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F. S. Queiroz

Publications and source records attributed to F. S. Queiroz.

At least 19 recordsLinked to original sources

Search for Light Dark Sectors Using Electron-Photon Collisions

The dark photon is a new gauge boson that naturally arises in many beyond the Standard Model theoretical models, featuring interactions that resemble quantum electrodynamics. Due to this feature, it is often considered the portal between dark and visible sectors. For this reason, it has become the target of many experimental searches worldwide. In this work, we propose a search for dark photons based on the Inverse Compton scattering, $γe^- \rightarrow A^\prime e^-$, to be conducted at electron accelerators. In this setup, photons from a laser source would impinge on the accelerated electron beam, producing a dark photon in the final state. We propose an experimental setup to take advantage of the photon counting technique, and we derive the projected sensitivity by considering the energy of the incident photon to be about 1 eV and an electron beam of 3 GeV. We show that this experimental setup could cover an unexplored region of parameter space and constitute a promising probe for dark sectors in the future.

hep-ph

Brazilian Report on Dark Matter 2024

One of the key scientific objectives for the next decade is to uncover the nature of dark matter (DM). We should continue prioritizing targets such as weakly-interacting massive particles (WIMPs), Axions, and other low-mass dark matter candidates to improve our chances of achieving it. A varied and ongoing portfolio of experiments spanning different scales and detection methods is essential to maximize our chances of discovering its composition. This report paper provides an updated overview of the Brazilian community's activities in dark matter and dark sector physics over the past years with a view for the future. It underscores the ongoing need for financial support for Brazilian groups actively engaged in experimental research to sustain the Brazilian involvement in the global search for dark matter particles

hep-ph

Updated Big Bang Nucleosynthesis Bounds on Long-lived Particles from Dark Sectors

As electromagnetic showers may alter the abundance of Helium, Lithium, and Deuterium, we can place severe constraints on the lifetime and amount of electromagnetic energy injected by long-lived particles. Considering up-to-date measurements of the light element abundances that point to $Y_p=0.245\pm 0.003$, $({\rm D/H})= (2.527\pm 0.03)\times 10^{-5}$, and the baryon-to-photon ratio obtained from the Cosmic Microwave Background data, $η=6.104 \times 10^{-10}$, we derive upper limits on the fraction of electromagnetic energy produced by long-lived particles. Our findings apply to decaying dark matter models, long-lived gravitinos, and other non-thermal processes that occurred in the early universe between $10^2-10^{10}$ seconds.

hep-ph

Update of the Brazilian Participation in the Next-Generation Collider Experiments

This proposal outlines the future plans of the Brazilian High-Energy Physics (HEP) community for upcoming collider experiments. With the construction of new particle colliders on the horizon and the ongoing operation of the High-Luminosity LHC, several research groups in Brazil have put forward technical proposals, covering both hardware and software contributions, as part of the Brazilian contribution to the global effort. The primary goal remains to foster a unified effort within the Brazilian HEP community, optimizing resources and expertise to deliver a high-impact contribution to the international HEP community.

hep-ex

Vector-Like Fermions and Inert Scalar Solutions to the Muon g-2 Anomaly and collider probes at the HL-LHC and FCC-hh

We examine simple models with an inert scalar and vector-like leptons that can explain the recent $g_μ-2$ measurement reported at FNAL. Prompted by this exciting result, we explore the viability of a simple interpretation and determine the required parameters. We also embed these models within a 3-3-1 gauge extension of the Standard Model (SM), showing that the $g_μ-2$ anomaly can be accommodated in agreement with current data. We also show how our theory can be tested at high-energy colliders such as HL-LHC and FCC-hh.

hep-ph

On the Role of LHC and HL-LHC in Constraining Flavor Changing Neutral Currents

The Standard Model (SM) has no flavor-changing neutral current (FCNC) processes at the tree level. Therefore, processes featuring FCNC in new physics are tightly constrained by data. Typically, the lower bounds on the scale of new physics obtained from $K-\bar{K}$ or $B-\bar{B}$ mixing lie well above 10 TeV, surpassing the reach of current and future colliders. In this paper, we demonstrate, using a specific Z' model, that such limits can be severely weakened by applying certain parametrizations of the quark mixing matrices with no prejudice while maintaining the CKM matrix in agreement with the data. We highlight the valuable role of the often-overlooked D0 mixing in deriving robust FCNC limits and show that the LHC and HL-LHC are promising probes for flavor-changing interactions mediated by a Z' boson.

