Naturalness of CP Violation in the Standard Model (original) (raw)

Asymptotic properties of CP violation in the Standard Model

Physical Review D

We present the analysis of the renormalization based evolution of the CP-violation observables obtained from the CCC matrix introduced by Jarlskog. We show that the observables vertdetCvert\vert\det C\vertvertdetCvert and operatornameTrC2\operatorname{Tr}C^{2}operatornameTrC2 decrease very fast with the energy and their value is reduced at the Planck's scale by 5 and 3 orders of magnitude with respect to their low energy values. On the other hand the Jarlskog's CKM matrix rephasing invariant JJJ increases with energy and at the Planck's scale is 25 % larger than at low energy. The absolute value of the coefficient aCPsimdetC/operatornameTrC2a_{CP}\sim \det C/\operatorname{Tr}C^{2}aCPsimdetC/operatornameTrC2 decreases with energy and at the Planck's scale it is 12 % smaller than at low energy. We also find that the pattern of the eigenvalues of the CCC matrix is such that two eigenvalues almost cancel each other and their absolute values are much bigger than the absolute value of the third eigenvalue. The low rate of the CP-violation is a consequence of this pattern of ...

Are CP Violating Effects in the Standard Model Really Tiny?

Nuclear Physics A, 2009

We derive an effective action of the bosonic sector of the Standard Model by integrating out the fermionic degrees of freedom in the worldline approach. The CP violation due to the complex phase in the CKM matrix gives rise to CP-violating operators in the effective action. We calculate the prefactor of the appropriate next-to-leading order operators and give general estimates of CP violation in the bosonic sector of the Standard Model. In particular, we show that the effective CP violation for weak gauge fields is not suppressed by the Yukawa couplings of the light quarks and is much larger than the bound given by the Jarlskog determinant.

CP violation beyond the standard model

Arxiv preprint hep-ph/9701231, 1997

We review CP violation in various extensions of the electroweak sector of the Standard Model. A particular emphasis is put on supersymmetric models. We describe the two CP problems of supersymmetry, concerning d N and ε K . We critically review the various mechanisms that have been suggested to solve these problems: exact universality, approximate CP symmetry, alignment, approximate universality and heavy squarks. We explain how future measurements of CP violation will test these mechanisms. We describe extensions of the quark sector and their implications on CP asymmetries in neutral B decays, on the K L → πνν decay and on ∆Γ(B s ). We discuss CP violation in charged scalar exchange in models with natural flavor conservation and explain how transverse lepton polarization in meson decays can probe such models. CP violation in neutral scalar exchange arises in models of horizontal symmetries and may be manifest in heavy quark (b and t) physics. We describe the implications of Left-Right Symmetric models on d N , ε K , ε /ε and CP asymmetries in B decays. Finally, we briefly discuss the potential of future measurements of CP violation to discover New Physics.

Possible evidence for the breakdown of the CKM-paradigm of CP-violation

2010

Using primarily experimental inputs for S(B d → ψKs), ∆MB s , ∆MB d , BR (B → τ ν) and K along with necessary inputs from the lattice, we find that the measured value of sin(2β) is smaller than expectations of the Standard Model by as much as 3.3 σ, and also that the measured value of the BR(B → τ ν) seems to be less than the predicted value by about 2.8 σ. However, through a critical study we show that most likely the dominant source of these deviations is in B d(s) mixings and in sin(2β) and less so in B → τ ν, and also that the bulk of the problem persists even if input from K is not used. The fact that kaon mixing and K are not the dominant source of the deviation from the Standard Model has the very important consequence that model independent considerations imply that the scale of the relevant new CP-violating physics is below O(2 TeV), and possibly even a few hundred GeVs, thus suggesting that direct signals of the new particle(s) may well be accessible in collider experiments at the LHC and perhaps even at the Tevatron.

Sizable CP violation in the bosonized Standard Model

Nuclear Physics B, 2009

Using the worldline method, we derive an effective action of the bosonic sector of the Standard Model by integrating out the fermionic degrees of freedom. The CP violation stemming from the complex phase in the CKM matrix gives rise to CP-violating operators in the one-loop effective action in the next-to-leading order of a gradient expansion. We calculate the prefactor of the appropriate operators and give general estimates of CP violation in the bosonic sector of the Standard Model. In particular, we show that the effective CP violation for weak gauge fields is not suppressed by the Yukawa couplings of the light quarks and is much larger than the bound given by the Jarlskog determinant.

Alternative theories of CP violation

Physics Letters B, 1998

Recent improvements to the limit of ∆M Bs imply that pure superweak theories, while not excluded, no longer provide a good fit to the data. A class of general superweak theories is introduced in which all flavor changing interactions are governed by an approximate flavor symmetry which gives a "3 mechanism". These theories are in good agreement with data, and predict low values for |V td |, |V ub /V cb |, B(K + → π +ν ν), ǫ ′ /ǫ and CP asymmetries in B decays, and high values for ∆M Bs and f B √ B B. An important example of such a theory is provided by weak scale supersymmetric theories with soft CP violation. The CP violation originates in the squark mass matrix, and, with phases of order unity, flavor symmetries can yield a correct prediction for the order of magnitude of ǫ K .

Standard Model Expectations for CP Violation

1995

I review the predictions and expectations of the CKM model for CP violation in both the K 0 −K 0 and B 0 −B 0 systems. A brief discussion of CP violation in charged K-and B-decays is also included, as well as some remarks on the electric dipole moments of the neutron and the electron.

QCD corrections in a class of spontaneous CP-violating models

Physics Letters B, 1985

We present a study of QCD corrections in a class of spontaneous CP-violating models. We find that the Higgs fields which are responsible for the CP-violating transitions should be one order of magnitude heavier than what is expected from tree order estimates. This implies so large a self-coupling of the Higgs fields that it makes the use of perturbation expansion questionable.

Light quark masses and the CP violation parameter ?' ?

Nucl Phys B Proc Suppl, 1997

We present estimates of light quarks masses using lattice data. Our main results are based on a global analysis of all the published data for Wilson and Staggered fermions, both in the quenched approximation and with n f = 2 dynamical flavors. The Wilson and Staggered results agree after extrapolation to the continuum limit for both the n f = 0, 2 theories. Our best estimates, in the M S scheme at scale 2 GeV, are m = 3.2(4) MeV and ms = 90(20) MeV in the quenched approximation, and m ∼ 2.7 MeV and ms ∼ 70 MeV for the n f = 2 theory. These estimates are significantly smaller than phenomenological estimates based on sum rules, but maintain the ratios predicted by chiral perturbation theory (χPT). Along with the new estimates of 4-fermion operators, lower quark masses have a significant impact on the extraction of ǫ ′ /ǫ from the Standard Model.