Related papers: High $p_T$ correlated tests of lepton universality…
We explore the sensitivity to new physics (NP) in the associated production of top-quarks with leptons $pp \to t \bar t \ell^+ \ell^-$, which leads to the multi-leptons signals $pp \to n \ell + {\tt jets} + \not\!\! E_T$, where $n = 2,3,4$.…
The associated production of a single-top with opposite-sign same-flavor (OSSF) di-leptons, $pp \to t \ell^+ \ell^-$ and $ pp \to t \ell^+ \ell^- + j$ ($j=$light jet), can lead to striking tri-lepton $pp \to \ell^\prime \ell^+ \ell^- + X$…
We propose a novel strategy to test lepton flavor universality (LFU) in top decays, applicable to top pair production at colliders. Our proposal exploits information in kinematic distributions and mostly hinges on data-driven techniques,…
The Standard Model of particle physics predicts that charged leptons have the same electroweak interaction strength. This symmetry, called lepton flavour universality, was found to hold in a wide range of particle decays. One observable…
$SU(2)_L$-invariance links charged dilepton and dineutrino couplings. Phenomenological implications are worked out for flavor changing neutral currents involving strange, charm, beauty and top quark transitions in a model-independent way.…
We investigate the impact of flavour-conserving, non-universal quark-lepton contact interactions on the dilepton invariant mass distribution in $p~p \to \ell^+ \ell^-$ processes at the LHC. After recasting the recent ATLAS search performed…
In the Standard Model of particle physics, charged leptons of different flavour couple to the electroweak force carriers with the same interaction strength. This property, known as lepton flavour universality, was found to be consistent…
As one of the hypothetical principles in the Standard Model (SM), lepton flavor universality (LFU) should be tested with a precision as high as possible such that the physics violating this principle can be fully examined. The run of $Z$…
We present a study of the rare baryonic decay $\Lambda_b \to \Lambda \tau^+ \tau^-$ as a probe of new physics (NP) coupled preferentially to third-generation fermions. Within the Standard Model, we evaluate the branching ratio and the…
A search for nonresonant new physics phenomena in high-mass dilepton events produced in association with b-tagged jets is performed using proton-proton collision data collected in 2016$-$2018 by the CMS experiment at the CERN LHC, at a…
We study the impact of contact interactions involving two leptons (electrons or muons) and two $b$-quarks ($b \bar{b} \ell^+ \ell^-$) on the high-mass di-lepton region at the LHC. We consider different selections of $b$-tagged jet…
We confront the indications of lepton flavor universality (LFU) violation observed in semi-tauonic $B$ meson decays with new physics (NP) searches using high $p_T$ tau leptons at the LHC. Using effective field theory arguments we correlate…
Recently hints of lepton flavor non-universality emerged in the BaBar and LHCb experiments. In this paper we propose tests of lepton universality in $\nu_{\tau}$ scattering. To parametrize the new physics we adopt an effective Lagrangian…
We present an overview of searches fo violation of lepton flavor universality with focus on low energy precision probes using pions, kaons, tau leptons, and nuclear beta decays. The current experimental results are reviewed, the theoretical…
Measurements of $t\bar{t}\ell^{+}\ell^{-}$ production in the region of high dilepton invariant mass with effective field theory (EFT) interpretations are presented. They are performed using final states with three isolated leptons…
We present a global analysis of lepton-flavor-specific operators in the Standard Model Effective Field Theory (SMEFT), combining data from collider and flavor physics experiments. We systematically explore various lepton-flavor scenarios,…
Semileptonic charged current $b \to c l^- \overline{\nu}_l$ decays offer a compelling avenue to probe the limits of the Standard Model and investigate lepton flavor universality (LFU). While the SM maintains flavor universality, new physics…
We construct an expression for a general lepton flavour universality (LFU) ratio, $R_{X}$, in $b\to s l^+ l^-$ decays in terms of a series of hadronic quantities which can be treated as nuisance parameters. This expression allows to include…
We analyze $K\to \pi \nu\bar \nu$ rates in a model with a TeV-scale leptoquark addressing $B$-meson anomalies, based on the flavor non-universal 4321 gauge group featuring third-generation quark-lepton unification. We show that, together…
The Standard Model predicts that the electroweak couplings to the three charged leptons are identical. However, in the last decade, experimental measurements have suggested that semileptonic processes involving taus could have a slightly…