Implications of D^{0}-D [over¯]^{0} mixing for new physics (original) (raw)

Implications of D0-D¯0 mixing for new physics

Physical Review D, 2007

We provide a comprehensive, up-to-date analysis of possible New Physics contributions to the mass difference ∆M D in D 0 -D 0 mixing. We consider the most general low energy effective Hamiltonian and include leading order QCD running of effective operators. We then explore an extensive list of possible New Physics models that can generate these operators, which we organize as including Extra Fermions, Extra Gauge Bosons, Extra Scalars, Extra Space Dimensions and Extra

Relating D0-D¯0 mixing and D0→l+l- with new physics

Physical Review D, 2009

We point out how, in certain models of New Physics, the same combination of couplings occurs in the amplitudes for both D 0 -D 0 mixing and the rare decays D 0 → ℓ + ℓ − . If the New Physics dominates and is responsible for the observed mixing, then a very simple correlation exists between the magnitudes of each; in fact the rates for the decay D 0 → ℓ + ℓ − are completely fixed by the mixing. Observation of D 0 → ℓ + ℓ − in excess of the Standard Model prediction could identify New Physics contributions to D 0 -D 0 mixing.

Observable contributions of new exotic quarks to quark mixing

Journal of High Energy Physics, 2000

Models with new vector-like quarks can produce observable quark mixing effects which are forbidden in the Standard Model. We classify all such models and write down the effective Lagrangian that results from integrating out the new quarks. We study the relations between neutral and charged currents and discuss how to distinguish among the different possibilities.

Effective description of quark mixing

Physics Letters B, 2000

We use the effective Lagrangian formalism to describe quark mixing. The new W ± , Z and H couplings generalizing the CKM matrix and the GIM mechanism fulfil relations and inequalities which allow to discriminate among different SM extensions. As a by-product we give a useful parametrization of the generalized CKM matrix. We also show that the largest possible departures from the SM predictions result from heavy exotic fermions, which can induce, for example, top FCNC large enough to be observable at future colliders.

The hunt for New Physics in the Flavour Sector with up vector-like quarks

Journal of High Energy Physics, 2012

We analyse the possible presence of New Physics (NP) in the Flavour Sector and evaluate its potential for solving the tension between the experimental values of A J/ΨK S and Br(B + → τ + ν τ) with respect to the Standard Model (SM) expectations. Updated model independent analyses, where NP contributions are allowed in B 0 d-B 0 d and B 0 s-B 0 s transitions, suggest the need of New Physics in the bd sector. A detailed analysis of recent Flavour data is then presented in the framework of a simple extension of the SM, where a Q = 2/3 vector-like isosinglet quark is added to the spectrum of the SM. Special emphasis is given to the implications of this model for correlations among various measurable quantities. We include constraints from all the relevant quark flavour sectors and give precise predictions for selected rare processes. We find important deviations from the SM in observables in the bd sector like the semileptonic asymmetry A d SL , B 0 d → µ + µ − and A s SL − A d SL. Other potential places where NP can show up include A J/ΨΦ , γ, K 0 L → π 0 νν, t → Zq and D 0 → µ + µ − among others. The experimental data favours in this model the existence of an up vector-like quark with a mass below 600(1000) GeV at 1(2) σ.

MINIMAL FLAVOUR MIXING OF QUARKS AND LEPTONS

Supersymmetry and Unification of Fundamental Interactions - Proceedings of the IX International Conference, 2002

Present situation in the flavour mixing of quarks and leptons is briefly reviewed and a new approach called the Minimal Flavour Mixing (MFM) is considered in detail. According to MFM the whole of the flavour mixing is basically determined by the physical mass generation of the first family of fermions. So, in the chiral symmetry limit when the masses of the lightest quarks, u and d, vanish, all the weak mixing angle vanish. This minimal pattern is shown to fit extremely well the already established CKM matrix elements and to give fairly distinctive predictions for the as yet poorly known ones. Remarkably, together with generically small quark mixing it also leads to the large neutrino mixing thus giving adequate solution to the solar and atmospheric neutrino oscillation problem. The possible origin of this approach in the MSSM extended by the high-scale SU(3) F chiral family symmetry is discussed.

Neutral BBB mixing from 2+1 flavor lattice-QCD: the Standard Model and beyond

We report on the status of our lattice-QCD calculation of the hadronic contribution to Bd0B_d^0Bd0 and B0sB^0_sB0s mixing, with 2+1 flavors of dynamical sea quarks. Preliminary results for hadronic mixing matrix elements are given for a basis of five four-quark, dimension-six, DeltaB=2\Delta B=2DeltaB=2 mixing operators that spans the space of all possible hadronic mixing contributions in the Standard Model and beyond. At the intermediate stage of analysis reported on in this work, our errors are competitive with published Standard Model matrix element results. For beyond the Standard Model matrix elements, this is the first unquenched calculation and the first new lattice-QCD calculation in ten years.

D^{0}-D¯^{0} mixing in the presence of isosinglet quarks

Physical Review D, 1995

We analyze ΔC=2 transitions in the framework of a minimal extension of the standard model where either a Q=2/3 or a Q=-1/3 isosinglet quark is added to the standard quark spectrum. In the case of a Q=2/3 isosinglet quark, it is shown that there is a significant region of ...