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Precision Computation of fK/fπ from Staggered 2+1+1 Flavor Simulations

Principal Investigator: Stephan Duerr, Wuppertal University and IAS/JSC at Forschungszentrum Jülich
HPC Platform: JUQUEEN of JSC
Date Published: October 2013
JSC Project ID: hwu07

Project “Precision computation of fK/fπ from staggered 2+1+1 flavor simulations“ aims at a precision test of the first-row unitarity relation of the Cabibbo-Kobayashi-Maskawa (CKM) matrix. To this end, a team of scientists of the University of Wuppertal and Forschungszentrum Jülich under leadership of Dr. Stephan Duerr computes the ratio fK/fπ of the leptonic decay constants of the kaon and the pion. The computation is from first principles, by solving the relevant equations of motion in the underlying fundamental theory, known as ``quantum chromodynamics'' (QCD). Once the result is in hand, the scientists use it to obtain a precise value of the CKM element |Vus| based on |Vud| which is known very accurately. By combining this with the known element |Vub| the scientists can test whether the relation

|Vud|2 + |Vus|2 + |Vub|2 = 1

holds within errors. Any deviation would signal the presence of new physics in the aforementioned leptonic decays.

Precision Computation of fK/fpi from Staggered 2+1+1 Flavor SimulationsCopyright: Copyright: University of Wuppertal

Dr. Stephan Duerr
Wuppertal University / IAS/JSC at Forschungszentrum Jülich
D-42119 Wuppertal / D-52425 Jülich

October 2013