Anomaly Mediation and Cosmology

We consider an extension of the MSSM wherein anomaly mediation is the source of supersymmetry breaking, and the tachyonic slepton problem is solved by a gauged U(1) symmetry, which is broken at high energies in a manner preserving supersymmetry, thereby also facilitating the see-saw mechanism for neutrino masses and a natural source for the Higgs mu-term. We show that these favourable outcomes can occur both in the presence and the absence of a large Fayet-Iliopoulos (FI) D-term associated with the new U(1). We explore the cosmological consequences of the model, showing that it naturally produces a period of hybrid inflation, terminating in the production of cosmic strings. In spite of the presence of a U(1) (even with an FI term), inflation is effected by the F-term, with a D-flat tree potential (the FI term, if present, being cancelled by non-zero squark and slepton fields). Calculating the 1-loop corrections to the inflaton potential, we estimate the constraints on the parameters of the model from Cosmic Microwave Background data. We will see that a consequence of these constraints is that the Higgs mu-term necessarily small. We briefly discuss the mechanisms for baryogenesis via conventional leptogenesis, the out-of-equilibrium production of neutrinos from the cosmic strings, or the Affleck-Dine mechanism. Cosmic string decays also boost the relic density of dark matter above the low value normally obtained in AMSB scenarios.Comment: 34 pages. Revised to incorporate discussion of the case when the Fayet-Ilipoulos term is absen

Segmentation of Highly Vocalic Speech Via Statistical Learning: Initial Results From Danish, Norwegian, and English

Research has shown that contoids (phonetically defined consonants) may provide more robust and reliable cues to syllable and word boundaries than vocoids (phonetically defined vowels). Recent studies of Danish, a language characterized by frequent long sequences of vocoids in speech, have suggested that the reduced occurrence of contoids may make speech in it intrinsically harder to segment than in closely related languages such as Norwegian. We addressed this hypothesis empirically in an artificial language learning experiment with native speakers of Danish, Norwegian, and English. We tested whether artificial speech consisting of concatenated contoid–vocoid syllables is easier to segment than speech consisting of vocoid–vocoid syllables where the first segment is a semivowel and the second a full vowel. Contrary to what was expected, we found no effect of the phonetic makeup of the syllables on speech segmentability. Possible interpretations and implications of this result are discussed

Segmentation of highly vocalic speech via statistical learning: Initial results from Danish, Norwegian, and English.

Research has shown that contoids (i.e., phonetically-defined consonants) may provide more robust and reliable cues to syllable and word boundaries than vocoids (i.e., phonetically-defined vowels). Recent studies of Danish — a language characterized by frequent long sequences of vocoids in speech — have suggested that the frequent lack reduced occurrence of consonantal sounds contoids may make speech intrinsically harder to segment than in closely related languages, such as Norwegian. In this study, we addressed this hypothesis empirically in an artificial language learning experiment with native speakers of Danish, Norwegian, and English. We tested whether artificial speech consisting of concatenated contoid-vocoid syllables is easier to segment than speech consisting of vocoid-vocoid syllables (where the first segment is a semivowel and the second a full vowel). Contrary to what was expected, we found no effect of the phonetic makeup of the syllables on speech segmentability. Possible interpretations and implications of this result are discussed