Browsing by Author "Rojas, Eduardo"
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Item B meson anomalies within the triplet vector boson model to the light of recent measurements from LHCb(American Physical Society, 2024) Cabarcas J.M.; Muñoz J.H.; Quintero Poveda, Néstor; Rojas, EduardoThe 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→sμ+μ- and b→cτν¯τ data (the so-called B meson anomalies). In this work, we carry out a revamped view of the TVB model by incorporating the most recent 2022 and 2023 LHCb measurements on the lepton-flavor universality ratios R(D(∗))=BR(B→D(∗)τν¯τ)/BR(B→D(∗)ℓ′ν¯ℓ′), R(Λc)=BR(Λb→Λcτν¯τ)/BR(Λb→Λcμν¯μ), and RK(∗)=BR(B→K(∗)μ+μ-)/BR(B→K(∗)e+e-). We perform a global fit to explore the allowed parameter space by the new data and all relevant low-energy flavor observables including the recent experimental progress from Belle, Belle II, and LHCb. Our results are confronted with the recent high-mass dilepton searches at the 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(∗)), consistent with LHC constraints. However, this framework is in strong tension with LHC bounds when one considers all data along with the world average values reported by the Heavy Flavor Averaging Group (BABAR, Belle, and LHCb) on R(D(∗)). Future measurements will be required in order to clarify such a situation.Item Charged current b →cτ ν τ anomalies in a general W′ boson scenario CHARGED CURRENT B →cτ ν τ ... GÓMEZ, QUINTERO, and ROJAS(American Physical Society, 2019-11-20) Gómez, John D.; Quintero, Nestor; Rojas, EduardoVery recent experimental information obtained from the Belle experiment, along with that accumulated by the BABAR and LHCb experiments, has shown the existence of anomalies in the ratios R(D) and R(D∗) associated with the charged-current transition b→cτντ. Although the Belle measurements are in agreement with standard model (SM) predictions, the new experimental world averages still exhibit a tension. In addition, the D∗ longitudinal polarization FL(D∗) related with the channel B→D∗τντ observed by the Belle Collaboration and the ratio R(J/ψ) measured by the LHCb Collaboration also show discrepancies with their corresponding SM estimations. We present a model-independent study based on the most general effective Lagrangian that yields a tree-level effective contribution to the transition b→cτντ induced by a general W′ boson. Instead of considering any specific new physics (NP) realization, we perform an analysis by considering all of the different chiral charges to the charm-bottom and τ-ντ interaction terms with a charged W′ boson that explain the anomalies. We present a phenomenological study of parameter space allowed by the new experimental b→cτντ data and with the mono-tau signature pp→τhX+MET at the LHC. For comparison, we include some of the W′ boson NP realizations that have already been studied in the literature. © 2019 authors. Published by the American Physical Society.