arXiv subjects

J. M. Cabarcas

Publications and source records attributed to J. M. Cabarcas.

10 recordsLinked to original sources

arXiv2023

Implications of NSI constraints from ANTARES and IceCube on a simplified $Z^\prime$ model

Recently the neutrino experiments ANTARES and IceCube have released new constraints to the non-standard neutrino interaction (NSI) parameter $ε^d_{μτ}$ (flavor off-diagonal). These new constraints are stronger than those obtained from a combination of COHERENT and neutrino oscillation data. In the light of the recent constraints from ANTARES and IceCube data on the NSI parameter $ε^d_{μτ}$, in this work, we study the new physics implications on the parameter space of a simplified $Z^\prime$ model with lepton flavor violating ($μτ$) couplings. For a $Z^\prime$ boson with a mass heavier than the $τ$ lepton, our results show that ANTARES and IceCube can provide additional constraints to such a new physics scenario with $μτ$ couplings, when compared to bounds from low-energy flavor physics. Moreover, these neutrino experiments can exclude a similar region than ATLAS experiment, showing the potential to provide complementary information to the one obtained from direct searches at the Large Hadron Collider. The impact of the expected sensitivity at DUNE and Belle II experiments is also studied.

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arXiv2023

$B$ meson anomalies within the triplet vector boson model to the light of recent measurements from LHCb

The triplet vector boson (TVB) is a simplified new physics model involving massive vector bosons transforming as a weak triplet vector. Such a model has been proposed as a combined explanation of the anomalous $b \to sμ^+μ^-$ and $b \to c τ\barν_τ$ data (the so-called $B$ meson anomalies). In this work, we carry out an updated view of the TVB model by incorporating the most recent 2022 and 2023 LHCb measurements on the lepton flavor universality ratios $R(D^{(\ast)}) = {\rm BR}(B \to D^{(\ast)}τ\barν_τ)/{\rm BR}(B \to D^{(\ast)}\ell^\prime \barν_{\ell^\prime})$, $R(Λ_c) = {\rm BR}(Λ_b \to Λ_cτ\barν_τ)/{\rm BR}(Λ_b \to Λ_cμ\barν_μ)$, and $R_{K^{(\ast)}} = {\rm BR}(B \to K^{(\ast)}μ^+μ^-)/{\rm BR}(B \to K^{(\ast)}e^+e^-)$. We perform a global fit to explore the allowed parameter space by the new data and all relevant low-energy flavor observables. Our results are confronted with the recent high-mass dilepton searches at the Large Hadron Collider (LHC). We find that for a heavy TVB mass of 1 TeV a common explanation of the $B$ meson anomalies is possible for all data with the recent LHCb measurements on $R(D^{(\ast)})$, in consistency with LHC constraints. However, this framework is in strong tension with LHC bounds when one considers all data along with the world average values (BABAR, Belle, and LHCb) on $R(D^{(\ast)})$. Future measurements will be required in order to clarify such a situation. In the end, the implications of our phenomenological analysis of the TVB model to some known flavor parametrizations are also discussed.

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arXiv2022

Singlet vector leptoquark model facing recent LHCb and BABAR measurements

Very recently the LHCb experiment released the first measurement of the ratio $R(Λ_c) = {\rm BR}(Λ_b \to Λ_cτ\barν_τ)/{\rm BR}(Λ_b \to Λ_cμ\barν_μ)$. Moreover, the BABAR experiment reported a new result of the leptonic decay ratio of Upsilon meson $Υ(3S)$, namely, $R_{Υ(3S)} = {\rm BR}(Υ(3S) \to τ^+τ^-)/{\rm BR}(Υ(3S) \to μ^+μ^-)$. Both measurements are below their corresponding Standard Model predictions (deficit), deviating by $\sim 1.1σ$ and $\sim 1.8σ$, respectively. Moreover, the LHCb recently presented the first search of the lepton flavor violating decay $B^0 \to K^{\ast 0}μ^\pmτ^\mp$. Motivated by these new data, in this work we study their impact on the phenomenology of the singlet vector leptoquark ($U_1$) model addressing the hints of lepton flavor universality violation in the semileptonic decays of $B$ mesons ($B$ meson anomalies), by carrying out a global fit analysis. In general, we found that a minimal version of the $U_1$ model with a mass of 1.8 TeV can successfully explain the $B$ meson anomalies, while being compatible with all other flavor observables and LHC bounds. Interestingly, our study shows that the new observables $R(Λ_c)$ and $R_{Υ(3S)}$ generate strong tension, leading to non-trivial effects on the global fit. Future improvements at the LHCb and Belle II experiments would help to understand their complementarity. Moreover, we also analyze the impact of the expected sensitivity on flavor observables at Belle II to provide a further test of the $U_1$ model. Finally, we study the minimal assumptions under which the $U_1$ model could, in addition, provide a combined explanation of the anomalous magnetic moment of the muon.

