Papers by Jonatan Vignatti
arXiv (Cornell University), Oct 10, 2023
The detection of gravitational waves (GWs) from a binary neutron star (BNS) merger by Advanced LI... more The detection of gravitational waves (GWs) from a binary neutron star (BNS) merger by Advanced LIGO and Advanced Virgo (GW170817), along with the discovery of the electromagnetic counterparts of this GW event, ushered in a new era of multimessenger astronomy, providing the first direct evidence that BNS mergers are progenitors of short gamma-ray bursts (GRBs). Such events may also produce very-high-energy (VHE, > 100GeV) photons which have yet to be detected in coincidence with a GW signal. The Cherenkov Telescope Array (CTA) is a next-generation VHE observatory which aims to be indispensable in this search, with an unparalleled sensitivity and ability to slew anywhere on the sky within a few tens of seconds. Achieving such a feat will require a comprehensive real-time strategy capable of coordinating searches over potentially very large regions of the sky. This work will evaluate and provide estimations on the number of GW-CTA events determined from simulated BNS systems and short GRBs, considering both onand off-axis emission. In addition, we will present and discuss the prospects of potential follow-up strategies with CTA.
European Physical Journal C, Apr 1, 2022
We consider the lepton-flavor violating (LFV) lepton-quark dimension-6 operators and analyze thei... more We consider the lepton-flavor violating (LFV) lepton-quark dimension-6 operators and analyze their contributions to the LFV leptonic decays of vector, pseudoscalar, and scalar neutral mesons M → 1 2 as well as to μ(τ ) → ee, γ γ decays. These operators contribute to the purely leptonic processes via quark loop. On the basis of quarkhadron duality, we relate these loops to the appropriate meson-exchange contributions. In this way, we extract lower bounds on the individual scales of the studied LFV operators from the experimental and phenomenological limits on the leptonic decays of mesons and leptons. As a byproduct, we shall obtain new limits on the LFV leptonic decays of flavored mesons from the experimental bounds on the threebody lepton decays. We study the effects of QED and QCD radiative corrections to the LFV lepton-quark operators in question. We derive for them the one-loop matrix of the RGE evolution and examine its effect on the previously derived tree-level limits on these operators. We show that the QED corrections are particularly relevant due to operator mixing. Specifically, for some of them the limits on their individual LFV scales improve by up to 3 orders of magnitude. 0123456789().: V,-vol
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Modern imaging atmospheric Cherenkov telescopes have extensively observed young nearby supernova ... more Modern imaging atmospheric Cherenkov telescopes have extensively observed young nearby supernova remnants (SNRs), with ages of about 1000 years or less, in the very-high-energy (VHE) gamma-ray band. These efforts resulted in the detection of VHE emission from three young SNRs-Cassiopeia A, Tycho, and SN 1006-and provided significant evidence for emission from the more distant Kepler's SNR. However, many questions on the production of VHE gamma rays in these remnants remain unanswered. Using detailed physical models for Tycho's SNR based on the CR-hydro-NEI code and physically motivated models for the other young nearby remnants, we simulated observations with the Cherenkov Telescope Array (CTA) of these gamma-ray sources. We highlight properties of these remnants accessible for investigation with future CTA observations and discuss which questions are expected to be answered.
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Proceedings of 37th International Cosmic Ray Conference — PoS(ICRC2021), 2021
Very-High Energy (VHE) gamma-ray astroparticle physics is a relatively young field, and observati... more Very-High Energy (VHE) gamma-ray astroparticle physics is a relatively young field, and observations over the past decade have surprisingly revealed almost two hundred VHE emitters which appear to act as cosmic particle accelerators. These sources are an important component of the Universe, influencing the evolution of stars and galaxies. At the same time, they also act as a probe of physics in the most extreme environments known -such as in supernova explosions, and around or after the merging of black holes and neutron stars. However, the existing experiments have provided exciting glimpses, but often falling short of supplying the full answer. A deeper understanding of the TeV sky requires a significant improvement in sensitivity at TeV energies, a wider energy coverage from tens of GeV to hundreds of TeV and a much better angular and energy resolution with respect to the currently running facilities. The next generation gamma-ray observatory, the Cherenkov Telescope Array Observatory (CTAO), is the answer to this need. In this talk I will present this upcoming observatory from its design to the construction, and its potential science exploitation. CTAO will allow the entire astronomical community to explore a new discovery space that will likely lead to paradigm-changing breakthroughs. In particular, CTA has an unprecedented sensitivity to short (sub-minute) timescale phenomena, placing it as a key instrument in the future of multi-messenger and multi-wavelength time domain astronomy. I will conclude the talk presenting the first scientific results obtained by the LST-1, the prototype of one CTA telescope type -the Large Sized Telescope, that is currently under commission.
