This content will become publicly available on May 16, 2023
 Award ID(s):
 2013064
 Publication Date:
 NSFPAR ID:
 10340518
 Journal Name:
 The 38th International Symposium on Lattice Field Theory (LATTICE2021)
 Page Range or eLocationID:
 039
 Sponsoring Org:
 National Science Foundation
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We describe a recent latticeQCD calculation of the leptonic decay con stants of heavylight pseudoscalar mesons containing charm and bottom quarks and of the masses of the up, down, strange, charm, and bottom quarks. Results for these quantities are of the highest precision to date. Calculations use 24 isospinsymmetric ensembles of gaugefield configura tions with six different lattice spacings as small as approximately 0.03 fm and several values of the light quark masses down to physical values of the average up and downseaquark masses. We use the highlyimproved staggered quark (HISQ) formulation for valence and sea quarks, includ ing the bottom quark. The analysis employs heavyquark effective theory (HQET). A novel HQET method is used in the determination of the quark masses.

We present results for B(s) and D(s)meson semileptonic decays from ongoing calculations by the Fermilab Lattice and MILC Collaborations. Our calculation employs the highly improved stag gered quark (HISQ) action for both sea and valence quarks and includes several ensembles with physicalmass up, down, strange, and charm quarks and lattice spacings ranging from a ≈ 0.15 fm down to 0.06 fm. At most lattice spacings, an ensemble with physicalmass light quarks is included. The use of the highly improved action, combined with the MILC Collaboration’s gauge ensembles with lattice spacings down to a ≈ 0.042 fm, allows heavy valence quarks to be treated with the same discretization as the light and strange quarks. This unified treatment of the valence quarks allows (in some cases) for absolutely normalized currents, bypassing the need for perturbative matching, which has been a leading source of uncertainty in previous calculations of Bmeson decay form factors by our collaboration. All preliminary formfactor results are blinded.

We present highstatistics results for the isovector and flavor diagonal charges of the proton using 11 ensembles of 2+1+1 flavor HISQ fermions. In the isospin symmetric limit, results for the neutron are given by the $u \leftrightarrow d$ interchange. A chiralcontinuum fit with leading order corrections was made to extract the connected and disconnected contributions in the continuum limit and at $M_\pi=135$~MeV. All results are given in the $\overline{MS}$ scheme at 2~GeV. The isovector charges, $g_A^{ud} = 1.218(25)(30)$, $g_S^{ud} = 1.022(80)(60) $ and $g_T^{ud} = 0.989(32)(10)$, are used to obtain lowenergy constraints on novel scalar and tensor interactions, $\epsilon_{S}$ and $\epsilon_{T}$, at the TeV scale. The flavor diagonal axial charges are: $g_A^u \equiv \Delta u \equiv \langle 1 \rangle_{\Delta u^+} = 0.777(25)(30)$, $g_A^d \equiv \Delta d \equiv \langle 1 \rangle_{\Delta d^+} = 0.438(18)(30)$, and $g_A^s \equiv \Delta s \equiv \langle 1 \rangle_{\Delta s^+} = 0.053(8)$. Their sum gives the total quark contribution to the proton spin, $\sum_{q=u,d,s} (\frac{1}{2} \Delta q) = 0.143(31)(36)$. This result is in good agreement with the recent COMPASS analysis $0.13 < \frac{1}{2} \Delta \Sigma < 0.18$. Implications of results for the flavor diagonal tensor charges, $g_T^u = 0.784(28)(10)$, $g_T^d = 0.204(11)(10)$ and $g_T^s = 0.0027(16)$ formore »

Abstract We present the first unquenched latticeQCD calculation of the form factors for the decay
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