Gravitational collapse of a star occurs when the internal pressure cannot sustain the gravitational forces. There are two essentially different mechanisms. One is the collapse due to the relativistic effects in the degenerate Fermi Gas, known in the form of Chandrasekhar mass limit, associated with the collapse of white dwarfs or core of the massive stars in advanced stage. Other is due to...
White dwarfs are compact objects that stand against gravitational collapse by their internal pressure of degenerate matter. In this work we aimed to perform an introductory study on these stars, using two equations of state: (I) an ideal Fermi gas and (II) the one by Baym Pethick and Sutherland (BPS). In addition, we analyzed these two state equations in two scenarios, the Newtonian and the...
Central exclusive production (CEP) is a singular way to measure cross section as it presents a very clean environment on detector and can be calculated (almost) exactly in many cases. LHCb is one of the four big experiments in LHC accelerator. On LHCb we have a dedicated group to work and search for exclusive processes and the main purpose is to probe and search for new insights on...
In this work corrections to the usual SU(2)-flavor Nambu-Jona-Lasinio (NJL) coupling [1] and also to the chiral pion couplings to constituent quarks [2] due to a weak external magnetic field are calculated at the one loop level. A sea quark determinant is expanded for relatively large quark mass and weak electromagnetic field and magnetic-field-dependent low energy quark effective coupling...
In this work, we investigate the thermodynamics of Walecka model, constituted of a fermionic field interacting with real scalar and vector fields, in the presence of an external magnetic field and boundaries. By making use of mean-field approximation, we analyze the phase structure of this model at effective chemical equilibrium, under change of values of the relevant parameters of the model,...
We analyse the recent LHC data at 7 and 8 TeV for pp elastic scattering with special attention for the structure of the real part, which is shown to be crucial to describe the differential cross section in the forward region. Our description contains the zero of the real amplitude predicted by André Martin.
In the present work, we investigated the exclusive diffractive production of charmonium in pronton-nucleus collisions at the Large Hadron Collider (LHC) energies. Such exclusive production reactions possess a cleaner experimental signal than inclusive production once it is characterized by low multiplicity of particles between final produced state and the incident protons of collider beam. The...
In this contribution we investigate the inclusive double quarkonium production in $pp$ collisions at the Run 2 LHC energies. The cross sections are estimated using the Non-Relativistic QCD (NRQCD) factorization formalism, taking into account the color singlet and color octet contributions. We present predictions for the total cross sections for the $J/\Psi J/\Psi$ and $\Upsilon \Upsilon$...
In this work we discuss the two-fermions bound state problem in the extreme binding energy limit. To this end, we solve the Bethe-Salpeter equation in Minkowski space for the Yukawa model, where the interaction boson is a vector particle. We use the Nakanishi Integral Representation, which simplify the interaction Kernel of the system. Furthermore, we use the light-front projection which...
The advent of the high-energy colliders has motivated the study of the hadron structure at high energies. In such scenario, a hadron becomes a dense system and the nonlinear effects inherent to the QCD dynamics may become visible. Recent studies show that vector meson exclusive photoproduction has the potential to probe the QCD dynamics at high energies. In this work we present an analysis of...
The production of gravitons via two-photon fusion and ZZ fusion processes are considered using the scale of the gravitational interactions around a few TeV. We focus on the expected energies of the proposed electron–positron colliders with a center-of-mass energy at the TeV scale. The number of events is predicted, and the background from the Standard Model is analyzed. The dependence on the...
We explore the condensation of charged pions in the presence of a large isospin chemical potential, in the absence of baryons, within the Linear Sigma Model. A mean-field expansion is used to calculate the thermodynamics and the spectrum of excitations of the pion-condensed medium. The pion condensate is shown to explicitly break the $U(1)_{\tau_3}$ vector isospin symmetry associated with...
The study of the J/$\psi$ production in pp collisions provides important information on perturbative and non-perturbative quantum chromodynamics. The production of the heavy-quark pair can be described perturbatively while its hadronisation into quarkonium state is a non-perturbative process. These processes are not fully understood and additional experimental data are necessary to further...
The properties of magnetized color superconducting cold dense quark matter under compact star conditions are investigated using an SU(2) Nambu Jona-Lasinio (NJL)-type model in which the divergences are treated using a magnetic field independent regularization scheme in order to avoid unphysical oscillations. We study the phase diagram for several model parametrizations. The features of each...
We study the two flavor Nambu--Jona-Lasinio model within the Mean Field Approximation and RPA framework to evaluate the pole masses of the $\sigma$ and $\pi^0$ mesons in the presence of a constant magnetic field at finite temperatures.
First, we emphasize the importance of the regularization method used in this work. For this aim, we explicitly employ the Magnetic Field Independent...
The Fock-Tani formalism is a first principle method to obtain effective interactions from microscopic Hamiltonians. Originally derived for meson-meson or baryon-baryon scattering, we present the corresponding equations for meson-baryon scaterring. Then we include the gluon mass, a non-perturbative aspect, to the interaction potencial between quarks with gluon exchange. In particular, we shall...
The annihilation or production process $e^++e^-\rightarrow
\rho^+ + \rho^- $ is studied with respect to the
universal perturbative QCD (pQCD) predictions. Sub-leading contributions
are considered together with the universal leading pQCD amplitudes such that
the matrix elements of the $\rho$-meson electromagnetic current satisfy
the constraint from the light-front angular condition. The ...
