相关论文: New physics in $b\to s\ell\ell$ transitions at one…
While the LHC has not directly observed any new particle so far, experimental results from LHCb, BELLE and BABAR point towards the violation of lepton flavour universality in $b\to s\ell^{+}\ell^{-}$ and $b\to c\ell\nu$. In this context,…
Data in $B$-meson decays indicate violations of lepton flavour universality, thereby raising the question about such phenomena in the charm sector. We perform a model-independent analysis of NP contributions in (semi)-leptonic decays of…
There are theoretical and phenomenological motivations that there may exist additional heavy Z' bosons with family non-universal couplings. Flavor mixing in the quark and lepton sectors will then lead to flavor changing couplings of the…
A global fit to quark flavour-physics data disfavours the Standard Model with 3.6 standard deviations and points towards new CP-violating physics in meson-antimeson mixing amplitudes. Tevatron data call for a new Bs-Bs-bar mixing phase and…
Leptoquarks are prime candidates for explaining the intriguing hints for lepton flavour universality violation. In particular, the $SU(2)_L$ doublet of scalar leptoquarks $S_2$ is capable of providing an explanation for the tensions between…
We analyze the class of models with an extra $U(1)_X$ gauge symmetry that can account for the $b \to s \ell \ell$ anomalies by modifying the Wilson coefficients $C_{9e}$ and $C_{9\mu}$ from their standard model values. At the same time,…
The loop level flavor changing neutral currents transitions of the $\Sigma_{b}\to n l^+l^-$ and $\Sigma_{c}\to p l^+l^-$ are investigated in full QCD and heavy quark effective theory in the light cone QCD sum rules approach. Using the most…
Recent measurements have revealed a number of intriguing deviations from the Standard Model predictions in $B$ meson decays, in particular in observables testing lepton flavour universality. We review their experimental status and…
A new process with the lepton flavor violation (LFV) is presented in the setup for LHC. The LFV is induced by the one-loop effect through Higgs bosons in the framework of the type-III two Higgs doublet model. It is demonstrated that the…
We give a comprehensive account of the flavour physics of Beyond-Standard-Model (BSM) effects in $b \to c \bar{c} s$ transitions, considering the full set of 20 four-quark operators. We discuss the leading-order structure of their RG mixing…
A novel approach to study electroweak physics at one-loop level in generic ${\rm SU(2)_L \times U(1)_Y}$ theories is introduced. It separates the 1-loop corrections into two pieces: process specific ones from vertex and box contributions,…
The gauge interactions of any supersymmetric extension of the standard model involve new flavor mixing matrices. The assumptions involved in the construction of minimal supersymmetric models, both $SU(3) \times SU(2) \times U(1)$ and grand…
Upcoming experiments will improve the reach for the lepton flavour violating (LFV) processes $\mu \to e \gamma$, $\mu \to e \bar{e} e$ and $\mu A \to e A$ by orders of magnitude. We investigate whether this upcoming data could rule out some…
We explored the possibility that Higgs coupling to new physics violates flavor universality. In particular, we parameterize such models with dimension-six effective operators which modify the coupling between the first generation quarks,…
We study the implication of the recent $\Delta m_s$ measurement on $ b \to s \bar{q} q$ transitions. We show that it is possible, in the presence of a flavour symmetry, that the phase in $B_s$ mixing may be unobservable even with new CP odd…
We interpret the recent hints for lepton flavor universality violation in rare $B$ meson decays. Based on a model-independent effective Hamiltonian approach, we determine regions of new physics parameter space that give a good description…
We show that, unlike mass matrices, the fermionic gauge currents of the Standard Model exhibit, at the quantum level, remarkable SU(2)_f flavor properties at the observed values of the mixing angles. They accommodate all measured mixing for…
We derive a condition the short distance coefficients governing $b\to (s,d)\ell^+\ell^-$ transitions must satisfy in order for the forward-backward asymmetry to vanish in the exclusive modes $B\to (K^*,\rho)\ell^+\ell^-$. This relation,…
We study a non-universal flavor scenario at the level of the Standard Model Effective Field Theory, according to which the matrix of Wilson coefficients $c_{uW}$ of an up-type electroweak quark dipole operator is aligned with the up-type…
We constrain the flavor structure of Wilson coefficients in the Standard Model Effective Field Theory (SMEFT) from data. In the SMEFT, new physics effects in couplings of up-type and down-type quarks are related through the…