2024/05/02 by Judd Harrison, Harrison, Judd · 2 citations
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Lattice (hep-lat) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2405.01390
openalex publication_date 2024/05/02 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
We compute the hc (pseudo)scalar, (axial-)vector and (axial-)tensor susceptibilities as a function of u=mc/mh between u=mc/mb and u=0.8 using fully relativistic lattice QCD, employing nonperturbative current renormalisation and using the second generation 2+1+1 MILC HISQ gluon field configurations. We include ensembles with a≈ 0.09fm, 0.06fm, 0.045fm and 0.033fm and we are able to reach the physical b-quark on the two finest ensembles. At the physical mh=mb point we find mb2 χ1+=0.720(34)× 10-2, mb2 χ1-=1.161(54)× 10-2, χ0-=2.374(33)× 10-2, χ0+=0.609(14)× 10-2. Our results for the (pseudo)scalar, vector and axial-vector are compatible with the expected small size of nonperturbative effects at u=mc/mb. We also give the first nonperturbative determination of the tensor susceptibilities, finding mb2 χT=0.891(44)× 10-2 and mb2 χAT=0.441(33)× 10-2. Our value of mb2χAT is in good agreement with the O(αs) perturbation theory, while our result for mb2χT is in tension with the O(αs) perturbation theory at the level of 2σ. These results will allow for dispersively bounded parameterisations to be employed using lattice inputs for the full set of h→ c semileptonic form factors in future calculations, for heavy-quark masses in the range 1.25× mc ≤ mh ≤ mb.