We investigate some non-perturbative models for Quantum Chromodynamics (QCD) with the purpose of testing its validity in the perturbative region of nuclear interaction and to explore its behavior in the infrared region. In particular, we focus on the calculations and analysis of the potentials between supermassive quarks and antiquarks, since this observable might reveal the appearance of...
We show explicit the first radiative correction for the vertex and photon-photon 4-point function in Generalized Scalar Duffin-Kemmer-Petiau Quantum Electrodynamcis (GSDKP), utilizing the dimensional regularization method, where the gauge symmetry is manifest. As we shall see one of the consequences of the study is that the DKP algebra ensures the functioning of the WT identities in the first...
The $\mathcal{N}=1$ Super Yang-Mills theory in the presence of the local composite operator $A^2$ is analyzed in the Wess-Zumino gauge by employing the Landau gauge fixing condition. Due to the superymmetric structure of the theory, two more composite operators, $A_\mu \gamma_\mu \lambda$ and $\bar{\lambda}\lambda$, related to the susy variations of $A^2$
are also introduced. A BRST...
It is expected that the charmonium state $J/ \psi$ produced during the hadronization of the quark-gluon plasma suffers a rescattering process between the chemical freeze-out and the kinetical freeze-out. We present an updated study of the suppression and generation of the $J/\psi$ meson due to its interaction with a hadronic medium composed of light pseudo-scalar (as $\pi, K, \eta$) and...
A recently developed variational resummation technique, incorporating renormalization group properties consistently, has been shown to solve the scale dependence problem that plagues the evaluation of thermodynamical quantities, e.g., within the framework of approximations such as in the hard-thermal-loop resummed perturbation theory. This method is used in the present work to evaluate...
In this work we study the viability of the Mossbauer technique to measure neutrino-nucleus
interaction, specifically Coherent Elastic Neutrino Nucleus Scattering.
To describe the neutrino-nucleus interaction we propose a simple collective model in which the M\"ossbauer-nucleus is considered as an inert core with $A-1$ nucleons, and valence
neutron. The core is slightly deformed in the...
In this work we study the Wigner-Weyl formalism adequate for a theory with nucleons interacting through scalar and pseudoscalar fields, and for this we use the linear sigma model. Our goal is to understand the phenomena observed in experiments at laboratories such as the LHC or BNL, where a new state of matter is reached, the quark-gluon plasma. So we need to study chiral phase transitions,...
The quarkonium plus photon production in coherent hadron - hadron interactions at LHC is studied using the non-relativistic QCD (NRQCD) factorization formalism. We investigate a set of kinematic distributions and compute the total cross sections for M + γ (M = J/Ψ and ϒ) production. Our results demonstrate the feasibility of such process in the LHC kinematic regime and explore the...
The supersymmetry breaking of a supersymmetric harmonic oscillator with
polynomial interaction is analyzed. Some thermal effects are studied following TFD formalism. The restored supersymmetry results in nonvanishing energy at finite temperatures due the additivity of the thermal effects, while at $%
T=0$ the energy is zero.
In this work we calculate some exotic nuclear phase properties of the neutron-proton-electron matter known as “nuclear pasta” in the context of the Walecka model at zero temperature. We extend the usual spherical Thomas-Fermi Approximation by including non-spherical terms in the density and energy expansions in order to properly describe geometry deviations in the complex structures commonly...
The infrared behavior of the three gluon vertex is one of the most prominent subjects of study in current non perturbative QCD, playing a central role in dynamical gluon mass generation through the Schwinger mechanism and being an essential ingredient in the Bethe-Salpeter equation which governs glueballs. However, the analysis of this vertex through Schwinger-Dyson equations (SDEs) is...
In this work we show how to indroduce the magnetic field in hadronic matter in a thermodynamically consistent way. We revisit the literature and show that several common results that are derived magnetic field on hadronic matter are thermodynamically inconsistent and that affects the mass-radius results.
Utilizing the so called choatic magnetic field [1,2,3,4] we show that a...
Halo nuclei are composed by a core of strongly bound nucleons surrounded by a halo of weakly bound neutrons or protons. When scattered by a target nucleus, halo nuclei may undergo into a fragmentation process opening different possible exit channels for detection. For example, the surrounding nucleons can either by capture or emitted during the reaction. With more nucleons in the halo the...
In general, three-body decays can be described as quasi-two-body decays where intermediate resonances decay into two particles, and then observing a the final state constituted of three particles. To study these processes it is necessary to perform an amplitude analysis to the corresponding Dalitz Plot (the two-dimensional representation of the decay phase space). It is common to use the...
It is known that, at energies below the deuteron breakup, nd scattering
in the doublet channel exhibits both a virtual state and a zero in the
amplitude. We construct a halo/cluster EFT that takes both features into
account, and follow the behavior of observables as we decrease the deuteron
binding energy. Reaching the unitary limit, we demonstrate the nature of this
virtual state...
The origin of the elements has been one of the most fascinating questions scientists have tried to give an answer to in the last 7 decades. The formation of light elements in the primordial universe and heavier elements, both in the intergalactic environment and in the astrophysical sources, occurs through nuclear reactions. We can say that nuclear processes are responsible for the production...
