Isospin violation in pion-nucleon scattering

We construct the complete effective chiral pion-nucleon Lagrangian in the presence of virtual photons to one loop. As an application, we consider strong and electromagnetic isospin violation for scattering of neutral pions off nucleons. We show that for the scattering lengths these isospin violating terms are of the same size as the purely hadronic ones. We also analyze isospin-violating effects for the $\sigma$--term. These can be as large as 10% for the absolute value but are negligible for the shift to the Cheng-Dashen point.Comment: 13 pp, LaTeX, uses epsf, 1 fi

Renormalization of the chiral pion-nucleon Lagrangian beyond next-to-leading order

The complete renormalization of the generating functional for Green functions of quark currents between one-nucleon states in two flavor heavy baryon chiral perturbation theory is performed to order $q^4$. We show how the heat kernel method has to be extended for operators orthogonal to the heavy fermion four-velocity. A method is developed to treat the multi-coincidence limit arising from insertions of dimension two (and higher) operators on internal baryon propagators in self-energy graphs. As examples, we study the divergences in the isoscalar magnetic moment and the scalar form factor of the nucleon

Thermally induced subgap features in the cotunneling spectroscopy of a carbon nanotube

We report on nonlinear cotunneling spectroscopy of a carbon nanotube quantum dot coupled to Nb superconducting contacts. Our measurements show rich subgap features in the stability diagram which become more pronounced as the temperature is increased. Applying a transport theory based on the Liouville-von Neumann equation for the density matrix, we show that the transport properties can be attributed to processes involving sequential as well as elastic and inelastic cotunneling of quasiparticles thermally excited across the gap. In particular, we predict thermal replicas of the elastic and inelastic cotunneling peaks, in agreement with our experimental results.Comment: 21 pages, 9 figures, submitted to New Journal of Physic

Baryon magnetic moments in chiral perturbation theory

We consider the chiral expansion of the octet baryon magnetic moments in heavy baryon chiral perturbation theory including all terms which are of order $q^4$. These terms are formally of quadratic order in the quark masses. We show that despite the large non-analytic quark mass corrections to the Coleman-Glashow relations at order $q^3$, including all analytic and non-analytic corrections at order $q^4$, which in total are of moderate size, allows for a fit to the measured magnetic moments due to the appearance of counter terms with free coupling constants of natural size. In this scheme, the $\Lambda \Sigma^0$ transition moment is predicted to be $\mu_{\Lambda \Sigma^0} = (1.42 \pm 0.01) \mu_N$.Comment: 20 pp, LaTeX file, 2 figures (uses epsf), corrected versio

Allocating the Burdens of Climate Action: Consumption-Based Carbon Accounting and the Polluter-Pays Principle

Action must be taken to combat climate change. Yet, how the costs of climate action should be allocated among states remains a question. One popular answer—the polluter-pays principle (PPP)—stipulates that those responsible for causing the problem should pay to address it. While intuitively plausible, the PPP has been subjected to withering criticism in recent years. It is timely, following the Paris Agreement, to develop a new version: one that does not focus on historical production-based emissions but rather allocates climate burdens in proportion to each state’s annual consumption-based emissions. This change in carbon accounting results in a fairer and more environmentally effective principle for distributing climate duties

Circum-Mediterranean Neogene (Miocene and Pliocene) marine-continental chronologic correlations of European mammal units

This paper is an update of Steininger et al. 1989. It is mainly concerned with the chronologic correlation of the Miocene and Pliocene European Mammal Biozonations, the "European Neogene Mammal Faunal Zones" (MN zones, for discussion see Steininger et al. 1989) and the "European Mammal Faunal Units" (Agenic, Orleanic, etc., of Fahlbusch 1975; for discussion see Steininger et al. 1989), with the new Geomagnetic Polarity Time Scale (Cande and Kent 1992; in press) and the revised Geomagnetic Polarity Time Scale, Cenozoic Geochronology, Chronostratigraphy, and Planktonic Foraminifera Zonation (Berggren et al., in press). Within the last years rapid progress has been made in dating mammal-bearing Miocene and Pliocene sediments, either by radioisotopic dating (see also Swisher et al., this volume) and/or by geomagnetic dating (see also the following articles in this volume: Bernor et al.; Kappelman et al.: Sen; and Woodburne et al.). These recent results have been incorporated into this new data base. For a more recent compilation of the Pleistocene record see Agusti 1991 and Agusti et al. 1987