|MIT Department: Physics
Faculty Mentor: Prof. Kerstin Perez
Undergraduate Institution: University of Puerto Rico, Mayagüez
My name is Arianna H. Colón Cesaní and I was born and raised in Mayagüez, Puerto Rico. I am studying theoretical physics with a minor in applied mathematics at the University of Puerto Rico-Mayagüez Campus, and my goal is to earn a PhD in particle astrophysics when I graduate. Afterwards, I aspire to become a postdoctoral scholar and continue growing as an astroparticle physicist in the field. I currently work with the Planetary Habitability Laboratory at the University of Puerto Rico in Arecibo and the CMS Experimental Particle Physics Research Group in Mayagüez. I am cofounder and president of Women in Physics-Puerto Rico UPRM and I am passionate about supporting historically marginalized communities in STEM. My interests include dark matter theory or detection and gravitational wave research.
Can Interactions Between PeV Cosmic Rays and Local Galactic Molecular Clouds Explain the Positron Excess?
Arianna Colón Cesaní1, Field Rogers2, and Kerstin Perez2
1Department of Physics, University of Puerto Rico-Mayagüez
2Department of Physics, Massachusetts Institute of Technology
Cosmic rays (CRs) are energetic particles that traverse the galaxy and can provide information about different astrophysical phenomena. Rare antimatter particles, including positrons, are particularly interesting components of CRs because they are sensitive to the dynamics of cosmic ray propagation in the galaxy and could be probes of dark matter. An excess of positrons, relative to galactic CR models, has been observed at high energies by several observatories. These measurements disagree with conventional models of CR propagation and the production of secondary CRs, implying a source of positrons that is not included in the models. Moreover, leptons cannot propagate long distances in the galaxy without losing too much energy. As a result, sources close to Earth are necessary to explain the rise in CR positron flux. This project proposes a model to determine if the interactions of PeV-scale CR protons, which conventional CR propagation models do not consider, with local galactic molecular clouds (GMCs) could explain the observed excess near Earth. In this work, we use new catalogues of local GMCs, alongside positron flux data from AMS-02 and PeV-scale CR data from the IceTop detector. We calculate that the total positron rate from nearby GMCs is three orders of magnitude smaller than the positron excess, thus, our proposed mechanism cannot explain the excess.