The Gaia-ESO Survey: Hydrogen lines in red giants directly trace stellar mass Maria Bergemann, Aldo Serenelli, Ralph Schönrich, Greg Ruchti, Andreas Korn, Saskia Hekker, Mikhail Kovalev, Lyudmila Mashonkina, Gerry Gilmore, Sofia Randich et al. (20 more) A&A, 594 (2016) A120 Published online: 20 October 2016 DOI: 10.1051/0004-6361/201528010