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arXiv2013

Charged lepton mixing processes in 331 Models

Processes $τ\rightarrow lγ$, $τ\rightarrow lll$ with $l= e,μ$ and $μ(τ) \to e (μ) γ$ are evaluated in the framework of a model based on the extended symmetry gauge $SU(3)_c \otimes SU(3)_L \otimes U(1)_Y$ with a leptonic sector consistent of five triplets. Lepton flavor violating processes are allowed at tree level in this model through the new $Z'$ gauge boson. We obtained bounds for the mixing angles in the leptonic sector of the model, considering the experimental measurements of the processes from the BELLE and the BABAR collaborations.

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arXiv2013

Lepton Flavor Violation processes in 331 Models

Models based on the extended symmetry gauge $SU(3)_c \otimes SU(3)_L \otimes U(1)_Y$ can be build up with a leptonic sector consistent of five triplets in different $SU(3)_L$ representations where additional heavy fermions are included. Some of these models present flavor changing neutral currents in the leptonic sector which are mediated through the $Z'$ boson. One of these models is studied using the measurements of lepton flavor violation processes such as $τ\rightarrow lll$ with $l= e,μ$ and $μ(τ) \to e (μ) γ$.

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arXiv2013

Electric charge quantization in SU(3)XSU(4)XU(1) models

We obtain electric charge quantization in the context of models based on the gauge symmetry group SU(3) X SU(4) X U(1). The gauge models studied include three families to cancel out anomalies and a set of scalar fields to break spontaneously the symmetry. To show the electric charge quantization, we use clasical symmetry conditions and quantum quiral anomaly conditions.

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arXiv2011

Sources of FCNC in $SU(3)_C \otimes SU(3)_L \otimes U(1)_X$ models

There are different models based on the gauge symmetry $SU(3)_C \otimes SU(3)_L \otimes U(1)_X$ (331) some of them includes exotic particles and others are constructed without any exotic charges assigned to the fermionic spectrum. Each model build up on 331 symmetry has its own interesting properties according to the representations of the gauge group used for the fermionic spectrum; that is the main reason to explore and identify the possible sources of flavor changing neutral currents and lepton flavor violation at tree level.

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arXiv2010

Flavor changing neutral currents in 331 models

We carry out a general analysis of tree level flavor changing neutral currents in the context of 331 models, considering arbitrary quark and gauge boson mixing matrices. The results are applied to definite textures of quark mass matrices, and differences between various 331 scenarios are pointed out.

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arXiv2008

Phenomenological aspects of the exotic $T$ quark in 331 models

In the context of 331 models we analyze the phenomenology of exotic $T$ quarks with electric charge 2/3. We establish bounds for the corresponding masses and mixing angles and study the decay modes $T\to bW$, $tZ$ and $qH$. It is found that the decays into scalars are strongly dependent on the model parameters, and can be the dominant ones in a scenario with approximate flavor symmetry.

hep-ph↗

arXiv2008

Constraints on economical 331 models from mixing of K, Bd and Bs neutral mesons

We analyze the effect of flavor changing neutral currents within 331 models. In particular, we concentrate in the so-called "economical" models, which have a minimal scalar sector. Taking into account the experimental measurements of observables related to neutral K and B meson mixing, we study the resulting bounds for angles and phases in the mixing matrix for the down quark sector, and the mass and mixing parameters related to the new Z' gauge boson.

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