Ana Júlia Mizher

We compute the yield and elliptic flow coefficient for photons produced during the preequilibrium stage of semicentral relativistic heavy-ion collisions from the gluon fusion and splitting processes induced by the presence of a magnetic field. The calculation is performed for arbitrary values of the field strength. The preequilibrium gluon distribution is modeled with a glasma-inspired Bose-Einstein occupation factor, as well as with an anisotropic distribution that accounts for the rapid initial expansion along the beam axis. In both cases, we find a very good agreement between the calculation and the experimental data from PHENIX. Most notably, the shape and strength of the elliptic flow coefficient are described quite well, representing a step toward solving the outstanding photon puzzle.

We compute the running of the mass of a neutral boson and of its self-coupling in a simple model describing the self-interaction of three scalars, one of them neutral and the other two electrically charged, subject to the effects of a magnetic field, as functions of the field strength, at one-loop order. We resort to the environmentally friendly renormalization group approach, where the flow variable is taken as that describing the environmental conditions, in this case, the strength of the magnetic field. We find the magnetic field dependent mass and coupling beta functions and use them to set up the differential equations satisfied by the neutral scalar mass and coupling. We solve the resulting system of coupled equations both numerically and also analytically in the small-mass approximation. We find that the neutral scalar mass increases, while the coupling decreases with increasing field strength. The study is intended to set up the ideas to later use them in more sophisticated theories such as QED and QCD.

We show that a very clear signal of the presence of a strong magnetic field during the early stage of a high-energy heavy-ion collision is provided by the decay of the Z 0 into dimuon pairs. We find that the process is highly anisotropic, producing pairs mainly out of plane, as signaled by a negative value of v 2 , and leads to an antimuon transverse momentum distribution which peaks at a higher value of the transverse momentum compared to the peak of the muon transverse momentum distribution. We also show that the process does not produce a significant distortion of the Z 0 spectral function. The signal can be identified by comparing the dimuon-invariant mass and the individual muon and antimuon spectra produced in semicentral heavy-ion collisions with the corresponding scaled spectra produced in p + p collisions at the Z 0 peak.

¿Qué se necesita para ser científica? ¿Qué obstáculos enfrentan las mujeres que desean dedicarse a la ciencia? ¿Cómo abrir caminos para que más niñas y jóvenes puedan lograrlo? Este libro reúne las voces de ocho científicas de México, Brasil, Argentina y España, quienes comparten, desde sus vivencias y reflexiones, cómo nació su interés por la ciencia, los desafíos que han enfrentado y los logros alcanzados a lo largo de sus trayectorias. Sus historias reflejan no sólo un profundo compromiso con el conocimiento, sino también su perseverancia frente a obstáculos estructurales que aún limitan el acceso de las mujeres al ámbito científico. En estas historias contadas por sus protagonistas, el ser científica de manera activa y con agencia, es el motor de cambio para gozar de la ciencia. A través de sus relatos, comprendemos que el derecho a ser científica no es sólo una cuestión de equidad y justicia: es clave para el avance de nuestras sociedades y el bienestar colectivo. Se trata de una invitación a imaginar nuevos futuros, a inspirarse en quienes ya están abriendo camino y a sumarse a la construcción del quehacer científico diverso e incluyente. El derecho a ser científicas. Colección de ensayos está pensado para ti, que quizás estás descubriendo lo que te apasiona, que te preguntas si también podrías formar parte de ese universo llamado ciencia. La respuesta no está escrita en una sola historia, sino en todas estas voces que, al reunirse, te invitan a encontrar la tuya. Porque el futuro también se construye con mujeres en la ciencia.

Magnetic fields of a large intensity can be generated in peripheral high-energy heavy-ion collisions. Although their intensity drops fast and, moreover, it is not clear whether these fields last long enough to induce a magnetization during the quark-gluon plasma phase, most of the models and simulations predict a significant intensity that lasts up to proper times of order 1 fm after the beginning of the reaction, which is a typical time for the hydrodynamical phase to start. This interval of time is referred to as the pre-equilibrium stage. The evolution of the reaction during pre-equilibrium is thus likely to be influenced by these fields. In this work we adopt a strong field approximation to study the effects of the magnetic field-induced anisotropy on the gluon pressure. We include this anisotropy within the description obtained by means of effective kinetic theory and explore the consequences to reach isotropization at proper times of order 1 fm. We show that when including the magnetic field effects, isotropization is achieved faster. Published by the American Physical Society 2024

The Fried-Yennie gauge is a covariant gauge for which the mass-shell renormalization procedure can be performed without introducing spurious infrared divergences to the theory. It is usually applied in calculations in regular Quantum Electrodynamics (QED), but it is particularly interesting when employed in the framework of pseudo-QED (PQED), where fermions are constrained to 2 + 1 dimensions while the dynamical fields interacting with these fermions live in the bulk of a 3 + 1 space. In this context, the gauge parameter can be adjusted to match the power of the external momentum in the denominator of the photon propagator, simplifying the infrared region without the need for a photon mass. In this work, we apply this machinery, for the first time, to PQED, generalizing the procedure to calculate the self energy in arbitrary dimensions, allowing, of course, for different dimensionalities of fermions and gauge fields.

The Fried-Yennie gauge is a covariant gauge for which the mass-shell renormalization procedure can be performed without introducing spurious infrared divergences to the theory. It is usually applied in calculations in regular Quantum-Electrodynamics (QED), but it is particularly interesting to be employed in the framework of pseudo-QED (PQED), where fermions are constrained to 2+1 dimensions while external fields interacting with these fermions live in the bulk of a 3+1 space. In this context, the gauge parameter can be adjusted to match the power of the external momentum in the denominator of the photon propagator, simplifying the infrared region without the need of a photon mass. In this work we apply for the first time this machinery to PQED, generalizing the procedure to calculate the self energy in arbitrary dimensions, allowing of course for different dimensionality of fermions and gauge fields.

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.

We study the effect of a refined electron-photon vertex on the dynamical breaking of chiral symmetry in reduced quantum electrodynamics. We construct an educated ansatz for this vertex that satisfies the required discrete symmetries under parity, time reversal, and charge conjugation operations. Furthermore, it reproduces its asymptotic perturbative limit in the weak coupling regime and ensures the massless electron propagator is multiplicatively renormalizable in its leading logarithmic expansion. Employing this vertex ansatz, we solve the gap equation to compute dynamically generated electron mass whose dependence on the electromagnetic coupling is found to satisfy Miransky scaling law. We also investigate the gauge dependence of this dynamical mass as well as that of the critical coupling above which chiral symmetry is dynamically broken. As a litmus test of our vertex construction, both these quantities are rendered virtually gauge independent within a certain interval of values considered for the covariant gauge parameter.