Measurement of the Omega_c Lifetime

We present the measurement of the lifetime of the Omega_c we have performed using three independent data samples from two different decay modes. Using a Sigma- beam of 340 GeV/c we have obtained clean signals for the Omega_c decaying into Xi- K- pi+ pi+ and Omega- pi+ pi- pi+, avoiding topological cuts normally used in charm analysis. The short but measurable lifetime of the Omega_c is demonstrated by a clear enhancement of the signals at short but finite decay lengths. Using a continuous maximum likelihood method we determined the lifetime to be tau(Omega_c) = 55 +13-11(stat) +18-23(syst) fs. This makes the Omega_c the shortest living weakly decaying particle observed so far. The short value of the lifetime confirms the predicted pattern of the charmed baryon lifetimes and demonstrates that the strong interaction plays a vital role in the lifetimes of charmed hadrons.Comment: 15 pages, including 7 figures; gzipped, uuencoded postscrip

Search for the exotic Ξ−−(1860)\Xi^{--}(1860) Resonance in 340GeV/c Σ−\Sigma^--Nucleus Interactions

We report on a high statistics search for the $\Xi^{--}(1860)$ resonance in $\Sigma^-$-nucleus collisions at 340GeV/c. No evidence for this resonance is found in our data sample which contains 676000 $\Xi^-$ candidates above background. For the decay channel $\Xi^{--}(1860) \to \Xi^-\pi^-$ and the kinematic range 0.15$<x_F<$0.9 we find a 3$\sigma$ upper limit for the production cross section of 3.1 and 3.5 $\mu$b per nucleon for reactions with carbon and copper, respectively.Comment: 5 pages, 4 figures, modification of ref. 43 and 4

Heavy Baryons in SU(2) ×\times SU(6)

The spectrum of baryons containing heavy quarks of one flavor is described in terms of representations of the group SU(2) X SU(6), where the two factor groups refer to spin rotations of the heavy quarks and spin-flavor rotations of the light quarks, respectively. This symmetry has a natural interpretation in the heavy quark limit. We exhibit the decomposition of baryon mass operators under this symmetry and compare to experimental results. We discuss the relation of this analysis to that of large-N_c QCD as well as four-flavor SU(8), and indicate the generalization of this work to other properties of heavy baryons.Comment: 26 pages, hyperlatex with revte

Heavy Baryon Masses in the 1/mQ1/m_Q and 1/Nc1/N_c Expansions

The masses of baryons containing a single heavy quark are studied in a combined expansion in $1/m_Q$, $1/N_c$ and $SU(3)$ flavor symmetry breaking. Heavy quark baryon mass splittings are related to mass splittings of the octet and decuplet baryons. The $\Sigma_c^*$, $\Xi_c^\prime$ and $\Omega_c^*$ are predicted to the level of a few MeV. A number of bottom baryon mass splittings are predicted very accurately.Comment: 21 pages, REVtex, version to appear Phys. Rev.

The Heavy Hadron Spectrum

I discuss the spectrum of hadrons containing heavy quarks ($b$ or $c$), and how well the experimental results are matched by theoretical ideas. Useful insights come from potential models and applications of Heavy Quark Symmetry and these can be compared with new numerical results from the ab initio methods of Lattice QCD.Comment: 64 pages, Latex, lectures at Schladming Winter School 199

Do bilateral social security agreements deliver on the portability of pensions and health care benefits? A summary policy paper on four migration corridors between EU and non-EU member states

This policy paper summarizes four corridor studies on bilateral social security agreements (BSSAs) between four EU Member and two non-Member States, draws conclusions on their results, and offers recommendations. BSSAs between migrant-sending and migrant-receiving countries are seen as the most important instrument to establish portability of social security benefits for internationally mobile workers. Yet only about 23 percent of international migrants profit from BSSAs and their functioning has been little analyzed and even less assessed. The four corridors studied (Austria-Turkey, Germany-Turkey, Belgium-Morocco, and France-Morocco) were selected to allow for comparison of both similarities and differences in experiences. The evaluation of these corridors' BSSAs was undertaken against a methodological framework and three selected criteria: fairness for individuals, fiscal fairness for countries, and bureaucratic effectiveness for countries and migrant workers. The results suggest that the investigated BSSAs work and overall deliver reasonably well on individual fairness. The results on fiscal fairness are clouded by conceptual and empirical gaps. Bureaucratic effectiveness would profit from ICT-based exchanges on both corridors once available

