Lang, C. B., Leskovec, L., Padmanath, M. and Prelovsek, S.
(2017)
Pionnucleon scattering in the Roper channel from lattice QCD.
Physical Review D 95 (1).
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Other URL: http://doi.org/10.1103/PhysRevD.95.014510
Abstract
We present a lattice QCD study of N pi scattering in the positiveparity nucleon channel, where the puzzling Roper resonance N*(1440) resides in experiment. The study is based on the PACSCS ensemble of gauge configurations with Nf = 2 + 1 Wilsonclover dynamical fermions, m pi similar or equal to 156 MeV and L similar or equal to 2.9 fm. In addition to a number of qqq interpolating fields, we ...
Abstract
We present a lattice QCD study of N pi scattering in the positiveparity nucleon channel, where the puzzling Roper resonance N*(1440) resides in experiment. The study is based on the PACSCS ensemble of gauge configurations with Nf = 2 + 1 Wilsonclover dynamical fermions, m pi similar or equal to 156 MeV and L similar or equal to 2.9 fm. In addition to a number of qqq interpolating fields, we implement operators for N pi in pwave and N sigma in swave. In the centerofmomentum frame we find three eigenstates below 1.65 GeV. They are dominated by N(0), N(0) pi(0)pi(0) [mixed with N(0)sigma(0)] and N(p)pi(p) with p similar or equal to 2 pi/L, where momenta are given in parentheses. This is the first simulation where the expected multihadron states are found in this channel. The experimental Np phase shift wouldin the approximation of purely elastic Np scatteringimply an additional eigenstate near the Roper mass m(R) similar or equal to 1.43 GeV for our lattice size. We do not observe any such additional eigenstate, which indicates that N pi elastic scattering alone does not render a lowlying Roper. Coupling with other channels, most notably with N pi pi, seems to be important for generating the Roper resonance, reinforcing the notion that this state could be a dynamically generated resonance. Our results are in line with most of the previous lattice studies based just on qqq interpolators, which did not find a Roper eigenstate below 1.65 GeV. The study of the coupledchannel scattering including a threeparticle decay N pi pi remains a challenge.
Export bibliographical data
Item type:  Article 

Date:  2017 

Institutions:  Physics > Institute of Theroretical Physics 

Identification Number:  Value  Type 

10.1103/PhysRevD.95.014510  DOI 


Keywords:  FINITEVOLUME; QUARKMODEL; RESONANCE; BARYONS; ELECTROPRODUCTION; MATRIX; 

Dewey Decimal Classification:  500 Science > 530 Physics 

Status:  Published 

Refereed:  Yes, this version has been refereed 

Created at the University of Regensburg:  Yes 

Item ID:  38792 
