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Your search keyword '"Avancini, Sidney S."' showing total 7 results
Start Over Author "Avancini, Sidney S." Topic magnetic fields
7 results on '"Avancini, Sidney S."'

1. The influence of quark anomalous magnetic moment in the Nambu–Jona‐Lasinio model with different regularizations.

Author

Tavares, William R., Nunes, Rodrigo M., Avancini, Sidney S., and Farias, Ricardo L. S.

Subjects
NAMBU-Jona-Lasinio model, MAGNETIC moments, FIRST-order phase transitions, QUANTUM chromodynamics, QUARKS, MAGNETIC flux density, CHIRALITY of nuclear particles, MUONS
Abstract

The Nambu–Jona‐Lasinio model is known for its simplicity and capacity to reproduce some of the basic characteristics of the quantum chromodynamics phase diagram. However, since it is a nonrenormalizable model, there are regularization issues that should be treated conveniently. This is the case when considering the quark anomalous magnetic moment (AMM) when external constant magnetic fields are present. Regularization procedures based on entangled functions between the magnetic field and the cutoff of the model can predict first‐order phase transitions for chiral symmetry restoration at finite values of magnetic fields and inverse magnetic catalysis. The strengths of magnetic fields explored in NJL model and lattice QCD do not show first‐order phase transition. In the present work, we show that some of the previous results are regularization‐dependent effects and how to handle the divergences using the vacuum magnetic regularization scheme. [ABSTRACT FROM AUTHOR]

Published
2024
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2. The QCD phase diagram under magnetic fields.

Author

Avancini, Sidney S., Menezes, Débora P., Pinto, Marcus B., and Providência, Constança

Subjects
*QUANTUM chromodynamics, *PHASE diagrams, *MAGNETIC fields, *PHASE transitions, *CRITICAL point (Thermodynamics)
Abstract

We consider the the Nambu Jona-Lasinio model, in the presence of strong magnetic fields, in order to obtain the phase diagram associated with chiral transition. Our results show that magnetic fields influence the location of the critical point which emerge at higher temperatures and smaller chemical potential values while the first order transition line expands with increasing B. At the low temperature region of the phase diagram we observe that the coexistence chemical potential value appears to oscillate around the B = 0 value. We also review some results, at T = 0, which show that magnetic fields produce stiffer EoS whih can be relevant for the study of magnetars. [ABSTRACT FROM AUTHOR]

Published
2013
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3. Magnetized pole-mass of neutral ρ meson within full RPA evaluation.

Author

Avancini, Sidney S., Farias, Ricardo L.S., Tavares, William R., and Timóteo, Varese S.

Subjects
*NAMBU-Jona-Lasinio model, *MESONS, *MAGNETIC fields, *QUANTUM chromodynamics, *EVALUATION methodology, *QUARKS
Abstract

In this work we calculate the pole-mass of the ρ 0 meson with different spin projections s z = 0 , ± 1 in the context of the magnetized two-flavor Nambu–Jona–Lasinio model. Making use of the mean field approximation to obtain the effective quark mass as a function of the magnetic field, we apply the random phase approximation (RPA) to the vector channel in order to calculate the polarization function for each spin component. We adopt the magnetic field independent regularization (MFIR) in our evaluations as a method of separating divergences and the Pauli-Villars regularization for the vacuum contributions. The ρ 0 meson mass with spin projection s z = ± 1 is always catalyzed with the magnitude of the magnetic field, showing good agreement with Lattice QCD results. The mass projection s z = 0 has a non-monotonic behavior, decreasing until the minimum at e B ≲ 0.15 GeV2, which is in contrast with available LQCD data. [ABSTRACT FROM AUTHOR]

Published
2022
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4. QCD critical end point under strong magnetic fields.

