Experimental studies of QCD using flavour tagged jets with DELPHI

Identified $b\overline{b}g$ and $q\overline{q}\gamma$ events from DELPHI are used to measure the ratio of the mean charged particle multiplicity distribution between gluon and quark jets. The dependence of this ratio with the jet energy is established using about three million Z$^0$ decays. Results from all other detectors are discussed and compared. A nice agreement is found among all them. The ratio between the normalized total three-jet cross sections of $b\overline{b}g$ and $q\overline{q}g, q \equiv u,d,s$ events is also determined. The preliminary value obtained indicates that $b$ quarks are experimentaly seen to radiate less than light quarks due to their higher mass. The suggested experimental error is $\sim$300 MeV for the $b$ mass determination at the M$_Z$ scale.Comment: Latex, 5 pages, 3 figures,to appear in the Proceedings of the High Energy Physics International Euroconference on Quantum Chromodynamics (QCD '96), Montpellier, France, 4-12th July 1996. Ed. S. Narison, Nucl Phys. B (Proc. Suppl.

Extracting the top-quark running mass using ttˉt\bar{t}+1-jet events produced at the Large Hadron Collider

We present the calculation of the next-to-leading order QCD corrections for top-quark pair production in association with an additional jet at hadron colliders, using the modified minimal subtraction scheme to renormalize the top-quark mass. The results are compared to measurements at the Large Hadron Collider run I. In particular, we determine the top-quark running mass from a fit of the theoretical results presented here to the LHC data

Electronic structure of few-electron concentric double quantum rings

The ground state structure of few-electron concentric double quantum rings is investigated within the local spin density approximation. Signatures of inter-ring coupling in the addition energy spectrum are identified and discussed. We show that the electronic configurations in these structures can be greatly modulated by the inter-ring distance: At short and long distances the low-lying electron states localize in the inner and outer rings, respectively, and the energy structure is essentially that of an isolated single quantum ring. However, at intermediate distances the electron states localized in the inner and the outer ring become quasi-degenerate and a rather entangled, strongly-correlated system is formed.Comment: 16 pages (preprint format), 6 figure

Experimental determination of the b quark mass in DELPHI

The running mass of the b quark as defined in the MS-bar renormalization scheme, m_b, was measured at the M_Z scale using 2.8 million hadronic Z^0 decays collected by the DELPHI experiment at LEP. The result is m_b(M_Z) = 2.67 +- 0.25 (stat.) +- 0.34 (frag.) +- 0.27(theo.) GeV/c^2 which differs from that obtained at the Upsilon scale, by m_b(M_\Upsilon/2)-m_b(M_Z) = 1.49 +- 0.52 GeV/c^2. This measurement, performed far from the $b\bar{b}$ production threshold, provides the first experimental observation of the running of the quark masses.Comment: Talk given at the QCD 97 conference held in Montpellier, July 1997. Also available here http://hep.ph.liv.ac.uk/~martis

InAs/InP single quantum wire formation and emission at 1.5 microns

Isolated InAs/InP self-assembled quantum wires have been grown using in situ accumulated stress measurements to adjust the optimal InAs thickness. Atomic force microscopy imaging shows highly asymmetric nanostructures with average length exceeding more than ten times their width. High resolution optical investigation of as-grown samples reveals strong photoluminescence from individual quantum wires at 1.5 microns. Additional sharp features are related to monolayer fluctuations of the two dimensional InAs layer present during the early stages of the quantum wire self-assembling process.Comment: 4 pages and 3 figures submitted to Applied Physics Letter

Exciton Gas Compression and Metallic Condensation in a Single Semiconductor Quantum Wire

We study the metal-insulator transition in individual self-assembled quantum wires and report optical evidences of metallic liquid condensation at low temperatures. Firstly, we observe that the temperature and power dependence of the single nanowire photoluminescence follow the evolution expected for an electron-hole liquid in one dimension. Secondly, we find novel spectral features that suggest that in this situation the expanding liquid condensate compresses the exciton gas in real space. Finally, we estimate the critical density and critical temperature of the phase transition diagram at $n_c\sim1\times10^5$ cm$^{-1}$ and $T_c\sim35$ K, respectively.Comment: 4 pages, 5 figure

Clonal hematopoiesis in cardiovascular disease and therapeutic implications.

