medical works written in Morgagni's own handwriting should have been completely lost to sight until 1952, when Professor Adalberto Pazni, combing through the catalogues in the Laurenziana Library in Florence for the names of medieval doctors, should have discovered them by chance. How they came to be there is a story full of interest, a detective story...

Ultra high energy cosmic rays: subluminal and superluminal shocks

Diffusive shock acceleration is invoked to explain non-thermal particle acceleration in Supernova Remnants, Active Galactic Nuclei (AGN) Jets, Gamma ray Bursts (GRBs) and various large scale cosmic structures. The importance of achieving the highest observed particle energies by such a mechanism in a given astrophysical situation is a recurring theme. In this work, shock acceleration in relativ...