arXiv subjects

Jilberto Zamora-Saa

Publications and source records attributed to Jilberto Zamora-Saa.

At least 19 recordsLinked to original sources

arXiv2024

LHC and HL-LHC Bounds on Visible and Invisible Decays in the $B-L$ Model

In this work, we use publicly available data from ATLAS collaboration collected at LHC run 2 at a center-of-mass energy of $\sqrt{s}=13$TeV with an integrated luminosity of $139 fb^{-1}$ to derive lower mass limits on the $Z^\prime$ gauge boson associated with the B-L gauge symmetry. Using dilepton data we find that $M_{Z^\prime} > 4$TeV ($6$TeV) for $g_{BL}=0.1$ ($g_{BL}=0.5$) in the absence of invisible decays. Once invisible decays are turned on these limits are substantially relaxed. Assuming an invisible branching ratio of $BR_{inv}=0.9$, the LHC bound is loosened up to $M_{Z^\prime}> 4.8$TeV for $g_{BL}=0.5$. This analysis confirms that the LHC now imposes stricter constraints than the longstanding bounds established by LEP. We also estimate the projected HL-LHC bounds that will operate with at $\sqrt{s}=14$TeV and a planned integrated luminosity of $\mathcal{L}=3 ab^{-1}$ that will probe $Z^\prime$ masses up to $7.5$TeV.

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arXiv2024

Fermion Dark Matter in the Vector Scotogenic Model: A Survey of Signatures

In this work, we have studied the Vector Scotogenic Model in the context of the Dark Matter problem. Due to unitarity considerations, we have focused on the scenario with fermion dark matter, finding out that co-annihilations play a fundamental role in achieving dark matter relic abundance. Moreover, the coannihilation effects allow to separate the parameter space into two regions with different phenomenology. In addition, we have studied the detection prospects of these regions separately, focusing on signatures that can appear in lepton flavor violating decays, indirect and direct searches, and the production of these new particles at collider facilities.

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arXiv2024

Introducing Model Benchmark Analysis for dark matter models with isomorphic lagrangians

In this work, we propose a novel approach to particle physics phenomenology, which we dubbed as model benchmark analysis. We consider models that provide vertices with similar topology but different Lorentz and gauge structure, which we call isomorphic models. Under this setup, the coupling constants for each theory have the same meaning, in the sense that describe the topologically equivalent diagrams. Consequently, each model acts like a map of parameter space into the observable space. This definition allows to group isomorphic models into families with a common parameter space and perform calculations for each model. As a proof of concept, we obtained some guidelines for the search of leptophilic dark fermions at CLIC, making predictions oriented to discriminate between beyond the standard model scenarios in light of possible signals of new physics that could appear at lepton colliders. We present different observables that can be useful to help discriminating between models.

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arXiv2024

Recent Developments within The Cosmic Ray Extremely Distributed Observatory (CREDO)

This contribution presents the recent research developments within the Cosmic Ray Extremely Distributed Observatory (CREDO) in the search for resolution of various scientific puzzles, ranging from fundamental physical questions to applications like the determination of earthquake precursors. The state-of-the art theoretical, numerical and computational aspects of these phenomena are addressed, as well as recent experimental developments for detection.

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arXiv2023

Probing Left-handed Heavy Neutral Leptons in the Vector Scotogenic Model

In this work, we consider an extension to the Standard Model composed by a Massive Vector Doublet under SU(2)$_L$ and a Left-handed Heavy Neutral Lepton. We study the production of these exotic leptons with the Same Flavor Opposite Sign standard lepton pair, and jets, considering Drell-Yan and Vector Boson Fusion as independent cases. We find that for the latter, the dilepton angular distribution is different enough from the background to use it as a smoking-gun for our model. Based on this fact, we establish limits on the parameter space considering previous experimental searches in this final state.

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arXiv2023

Simulation of the isotropic ultra-high energy photons flux in the solar magnetic field and a comparison with observations made by the HAWC and Fermi-LAT observatories

In this contribution we study the possibility of the formation of cosmic ray ensembles (CRE) created by the interaction of ultra-high energy (UHE) photons with the magnetic field of the Sun. The lack of observation of those UHE and the difficulties for their identification given the current methodologies motivates this study. We performed simulations using the PRESHOWER program in order to simulate the expected extensive air showers which might be spatially correlated generated upon entering the Earth's atmosphere. We found characteristic features like very thing and extremely elongates cascades of secondary photons with their corresponding energies spanning the entire cosmic range spectrum. Shower footprints are as large as hundreds of kilometres. An application of this study is the scenario of gamma-ray emission from the vicinity of the Sun as a result of ultra-high energy photon cascading in the solar magnetic field in order to understand recent observations made by the HAWC and Fermi-LAT observatories.

