Hbb Recommendation for Alejandro

Dear Matthias, Mauro and Meng,

I am writing to recommend Alejandro Espinosa for the Hbb convenership. Alejandro is a senior postdoc in my group at CMU, working on HH→4b and on extending the jet acceptance in HH→bbWW down to low pT (~10 GeV). He has been an invaluable asset to our group and is excited about this opportunity.

Alejandro is well qualified for this role. He has deep experience in Hbb physics: he led the boosted ttH(bb) measurements at ETH during Run 2, he is a primary author of our HH→4b result (CMS-PAS-HIG-24-011, submitted to PRD), and he contributed to the ttH/tH and inclusive H→bb measurements. He is currently central to two of our Hbb analyses at CMU, 4b and bbWW.

Alejandro is a natural leader, with deep POG/CAT leadership experience. He convened the JetMET JMAR group from 2019 to 2021, coordinating ten or more teams on jet algorithms, substructure, and tagging. He was the JetMET–Higgs contact from 2018 to 2021, reviewing the use of jet/MET objects across all CMS Higgs analyses. He coming off a conveenership of the CAT Workflow Orchestration and Analysis Preservation group. He knows how to organize people and analyses across the collaboration.

Alejandro is also an effective communicator and teacher. In our large CMS group he is the point person for onboarding new students and postdocs, and he supports our shared coffea framework. Across CMS he is a CMSDAS facilitator for the jet exercises, he wrote the coffea and Snakemake/REANA tutorials that many people use, he serves on analysis review committees for several Higgs papers, and he has given plenary talks for CMS, including the Higgs 2025 plenary on experimental methods in Higgs measurements.

Alejandro was recently recognized with an LPC Distinguished Researcher award on the strengths of his work.

In summary, Alejandro would be a great fit for this role. He is excited about it, and as his PI I will fully support him with my group's resources and students. I recommend him without reservation.

john