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Title: Connecting physical resonant amplitudes and lattice QCD

Here, we present a determination of the isovector, $P$-wave $$\pi\pi$$ scattering phase shift obtained by extrapolating recent lattice QCD results from the Hadron Spectrum Collaboration using $$m_\pi =236$$ MeV. The finite volume spectra are described using extensions of L\"uscher's method to determine the infinite volume Unitarized Chiral Perturbation Theory scattering amplitude. We exploit the pion mass dependence of this effective theory to obtain the scattering amplitude at $$m_\pi= 140$$ MeV. The scattering phase shift is found to be in good agreement with experiment up to center of mass energies of 1.2 GeV. The analytic continuation of the scattering amplitude to the complex plane yields a $$\rho$$-resonance pole at $$E_\rho= \left[755(2)(1)(^{20}_{02})-\frac{i}{2}\,129(3)(1)(^{7}_{1})\right]~{\rm MeV}$$. The techniques presented illustrate a possible pathway towards connecting lattice QCD observables of few-body, strongly interacting systems to experimentally accessible quantities.
ORCiD logo [1] ;  [2] ;  [3]
  1. Univ. of Colorado, Boulder, CO (United States); Baylor Univ., Waco, TX (United States)
  2. Thomas Jefferson National Accelerator Facility (TJNAF), Newport News, VA (United States)
  3. Old Dominion Univ., Norfolk, VA (United States)
Publication Date:
Report Number(s):
JLAB-THY-15-2103; DOE/OR/23177-3658; arXiv:1507.07928
Journal ID: ISSN 0370-2693; PII: S0370269316300144
Grant/Contract Number:
AC05-06OR23177; SC0006765
Published Article
Journal Name:
Physics Letters. Section B
Additional Journal Information:
Journal Volume: 757; Journal ID: ISSN 0370-2693
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
72 PHYSICS OF ELEMENTARY PARTICLES AND FIELDS; lattice QCD; chiral perturbation theory; pion elastic scattering
OSTI Identifier:
Alternate Identifier(s):
OSTI ID: 1242482