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arXiv2023

Unveiling the Heavy Neutrino Nature at LHCb

In this work, we study the lepton number violating Bc meson decays via one intermediate on-shell heavy neutrino. The specific studied process is $B_{c}^{+} \to μ^{+} \ N \to μ^{+} μ^{+} τ^{-} ν$ which could allow distinguishing the nature of the heavy neutrino nature (Dirac or Majorana) by studying the tau lepton energy spectrum in the LHCb experiment. The result suggests that this signature could be observed in the collected data during the HL-LHCb lifetime.

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arXiv2022

Discovering heavy neutrino oscillations in rare Bc meson decays at HL-LHCb

In this work, we study the lepton flavor and lepton number violating $B_{c}$ meson decays via two intermediate on-shell Majorana neutrinos $N_j$ into two charged leptons and a charged pion $B_{c}^{\pm} \to μ^{\pm} \ N_j \to μ^{\pm} τ^{\pm} π^{\mp}$. We evaluated the possibility to measure the modulation of the decay width along the detector length produced as a consequence of the lepton flavor violating process, in a scenario where the heavy neutrinos masses range between $2.0$ GeV $\leq M_N \leq 6.0$ GeV. We study some realistic conditions which could lead to the observation of this phenomenon at futures $B$ factories such HL-LHCb.

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arXiv2021

Simulations of Cosmic Ray Ensembles originated nearby the Sun

Cosmic Ray Ensembles (CRE) are yet not observed groups of cosmic rays with a common primary interaction vertex or the same parent particle. One of the processes capable of initiating identifiable CRE is an interaction of an ultra-high energy (UHE) photon with the solar magnetic field which results in an electron pair production and the subsequent synchrotron radiation. The resultant electromagnetic cascade forms a very characteristic line-like front of a very small width ($\sim$ meters), stretching from tens of thousands to even many millions of kilometers. In this contribution we present the results of applying a toy model to simulate detections of such CRE at the ground level with an array of ideal detectors of different dimensions. The adopted approach allows us to assess the CRE detection feasibility for a specific configuration of a detector array. The process of initiation and propagation of an electromagnetic cascade originated from an UHE photon passing near the Sun, as well as the resultant particle distribution on ground, were simulated using the CORSIKA program with the PRESHOWER option, both modified accordingly. The studied scenario results in photons forming a cascade that extends even over tens of millions of kilometers when it arrives at the top of the Earth's atmosphere, and the photon energies span practically the whole cosmic ray energy spectrum. The topology of the signal consists of very extended CRE shapes, and the characteristic, very much elongated disk-shape of the particle distribution on ground illustrates the potential for identification of CRE of this type.

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arXiv2020

Exploring CP-violation, via heavy neutrino oscillations, in rare B meson decays at Belle II

In this article we study the rare B-meson decay via two on-shell almost-degenerate Majorana Heavy Neutrinos, into two charged leptons and two pseudoscalar mesons ($B^{\pm} \to D^0 \ell^{\pm}_1 \ell^{\pm}_2 π^{\mp}$). We consider the scenario where the heavy neutrino masses are $\sim 2$ GeV and the heavy-light mixing coefficients are $|B_{\ell N}|^2 \sim 10^{-5}$, and evaluate the possibility to measure the CP-asymmetry at Belle II. We present some realistic conditions under which the asymmetry could be detected.

