Rua do Matão

Jul 9, 2024 | link.aps.org | Instituto de Física |Rua do Matão

In this work, we evaluate the X(3872) to ψ(2S) yield ratio (NX/Nψ(2S)) in Pb-Pb collisions, taking into account the interactions of the ψ(2S) and X(3872) states with light mesons in the hadron gas formed at the late stages of these collisions. We employ an effective Lagrangian approach to estimate the thermally averaged cross sections for the production and absorption of the ψ(2S) and use them in the rate equation to determine the time evolution of Nψ(2S).

Jun 14, 2024 | link.aps.org | Rua do Matão

We present a new exactly solvable case in strong-field QED with a one-dimensional step potential (x-step). The corresponding x-step is given by an analytic asymmetric with respect to the axis x reflection function. The step can be considered as a certain analytic “deformation” of the symmetric Sauter field. Moreover, it can be treated as a new regularization of the Klein step field.

Apr 17, 2024 | academic.oup.com | Instituto de Astronomia |Rua do Matão

A richer and more detailed understanding of the history of our Galaxy has, since the 18th century, been one of the main goals of astronomy, with early research conducted by William Herschel’s maps of star densities, spiral structures detected by William Parsons in other galaxies, the flattened disc shape proposed by Jacobus Kapteyn, followed by the great debate between Shapley and Curtis that finally culminated in Hubble (1925) confirming the ‘island universes’ scenario in the 1920s.

Mar 7, 2024 | link.aps.org | Rua do Matão |Peter F. Stadler |Bioinformatics Group

Graphs have become widely used to represent and study social, biological, and technological systems. Statistical methods to analyze empirical graphs were proposed based on the graph's spectral density. However, their running time is cubic in the number of vertices, precluding direct application to large instances. Thus, efficient algorithms to calculate the spectral density become necessary.

Jan 10, 2024 | link.aps.org | Instituto de Física |Rua do Matão |A. Feijoo

We perform a study of the B*+B0,B*0B+ correlation functions using an extension of the local hidden gauge approach which provides the interaction from the exchange of light vector mesons and gives rise to a bound state of these components in I=0 with a binding energy of about 21 MeV.