Combining QED and QCD transverse-momentum resummation for Z boson production at hadron colliders

We consider the transverse-momentum ($q_T$) distribution of $Z$ bosons produced in hadronic collisions. At small values of $q_T$, we perform the analytic resummation of the logarithmically enhanced QED contributions up to next-to-leading logarithmic accuracy, including the mixed QCD-QED contributions at leading logarithmic accuracy. Resummed results are consistently matched with the next-to-leading fixed-order results (i.e. $\mathcal{O}(\alpha^2)$) at small, intermediate and large values of $q_T$. We combine the QED corrections with the known QCD results at next-to-next-to-leading order ($\mathcal{O}(\alpha_S^2)$) and next-to-next-to-leading logarithmic accuracy. We show numerical results at LHC and Tevatron energies, studying the impact of the QED corrections and providing an estimate of the corresponding perturbative uncertainty. Our analytic results for the combined QED and QCD resummation, obtained through an extension of the $q_T$ resummation formalism in QCD, are valid for the production of generic neutral and colourless high-mass systems in hadronic collision.Comment: 13 pages, 3 figure

Intercalation and dynamics of hydrated Fe2+ in the vermiculites from Santa Olalla and Ojén

Although the intercalation of Fe3+ into layered phyllosicilicates-especially into smectites-attracted much attention in the past two decades, the information about Fe2+ loaded phyllosilicates is sparse. Here we present an investigation of the Fe2+ exchanged vermiculites from Santa Olalla and Ojén (Andalusia, Spain) by means of Mössbauer spectroscopy. The room temperature Mössbauer spectra are very similar to those of the starting compounds (Na forms) except for a decrease of the contribution of structural Fe3+ and a concomitant increase of the contribution of Fe2+ sites, indicating an internal redox process. The extent of this redox reaction is different for the two vermiculites. Thus, the intercalated Fe2+ acts as an electron mediator from the external medium to the structural Fe3+ ions. A new component attributable to intercalated Fe2+ is practically invisible in the room temperature Mössbauer spectra, but increases strongly and continuously during cooling to 4.2 K, where it is the dominant feature of the Mössbauer patterns. At 4.2 K, its quadruple splitting amounts to 3.31 mm/s, which is in excellent agreement with the quadrupole slitting of Fe2+ coordinated to six water molecules in a highly symmetric octahedral arrangement. The strong decrease of the Mössbauer-Lamb factor of this component with increasing temperature indicates a weak bonding of the Fe 2+ in the interlayer space

Associated WH production at hadron colliders: a fully exclusive QCD calculation at NNLO

We consider QCD radiative corrections to Standard Model Higgs boson production in association with a W boson in hadron collisions. We present a fully exclusive calculation up to next-to-next-to-leading order (NNLO) in QCD perturbation theory. To perform this NNLO computation, we use a recently proposed version of the subtraction formalism. Our calculation includes finite-width effects, the leptonic decay of the W boson with its spin correlations, and the decay of the Higgs boson into a bbbar pair. We present selected numerical results at the Tevatron and the LHC.Comment: 7 pages, 2 figure

The nature and rationale for European social rights

Over the last few years, the European Commission has repeatedly emphasized that, in the face of global uncertainty, the EU has to strengthen its social dimension and foster better working and living conditions for its citizens. To achieve this, the EU wants to strengthen social citizenship by advancing social rights, implementing the principles in the European Pillar of Social Rights at both the European and national level. The overarching objective of the EuSocialCit project, of which this paper is part, is to examine the state of EU social citizenship as well as possible policy scenarios that may strengthen it. This prompts initial foundational questions for the project: what is the nature of EU social citizenship and the social rights associated with it? And, what is the rationale for the EU to be involved in providing social rights? In order to understand the state and nature of EU social citizenship and the role that the EU plays in this now and in the future, we believe that it is necessary to ‘dissect’ the constitutive elements of social rights at the various levels (local, national and EU) at which they are provided. To this end, this paper develops a resource-based and multi-level conception of social rights. With regard to the rationale, we offer an overview of the main approaches that prevail in the long-standing debate on the justification and feasibility of a stronger EU social citizenship and present a synthesis of these approaches that may help further the debate

Monitoring the solid-state dewetting of densely packed arrays of Au nanoparticles

We report a real time, in-situ spectroscopic ellipsometry study of the temperature-induced solid-state dewetting of Au nanowires into nanoparticles. Very large spectral variations are observed at different temperatures. Analysis of the key features in the acquired spectra reveals two different regimes: up to 300 \ub0C the variation in the optical response is dominated by solid-state dewetting, while above that temperature, smaller variations not compatible with such mechanism are visible. Therefore our ellipsometry measurements allow us to determine in real time at which temperature the solid-state dewetting ceases and the morphology of our sample becomes stable. We point out that this observation is possible thanks to the higher sensitiviy of ellipsometry with respect to reflectance/transmittance measurements

