Demise of CKM & its aftermath

TL;DR

This paper presents evidence that the Standard Model's CKM paradigm conflicts with experimental data, suggesting new physics at a scale below a few TeV, with implications for models like warped extra dimensions and a 4th quark generation.

Contribution

It provides a model-independent analysis showing the need for new physics to explain discrepancies in B-meson mixing and CP violation measurements.

Findings

Standard Model predicts sin(2 beta) too high by over 3 sigma.

New physics likely affects B-mixing and B_d -> psi K_s, not kaon-mixing.

Possible new physics scale is less than a few TeV, possibly as low as a few hundred GeV.

Abstract

Using firmly established experimental inputs such as epsilon_K, Delta M_d, Delta M_s, BR(B -> tau nu), gamma, V_cb along with corresponding lattice matrix elements which have been well studied and are in full QCD such as B_K, SU3 breaking ratio xi, B_Bs and in particular without using V_ub or the pseudoscalar decay constants f_Bd or f_Bs from the latice, we show that the CKM-paradigm now appears to be in serious conflict with the data. Specifically the SM predicted value of sin(2 beta) seems too high compared to direct experimental measured value by over 3 sigma. Furthermore, our studiy shows that new physics predominantly effects B-mixings and B_d -> psi K_s, and not primarily in kaon-mixing or in B -> tau nu. Model independent operator analysis suggests the scale of underlying new physics, accompanied by a BSM CP-odd phase, responsible for breaking of the SM is less than a few TeV, possibly as low as a few hundred GeV. Two possible BSM scenarios, namely warped extra-dimensions and SM with a 4th generation, are briefly discussed. Generic predictions of warped flavor models are briefly discussed. While SM with 4th generation (SM4) is a very simple way to account for the observed anomalies, SM4 is also well motivated due to its potential role in dynamical electrweak symmetery breaking via condensation of heavy quarks and in barygenesis.