Author

Avancini, Sidney S., Menezes, Débora P., Pinto, Marcus B., and Providencia, Constança

Subjects
*QUANTUM chromodynamics, *MAGNETIC fields, *FLAVOR in particle physics, *MATHEMATICAL models, *QUARKS, *MEAN field theory, *APPROXIMATION theory
Abstract

We use the three-flavor Nambu-Jona-Lasinio model, which includes strangeness and quark physical masses in the mean field approximation, to investigate the influence of strong magnetic fields on the QCD phase diagram covering the whole T-&mgr; plane. It is found that the first order segment of the transition line becomes longer as the field strength increases so that a larger coexistence region for hadronic and quark matter should be expected for strong magnetic fields. The location of the critical end point is also affected by the presence of magnetic fields that invariably increase the temperature value at which the first order line terminates. On the other hand, at low temperatures, the critical chemical potential displays an oscillation around the B = 0 value for magnetic fields within the 1017 - 1020 G range. These findings may have nontrivial consequences for the physics of magnetars and heavy ion collisions. [ABSTRACT FROM AUTHOR]

Published
2012
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5. Light pseudoscalar meson masses under strong magnetic fields within the SU(3) Nambu-Jona-Lasinio model.

Author

Avancini, Sidney S., Sodré, Joana C., Coppola, Máximo, and Scoccola, Norberto N.

Subjects
*NAMBU-Jona-Lasinio model, *MESONS, *MAGNETIC fields, *TRANSITION temperature, *QUANTUM chromodynamics
Abstract

We calculate the pole masses of pseudoscalar mesons in a strongly magnetized medium within the framework of the SU(3) Nambu-Jona-Lasinio model, using a magnetic field-independent regularization scheme. We employ both a constant and a magnetic field-dependent coupling G(B), the latter being fitted to reproduce lattice QCD results for the pseudocritical chiral transition temperature. Numerical results for the pole masses are obtained for definite parametrizations of the model. For neutral mesons, the use of G(B) provides closer agreement with lattice QCD results, which reveal a decrease of the mass with the external field. On the contrary, charged mesons masses are enhanced by B, showing no sign of the nonmonotonous behavior found in recent lattice QCD simulations. [ABSTRACT FROM AUTHOR]

Published
2021
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6. NJL-type models in the presence of intense magnetic fields: The role of the regularization prescription.

Author

Avancini, Sidney S., Farias, Ricardo L. S., Scoccola, Norberto N., and Tavares, William R.

Subjects
*QUARK matter, *MAGNETIC fields, *NAMBU-Jona-Lasinio model, *MATHEMATICAL regularization, *MEDICAL prescriptions, *QUARKS
Abstract

We study the regularization dependence of the Nambu-Jona-Lasinio model (NJL) predictions for some properties of magnetized quark matter at zero temperature (and baryonic density) in the mean field approximation. The model parameter dependence for each regularization procedure is also analyzed in detail. We calculate the average and difference of the quark condensates using different regularization methods and compare with recent lattice results. In this context, the reliability of the different regularization procedures is discussed. [ABSTRACT FROM AUTHOR]

Published
2019
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7. Neutral meson properties in hot and magnetized quark matter: A new magnetic field independent regularization scheme applied to an NJL-type model.

Author

Avancini, Sidney S., Farias, Ricardo L. S., and Tavares, William R.

Subjects
*QUARK matter, *MAGNETIC fields, *MATHEMATICAL regularization, *NAMBU-Jona-Lasinio model, *MESONS, *THERMODYNAMIC potentials
Abstract

A magnetic field independent regularization scheme (zMFIR) based on the Hurwitz-Riemann zeta function is introduced. The new technique is applied to the regularization of the mean-field thermodynamic potential and mass gap equation within the SU(2) Nambu-Jona-Lasinio model in a hot and magnetized medium. The equivalence of the new and the standard MFIR scheme is demonstrated. The neutral meson pole mass is calculated in a hot and magnetized medium and the advantages of using the new regularization scheme are shown. [ABSTRACT FROM AUTHOR]

Published
2019
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