Determining for the first time the Darwin operator contribution for the non-leptonic charm-quark decays and using new non-perturbative results for the matrix elements of ∆C = 0 four-quark operators, including eye-contractions, we present a comprehensive study of the lifetimes of charmed mesons and inclusive semileptonic decay rates as well as the ratios, within the framework of the Heavy Quark Expansion (HQE). We find good agreement with experiment for the ratio τ (D + )/τ (D 0 ), for the total D + s -meson decay rate, for the semileptonic rates of all three mesons D 0 , D + and D + s , and for the semileptonic ratio Γ D + sl /Γ D 0 sl . The total decay rates of the D 0 and D + mesons are underestimated in our HQE approach and we suspect that this is due to missing higher-order QCD corrections to the free charm quark decay and the Pauli interference contribution. For the SU (3) F breaking ratios τ (D + s )/τ (D 0 ) and Γ D + s sl /Γ D 0 sl our predictions lie closer to one than experiment. This might originate from the poor knowledge of the non-perturbative parameters µ 2 G , µ 2 π and ρ 3 D in the D 0 and D + s systems. These parameters could be determined by experimental studies of the moments of inclusive semileptonic D meson decays.

We calculate the amplitude of the rare flavour-changing neutral-current decay B → π + − at large recoil of the pion. The nonlocal contributions in which the weak effective operators are combined with the electromagnetic lepton-pair emission are systematically taken into account. These amplitudes are calculated at off-shell values of the lepton-pair mass squared, q 2 < 0, employing the operator-product expansion, QCD factorization and light-cone sum rules. The results are fitted to hadronic dispersion relations in q 2 , including the intermediate vector meson contributions. The dispersion relations are then used in the physical region q 2 > 0. Our main result is the process-dependent addition ∆C (Bπ) 9 arXiv:1506.07760v3 [hep-ph] 8 Oct 2015The first measurement of the B + → π + µ + µ − decay by the LHCb Collaboration [1] paved the way for more detailed measurements of b → d + − decays. These results will complement the available data on b → s + − decays, providing new important insight in the dynamics of flavour-changing neutral-current (FCNC) transitions in Standard Model (SM) and beyond.One important feature of exclusive b → d + − decays is a non-vanishing direct CP-asymmetry. In Standard Model (SM) this effect is caused by the interference between the dominant short-distance contributions of semileptonic and magnetic dipole operators and the contributions of other effective operators accompanied by the electromagnetic lepton-pair emission. The amplitudes of the latter contributions are process-dependent, and are defined as hadronic matrix elements of nonlocal operator products. Importantly, the parts of the exclusive b → d + − decay amplitudes proportional to λ u ≡ V ub V * ud and λ c ≡ V cb V * cd are of the same order of Cabibbo suppression and, in addition to a relative CKM phase, have different strong phases originating from the nonlocal amplitudes. The main goal of this work is to calculate the hadronic matrix elements of nonlocal contributions to B → π + − at large recoil of the pion, that is, at small and intermediate lepton-pair mass, q 2 m 2 B . An advanced theoretical description of the exclusive semileptonic FCNC decays was developed on the basis of QCD factorization (QCDF) approach [2], applied first to the decays B → K ( * ) + − in Ref. [3] and to B → ρ + − in Ref. [4]; see also further applications to B → K + − [5], and to B → π + − [6]. An approach combining QCD light-cone sum rules with QCDF at q 2 > 0 for B → K ( * ) + − was used in [7].In QCDF, the nonlocal effects in these decays are described in terms of hardscattering quark-gluon amplitudes with virtual photon emission, convoluted with light-cone distribution amplitudes (DAs) of the initial B meson and final light meson. Soft gluons, responsible for the onset of long-distance effects in the channel of the electromagnetic current, including vector resonance formation and nonfactorizable interactions with initial and final meson remain beyond the reach of QCDF. Hence, these contributions have to be kept small, protected by their power suppres...

In light of the recent LHCb observation of CP violation in the charm sector, we review standard model (SM) predictions in the charm sector and in particular for ∆A CP. We get as an upper bound in the SM |∆A SM CP | ≤ 3.6 × 10 −4 , which can be compared to the measurement of ∆A LHCb2019 CP = (−15.4 ± 2.9) × 10 −4. We discuss resolving this tension within an extension of the SM that includes a flavour violating Z that couples only toss andcu. We show that for masses below 80 GeV and flavour violating coupling of the order of 10 −4 , this model can successfully resolve the tension and avoid constraints from dijet searches, D 0 − D 0 mixing and measurements of the Z width.

We perform a comprehensive study of the allowed parameter space of the Two Higgs Doublet Model of Type II (2HDM-II). Using the theoretical framework flavio we combine the most recent flavour, collider and electroweak precision observables with theoretical constraints to obtain bounds on the mass spectrum of the theory. In particular we find that the 2HDM-II fits the data slightly better than the Standard Model (SM) with best fit values of the heavy Higgs masses around 2 TeV and a value of tan β ≈ 4. Moreover, we conclude that the wrong-sign limit is disfavoured by Higgs signal strengths and excluded by the global fit by more than five standard deviations and potential deviations from the alignment limit can only be tiny. Finally we test the consequences of our study on electroweak baryogenesis via the program package BSMPT and we find that the allowed parameter space strongly discourages a strong first order phase transition within the 2HDM-II.