B-meson physics with domain-wall light quarks and relativistic heavy quarks

We propose to compute B-meson weak matrix elements needed to constrain the CKM unitarity triangle and test the Standard Model in the quark flavor sector using the 2+1 flavor dynamical domain-wall fermion gauge field configurations generated by the LHP, RBC, and UKQCD Collaborations and relativistic b quarks. In the upcoming year we aim to finish our calculation of the B-meson leptonic decay constants fBd and fBs , the B − B0 mixing matrix elements, and their ratio, ξ ≡ fBs √ BBs/fBd √ BBd . The SU(3)-breaking ratio ξ provides an important constraint on the apex of the CKM triangle and was therefore highlighted as a key goal in flavor physics in the USQCD Collaboration’s 2007 white paper. We will also calculate the B → π`ν form factor using the same method, which will enable a determination of the CKM Matrix element |Vub|. Calculations of |Vub| are particularly critical due to the worrisome ≈ 3σ tension between inclusive and exclusive determinations. For all of these B-meson weak matrix elements we expect to obtain precise results that are competitive with other approaches, and that will place strong constraints on the CKM unitarity triangle fits. Our calculations will provide independent and valuable crosschecks of the results by HPQCD and Fermilab/MILC who both use the same set of gauge field configurations (different than those used in this proposal). We request the equivalent of 3.3 million jpsi core-hours on the Fermilab clusters plus 100 Tbytes of tape storage (the equivalent of ∼ 0.3 million jpsi core-hours) and 0.4 Tbytes of disk storage (the equivalent of ∼ 12k jpsi core-hours) for this project.