PPC 2023: XVI International Conference on Interactions between Particle Physics and Cosmology

Lepton Universality Violations by Kaluza-Klein Neutrinos in b→cτν Transition

Not scheduled

20m

305 (IBS Science and Culture Center)

Flavor Physics Parallel: BSM Theories and Flavor Physics

Speaker

Janus Aban (National Taiwan Normal University (NTNU))

Description

A new world average calculated using the data from Belle, BaBar, and LHCb collaborations in 2022 yielded $R_D^{ave}=0.358\pm 0.028$ and $R_{D^{\ast }}^{ave}=0.285\pm 0.013$. The combined new world average has the largest pull of $4.1\sigma$ from SM predictions after incorporating all the recent developments in $B\to D^{(\ast )}$ that include form factors for predicting $R_{D^{(\ast )}}^{SM}$. However, even if we include the most recent results from LHCb using the data collected in 2015 and 2016 the global picture of the most updated combined world average does not change. In this paper, we show how the anomaly can be explained by the cumulative effects of three right-handed neutrinos Kaluza-Klein (KK) modes propagating in extra dimensions. In the presence of only two extra dimensions, the neutrino bounds for the size of extra dimensions are $R<0.2\mu m$ and $R<0.1\mu m$, for NO and IO, respectively. The lower limits for the fundamental scale $M_F$ must be 110 TeV and 128 TeV for NO and IO, respectively, to satisfy these bounds. With Yukawa coupling strength $h_{\tau }=5$, the predictions in KK model for $R_D$ and $R_{D^{\ast }}$ are 0.303 (0.301) and 0.258 (0.257), for NO and IO, respectively.