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arXiv2020

Cosmic Ray Extremely Distributed Observatory

The Cosmic Ray Extremely Distributed Observatory (CREDO) is a newly formed, global collaboration dedicated to observing and studying cosmic rays (CR) and cosmic ray ensembles (CRE): groups of a minimum of two CR with a common primary interaction vertex or the same parent particle. The CREDO program embraces testing known CR and CRE scenarios, and preparing to observe unexpected physics, it is also suitable for multi-messenger and multi-mission applications. Perfectly matched to CREDO capabilities, CRE could be formed both within classical models (e.g. as products of photon-photon interactions), and exotic scenarios (e.g. as results of decay of Super Heavy Dark Matter particles). Their fronts might be significantly extended in space and time, and they might include cosmic rays of energies spanning the whole cosmic ray energy spectrum, with a footprint composed of at least two extensive air showers with correlated arrival directions and arrival times. Since CRE are mostly expected to be spread over large areas and, because of the expected wide energy range of the contributing particles, CRE detection might only be feasible when using available cosmic ray infrastructure collectively, i.e. as a globally extended network of detectors. Thus, with this review article, the CREDO Collaboration invites the astroparticle physics community to actively join or to contribute to the research dedicated to CRE, and in particular to share any cosmic ray data useful for the specific CRE detection strategies.

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arXiv2020

Search for ultra-high energy photons through preshower effect with gamma-ray telescopes: Study of CTA-North efficiency

We study the feasibility of detecting preshower initiated by ultra-high energy photons using Monte-Carlo simulations of nearly horizontal air showers for the example of the La Palma site of the Cherenkov Telescope Array. We investigate the efficiency of multivariate analysis in correctly identifying preshower events initiated by 40 EeV photons and cosmic-ray dominated background simulated in the energy range 10 TeV -- 10 EeV. The effective areas for such kind of events are also investigated and event rate predictions related to different ultra-high energy photons production models are presented. While the expected number of preshowers from diffuse emission of UHE photon for 30 hours of observation is estimated around $3.3\times10^{-5}$ based on the upper limits put by the Pierre Auger Observatory, this value is at the level of $2.7\times10^{-4}$ ($5.7\times 10^{-5}$) when considering the upper limits of the Pierre Auger Observatory (Telescope Array) on UHE photon point sources. However, UHE photon emission may undergo possible "boosting" due to gamma-ray burst, increasing the expected number of preshower events up to 0.17 and yielding a minimum required flux of $\sim 0.2$ $\mathrm{km^{-2}yr^{-1}}$ to obtain one preshower event, which is about a factor 10 higher than upper limits put by the Pierre Auger Observatory and Telescope Array (0.034 and 0.019 $\mathrm{km^{-2}yr^{-1}}$, respectively).

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arXiv2019

Measuring the heavy neutrino oscillations in rare W boson decays at the Large Hadron Collider

Majorana neutrinos in the seesaw model can have sizable mixings through which they can be produced at the Large Hadron Collider (LHC) and show a remarkable Lepton Number Violating (LNV) signature. In this article we study the LNV decay of the W boson via two almost degenerate heavy on-shell Majorana neutrinos $N_j$, into three charged leptons and a light neutrino. We consider the scenario where the heavy neutrino masses are within $1$ GeV $\leq M_N \leq 10$ GeV. We evaluated the possibility to measure a LNV oscillation process in such a scenario, namely, the modulation of the quantity $d Γ/d L$ for the process at the LHC where $W^{\pm} \to μ^{\pm} N \to μ^{\pm} τ^{\pm} W^{\mp *}$ $ \to μ^{\pm} τ^{\pm} e^{\mp} ν_e$. $L$ is the distance within the detector between the two vertices of the process. We found out some realistic conditions under which such a modulation could be probed at the LHC.

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arXiv2019

Recognition and classification of the cosmic-ray events in images captured by CMOS/CCD cameras

Muons and other ionizing radiation produced by cosmic rays and radiative decays affect CMOS/CCD sensor. When particles colliding with sensors atoms cause specific kind of noise on images recorded by cameras. We present a concept and preliminary implementation of method for recognizing those events and algorithms for image processing and their classification by machine learning. Our method consists of analyzing the shape of traces present in images recorded by a camera sensor and metadata related to an image like camera model, GPS location of camera, vertical and horizontal orientation of a camera sensor, timestamp of image acquisition, and other events recognized near-by sensors. The so created feature vectors are classified as either a muon-like event, an electron-like event or the other event, possibly noise. For muon-like events our method estimates azimuth of a muon track. Source of the data is database of CREDO (Cosmic-Ray Extremely Distributed Observatory) project and ESO (European Southern Observatory) archives. The telescope dark frames from ESO are analysed. CREDO project collected so far over 2 millions images of events from many kinds of cameralike: smartphones camera, laptop webcams and Internet of Things cameras localised around the globe.