hep-ph

Constraints on Hidden Sectors Using Rare Kaon Decays

The charged Kaon meson ($K^+$) features several hadronic decay modes, but the most relevant contribution to its decay width stems from the leptonic decay $K^+ \rightarrow μ^+ ν_μ$. Given the precision acquired on the rare decay mode $K^+ \rightarrow μ^+ ν_μ+ X$, one can use the data to set constraints on sub-GeV hidden sectors featuring light species that could contribute to it. Light gauge bosons that couple to muons could give rise to sizeable contributions. In this work, we will use data from the $K^+ \rightarrow μ^+ν_μ l^+l^-$, and $K^+ \rightarrow μ^+ ν_μ ν\barν$ decays to place limits on light vector bosons present in Two Higgs Doublet Models (2HDM) augmented by an Abelian gauge symmetry, 2HDM-$U(1)_X$. We put our findings into perpective with collider bounds, atomic parity violation, neutrino-electron scattering, and polarized electron scattering probes to show that rare Kaon decays provide competitive bounds in the sub-GeV mass range for different values of $\tanβ$.

hep-ph

Searching for a Leptophilic Z' and a 3-3-1 symmetry at CLIC

We derive the discovery potential of a leptophilic Z', and a Z' rising from a $SU(3) \times SU(3)_L \times U(1)_N$ symmetry at the Compact Linear Collider (CLIC), which is planned to host $e^+e^-$ collisions with 3 TeV center-of-mass energy. We perform an optimized selection cut strategy on the transverse momentum, pseudorapidity, and invariant mass of the dileptons in order to enhance the collider sensitivity. We find that CLIC can potentially reach a $5σ$ signal of a $1-3$~TeV leptophilic Z' with less than $1fb^{-1}$ of integrated luminosity. As for the Z' belonging to a 3-3-1 symmetry, CLIC will offer a complementary probe with the potential to impose $M_{Z^\prime} > 3$~TeV with $\mathcal{L}=2fb^{-1}$.

hep-ph

Toward a search for axion-like particles at the LNLS

Axion-Like Particles (ALPs) appear in several dark sector studies. They have gained increasing attention from the theoretical and experimental community. In this work, we propose the first search for ALPs to be conducted at the Brazilian Synchrotron Light Laboratory (LNLS). In this work, we derive the projected sensitivity of a proposed experiment for the production of ALPs via the channel $e^+ e^- \to a γ$. We show that such an experiment could probe ALP masses between $1-55\,\mbox{MeV}$, and ALP-electron couplings down to $g_{aee}=2-6\times10^{-4} \,\mbox{GeV}^{-1}$ depending on the energy beam, thickness of the target, and background assumptions. Therefore, this quest would cover an unexplored region of parameter space for experiments of this kind, constitute a promising probe for dark sectors, and potentially become the first Latin-American dark sector detector.

hep-ph

Flavor changing interactions confronted with meson mixing and hadron colliders

We have witnessed some flavor anomalies appeared in the past years, and explanations based on extended gauge sectors are among the most popular solutions. These beyond the Standard Model (SM) theories often assume flavor changing interactions mediated by new vector bosons, but at the same time they could yield deviations from the SM in the $K^{0}-\bar{K}^{0}$, $D^{0}-\bar{D}^{0}$, $B^0_d-\bar{B^0}_d$ and $B^0_s-\bar{B^0}_s$ meson systems. Using up-to-date data on the mass difference of these meson systems, we derive lower mass bounds on vector mediators for two different parametrizations of the quark mixing matrices. Focusing on a well-motivated model, based on the fundamental representation of the weak SU(3) gauge group, we put our findings into perspective with current and future hadron colliders to conclude that meson mass systems can give rise to bounds much more stringent than those from high-energy colliders and that recent new physics interpretations of the $b\rightarrow s$ and $R(D^{\ast})$ anomalies are disfavored.

hep-ph

Resonant Lepton-Gluon Collisions at the Large Hadron Collider

We study the lepton-induced resonant production of color-adjoint leptons (leptogluons) at the LHC employing the lepton parton density function of the proton. We demonstrate that this production mechanism can be useful to extend the LHC ability to search for leptogluons beyond purely quark/gluon initiated production processes up to ~ 3.5 TeV leptogluon masses and O(1) TeV compositeness scales. Discerning leptogluons from scalar and vector leptoquarks is also possible in this channel, given a data sample containing the order of 100 signal events. We argue that the resonant channel can be combined with leptogluon pair and associated leptogluon-lepton productions to boost exclusion limits and discovery prospects at the LHC.

hep-ph

Constraining 3-3-1 Models at the LHC and Future Hadron Colliders

In this work, we derive lower mass bounds on the Z' gauge boson based on the dilepton data from LHC with 13 TeV of center-of-mass energy, and forecast the sensitivity of the High-Luminosity-LHC with $L=3000 fb^{-1}$, the High-Energy LHC with $\sqrt{s}=27$ TeV, and also at the Future Circular Collider with $\sqrt{s}=100$ TeV. We take into account the presence of exotic and invisible decays of the Z' gauge boson to find a more conservative and robust limit, different from previous studies. We investigate the impact of these new decays channels for several benchmark models in the scope of two different 3-3-1 models. We found that in the most constraining cases, LHC with $139fb^{-1}$ can impose $m_{Z^{\prime}}>4$ TeV. Moreover, we forecast HL-LHC, HE-LHC, and FCC bounds that yield $m_{Z^{\prime}}>5.8$ TeV, $m_{Z^{\prime}}>9.9$ TeV, and $m_{Z^{\prime}}> 27$ TeV, respectively. Lastly, put our findings into perspective with dark matter searches to show the region of parameter space where a dark matter candidate with the right relic density is possible.

