Similarity Renormalization Group Evolution of Chiral Effective Nucleon-Nucleon Potentials in the Subtracted Kernel Method Approach

Methods based on Wilson's renormalization group have been successfully applied in the context of nuclear physics to analyze the scale dependence of effective nucleon-nucleon ($NN$) potentials, as well as to consistently integrate out the high-momentum components of phenomenological high-precision $NN$ potentials in order to derive phase-shift equivalent softer forms, the so called $V_{low-k}$ potentials. An alternative renormalization group approach that has been applied in this context is the Similarity Renormalization Group (SRG), which is based on a series of continuous unitary transformations that evolve hamiltonians with a cutoff on energy differences. In this work we study the SRG evolution of a leading order (LO) chiral effective $NN$ potential in the $^1 S_0$ channel derived within the framework of the Subtracted Kernel Method (SKM), a renormalization scheme based on a subtracted scattering equation.Comment: Published versio

Peripheral NN scattering from subtractive renormalization of chiral interactions

We apply five subtractions in the Lippman-Schwinger (LS) equation in order to perform a non-perturbative renormalization of chiral N3LO nucleon-nucleon interactions. Here we compute the phase shifts for the uncoupled peripheral waves at renormalization scales between $0.1~ \rm{fm}^{-1}$ and $1 ~ \rm{fm}^{-1}$. In this range, the results are scale invariant and provide an overall goof agreement with the Nijmegen partial wave analysis up to at least $E_{\rm{lab}} = 150 ~ \rm{MeV}$, with a cutoff at $\Lambda = 30~\rm{fm}^{-1}$.Comment: Talk given at the XXXVI RTFNB, Maresias Beach, Brazil, September 201

The Contribution of Microbunching Instability to Solar Flare Emission in the GHz to THz Range of Frequencies

Recent solar flare observations in the sub-terahertz range have provided evidence of a new spectral component with fluxes increasing for larger frequencies, separated from the well-known microwave emission that maximizes in the gigahertz range. Suggested interpretations explain the terahertz spectral component but do not account for the simultaneous microwave component. We present a mechanism for producing the observed double spectra. Based on coherent enhancement of synchrotron emission at long wavelengths in laboratory accelerators, we consider how similar processes may occur within a solar flare. The instability known as microbunching arises from perturbations that produce electron beam density modulations, giving rise to broadband coherent synchrotron emission at wavelengths comparable to the characteristic size of the microbunch structure. The spectral intensity of this coherent synchrotron radiation (CSR) can far exceed that of the incoherent synchrotron radiation (ISR), which peaks at a higher frequency, thus producing a double-peaked spectrum. Successful CSR simulations are shown to fit actual burst spectral observations, using typical flaring physical parameters and power-law energy distributions for the accelerated electrons. The simulations consider an energy threshold below which microbunching is not possible because of Coulomb repulsion. Only a small fraction of the radiating charges accelerated to energies above the threshold is required to produce the microwave component observed for several events. The ISR/CSR mechanism can occur together with other emission processes producing the microwave component. It may bring an important contribution to microwaves, at least for certain events where physical conditions for the occurrence of the ISR/CSR microbunching mechanism are possible

Solar Submillimeter Telescope next generation

The Solar Submillimeter Telescope (SST) is an unique instrument that has been observing the Sun daily since 2001 bringing a wealth of information and raising new questions about the particle acceleration and transport, and emission mechanisms during flares. We are now designing its successor, the SSTng, that will expand the scientific goals of the instrument, including non-solar source observations.Comment: Accepted for the URSI GASS 2023, Sapporo, japan, 19-26 August 2023. 4 pages, 4 figure

Analysis of the Variability in the Atmospheric Electric Field and Natural Gamma Radiation in Different Weather Conditions

In recent years the analysis of the variability of the natural gamma radiation and its relationshipwith high atmospheric electric fields in disturbed weather, e.g., thunderstorms, have been important, as well as the relationship between these parameters in fair weather conditions. In this paper we analyze the diurnal variation of the atmospheric electric field and natural gamma radiation, in fair and disturbed weather conditions, recorded in the Argentinian Andes mountain (2552 masl) between April 2018 and February 2019. In fair weather conditions, it was found a higher linear correlation coefficient (R) between the atmospheric electric field diurnal curve and the ‘universal’ Carnegie curve (R=0.93), and a high negative correlation between the atmospheric electric field and natural gamma radiation diurnal curve (R=-0.9). On the other hand, in disturbed weather conditions, we reported thirteen events where it was found intense natural gamma radiation enhancements associated with high atmospheric electric field variability. A maximum of 35 % excess in the natural gamma radiation was detected, which was associated with thunderstorms and rain precipitation. It was observed a high correlation between the excesses of the gamma natural radiation enhancement with the atmospheric electric field values (R=0.80) and with the rain precipitation rate (R=0.59).Fil: Rosa de Oliveira, Rafael Ricardo. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; BrasilFil: Tacza, José. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; Brasil. Polish Academy of Sciences; ArgentinaFil: Raulin, Jean Pierre. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; BrasilFil: Szpigel, Sergio. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; BrasilFil: Makhmutov, Vladimir. Lebedev Physical Institute; RusiaFil: Philippov, Maxim. Lebedev Physical Institute; RusiaFil: Ccopa, Josué. Universidade Presbiteriana Mackenzie. Escola de Engenharia. Centro de Radio Astronomia e Astrofisica; BrasilFil: Marun, Adolfo Hector. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Fernandez, German Enzo Leonel. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Complejo Astronómico "El Leoncito". Universidad Nacional de Córdoba. Complejo Astronómico "El Leoncito". Universidad Nacional de la Plata. Complejo Astronómico "El Leoncito". Universidad Nacional de San Juan. Complejo Astronómico "El Leoncito"; Argentin