Scaling in few-body nuclear physics

The nuclear matter calculations with realistic nucleon-nucleon potentials present a general scaling between the nucleon-nucleus binding energy, the corresponding saturation density, and the triton binding energy. The Thomas-Efimov three-body effect implies in correlations among low-energy few-body and many-body observables. It is also well known that, by varying the short-range repulsion, keeping the two-nucleon information (deuteron and scattering) fixed, the four-nucleon and three-nucleon binding energies lie on a very narrow band known as a Tjon line. By looking for a universal scaling function connecting the proper scales of the few-body system with those of the many-body system, we suggest that the general nucleus-nucleon scaling mechanism is a manifestation of a universal few-body effect.

Renormalization in few-body nuclear physics

Renormalized fixed-point Hamiltonians are formulated for systems described by interactions that originally contain point-like singularities (as the Dirac-delta and/or its derivatives). They express the renormalization group invariance of quantum mechanics. The present approach for the renormalization scheme relies on a subtracted T-matrix equation.

Busca por ressonâncias de grávitons em modelos com dimensões extras no LHC

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Áxions, májorons e neutrinos em extensões do modelo padrão

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Busca por dimensões extras no detector CMS do large hadron collider

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Confecção e caracterização de filmes finos de boro para a medida da taxa de reação 10B(N, a)7LI na terapia por captura de nêutrons pelo boro

The Boron Neutron Capture Therapy (BNCT), based on the 10B(n,α)7Li reaction, represents a promising modality for the treatment of cancers that are resistents to conventional treatments. So, it is necessary to find drugs (boron compounds) with high selectivity for each type of cancer, the neutrons source should be well characterized and the rate of 10B(n,α)7Li reaction should be measured with great accuracy as possible. This study aimed to develop a method for manufacturing thin films of boron, for measure the 10B(n,α)7Li reaction, and analyze the uniformity of the films. Five thin films of boron were manufactured with three different concentrations of boric acid, heated to transform the acid in boron, irradiated with thermic neutrons coupled to CR-39 detectors, in BNCT line at the reactor IEA-R1 IPEN/CNEN, São Paulo. After the irradiation, the detectors were chemically attacked with NaOH to reveal the tracks. The methodology presented is effective because it resulted in deposition of boron as thin film enabling the quantitative analysis of 10B(n,α)7Li reaction. The analysis of the uniformity of density of the induced tracks in CR-39 shows that, in most of the films, there is no uniformity in surface distribution of boron, but when the film is divided, we obtain some uniform sectors

Simetria quiral: fótons, píons e núcleons

Pós-graduação em Física - IFT

Quantização de partículas com spin

Pós-graduação em Física - IFT

Thermodynamics of quasi-particles

We present in this work a generalization of the solution of Gorenstein and Yang to the inconsistency problem of thermodynamics for systems with a temperature dependent Hamiltonian. We show that there are, in principle, an infinite number of solutions.

Connection between UHECR's and supermassive relic particles

One of the models proposed for the origin of ultra high energy cosmic rays (UHECR's) suggests that these events are the decay products of relic superheavy metastable particles, which we call S particles. These particles can be produced in the reheating period following the inflationary epoch of the early Universe. We study this possibility and obtain constraints on some parameters such as the lifetime and direct couplings of the X-particle to the inflaton field from the requirement that they are responsible for the observed UHECR flux.

Thermodynamics of quasi-particles

We present in this work a generalization of the solution of Gorenstein and Yang for a consistent thermodynamics for systems with a temperature dependent Hamiltonian. We show that there is a large class of solutions, work out three particular ones. and discuss their physical relevance. We apply the particular solutions for an ideal gas of quasi-gluons, and compare the calculation to lattice and perturbative QCD results. (c) 2007 Elsevier B.V. All rights reserved.

Stochastic variational approach applied to 2, 3 and 4 alpha particles

A stochastic variational method is applied to calculate the binding energies and root-mean-square radii of 2, 3 and 4 alpha particles using an S-wave Ali-Bodmer potential. The results agree with other calculations. We discuss the application of the present method to study the universality in weakly-bound three and four-body systems in the context of ultracold atomic traps.

Thermodynamics of quasi-particles at finite chemical potential

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Spin and pseudospin symmetries and the equivalent spectra of relativistic spin-1/2 and spin-0 particles

We show that the conditions which originate the spin and pseudospin symmetries in the Dirac equation are the same that produce equivalent energy spectra of relativistic spin-1/2 and spin-0 particles in the presence of vector and scalar potentials. The conclusions do not depend on the particular shapes of the potentials and can be important in different fields of physics. When both scalar and vector potentials are spherical, these conditions for isospectrality imply that the spin-orbit and Darwin terms of either the upper component or the lower component of the Dirac spinor vanish, making it equivalent, as far as energy is concerned, to a spin-0 state. In this case, besides energy, a scalar particle will also have the same orbital angular momentum as the (conserved) orbital angular momentum of either the upper or lower component of the corresponding spin-1/2 particle. We point out a few possible applications of this result. © 2007 The American Physical Society.

Measurement of the elliptic anisotropy of charged particles produced in PbPb collisions at √sNN=2.76 TeV

The anisotropy of the azimuthal distributions of charged particles produced in √sNN=2.76 TeV PbPb collisions is studied with the CMS experiment at the LHC. The elliptic anisotropy parameter, v2, defined as the second coefficient in a Fourier expansion of the particle invariant yields, is extracted using the event-plane method, two- and four-particle cumulants, and Lee-Yang zeros. The anisotropy is presented as a function of transverse momentum (pT), pseudorapidity (η) over a broad kinematic range, 0.3