Why quarkonium hybrid coupling to two S-wave heavy-light mesons is not suppressed

We examine the couplings of quarkonium hybrids to heavy-light meson pairs in the Born-Oppenheimer approximation for QCD. The lowest hybrid multiplets consist of bound states of the $\Pi_u$ and $\Sigma_u^-$ potentials. We find that the $\Sigma_u^-$ potential can couple to pairs of $S$-wave mesons through string breaking, while the $\Pi_u$ potential cannot. From this observation, we derive model-independent selection rules that contradict previous expectations that quarkonium hybrids are forbidden to decay into pairs of $S$-wave mesons. These Born-Oppenheimer selection rules are consistent with the partial decay widths of the lowest charmonium hybrid with exotic quantum numbers $J^{PC}=1^{-+}$ recently calculated in lattice QCD.Comment: 4 pages, 1 tabl

Heavy-Quark spin symmetry breaking in the Born-Oppenheimer approximation

Heavy-quark spin symmetry is explicitly broken by the mass splitting between a heavy-light pseudoscalar meson and its vector partner. This fact plays a pivotal role in the physics of states whose mass lies close to the threshold of an open-flavor meson pair, like $X(3872)$. We show that this source of heavy-quark spin symmetry breaking can be systematically included within the diabatic representation of the Born-Oppenheimer approximation. We verify that including all the appropriate coupled channels guarantees conservation of total angular momentum, parity, and charge-conjugation parity. This marks a fundamental step towards a unified, first-principles study of quarkonia and meson molecules with hidden flavor.Comment: 28 pages; v2: added new appendix, edited text in sections I and V, corrected several typos in various equations, introduced additional references; v3: version accepted in JHEP, several minor modifications and additions in the text and equations, new references, typos correcte

The aging bladder

The aging of the population is exposing patients and physicians to new challenging urological conditions. The prevalence of lower urinary tract symptoms (LUTS) increases significantly over the age of 65 in both sexes and severely impairs patients’ quality of life (QOL). A better understanding of the possible causes involved in this process will clarify some forms of treatment and stimulate new researches on this matter. The purpose of this review is to better describe the pathophysiological implications related to the aging bladder, allowing a more accurate management of this specific entity.O envelhecimento populacional expõe as pessoas a problemas urológicos desafiadores em natureza e frequência. A prevalência de sintomas do trato urinário inferior aumenta significativamente após os 65 anos de idade, em ambos os sexos, afetando intensamente a qualidade de vida. Para melhor entendimento das possíveis causas dos processos envolvidos melhorará o enfoque terapêutico e estimulará pesquisas neste campo em crescimento. O objetivo desta revisão é descrever os princípios fisiopatológicos envolvidos no envelhecimento vesical

Commercial Systems for the Direct Detection of Explosives (for Explosive Ordnance Disposal Tasks)

The main goal of this study, carried out by the author on behalf of the Swiss Defence Procurement Agency (DPA), was to characterise existing technologies, and identify corresponding commercially available systems, for the direct detection of explosives for Explosive Ordnance Disposal (EOD) tasks. Systems should be able to determine if a given piece of munition contains explosives or is inert, and ideally in the former case to establish the type of explosive (see also Annex A2.1). This will be often referred to in the following as the “task at hand”, or the “task of interest to us”. Note that the object in questions has already been detected by other means (usually visually, e.g. lying on the surface) – what is needed is the capacity to characterise its contents (explosive or inert)

A Multidisciplinary Analysis of Frequency Domain Metal Detectors for Humanitarian Demining

This thesis details an analysis of metal detectors (low frequency electromagnetic induction devices) with emphasis on Frequency Domain (FD) systems and the operational conditions of interest to humanitarian demining. After an initial look at humanitarian demining and a review of their basic principles we turn our attention to electromagnetic induction modelling and to analytical solutions to some basic FD direct (forward) problems. The second half of the thesis focuses then on the analysis of an extensive amount of experimental data. The possibility of target classification is first discussed on a qualitative basis, then quantitatively. Finally, we discuss shape and size determination via near field imaging