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 ...

mixing and new physics: General considerations and constraints on the MSSM

Physics Letters B, 2007

Combining the recent experimental evidence of D-D mixing, we extract model-independent information on the mixing amplitude and on its CP-violating phase. Using this information, we present new constraints on the flavour structure of up-type squark mass matrices in supersymmetric extensions of the Standard Model.

Constraints on New Physics from the Quark Mixing Unitarity Triangle

Physical Review Letters, 2006

The status of the Unitarity Triangle beyond the Standard Model including the most recent results on ∆ms, on dilepton asymmetries and on width differences is presented. Even allowing for general New Physics loop contributions the Unitarity Triangle must be very close to the Standard Model result. With the new measurements from the Tevatron, we obtain for the first time a significant constraint on New Physics in the Bs sector. We present the allowed ranges of New Physics contributions to ∆F = 2 processes, and of the time-dependent CP asymmetry in Bs → J/Ψφ decays.

B meson mixing and low-energy dynamical flavour

Physics Letters B, 1990

The low-energy quantum flavour dynamics offered by the local horizontal symmetry SU ( 3 ) n for quark-lepton families is presented in some detail. It is shown that spontaneous breaking of this symmetry naturally leads to the simple Fritzsch ansatz for the quark mass matrices and simultaneously provides the observed magnitude ofB°-13 ° mixing without any appreciable perturbation of the K°-I~ ° system. This mixing determines a real scale for the masses of the SU (3)N gauge bosons. In marked contrast to the standard model this new approach is certain to give rise to small B°-l] ° mixing and large D°-I) ° mixing that can be of real interest in the near future.

Dark origin of the quark flavor hierarchy and mixing

Physical Review D, 2020

We provide a dynamical mechanism for the generation of the Cabibbo-Kobayashi-Maskawa matrix in the context of a recently proposed model of flavor. The framework, based on the paradigm that Yukawa couplings are effective low energy couplings generated radiatively by dark sector interactions, is here extended to include a new scalar field which plays the role of a dark flavon. Being singlet under the Standard Model gauge group but charged under the U (1) symmetry of the dark sector, this particle sources new two-and three-loop diagrams that result in off-diagonal Yukawa interactions, thereby providing a simple explanation for the observed structure of the CKM matrix. By using an effective parametrization of these new loop contributions, we show that the CKM matrix elements can be correctly reproduced for perturbative values of the involved couplings. We outline the rich phenomenology predicted by the scenario and detail its implications for the LHC and future collider experiments.

Configuration mixing in the quark model

Journal of Physics: Conference Series, 2012

We discuss the flavor asymmetry and the strangeness content of the proton in an unquenched quark model. It is shown that the inclusion of hadron loops leads automatically to an excess ofd overū, but gives very small contributions to the strange magnetic moment and strangeness radius of the proton, both of which are in agreement with experimental data.

Mass mixing, CP violation and left-right symmetry for heavy neutral mesons

Zeitschrift für Physik C Particles and Fields, 1986

We investigate M~ ~ mixing and CP violation in the minimal left-right symmetric gauge model with spontaneous P and CP violation. The dominant contributions to the mixing amplitude including QCD corrections are calculated explicitly for B~ ~ While the amount of mixing is not much changed with respect to the standard model leftright symmetry can give rise to significantly larger CP violation in the Bs ~ _/~o system (up to two orders of magnitude for the dilepton charge asymmetry). Sizable CP violating effects require that the left-right contribution to the KLK s mass difference has the same sign as the standard model contribution. We also comment on D o _/5o mixing including a careful discussion of the standard model prediction for the short distance part.

CPT-P040-2010 Anatomy of New Physics in B–B mixing

2010

We analyse three different New Physics scenarios for ∆F = 2 flavour-changing neutral currents in the quark sector in the light of recent data on neutral-meson mixing. We parametrise generic New Physics contributions to B q − B q mixing, q = d, s, in terms of one complex quantity ∆ q , while three parameters ∆ tt K , ∆ ct K and ∆ cc K are needed to describe K −K mixing. In Scenario I, we consider uncorrelated New Physics contributions in the B d , B s , and K sectors. In this scenario, it is only possible to constrain the parameters ∆ d and ∆ s whereas there are no non-trivial constraints on the kaon parameters. In Scenario II, we study the case of Minimal Flavour Violation (MFV) and small bottom Yukawa coupling, where ∆ ≡ ∆ d = ∆ s = ∆ tt K. We show that ∆ must then be real, so that no new CP phases can be accomodated, and express the remaining parameters ∆ cc K and ∆ ct K in terms of ∆ in this scenario. Scenario III is the generic MFV case with large bottom Yukawa couplings. In this case, the Kaon sector is uncorrelated to the B d and B s sectors. As in the second scenario one has ∆ d = ∆ s ≡ ∆, however, now with a complex parameter ∆. Our quantitative analyses consist of global CKM fits within the Rfit frequentist statistical approach, determining the Standard Model parameters and the new physics parameters of the studied scenarios simultaneously. We find that the recent measurements indicating discrepancies with the Standard Model are well accomodated in Scenarios I and III with new mixing phases, with a slight preference for Scenario I that permits different new CP phases in the B d and B s systems. Within our statistical framework, we find that the Standard-Model hypothesis ∆ d = ∆ s = 1 is disfavoured with p-values of 3.4σ and 3.1σ in Scenarios I and III respectively. CONTENTS * We use the same notation for operators in the B and K systems (cf. Eq. (8)), implying the corresponding flavours (b, s or d) of the quark fields.

$D$-meson Mixing in 2+1-Flavor Lattice QCD

Proceedings of 34th annual International Symposium on Lattice Field Theory — PoS(LATTICE2016)

We present results for neutral D-meson mixing in 2+1-flavor lattice QCD. We compute the matrix elements for all five operators that contribute to D mixing at short distances, including those that only arise beyond the Standard Model. Our results have an uncertainty similar to those of the ETM collaboration (with 2 and with 2+1+1 flavors). This work shares many features with a recent publication on B mixing and with ongoing work on heavy-light decay constants from the Fermilab Lattice and MILC Collaborations.

Fermion masses and mixing in general warped extra dimensional models

Physical Review D, 2015

We analyze fermion masses and mixing in a general warped extra dimensional model, where all the Standard Model (SM) fields, including the Higgs, are allowed to propagate in the bulk. In this context, a slightly broken flavor symmetry imposed universally on all fermion fields, without distinction, can generate the full flavor structure of the SM, including quarks, charged leptons and neutrinos. For quarks and charged leptons, the exponential sensitivity of their wave-functions to small flavor breaking effects yield naturally hierarchical masses and mixing as it is usual in warped models with fermions in the bulk. In the neutrino sector, the exponential wave-function factors can be flavor-blind and thus insensitive to the small flavor symmetry breaking effects, directly linking their masses and mixing angles to the flavor symmetric structure of the 5D neutrino Yukawa couplings. The Higgs must be localized in the bulk and the model is naturally more successful in generalized warped scenarios where the metric background solution is different than AdS 5 . We study these features in two simple frameworks, flavor complimentarily, and flavor democracy, which provide specific predictions and correlations between quarks and leptons, testable as more precise data in the neutrino sector becomes available. a mariana.frank@concordia.ca b