Smooth Approximation of Lipschitz functions on Riemannian manifolds

We show that for every Lipschitz function $f$ defined on a separable Riemannian manifold $M$ (possibly of infinite dimension), for every continuous $\epsilon:M\to (0,+\infty)$, and for every positive number $r>0$, there exists a $C^\infty$ smooth Lipschitz function $g:M\to\mathbb{R}$ such that $|f(p)-g(p)|\leq\epsilon(p)$ for every $p\in M$ and $\textrm{Lip}(g)\leq\textrm{Lip}(f)+r$. Consequently, every separable Riemannian manifold is uniformly bumpable. We also present some applications of this result, such as a general version for separable Riemannian manifolds of Deville-Godefroy-Zizler's smooth variational principle.Comment: 10 page

F015 Role des fibroblastes cardiaques dans la tolérance des cardiomyocytes à l’ischémie reperfusion

ObjectifLes fibroblastes cardiaques sont la population cellulaire majoritaire du tissu cardiaque. Leurs possibles implications au cours de la séquence ischémie-reperfusion n’a jamais été étudiée. Le présent travail a donc pour but de déterminer si les fibroblastes sont impliqués dans une modulation de la cardioprotection.Matériel et MéthodesNous avons utilisé dans cette étude un modèle de cardiomyocytes de rats nouveau-nés soumis à une séquence d’ischémie-reperfusion simulées. Les cellules ont été isolées à partir de ventricules de rats nouveau nés. Les myocytes cardiaques ont été purifiés par attachements différentiels puis cultivés en présence d’un milieu de culture supplémenté en cytosine arabinoside (Ara C, 10μm). Les cardiomyocytes et les fibroblastes ont été cultivés séparément puis placés en contact direct (cultures mixtes) ou indirect (insert). Ces co-cultures ont subi une ischémie de 3H en absence de nutriments et d’O2 suivie d’une reperfusion de 20H en présence de nutriments et d’O2. Des tests de viabilité (test MTT) et de mortalité cellulaire (dosage de l’activité LDH et Troponine I) ont été effectués à la fin de la reperfusion.RésultatsNous avons montré qu’il était possible de simuler des séquences d’ischémie reperfusion et d’induire une souffrance cellulaire détectable pour une durée d’ischémie de 3H et de reperfusion de 20H. Dans les cultures mixtes (cardiomyocytes + fibroblastes), les tests MTT et LDH ont montré une amélioration de la viabilité cellulaire globale en comparaison avec la viabilité spécifique de chaque type cellulaire seul. Pour les cultures placées en insert, les tests MTT et Troponine I ont montré une amélioration de la viabilité des cardiomyocytes en présence des fibroblastes (p<0.001).ConclusionsNos résultats indiquent que les fibroblastes cardiaques semblent être impliqués dans une modulation de la cardioprotection lors de l’ischémie reperfusion. Cette modulation passe au moins en partie par des mécanismes de type paracrine et elle est dépendante de la quantité de fibroblastes en co-culture avec les cardiomyocytes

Quantum effects on Higgs-strahlung events at Linear Colliders within the general 2HDM

The associated production of neutral Higgs bosons with the Z gauge boson is investigated in the context of the future linear colliders, such as the ILC and CLIC, within the general two-Higgs-doublet model (2HDM). We compute the corresponding production cross-sections at one-loop, in full consistency with the available theoretical and phenomenological constraints. We find that the wave-function renormalization corrections to the external Higgs fields are the dominant source of the quantum effects, which turn out to be large and negative, and located predominantly in the region around \tan\beta=1 and moderate values of the parameter \lambda_5 (being \lambda_5 < 0). This behavior can be ultimately traced back to the enhancement potential of the triple Higgs boson self-couplings, a trademark feature of the 2HDM with no counterpart in the Higgs sector of the Minimal Supersymmetric Standard Model. The predicted Higgs-strahlung rates comfortably reach a few tens of femtobarn, which means barely 10^3 - 10^4 events per 500 inverse femtobarn of integrated luminosity. Due to their great complementarity, we argue that the combined analysis of the Higgs-strahlung events and the previously computed one-loop Higgs-pair production processes could be instrumental to probe the structure of the Higgs sector at future linac facilities.Comment: LaTeX, 16 pages, 9 Figures, 2 Tables. Extended discussion, references added, matches published version in Phys. Rev.