Writing

Below, you’ll find my writing organized by publication type and year. For questions on any specific publication, feel free to message my office, and a teaching staff member will respond as soon as possible.

Research papers

2022

Abstract: Primordial Black Holes (PBH) could dominate in the early universe and, evaporating before Big bang Nucleosynthesis, can provide new freeze in mechanism of dark matter (DM) production. The proposed scenario is considered for two possible mechanisms of PBH formation and the corresponding continuous PBH mass spectra so that the effect of non-single PBH mass spectrum is taken into account in the results of PBH evaporation, by which PBH dominance in the early universe ends. We specify the conditions under which the proposed scenario can explain production of dark matter in very early Universe.

2021

https://arxiv.org/abs/2110.00331

Abstract: We propose and prove a new formula for the one-loop all same helicity Yang-Mills amplitudes. These amplitudes are seen to arise as a sum of products of two tree-level Berends-Giele currents connected by an effective propagator. To make sense of the propagators one needs to introduce the so-called region, or dual momenta. The formula is proven by observing that it readily implies the correct collinear limit properties. The only non-trivial part of the proof is establishing that our formula for the amplitude is invariant under shifts of the region momenta.

https://arxiv.org/abs/2209.11288

Abstract: Primordial Black Holes (PBH) could dominate in the early universe and, evaporating before Big bang Nucleosynthesis, can provide new freeze in mechanism of dark matter (DM) production. The proposed scenario is considered for two possible mechanisms of PBH formation and the corresponding continuous PBH mass spectra so that the effect of non-single PBH mass spectrum is taken into account in the results of PBH evaporation, by which PBH dominance in the early universe ends. We specify the conditions under which the proposed scenario can explain production of dark matter in very early Universe.

2020

https://arxiv.org/abs/2002.11390

Abstract: It has been suggested a long time ago by W. Bardeen that non-vanishing of the one-loop same helicity YM amplitudes, in particular such an amplitude at four points, should be interpreted as an anomaly. However, the available derivations of these amplitudes are rather far from supporting this interpretation in that they share no similarity whatsoever with the standard triangle diagram chiral anomaly calculation. We provide a new computation of the same helicity four-point amplitude by a method designed to mimic the chiral anomaly derivation. This is done by using the momentum conservation to rewrite the logarithmically divergent four-point amplitude as a sum of linearly and then quadratically divergent integrals. These integrals are then seen to vanish after appropriate shifts of the loop momentum integration variable. The amplitude thus gets related to shifts, and these are computed in the standard textbook way. We thus reproduce the usual result but by a method which greatly strengthens the case for an anomaly interpretation of these amplitudes.

2017

https://arxiv.org/abs/1703.09541

Abstract: The naturalness of electroweak scale in the models of type-I seesaw mechanism with order (1) Yukawa couplings requires TeV scale masses for the fermion singlets. In this case, the tiny neutrino masses have to arise from the cancellations within the seesaw formula which are arranged by fine-tuned correlations between the Yukawa couplings and the masses of fermion singlets. We motivate such correlations through the framework of discrete symmetries. In the case of three Majorana fermion singlets, it is shown that the exact cancellation arranged by the discrete symmetries in seesaw formula necessarily leads to two mass degenerate fermion singlets. The remaining fermion singlet decouples completely from the standard model. We provide two candidate models based on two discrete groups and discuss the generic perturbations to this approach which can lead to the viable neutrino masses.

Essays

2023

Goodwill, Sam. 2023. “Article Name Here.” Publication Name, January 1, 2023. Article Link.

2022

Goodwill, Sam. 2022. “Article Name Here.” Publication Name, January 1, 2023. Article Link.

2021

Goodwill, Sam. 2021. “Article Name Here.” Publication Name, January 1, 2023. Article Link.

Opinion

2023

Goodwill, Sam. 2023. “Article Name Here.” Publication Name, January 1, 2023. Article Link.

2022

Goodwill, Sam. 2022. “Article Name Here.” Publication Name, January 1, 2023. Article Link.

2021

Goodwill, Sam. 2021. “Article Name Here.” Publication Name, January 1, 2023. Article Link.