B- and D-meson leptonic decay constants and quark masses from four-flavor lattice QCD
We describe a recent lattice-QCD calculation of the leptonic decay con- stants of heavy-light 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 isospin-symmetric ensembles of gauge-field 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 down-sea-quark masses. We use the highly-improved staggered quark (HISQ) formulation for valence and sea quarks, includ- ing the bottom quark. The analysis employs heavy-quark effective theory (HQET). A novel HQET method is used in the determination of the quark masses.
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NSF-PAR ID:
10093396
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13th Conference on the Intersections of Particle and Nuclear Physics
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arXiv:1810.00250
3. A bstract The radiative energy loss of fast partons traveling through the quark-gluon plasma (QGP) is commonly studied within perturbative QCD (pQCD). Nonperturbative (NP) effects, which are expected to become important near the critical temperature, have been much less investigated. Here, we utilize a recently developed T -matrix approach to incorporate NP effects for gluon emission off heavy quarks propagating through the QGP. We set up four cases that contain, starting from a Born diagram calculation with color- Coulomb interaction, an increasing level of NP components, by subsequently including (remnants of ) confining interactions, resummation in the heavy-light scattering amplitude, and off-shell spectral functions for both heavy and light partons. For each case we compute the power spectra of the emitted gluons, heavy-quark transport coefficients (drag and transverse-momentum broadening, $$\hat{q}$$ q ̂ ), and the path-length dependent energy loss within a “QGP brick” at fixed temperature. Investigating the differences in these quantities between the four cases illustrates how NP mechanisms affect gluon radiation processes. While the baseline perturbative processes experience a strong suppression of soft radiation due to thermal masses of the emitted gluons, confining interactions, ladder resummations and broad spectral functions (re-)generate a large enhancement toward lowmore »