Charmed and light pseudoscalar meson decay constants from four-flavor lattice QCD with physical light quarks

Journal Article · Thu Oct 30 00:00:00 EDT 2014 · Physical Review. D, Particles, Fields, Gravitation and Cosmology

DOI: https://doi.org/10.1103/PhysRevD.90.074509 · OSTI ID:1296747

Bazavov, A.; Bernard, C.; Komijani, J.; Bouchard, C. M.; DeTar, C.; Foley, J.; Levkova, L.; Du, D.; Laiho, J.; El-Khadra, A. X.; Freeland, E. D.; Gámiz, E.; Gottlieb, Steven; Heller, U. M.; Kim, J.; Toussaint, D.; Kronfeld, A. S.; Mackenzie, P. B.; Simone, J. N.; Van de Water, R. S. ; Zhou, R.; Neil, E. T.; Sugar, R.

We compute the leptonic decay constants f_D+, f_Ds , and f_K+, and the quark-mass ratios m_c=m_s and m_s=m_l in unquenched lattice QCD using the experimentally determined value of f_π+ for normalization. We use the MILC Highly Improved Staggered Quark (HISQ) ensembles with four dynamical quark flavors -- up, down, strange, and charm -- and with both physical and unphysical values of the light sea-quark masses. The use of physical pions removes the need for a chiral extrapolation, thereby eliminating a significant source of uncertainty in previous calculations. Four different lattice spacing ranging from a ≈ 0:06 fm to 0:15 fm are included in the analysis to control the extrapolation to the continuum limit. Our primary results are f_D+ = 212:6(0:4)$$(^{+1.0}_{-1.2})$$ MeV, f_Ds = 249:0(0:3)$$(^{+1.1}_{-1.5})$$ MeV, and f_Ds/f_D+ = 1:1712(10)$$(^{+29}_{-32})$$, where the errors are statistical and total systematic, respectively. The errors on our results for the charm decay constants and their ratio are approximately two to four times smaller than those of the most precise previous lattice calculations. We also obtain f_K+/ f_π+ = 1:1956(10)$$(^{+26}_{-18})$$, updating our previous result, and determine the quark-mass ratios m_s/m_l = 27:35(5)$$(^{+10}_{-7})$$ and m_c/m_s = 11:747(19)$$(^{+59}_{-43})$$. When combined with experimental measurements of the decay rates, our results lead to precise determinations of the CKM matrix elements !Vus! = 0:22487(51)(29)(20)(5), !Vcd! = 0:217(1)(5)(1) and !Vcs! = 1:010(5)(18)(6), where the errors are from this calculation of the decay constants, the uncertainty in the experimental decay rates, structure-dependent electromagnetic corrections, and, in the case of !Vus!, the uncertainty in |Vud|, respectively.

• Research Organization: Fermi National Accelerator Laboratory (FNAL), Batavia, IL (United States); Brookhaven National Laboratory (BNL), Upton, NY (United States)
• Sponsoring Organization: USDOE Office of Science (SC), High Energy Physics (HEP) (SC-25)
• Contributing Organization: Fermilab Lattice and MILC Collaborations
• Grant/Contract Number: AC02-07CH11359
• OSTI ID: 1296747
• Report Number(s): FERMILAB-PUB--14-230-T; arXiv:1407.3772; 1306303
• Journal Information: Physical Review. D, Particles, Fields, Gravitation and Cosmology, Journal Name: Physical Review. D, Particles, Fields, Gravitation and Cosmology Journal Issue: 7 Vol. 90; ISSN PRVDAQ; ISSN 1550-7998
• Publisher: American Physical Society (APS)Copyright Statement
• Country of Publication: United States
• Language: English