New States with Heavy Quarks

¹ Raymond and Beverly Sackler School of Physics and Astronomy, Tel Aviv University, Israel
² Department of Particle Physics, Weizmann Institute of Science, Rehovot 76100, Israel
³ High Energy Physics Division, Argonne National Laboratory Argonne, IL 60439-4815, USA
⁴ Department of Physical Sciences, University of Helsinki, POB 64, FIN-0014 Finland

^a e-mail: marek@proton.tau.ac.il
^b e-mail: harry.lipkin@weizmann.ac.il
^c e-mail: nils.tornqvist@helsinki.fi

Published online: 10 April 2014

Abstract

We discuss several highly accurate theoretical predictions for masses of baryons containing the b quark which have been recently confirmed by experimental data. Proper treatment of the color-magnetic hyperfine interaction in QCD is crucial for obtaining these results. Several predictions are given for additional properties of heavy baryons. We also discuss the two charged exotic resonances Z_b with quantum numbers of a (b$\overline{b}$u$\overline{d}$) tetraquark, very recently reported by Belle in the channel [ϒ(nS )π⁺, n = 1, 2, 3]. Among possible implications are deeply bound I= 0 counterparts of the Z_b-s and existence of a Σ_b⁺Σ_b⁻ dibaryon, a beauteron.