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Title: Rho resonance parameters from lattice QCD

We perform a high-precision calculation of the phase shifts for $$\pi$$-$$\pi$$ scattering in the I = 1, J = 1 channel in the elastic region using elongated lattices with two mass-degenerate quark favors ($$N_f = 2$$). We extract the $$\rho$$ resonance parameters using a Breit-Wigner fit at two different quark masses, corresponding to $$m_{\pi} = 226$$MeV and $$m_{\pi} = 315$$MeV, and perform an extrapolation to the physical point. The extrapolation is based on a unitarized chiral perturbation theory model that describes well the phase-shifts around the resonance for both quark masses. We find that the extrapolated value, $$m_{\rho} = 720(1)(15)$$MeV, is significantly lower that the physical rho mass and we argue that this shift could be due to the absence of the strange quark in our calculation.
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Publication Date:
OSTI Identifier:
Report Number(s):
JLAB-THY-16-2313; DOE/OR/23177-3912; arXiv:1605.03993
Journal ID: ISSN 2470-0010; PRVDAQ
DOE Contract Number:
PHY-1151648; PHY-1452055; 1415459
Resource Type:
Journal Article
Resource Relation:
Journal Name: Physical Review D; Journal Volume: 94; Journal Issue: 3; Related Information: Jefferson Lab publications:
Research Org:
Thomas Jefferson National Accelerator Facility, Newport News, VA (United States)
Sponsoring Org:
USDOE Office of Science (SC), Nuclear Physics (NP) (SC-26)
Country of Publication:
United States