Search results for "87"

One-photon decay of the tetraquark stateX(3872)→γ+J/ψin a relativistic constituent quark model with infrared confinement

2011

We further explore the consequences of treating the $X(3872)$ meson as a tetraquark bound state by analyzing its one-photon decay $X\ensuremath{\rightarrow}\ensuremath{\gamma}+J/\ensuremath{\psi}$ in the framework of our approach developed in previous papers which incorporates quark confinement in an effective way. To introduce electromagnetism we gauge a nonlocal effective Lagrangian describing the interaction of the $X(3872)$ meson with its four constituent quarks by using the $P$-exponential path-independent formalism. We calculate the matrix element of the transition $X\ensuremath{\rightarrow}\ensuremath{\gamma}+J/\ensuremath{\psi}$ and prove its gauge invariance. We evaluate the $X\ens…

X(3872) and its charmonium content in Heavy Quark limit

2016

X (3872) still presents many puzzles more than a decade after its discovery. Some of its properties, like the isospin violating decays, can easily be accommodated in a molecular model, whereas its other properties, such as radiative decays can be more naturally explained in the quarkonium picture. The best of these schemes can be combined in a picture of X (3872) where it is dominantly a molecular state with some charmonium components. In this work, we present a model based on heavy quark symmetry which describes X (3872) as a superposition of molecular and charmonium components.

Charmonium spectroscopy above thresholds

2009

We present a systematic and self-consistent analysis of four-quark charmonium states and applied it to study compact four-quark systems and meson-meson molecules. Our results are robust and should serve to clarify the situation of charmonium spectroscopy above the threshold production of charmed mesons.

Decay widths of the spin-2 partners of the X (3872)

2015

We consider the $X(3872)$ resonance as a $J^{PC}=1^{++}$ $D\bar D^*$ hadronic molecule. According to heavy quark spin symmetry, there will exist a partner with quantum numbers $2^{++}$, $X_{2}$, which would be a $D^*\bar D^*$ loosely bound state. The $X_{2}$ is expected to decay dominantly into $D\bar D$, $D\bar D^*$ and $\bar D D^*$ in $d$-wave. In this work, we calculate the decay widths of the $X_{2}$ resonance into the above channels, as well as those of its bottom partner, $X_{b2}$, the mass of which comes from assuming heavy flavor symmetry for the contact terms. We find partial widths of the $X_{2}$ and $X_{b2}$ of the order of a few MeV. Finally, we also study the radiative $X_2\to …

First coincidences in pre-clinical Compton camera prototype for medical imaging

2003

Abstract Compton collimated imaging may improve the detection of gamma rays emitted by radioisotopes used in single photon emission computed tomography (SPECT). We present a crude prototype consisting of a single 500 μm thick, 256 pad silicon detector with pad size of 1.4×1.4 mm 2 , combined with a 15×15×1 cm 3 NaI scintillator crystal coupled to a set of 20 photo multipliers. Emphasis is placed on the performance of the silicon detector and the associated read-out electronics, which has so far proved to be the most challenging part of the set-up. Results were obtained using the VATAGP3, 128 channel low-noise self-triggering ASIC as the silicon detector's front-end. The noise distribution (…

Triangle singularity in the B−→K−π0X(3872) reaction and sensitivity to the X(3872) mass

2020

We have done a study of the ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{\ensuremath{\pi}}^{0}X(3872)$ reaction by means of a triangle mechanism via the chain of reactions: ${B}^{\ensuremath{-}}\ensuremath{\rightarrow}{K}^{\ensuremath{-}}{D}^{*0}{\overline{D}}^{*0}$; ${D}^{*0}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{0}{D}^{0}$; ${D}^{0}{\overline{D}}^{*0}\ensuremath{\rightarrow}X(3872)$. We show that this mechanism generates a triangle singularity in the ${\ensuremath{\pi}}^{0}X(3872)$ invariant mass for a very narrow window of the $X(3872)$ mass, around the present measured values, and show that the peak positions and the shape of the mass distributions are sensitiv…

La sensación sonora y visual del mar en la pintura valenciana de finales del siglo XIX

2010

This work presents an interpretation from a phenomenological point of view of the visual and sonorous experience on the perception of the sea in the context of XIX century Valencian painting. The use of senses to generate images of the sea establishes a network of links between them that plays a key role in the comprehension and interpretation of its image. The analysis starts from the identification of an autonomous and separated poetics of the sea, focusing on the study of its immensity from the different points of view that its contemplation presents. It ends on the interpretation of the sonorous and mobile potentiality of its matter. The study has identified in the chosen images of the …

La Acción colectiva: Todo poder viene de abajo

2011

RESUMEN. Con este trabajo queremos reflexionar sobre el poder de la acción colectiva en relación con las transformaciones políticas. Para ello, nos hemos centrado en la noción de intencionalidad colectiva del filósofo John Searle y algunos otros autores que han analizado la capacidad de regeneración democrática que surge de las reivindicaciones de los ciudadanos. De nuevo se constata que no existe alternativa a la legitimidad del poder político si no se la otorgan los pueblos.  ABSTRACT. In this paper we reflect on the power of collective action in relation to political transformations. To do this, we have focused on the notion of collective intentionality of the philosopher John Searle and…

Segunda parte, En que prosigue la verdadera relacion del lastimoso estrago acaecido en la Ciudad de Sanguesa, del Reyno de Navarra, la noche del vein…

Grav. xil. enmarcat de la Mare de Déu Banda tip. al final de la primera part Sign.: [ ]4 Text a dues col Reclams

Antoniego Zabłockiego relacja o pobycie Katarzyny II i Józefa II w Chersoniu i na Krymie w roku 1787

2022

From July 1784 to mid-1792, a Polish trade and diplomatic post operated in Kherson (until the spring of 1788), and then in Mirgorod, in the Black Sea territories of the Russian Empire. From mid-1784 until the end of 1791, Antoni Zabłocki, a former soldier of the Crown Army, the Bar Confederate, and an exile in Russia, was the head of the facility, and from the summer-autumn 1786, the consul. He did not have any diplomatic preparation, and his qualifications were limited to the knowledge of the Russian language and the realities of social and economic life in the tsarist state, as well as to close contacts with the surroundings of King Stanisław August. This secured him a job as a royal agen…