hep-ph

Search for Dark Sector by Repurposing the UVX Brazilian Synchrotron

We propose the first Search for Dark Sector at the Brazilian Synchrotron Light Laboratory, site of Sirius, a fourth-generation storage ring. We show that UVX, Sirius predecessor, can be a promising dark sector detector, SeDS, with unprecedented sensitivity. The search is based on a 1-3 GeV positron beam impinging on a thick target leading the $e^+ e^- \rightarrow γA'$ reaction, followed by a missing mass spectrum event reconstruction. We show that SeDS has the potential to probe dark photons with masses up to 55 MeV and kinetic coupling down to $ε\sim 10^{-14}$ within months of data. Therefore, such experiment would constitute the best dark photon probe worldwide in the 10-55 MeV mass range, being able to probe an unexplored region of parameter space.

hep-ph

Right-handed Neutrino Dark Matter, Neutrino Masses, and non-Standard Cosmology in a 2HDM

We explore the dark matter phenomenology of a weak-scale right-handed neutrino in the context of a Two Higgs Doublet Model. The expected signal at direct detection experiments is different from the usual spin-independent and spin-dependent classification since the scattering with quarks depends on the dark matter spin. The dark matter relic density is set by thermal freeze-out and in the presence of non-standard cosmology, where an Abelian gauge symmetry is key for the dark matter production mechanism. We show that such symmetry allows us to simultaneously address neutrino masses and the flavor problem present in general Two Higgs Doublet Model constructions. Lastly, we outline the region of parameter space that obeys collider, perturbative unitarity and direct detection constraints.

hep-ph

Vector-Like Leptons and Inert Scalar Triplet: Lepton Flavor Violation, $g-2$ and Collider Searches

We investigate simplified models involving an inert scalar triplet and vector-like leptons that can account for the muon $g-2$ anomaly. These simplified scenarios are embedded in a model that features W' and Z' bosons, which are subject to stringent collider bounds. The constraints coming from the muon $g-2$ anomaly are put into perspective with collider bounds, as well as bounds coming from lepton flavor violation searches. The region of parameter space that explains the $g-2$ anomaly is shown to be within reach of lepton flavor violation probes and future colliders such as HL-LHC and HE-LHC.

hep-ph

Brazilian Community Report on Dark Matter

This white paper summarizes the activities of the Brazilian community concerning dark matter physics and highlights the importance of financial support to Brazilian groups that are deeply involved in experimental endeavours. The flagships of the Brazilian dark matter program are the Cherenkov Telescope Array, DARKSIDE, SBN and LHC experiments, but we emphasize that smaller experiments such as DAMIC and CONNIE constitute important probes to dark sectors as well and should receive special attention. Small experimental projects showing the potential to probe new regions of parameter space of dark matter models are encouraged. On the theoretical and phenomenological side, some groups are devoted to astrophysical aspects such as the dark matter density profile while others explore the signature of dark matter models at colliders, direct and indirect detection experiments. In summary, the Brazilian dark matter community that was born not long ago has grown tremendously in the past years and now plays an important role in the hunt for a dark matter particle.

hep-ph

Novel sources of Flavor Changed Neutral Currents in the $331_{RHN}$ model

Sources of Flavor Changed Neutral Currents (FCNC) naturally emerge from a well motivated framework called 3-3-1 with right-handed neutrinos model, $331_{RHN}$ for short, mediated by an extra neutral gauge boson $Z^{\prime}$. Following previous works we calculate these sources and in addition we derive new ones coming from CP-even and -odd neutral scalars which appear due to their non-diagonal interactions with the physical standard quarks. Furthermore we show that bounds related to the neutral mesons systems $K_L-K_S$ and $D_1^0 - D_2^0$ may be significantly strengthened in the presence of these new interactions allowing us to infer stronger constraints on the parameter space of the model.

hep-ph

Probing 3-3-1 Models in Diphoton Higgs Boson Decay

We investigate the Higgs boson production through gluon fusion and its decay into two photons at the LHC in the context of the minimal 3-3-1 model and its alternative version with exotic leptons. The diphoton Higgs decay channel presents an enhanced signal in this model compared to the Standard Model due to the presence of an extra singly charged vector boson and a doubly charged one. Prospects for the Higgs boson detection at 7 TeV center-of-mass energy with up to 10 fb$^{-1}$ are presented. Our results suggest that a Higgs boson from these 3-3-1 models can potentially explain the small excess for $m_H\leq 145$ GeV observed at the LHC. Otherwise, if this excess reveals to be only a statistical fluctuation of the Standard Model backgrounds severe constraints can be put on these models.

hep-ph