Related papers: Leptonic universality breaking in Upsilon decays a…
We study some possible experimental consequences of new physics on the spectrum and decays of bottomonium states below $B\bar{B}$ threshold. In addition to lepton universality breaking in Upsilon decays, large widths of pseudoscalar…
New Physics can show up in various well-known processes already studied in the Standard Model, in particular by modifying decay rates to some extent. In this work, I examine leptonic decays of $\Upsilon$ vector resonances of bottomonium…
A non-standard CP-odd Higgs boson could induce a slight (but observable) lepton universality breaking in Upsilon leptonic decays. Moreover, mixing between such a pseudoscalar Higgs boson and $\eta_b$ states might shift their mass levels,…
A non-standard light CP-odd Higgs boson could induce a slight (but observable) lepton universality breakdown in Upsilon leptonic decays. Moreover, the mixing between such a pseudoscalar Higgs and $\eta_b$ states might shift the mass levels…
Heavy quarkonium decays can be used to search for New Physics beyond the Standard Model. In particular, a light Higgs boson could induce a slight (but observable) lepton universality breaking in Upsilon decays. In fact, current experimental…
Leptonic decays of vector-states of bottomonium are analized searching for a light pseudoscalar Higgs-like neutral boson manifesting via an apparent breaking of lepton universality.
We calculate the inclusive decay width of $\Upsilon \to l^+ l^-$. Then we get the ratio $R_{\tau\mu}=\Gamma[\Upsilon \to \tau^+\tau^-]/ \Gamma[\Upsilon \to \mu^+\mu^-]$ to ${\cal{O}}(\alpha)$ and ${\cal{O}}(\alpha_s^2)$ within the Standard…
We present a proposal for detecting new physics at a B-factory running at the $\Upsilon(3S)$ resonance by testing lepton universality to the few percent level in the leptonic decays of the $\Upsilon(1S)$ and $\Upsilon(2S)$ resonances tagged…
The most recent measurements of the observables $R_{D^{(*)}}$ are in tension with the Standard Model offering hints of New Physics in $b\rightarrow c \ell \bar{\nu}_{\ell}$ transitions. Motivated by these results, in this work we present an…
Experimental measurements of the ratios $R(D^{(*)})\equiv\frac{\Gamma(B\to D^{(*)}\tau\nu)}{\Gamma(B\to D^{(*)}\ell\nu)}$ ($\ell=e,\mu$) show a $3.9\sigma$ deviation from the Standard Model prediction. In the absence of light right-handed…
We propose two different and complementary observables for singling out possible signals of physics beyond the standard model in the semi-leptonic decays $\Lambda_b \to \Lambda_c \ell{\bar \nu}_{\ell}$, both with the $\tau$ lepton and with…
psi and Upsilon decays may be used to search for light neutral spin-1 or spin-0 bosons associated with a broken extra-U(1) symmetry, local or global, acting axially on quarks and leptons, as may be present in supersymmetric theories with a…
In recent times, several hints of lepton non-universality have been observed in semileptonic $B$ meson decays, both in the charged-current ($b \to c l \bar \nu_l$) and neutral-current ($b \to s ll $) transitions. Motivated by these…
Lepton flavor universality can be tested through the ratio of semileptonic $B$ meson decays and leptonic $\Upsilon$ meson decays, with $\Upsilon \equiv \Upsilon(nS)$ ($n=1,2,3$). For the charged-current transitions $b \to…
Several measurements on $R_D, R_{D^*}$, and $R_{J/ \psi}$ by the BaBar, Belle, and LHCb experiments show significant deviations from their Standard Model (SM) predictions, which illustrate the fact that the concept of lepton flavor…
We analyze the possibility of universality violation in diagonal leptonic decays of the $Z$ boson, in the context of interfamily "see-saw" models. In a minimal extension of the Standard Model with right-handed neutrino fields, we find that…
Several scenarios beyond the minimal extension of the Standard Model still allow light non-standard Higgs bosons evading LEP bounds. We examine the mixing between a light CP-odd Higgs boson and $\eta_b$ states and its implications on a…
In this article, we assume the two nonets of scalar mesons below and above 1 GeV are all $\bar{q}q$ states, and study the semi-leptonic decays $B\to S\ell^-\bar{\nu}_{\ell}$, $B\to S\ell^+\ell^-$ and $B\to S\bar{\nu}\nu$ both in the…
We present recent tests of lepton universality as crucial probes of the Standard Model in semileptonic $B$-meson decays at Belle II. All presented analyses use a data sample collected at the $\Upsilon(4S)$ resonance by the Belle II…
Using a sample of 122 million Upsilon(3S) decays collected with the BaBar detector at the PEP-II asymmetric energy collider at the SLAC National Accelerator Laboratory, we measure the ratio…