Clonal hematopoiesis arises from somatic mutations that provide a fitness advantage to hematopoietic stem cells and the outgrowth of clones of blood cells. Clonal hematopoiesis commonly involves mutations in genes that are involved in epigenetic modifications, signaling and DNA damage repair. Clonal hematopoiesis has emerged as a major independent risk factor in atherosclerotic cardiovascular disease, thrombosis and heart failure. Studies in mouse models of clonal hematopoiesis have shown an increase in atherosclerosis, thrombosis and heart failure, involving increased myeloid cell inflammatory responses and inflammasome activation. Although increased inflammatory responses have emerged as a common underlying principle, some recent studies indicate mutation-specific effects. The discovery of the association of clonal hematopoiesis with cardiovascular disease and the recent demonstration of benefit of anti-inflammatory treatments in human cardiovascular disease converge to suggest that anti-inflammatory treatments should be directed to individuals with clonal hematopoiesis. Such treatments could target specific inflammasomes, common downstream mediators such as IL-1β and IL-6, or mutations linked to clonal hematopoiesis.A.T. and J.J.F. are supported by a grant from the Leducq Foundation (TNE-18CVD04). A.T. is supported by NIH grant 155431. We thank M. A. Zuriaga for assistance with figure design.S

Type III Einstein-Yang-Mills solutions

We construct two distinct classes of exact type III solutions of the D=4 Einstein-Yang-Mills system. The solutions are embeddings of the non-abelian plane waves in spacetimes in Kundt's class. Reduction of the solutions to type N leads to generalized $pp$ and Kundt waves. The geodesic equations are briefly discussed.Comment: revtex, 4 pages, minor changes, some factors and references corrected, footnote adde

Effect of direct bubble-bubble interactions on linear-wave propagation in bubbly liquids

We study the influence of bubble-bubble interactions on the propagation of linear acoustic waves in bubbly liquids. Using the full model proposed by Fuster and Colonius J. Fluid Mech. 688, 253 ( 2011)], numerical simulations reveal that direct bubble-bubble interactions have an appreciable effect for frequencies above the natural resonance frequency of the average size bubble. Based on the new results, a modification of the classical wave propagation theory is proposed. The results obtained are in good agreement with previously reported experimental data where the classical linear theory systematically overpredicts the effective attenuation and phase velocity

Un elemento finito 3D para el análisis cinemáticamente no lineal de láminas elastoplásticas

En el análisis de láminas elastoplásticas se debe recurrir a temías de la plasticidad ad hoc, no derivadas de la teoría tridimensional general sino postuladas a priori y basadas en muchas simplificaciones, o bien tratar el cuerpo como 3D. En este segundo caso, la utilización de elementos convencionales en el Método de los Elementos Finitos (M.E.F.) plantea importantes problemas numéricos, y requiere un tiempo de compntación excesivamente dilatado. En este escrito se presenta un elemento finito 3D pensado especialmente para superar estos inconvenientes. Su desarrollo consta de tres partes bien diferenciadas: la obtención de las inatrices cineináticas necesarias para la resolución del problema estático de un continuo 3D cualquiera, supuesta conocida la interpolación del campo de desplazamientos; la particularización de éstas al caso laminar, mediante el uso del mode1,o de comportamiento transversal CT1 coino función de interpolación en el espesor; y la reorganización del algoritmo resultante de las dos fases anteriores para evitar el aumento desmesurado del tiempo de cálculo cuando se increiiienta el número de puntas de integración en el espesor. Finalmente se incluyen varios ejeinplos que muestran el buen comportamiento del elemento presentado, cuyas principales ventajas son: en primer lugar, que permite proceciar un elevado número de puntos de integración en el espesor con un coste computacional razonable, y a continuación, la capacidad para tratar cualquier geometría de la superficie de referencia de modo muy sencillo pero sin introducir siiiiplificaciones, y la posibilidad de tratar otros tipos estructurales derivados del laminar utilizando el misnio algoritiiio.When dealing with elastoplastic shell analysis, we must appeal either to suitable theories of plasticity, which aren't the result of the general three-dimensional theory as they have been forinulated a priori and based on many siinplifications, or to the treateinent of the body as a tliree dimensional one (3D). In tlie second case, there are a lot of numerical probleins arising from the use of conventional eleinents in the Finite Elenient Metliod (F.E.M.), and also, a long tinie of computation isrequired. In this paper we present a 3D finite element, which is aimed at overcoming the aforesaid disavantages. Its development is divided into three different parts, first of all the obtention of the kinematic matrices required to solve a static problem of whatever 3D continuous medium, once the interpolation for the displacement field is known. Secondly, their particularization to tbe shell case, through the use of the model of transversal behaviour CTl as the function of interpolation in thickness. The third one is the reorganization of the resulting algorithm from the two previous steps to avoid an excessive increase in the calculation time when the number OS integration points in thickness is raised. Finally we include severa1 examples showing the good results of the described element, having some advantages such as: first, the processing of a high number of integration points with a reasonable computational cost; secondly, the ability to deal with any reference surface geometry in a very simple way, without introducing any simplification, and in the third place, the possibility to deal with other kinds of structures derived from the shell model by using the same algorithm.Peer Reviewe