Search results for "dron"
showing 10 items of 4363 documents
Limits to the fixed center approximation to Faddeev equations: The case of theϕ(2170)
2011
The fixed center approximation to the Faddeev equations has been used lately with success in the study of bound systems of three hadrons. It is also important to set the limits of the approach in those problems to prevent proliferation of inaccurate predictions. In this paper, we study the case of the $\ensuremath{\phi}(2170)$, which has been described by means of Faddeev equations as a resonant state of $\ensuremath{\phi}$ and $K\overline{K}$, and show the problems derived from the use of the fixed center approximation in its study. At the same time, we also expose the limitations of an alternative approach recently proposed.
The helicity matching approach to heavy hadron form factors
1991
Abstract I discuss the helicity matching approach to current-induced transitions among heavy hadrons. This approach provides a simple and intuitively appealing access to the calculation of heavy hadron form factors which is entirely equivalent to the approach of Isgur and Wise and other authors, who use different techniques to obtain the same results. We work out explicit examples in the meson and baryon sectors and discuss possible approximations to the most general approach and some of their implications for future experiments.
Rare baryon decaysΛb→Λℓ+ℓ−(ℓ=e,μ,τ) andΛb→Λγ: Differential and total rates, lepton- and hadron-side forward-backward asymmetries
2013
Using the covariant constituent quark model previously developed by us, we calculate the differential rate and the forward-backward asymmetries on the lepton and hadron side for the rare baryon decays ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}{\ensuremath{\ell}}^{+}{\ensuremath{\ell}}^{\ensuremath{-}}$ ($\ensuremath{\ell}=e$, $\ensuremath{\mu}$, $\ensuremath{\tau}$) and ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}\ensuremath{\gamma}$. We use helicity methods to write down a threefold joint angular decay distribution for the cascade decay ${\ensuremath{\Lambda}}_{b}\ensuremath{\rightarrow}\ensuremath{\Lambda}(\ensuremath{\rightarrow}p{\…
Resonances in chiral unitary approaches
2008
The extension of chiral theories to the description of resonances, via the incorporation of unitarity in coupled channels, has provided us with a new theoretical perspective on the nature of some of the observed excited hadrons. In this contribution some of the early achievements in the field of baryonic resonances are reviewed, the recent evidence of the two-pole nature of the Lambda(1405) is discussed and results on charmed baryon resonances are presented.
Fits of the baryon magnetic moments to the quark model and spectrum-generating SU(3)
1982
We show that for theoretical as well as phenomenological reasons the baryon magnetic moments that fulfill simple group transformation properties should be taken in intrinsic rather than nuclear magnetons. A fit of the recent experimental data to the reduced matrix elements of the usual octet electromagnetic current is still not good, and in order to obtain acceptable agreement, one has to add correction terms to the octet current. We have texted two kinds of corrections: U-spin-scalar terms, which are singles out by the model-independent algebraic properties of the hadron electromagnetic current, and octet U-spin vectors, which could come from quark-mass breaking in a nonrelativistic quark …
Cation Environment in BaCeO3-Based Protonic Conductors: a Computational Study
2009
Geometry calculations were performed on pure BaCeO(3) fragments and on Y- and In-doped derivatives. HF and DFT approaches were used to investigate monoclinic and orthorhombic structures. The computational methods, structural models, and electronic structure investigation protocols were tuned taking into consideration and balancing the consistency of the results against the computational cost. The calculated structures and energetics parameter, as well as the detailed orbital analysis performed on the corresponding BaCeO(3) derivatives allowed us to explain experimental findings and to develop a procedure to study the cationic octahedral environment of doped X:BaCeO(3) (X = Y, In) and undope…
CCDC 1564495: Experimental Crystal Structure Determination
2017
Related Article: Fernando Rabasa-Alcañiz, Javier Torres, María Sánchez-Roselló, Tomás Tejero, Pedro Merino, Santos Fustero, Carlos del Pozo|2017|Adv.Synth.Catal.|359|3752|doi:10.1002/adsc.201700975
Big Data Processing in the ATLAS Experiment: Use Cases and Experience
2015
Abstract The physics goals of the next Large Hadron Collider run include high precision tests of the Standard Model and searches for new physics. These goals require detailed comparison of data with computational models simulating the expected data behavior. To highlight the role which modeling and simulation plays in future scientific discovery, we report on use cases and experience with a unified system built to process both real and simulated data of growing volume and variety.
Bis(dimethylammonium) pentachloroantimonate(III), on the deformation of the octahedral coordination of Sb III
1998
The structure of the title compound, [NH2(CH3)2]2SbCl5, was determined at 295 and 85 K. It consists of polymeric (SbCl52−)n chains composed of deformed SbCl63− octahedra connected by corners and dimethylammonium cations. The temperature dependence of the Sb–Cl bond lengths is discussed. It is argued that the deformation of the octahedral coordination of the SbIII atom is caused by electrostatic interaction/hydrogen bonds.
Experimental and theoretical studies of the molecular and crystal structures of trialkoxy- and chlorodialkoxy-stibanes
2001
The molecular structures of triisopropoxystibane, Sb((OPr)-Pr-i)(3), and chlorodiisopropoxystibane, SbCl((OPr)-Pr-i)(2), were determined in the solid state by single crystal X-ray diffraction. Sb((OPr)-Pr-i)(3) forms discrete centrosymmetric dimers in the solid state via Sb . . .O-Sb interactions, leading to pseudo trigonal bipyramidal configurations of the four co-ordinate Sb atoms, while SbCl((OPr)-Pr-i)(2) forms chains via Sb . . .O-Sb and Sb . . . Cl-Sb bridges, resulting in five-co-ordinate Sb atoms with pseudo octahedral configurations. Comparison of the solid state structures and the density functional optimized molecular structures of Sb(OMe)(3), SbCl(OMe)(2) and their dimers reveal…