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arXiv2019

A communication solution for portable detectors of the Cosmic Ray Extremely Distributed Observatory

The search for Cosmic-Ray Ensembles (CRE), groups of correlated cosmic rays that might be distributed over very large areas, even of the size of the planet, requires a globally spread and dense network of detectors, as proposed by the Cosmic-Ray Extremely Distributed Observatory (CREDO) Collaboration. This proposal motivates an effort towards exploring the potential of using even very much diversified detection technologies within one system, with detection units located even in hard-to-reach places, where, nevertheless, the sensors could work independently - without human intervention. For these reasons we have developed a dedicated communication solution enabling the connection of many different types of detectors, in a range of environments. The proposed data transmission system uses radio waves as an information carrier on the 169MHz frequency band in a contrast to the typical commercially used frequencies in a IoT systems (868MHz). The connectivity within the system is based on the star topology, which ensures the least energy consumption. The solution is now being prepared to being implemented using the prototype detection system based on the CosmicWatch open hardware design: a portable, pocket size, and economy particle detector using the scintillation technique. Our prototype detector is equipped with a dedicated software that integrates it with the already operational CREDO server system.

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arXiv2019

Search for ultra-high energy photons: observing the preshower effect with gamma-ray telescopes

Ultra-high energy photons constitute one of the most important pieces of the astroparticle physics problems. Their observation may provide new insight on several phenomena such as supermassive particle annihilation or the GZK effect. Because of the absence of any significant photon identification by a leading experiments such as the Pierre Auger Observatory, we consider a screening phenomenon called preshower effect which could efficiently affect ultra-high energy photon propagation. This effect is a consequence of photon interactions with the geomagnetic field and results in large electromagnetic cascade of particles several thousands kilometers above the atmosphere. This collection of particles, called cosmic-ray ensembles (CRE), may reach the atmosphere and produce the well-known air showers. In this paper we propose to use gamma-ray telescopes to look for air showers induced by CRE. Possible sources of ultra-high energy photons include the GZK effect and Super Heavy Dark Matter particles. Simulations involving the preshower effect and detectors response are performed and properties of these peculiar air showers are investigated. The use of boosted decision trees to obtain the best cosmic-ray ensemble/hadron separation, the aperture and event rate predictions for a few models of photon production are also presented.

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arXiv2019

Public engagement as a scientific tool to implement multi-messenger strategies with the Cosmic-Ray Extremely Distributed Observatory

The Cosmic-Ray Extremely Distributed Observatory (CREDO) uses the hunt for particle cascades from deep space as a vehicle for a unique "bottom-up" approach to scientific research. By engaging the non-specialist public of all ages as "citizen scientists" we create opportunities for lifelong learning for individuals as well as for cooperation and the sharing of common educational tools amongst institutions. The discoveries of these citizen scientists will feed directly into a pioneering new area of scientific research oriented on Cosmic Ray Ensembles (CRE). The detection (or non-detection) of such particle groups promises to open up a new method for exploring our universe, and a new channel on the multi-messenger stage, oriented on both astro- and geo-investigations. The opportunities this would create for cross-disciplinary research are significant and beneficial for individuals, networks of institutions and the global communities of both professional scientists and science enthusiasts.

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arXiv2019

Cosmic Ray Extremely Distributed Observatory: Status and perspectives of a global cosmic ray detection framework

The Cosmic-Ray Extremely Distributed Observatory (CREDO) is a project dedicated to global studies of extremely extended cosmic-ray phenomena, the cosmic-ray ensembles (CRE), beyond the capabilities of existing detectors and observatories. Up to date cosmic-ray research has been focused on detecting single air showers, while the search for ensembles of cosmic-rays, which may spread over a significant fraction of the Earth, is a scientific terra incognita. The key idea of CREDO is to combine existing cosmic-ray detectors (large professional arrays, educational instruments, individual detectors, such as smartphones, etc.) into a worldwide network, thus enabling a global analysis. The second goal of CREDO involves a large number of participants (citizen science!), assuring the geographical spread of the detectors and managing manpower necessary to deal with vast amount of data to search for evidence for cosmic-ray ensembles. In this paper the status and perspectives of the project are presented.

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