Quarkonium at nonzero isospin density

We calculate the energies of quarkonium bound states in the presence of a medium of nonzero isospin density using lattice QCD. The medium, created using a canonical (fixed isospin charge) approach, induces a reduction of the quarkonium energies. As the isospin density increases, the energy shifts fi...

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Bibliographic Details
Main Authors: Detmold, William, Meinel, Stefan, Shi, Zhifeng
Other Authors: Massachusetts Institute of Technology. Center for Theoretical Physics
Format: Article
Language:en_US
Published: American Physical Society 2013
Online Access:http://hdl.handle.net/1721.1/80291
https://orcid.org/0000-0002-0400-8363
Description
Summary:We calculate the energies of quarkonium bound states in the presence of a medium of nonzero isospin density using lattice QCD. The medium, created using a canonical (fixed isospin charge) approach, induces a reduction of the quarkonium energies. As the isospin density increases, the energy shifts first increase and then saturate. The saturation occurs at an isospin density close to that where previously a qualitative change in the behavior of the energy density of the medium has been observed, which was conjectured to correspond to a transition from a pion gas to a Bose-Einstein condensed phase. The reduction of the quarkonium energies becomes more pronounced as the heavy-quark mass is decreased, similar to the behavior seen in two-color QCD at nonzero quark chemical potential. In the process of our analysis, the η[subscript b]-π and Υ-π scattering phase shifts are determined at low momentum. An interpolation of the scattering lengths to the physical pion mass gives a[subscript ηb,π]=0.0025(8)(6)  fm and a[subscript Υ,π]=0.0030(9)(7)  fm.