Browsing by Author "Dib, C. O."

We study the current estimates of Bc→Bsπ to extract the fragmentation fraction fc/fs at the LHCb. A rather robust estimate of Br(Bc→Bsπ) based on factorization and lattice results for the form factor gives fc/fs∼0.056 with a 16% error. We also revisit the extraction of fs/fd using B→Dπ instead of the theoretical cleaner but more suppressed channel B→DK. We also find a tension on the predictions of Br(Bc→J/ψπ) and Br(Bc→Bsπ) considering the measurements of these modes at LHCb, and find that, within a 23% uncertainty, only the lower end of the current prediction range Br(Bc→J/ψ)∼0.4%−1.7% would be consistent with the LHCb measurements.

Axionlike particles (ALPs) appear in several dark sector studies. They have gained increasing attention from the theoretical and experimental community. In this work, we propose the first search for ALPs to be conducted at the Brazilian Synchrotron Light Laboratory (LNLS). In this work, we derive the projected sensitivity of a proposed experiment for the production of ALPs via the channel eþe− → aγ. We show that such an experiment could probe ALP masses between 1–55 MeV, and ALP-electron couplings down to gaee ¼ 2–6 × 10−4 GeV−1 depending on the energy beam, thickness of the target, and background assumptions. Therefore, this quest would cover an unexplored region of parameter space for experiments of this kind, constitute a promising probe for dark sectors, and potentially become the first Latin American dark sector detector