TY - JOUR
T1 - Stringent tests of constrained Minimal Flavor Violation through ΔF=2 transitions
AU - Buras, Andrzej J.
AU - Girrbach, Jennifer
N1 - Funding Information:
We thank Jean-Marc Gérard for many illuminating comments and Chris Sachrajda for useful information on the progress in lattice calculations. This research was fully financed and done in the context of the ERC Advanced Grant project “FLAVOUR” (267104).
PY - 2013/9
Y1 - 2013/9
N2 - New Physics contributions to ΔF=2 transitions in the simplest extensions of the Standard Model (SM), the models with constrained Minimal Flavor Violation (CMFV), are parametrized by a single variable S(v), the value of the real box diagram function that in CMFV is bounded from below by its SM value S 0(x t). With already very precise experimental values of ε K, ΔM d, ΔM s and precise values of the CP-asymmetry SψKS and of B̂K entering the evaluation of ε K, the future of CMFV in the ΔF=2 sector depends crucially on the values of {pipe}V cb{pipe}, {pipe}V ub{pipe}, γ, FBs √̂BBs and FBd √̂BBd. The ratio ξ of the latter two non-perturbative parameters, already rather precisely determined from lattice calculations, allows then together with ΔM s/ΔM d and Sψ KS to determine the range of the angle γ in the unitarity triangle independently of the value of S(v). Imposing in addition the constraints from {pipe}ε K{pipe} and ΔM d allows to determine the favorite CMFV values of {pipe}V cb{pipe}, {pipe}V ub{pipe}, FBs √̂BBs and FBd √̂BBd as functions of S(v) and γ. The {pipe}V cb{pipe}4 dependence of ε K allows to determine {pipe}V cb{pipe} for a given S(v) and γ with a higher precision than it is presently possible using tree-level decays. The same applies to {pipe}V ub{pipe}, {pipe}V td{pipe} and {pipe}V ts{pipe} that are automatically determined as functions of S(v) and γ. We derive correlations between FBs √̂BBs and FBd √̂BBd, {pipe}V cb{pipe}, {pipe}V ub{pipe} and γ that should be tested in the coming years. Typically FBs √̂BBs and FBd √̂BBd have to be lower than their present lattice values, while {pipe}V cb{pipe} has to be higher than its tree-level determination, with a significance depending on the evolution of their errors. Within the SM this would imply values for B(K+ → π+νν̄ and B(KL → π0νν̄) that are typically larger by (15-20) % than those presently quoted in the literature. The region in the space of these three parameters allowed by CMFV indicates tensions in this class of models and hints for the presence of new sources of flavor violation and/or new local operators in ΔF=2 data that are strongly suppressed in these models. As a byproduct we propose to reduce the present uncertainty in the charm contribution to ε K by using the experimental value of ΔM K.
AB - New Physics contributions to ΔF=2 transitions in the simplest extensions of the Standard Model (SM), the models with constrained Minimal Flavor Violation (CMFV), are parametrized by a single variable S(v), the value of the real box diagram function that in CMFV is bounded from below by its SM value S 0(x t). With already very precise experimental values of ε K, ΔM d, ΔM s and precise values of the CP-asymmetry SψKS and of B̂K entering the evaluation of ε K, the future of CMFV in the ΔF=2 sector depends crucially on the values of {pipe}V cb{pipe}, {pipe}V ub{pipe}, γ, FBs √̂BBs and FBd √̂BBd. The ratio ξ of the latter two non-perturbative parameters, already rather precisely determined from lattice calculations, allows then together with ΔM s/ΔM d and Sψ KS to determine the range of the angle γ in the unitarity triangle independently of the value of S(v). Imposing in addition the constraints from {pipe}ε K{pipe} and ΔM d allows to determine the favorite CMFV values of {pipe}V cb{pipe}, {pipe}V ub{pipe}, FBs √̂BBs and FBd √̂BBd as functions of S(v) and γ. The {pipe}V cb{pipe}4 dependence of ε K allows to determine {pipe}V cb{pipe} for a given S(v) and γ with a higher precision than it is presently possible using tree-level decays. The same applies to {pipe}V ub{pipe}, {pipe}V td{pipe} and {pipe}V ts{pipe} that are automatically determined as functions of S(v) and γ. We derive correlations between FBs √̂BBs and FBd √̂BBd, {pipe}V cb{pipe}, {pipe}V ub{pipe} and γ that should be tested in the coming years. Typically FBs √̂BBs and FBd √̂BBd have to be lower than their present lattice values, while {pipe}V cb{pipe} has to be higher than its tree-level determination, with a significance depending on the evolution of their errors. Within the SM this would imply values for B(K+ → π+νν̄ and B(KL → π0νν̄) that are typically larger by (15-20) % than those presently quoted in the literature. The region in the space of these three parameters allowed by CMFV indicates tensions in this class of models and hints for the presence of new sources of flavor violation and/or new local operators in ΔF=2 data that are strongly suppressed in these models. As a byproduct we propose to reduce the present uncertainty in the charm contribution to ε K by using the experimental value of ΔM K.
UR - http://www.scopus.com/inward/record.url?scp=84883292395&partnerID=8YFLogxK
U2 - 10.1140/epjc/s10052-013-2560-1
DO - 10.1140/epjc/s10052-013-2560-1
M3 - Article
AN - SCOPUS:84883292395
SN - 1434-6044
VL - 73
SP - 1
EP - 14
JO - European Physical Journal C
JF - European Physical Journal C
IS - 9
M1 - 2560
ER -