Lattice study of D and Ds meson form factors with twisted boundary conditions

Exploring the flavor content of light and heavy-light pseudoscalars

“…Analogous qualitative explanation of the fact that r K + < r π + should be valid. As we will discuss later on, LQCD results obtained using consistent data sets shows that r D + s < r D + [16,17], supporting our expectation.…”

“…The results from LQCD for decay constants were taken from Refs. [49,50], the D + charge radius comes from [16] and for D + and D + s from [17]. In general, the decay constants are quite close to the experimental values, while for the charge radii there is a spread in the theory results.…”

“…The comparison of our results and a selection of models from the literature [39,41,[44][45][46][47] is presented in Table III, together with the outcomes of LQCD calculations [16,17,[49][50][51][52]. In the table we present the charge radii and weak decay constants for D + and D + s mesons, as well as the experimental data from…”

“…However, it is still missing experimental information on the elastic EM form factors of the charged D and D s mesons, which would be essential to address the structural modifications moving from Goldstone bosons to the heavy-light pseudoscalars. On the other side, abinitio calculations of the D and D s charge radii at the physical pion mass point are not yet available, although some results were obtained within a 2+1 flavor LQCD [16] for pion masses from 300 up to 700 MeV and with twisted boundary conditions [17] for pion masses of 300 and 315 MeV. The extracted charge radius were found around 0.4 fm for the D + and somewhat smaller for the D + s , indicating the decrease in the size of these mesons with respect to the charged pion and kaon, as follows from the Higgs coupling to the heavy quarks in opposition to the light ones acquiring dynamically their masses.…”

“…The performed flavor decomposition of the charge radius clearly supports the physical picture outlined before. Additionally, the EM form factors and the corresponding flavor decomposition for the D + up to 1.5 GeV 2 [16] and for D + and D + s below 1.2 GeV 2 were computed within LQCD [17]. It is of note that the scarce information of the EM structure of the pseudoscalar mesons is contrasted by the knowledge of the weak decay constants from the experiments and LQCD calculations (see e.g.…”