Labor force- and work volume-projections until 2060

Diese Arbeit analysiert die Auswirkungen des demografischen Wandels auf das Arbeitsangebot und leitet auf Basis verschiedener Szenarien Politikempfehlungen ab, um dem demografisch bedingten Arbeitskräfterückgang zu begegnen. In einem ersten Schritt werden hierbei Erwerbspersonenprojektion anhand eines Kohorten-Komponenten-Modells vorgenommen und durch verschiedene Modellrechnungen ergänzt. Neben einer Abschätzung der Erwerbspersonenzahl bei einer Erhöhung des effektiven Renteneintrittsalters werden die Konsequenzen eines früheren Erwerbseintritts, einer steigenden Erwerbsbeteiligung der über 60-Jährigen, einer verstärkten Erwerbsbeteiligung von Menschen mit Migrationshintergrund sowie einer erhöhten Erwerbsbeteiligung der Frauen untersucht. In einem zweiten Schritt werden die Effekte einer sinkenden Erwerbslosenquote sowie einer steigenden Arbeitszeit je Erwerbstätigen betrachtet, um so Rückschlüsse über das zukünftige Arbeitsvolumen zu ziehen. Unsere Ergebnisse legen nahe, dass eine hinreichende Stabilisierung des jährlich geleisteten Arbeitsvolumens möglich ist, so dass bereits geringe Produktivitätssteigerungen dafür ausreichen werden, das Bruttoinlandsprodukt je Einwohner auf dem heutigen Niveau zu stabilisieren

Public Pensions and Immigration Policy When Voters are Differently Skilled

Although immigration of workers generates a positive externality on members of domestic pension systems, many countries are very reluctant to allow foreigners into their labor markets. In a political economic framework, we explain this voting outcome by considering a young unskilled median voter who faces - in addition to a reduction of contribution rates - negative effects from immigration as well

Charge Asymmetries for D, D_s and Lambda_c Production in Sigma- - Nucleus Interactions at 340 GeV/c

CERN experiment WA89 has studied charmed particles produced by a Sigma^- beam at 340 GeV/c on nuclear targets. Production of particles which have light quarks in common with the beam is compared to production of those which do not. Considerable production asymmetries between D^- and D^p, D_s^ and D_s^+ and Lambda_c and Antilambda_c are observed. The results are compared with pion beam data and with theoretical calculations.Comment: LaTeX ; 16 pages including 4 ps figure

Crystal structure of sinhalite MgAlBO4 under high pressure

This document is the Accepted Manuscript version of a Published Work that appeared in final form in Journal of Physical Chemistry C, copyright © American Chemical Society after peer review and technical editing by the publisher. To access the final edited and published work see http://dx.doi.org/10.1021/jp512131eWe report on high-pressure angle-dispersive X-ray diffraction data up to 27 GPa for natural MgAlBO4 sinhalite mineral and ab initio total energy calculations. The experimental bulk modulus of sinhalite is B-0 = 171(3) GPa with a first-pressure derivative of B-0' = 4.2(3). A comparison with other olivine-type compounds shows that the value for B0 is 27% larger than that of Mg2SiO4 forsterite and 29% smaller than that of Al2BeO4 chrysoberyl. These differences are interpreted, on the basis of our ab initio calculations, in terms of the relative incompressibility of Al-O bonds in AlO6 octahedra (with a calculated bulk modulus of 250(1) GPa) as compared to Mg-O bonds in MgO6 octahedra (with a calculated bulk modulus of 130(1) GPa). The spatial cation distribution in the Pbnm orthorhombic unit cell and different polyhedral compressibilities entails a strong anisotropic compression comparable to that of forsterite. The axial compressibilities are 1.06(2) x 10(-3), 2.17(2) x 10(-3), and 1.30(3) x 10(-3) GPa(-1) for a, b, and c axes, respectively. The crystal chemistry of sinhalite under compression is compared to that of other olivine-like compounds. Compressibility trends and possible high-pressure phases are discussed.This study was supported by the Spanish government MEC under Grants No: MAT2010-21270-C04-01/03/04, MAT2013-46649-C4-1/2/3-P, and CTQ2009-14596-C02-01, by the Comunidad de Madrid and European Social Fund (S2009/PPQ1551 4161893), by MALTA Consolider Ingenio 2010 project (CSD2007-00045), and by Generalitat Valenciana (GVA-ACOMP-2013-1012 and GVA-ACOMP-2014-243). Experiments were performed at MSPD beamline at ALBA Synchrotron Light Facility with the collaboration of ALBA staff A.M. and P.R-H. acknowledge computing time provided by Red Espanola de Supercomputacion (RES) and MALTA-Cluster. J.A.S. acknowledges financial support through the Juan de la Cierva fellowship. We are particularly grateful to Angel Vegas for stimulating discussions and critical reading of this manuscript.Santamaría Pérez, D.; Errandonea, D.; Gomis, O.; Sans Tresserras, JÁ.; Pereira, ALJ.; Manjón Herrera, FJ.; Popescu, C.... (2015). Crystal structure of sinhalite MgAlBO4 under high pressure. Journal of Physical Chemistry C. 119(12):6777-6784. https://doi.org/10.1021/jp512131eS677767841191