Browsing by Author "Ayala, Alejandro"

Now showing 1 - 11 of 11
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    Anisotropic photon emission from gluon fusion and splitting in a strong magnetic background: The two-gluon one-photon vertex
    (2022) Ayala, Alejandro; Castano-Yepes, Jorge David; Hernandez, L. A.; Mizher, Ana Julia; Tejeda-Yeomans, Maria Elena; Zamora, R.
    Having in mind the pre-equilibrium stage in peripheral heavy-ion collisions as a possible scenario for the production of electromagnetic radiation, we compute the two-gluon one-photon vertex in the presence of an intense magnetic field at one-loop order. The quarks in the loop are taken such that two of them occupy the lowest Landau level, with the third one occupying the first excited Landau level. When the field strength is the largest of the energy (squared) scales, the tensor basis describing this vertex corresponds to two of the three-vector particles polarized in the longitudinal direction whereas the third one is polarized in the transverse direction. However, when the photon energy is of the same order as or larger than the field strength, the explicit one-loop computation contains extra tensor structures that spoil the properties of the basis compared with the case when the field strength is the largest of the energy scales, which signals that the calculation is incomplete. Nevertheless, by projecting the result onto the would-be basis, we show that the squared amplitude for processes involving two gluons and one photon exhibits the expected properties such as a preferred in-plane photon emission and a slightly decreasing strength for an increasing magnetic-field strength. We comment on possible venues to improve the one-loop calculation that include accounting for progressive occupation of the three quarks of the lowest and first-excited Landau levels such that, still working in the large field limit, a more complete description can be achieved when the photon energy increases.
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    Effects of superstatistics on the location of the effective qcd critical end point
    (2019) Ayala, Alejandro; Hentschinski, Martin; Hernández, Luis Alberto; Loewe Lobo, Marcelo Patricio; Zamora Jofré, Renato Andrés
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    Finite Temperature QCD Sum Rules: A Review
    (2017) Ayala, Alejandro; Dominguez, C. A.; Loewe, M.
    The method of QCD sum rules at finite temperature is reviewed, with emphasis on recent results. These include predictions forthe survival of charmonium and bottonium states, at and beyond the critical temperature for deconfinement, as later confirmed by lattice QCD simulations. Also included are determinations in the light-quark vector and axial-vector channels, allowing analysing the Weinberg sum rules and predicting the dimuon spectrum in heavy-ion collisions in the region of the rho-meson. Also, in this sector, the determination of the temperature behaviour of the up-down quark mass, together with the pion decay constant, will be described. Finally, an extension of the QCD sum rule method to incorporate finite baryon chemical potential is reviewed.
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    Magnetized effective QCD phase diagram
    (2015) Ayala, Alejandro; Domínguez, C. A.; Hernández, L. A.; Loewe Lobo, Marcelo Patricio; Zamora Jofré, Renato Andrés
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    Publisher's note: Magnetic catalysis of a charged bose-einstein condensate
    (2012) Ayala, Alejandro; Loewe Lobo, Marcelo Patricio; Rojas Gómez-Lobo, Juan Cristóbal; Villavicencio Reyes, Cristián Luis
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    Superstatistics and the effective QCD phase diagram
    (2018) Ayala, Alejandro; Hentschinski, Martin; Hernandez, L.A.; Loewe Lobo, Marcelo Patricio; Zamora Jofré, Renato Andrés
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    The QCD phase diagram from Schwinger-Dyson equations
    (2014) Gutierrez, Enif; Ahmad, Aftab; Ayala, Alejandro; Bashir, Adnan; Raya, Alfredo
    We study the phase diagram of quantum chromodynamics (QCD). For this purpose we employ the Schwinger-Dyson equations (SDEs) technique and construct a truncation of the infinite tower of equations by demanding a matching with the lattice results for the quark-anti-quark condensate at finite temperature (T), for zero quark chemical potential (mu), that is, the region where lattice calculations are expected to provide reliable results. We compute the evolution of the phase diagram away from T = 0. To chart the chiral symmetry restoration transition, we follow the evolution of the derivative of the condensate with respect to the temperature as a function of T and mu. The behavior of this thermodynamic variable clearly demonstrates the existence of a cross-over for mu less than a critical value. However, the derivative of the condensate with respect to the temperature develops a singularity near mu approximate to 0.22 GeV marking the onslaught of a first order phase transition characterized by the existence of a critical point. The critical line continues until mu approximate to 0.44 GeV where T-c = 0 and thus chiral symmetry is finally restored. For the deconfinement transition we look for the violation of the axiom of reflection positivity in the quark propagator. The critical end point appears to be the same as observed for the transition to chirally symmetric phase. However, near T = 0 axis, due to lack of data points, we are unable to claim against coincidental chiral symmetry restoration and deconfinement transitions along that axis.
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    Thermo-magnetic behavior of the quark-gluon vertex
    (2016) Ayala, Alejandro; Cobos Martínez, J. J.; Loewe Lobo, Marcelo Patricio; Tejeda Yeomans, María Elena; Zamora Jofré, Renato Andrés
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    Thermomagnetic correlation lengths of strongly interacting matter in the Nambu-Jona-Lasinio model
    (2017) Ayala, Alejandro; Hernández, L. A.; Loewe Lobo, Marcelo Patricio; Raya, Alfredo; Rojas, J. C.; Zamora Jofré, Renato Andrés
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    Thermomagnetic evolution of the QCD strong coupling
    (2018) Ayala, Alejandro; Dominguez, C. A.; Hernandez-Ortiz, Saul; Hernandez, L. A.; Loewe Lobo, Marcelo Patricio; Manreza Paret, D.; Zamora, R.
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    Thermomagnetic properties of the strong coupling in the local Nambu–Jona-Lasinio model
    (2016) Ayala, Alejandro; Domínguez, C. A.; Hernández, L. A.; Loewe Lobo, Marcelo Patricio; Raya, Alfredo; Rojas, J. C.; Villavicencio Reyes, Cristián Luis