Proceedings of 38th International Cosmic Ray Conference — PoS(ICRC2023)
Graph data models are widely used in many areas, for example, bioinformatics, graph databases. In... more Graph data models are widely used in many areas, for example, bioinformatics, graph databases. In these areas, it is often required to process queries for large graphs. Some of the most common graph queries are navigational queries. The result of query evaluation is a set of implicit relations between nodes of the graph, i.e. paths in the graph. A natural way to specify these relations is by specifying paths using formal grammars over the alphabet of edge labels. An answer to a context-free path query in this approach is usually a set of triples (A, m, n) such that there is a path from the node m to the node n, whose labeling is derived from a non-terminal A of the given context-free grammar. This type of queries is evaluated using the relational query semantics. Another example of path query semantics is the single-path query semantics which requires presenting a single path from the node m to the node n, whose labeling is derived from a non-terminal A for all triples (A, m, n) evaluated using the relational query semantics. There is a number of algorithms for query evaluation which use these semantics but all of them perform poorly on large graphs. One of the most common technique for efficient big data processing is the use of a graphics processing unit (GPU) to perform computations, but these algorithms do not allow to use this technique efficiently. In this paper, we show how the context-free path query evaluation using these query semantics can be reduced to the calculation of the matrix transitive closure. Also, we propose an algorithm for context-free path query evaluation which uses relational query semantics and is based on matrix operations that make it possible to speed up computations by using a GPU.
We consider the lepton-flavor violating (LFV) lepton-quark dimension-6 operators and analyze thei... more We consider the lepton-flavor violating (LFV) lepton-quark dimension-6 operators and analyze their contributions to the LFV leptonic decays of vector, pseudoscalar, and scalar neutral mesons M→ℓ_1 ℓ_2 as well as to μ(τ) →ℓ ee, ℓγγ decays. These operators contribute to the purely leptonic processes via quark loop. On the basis of quark-hadron duality, we relate these loops to the appropriate meson-exchange contributions. In this way, we extract lower bounds on the individual scales of the studied LFV operators from the experimental and phenomenological limits on the leptonic decays of mesons and leptons. As a byproduct, we shall obtain new limits on the LFV leptonic decays of flavored mesons from the experimental bounds on the three-body lepton decays. We study the effects of QED and QCD radiative corrections to the LFV lepton-quark operators in question. We derive for them the one-loop matrix of the RGE evolution and examine its effect on the previously derived tree-level limits on ...
We construct a viable extension of the SM with a heavy vector in the fundamental SU( 2) _L repres... more We construct a viable extension of the SM with a heavy vector in the fundamental SU( 2) _L representation and nine SM singlet scalar fields, consistent with the current SM fermion mass spectrum and fermionic mixing parameters. The small masses for the active neutrinos are generated from radiative seesaw mechanism at one loop level mediated by the neutral components of the heavy vector as well as by the left handed Majorana neutrinos. We carry out an analysis of the predictions in the lepton sector, where the model is only viable in the scenario of inverted neutrino mass ordering.
Revista de Investigación de Física
Mostramos el campo de Dirac para una partícula masiva libre que describe el movimiento de un ferm... more Mostramos el campo de Dirac para una partícula masiva libre que describe el movimiento de un fermión relativístico, usando el formalismo de la teoría cuántica de campos. Introducimos una sustitución no-mínima en el operador de momentum, el cual nos produce el oscilador de Dirac, entonces procedemos a cuantizarlo canónicamente y expresamos el operador del campo del oscilador de Dirac en función de los operadores de creación y aniquilación.
We consider the lepton-flavor violating (LFV) lepton-quark dimension-6 operators and analyze thei... more We consider the lepton-flavor violating (LFV) lepton-quark dimension-6 operators and analyze their contributions to the LFV leptonic decays of vector, pseudoscalar, and scalar neutral mesons M → `1`2 as well as to μ(τ) → `ee, `γγ decays. These operators contribute to the purely leptonic processes via quark loop. On the basis of quark-hadron duality, we relate these loops to the appropriate meson-exchange contributions. In this way, we extract lower bounds on the individual scales of the studied LFV operators from the experimental and phenomenological limits on the leptonic decays of mesons and leptons. As a byproduct, we shall obtain new limits on the LFV leptonic decays of flavored mesons from the experimental bounds on the three-body lepton decays. We study the effects of QED and QCD radiative corrections to the LFV lepton-quark operators in question. We derive for them the one-loop matrix of the RGE evolution and examine its effect on the previously derived tree-level limits on t...
Journal of Physics G: Nuclear and Particle Physics
We construct two viable extensions of the SM with a heavy vector in the fundamental SU (2) L repr... more We construct two viable extensions of the SM with a heavy vector in the fundamental SU (2) L representation and nine SM singlet scalar fields, consistent with the current SM fermion mass spectrum and fermionic mixing parameters. The small masses for the active neutrinos are generated from radiative seesaw mechanism at one loop level mediated by the neutral components of the heavy vector as well as by the left handed Majorana neutrinos. The proposed models predicts rates for charged lepton flavor violating processes within the reach of the forthcoming experiments.
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Papers by Jonatan Vignatti