TY - JOUR

T1 - Λc → Λl+νl Form Factors and Decay Rates from Lattice QCD with Physical Quark Masses

AU - Meinel, Stefan

PY - 2017/2/21

Y1 - 2017/2/21

N2 - The first lattice QCD calculation of the form factors governing Λc→Λℓ+νℓ decays is reported. The calculation was performed with two different lattice spacings and includes one ensemble with a pion mass of 139(2) MeV. The resulting predictions for the Λc→Λe+νe and Λc→Λμ+νμ decay rates divided by Vcs2 are 0.2007(71)(74) and 0.1945(69)(72) ps-1, respectively, where the two uncertainties are statistical and systematic. Taking the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vcs from a global fit and the Λc lifetime from experiments, this translates to branching fractions of B(Λc→Λe+νe)=0.0380(19)LQCD(11)τΛc and B(Λc→Λμ+νμ)=0.0369(19)LQCD(11)τΛc. These results are consistent with, and two times more precise than, the measurements performed recently by the BESIII Collaboration. Using instead the measured branching fractions together with the lattice calculation to determine the CKM matrix element gives Vcs=0.949(24)LQCD(14)τΛc(49)B.

AB - The first lattice QCD calculation of the form factors governing Λc→Λℓ+νℓ decays is reported. The calculation was performed with two different lattice spacings and includes one ensemble with a pion mass of 139(2) MeV. The resulting predictions for the Λc→Λe+νe and Λc→Λμ+νμ decay rates divided by Vcs2 are 0.2007(71)(74) and 0.1945(69)(72) ps-1, respectively, where the two uncertainties are statistical and systematic. Taking the Cabibbo-Kobayashi-Maskawa (CKM) matrix element Vcs from a global fit and the Λc lifetime from experiments, this translates to branching fractions of B(Λc→Λe+νe)=0.0380(19)LQCD(11)τΛc and B(Λc→Λμ+νμ)=0.0369(19)LQCD(11)τΛc. These results are consistent with, and two times more precise than, the measurements performed recently by the BESIII Collaboration. Using instead the measured branching fractions together with the lattice calculation to determine the CKM matrix element gives Vcs=0.949(24)LQCD(14)τΛc(49)B.

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U2 - 10.1103/PhysRevLett.118.082001

DO - 10.1103/PhysRevLett.118.082001

M3 - Article

C2 - 28282163

AN - SCOPUS:85014454746

VL - 118

JO - Physical Review Letters

JF - Physical Review Letters

SN - 0031-9007

IS - 8

M1 - 082001

ER -