Roy–Steiner-equation analysis of pion–nucleon scattering

Hoferichter, Martin; Elvira, J. Ruiz de; Kubis, Bastian; Meißner, Ulf‐G.

doi:10.1016/j.physrep.2016.02.002

Cited by 244 publications

(275 citation statements)

References 494 publications

(771 reference statements)

Supporting

Mentioning

265

Contrasting

Unclassified

Order By: Relevance

“…In particular, the corresponding factor F V π (q 2 1 )F V π (q 2 2 ) can be moved out of the integrals in (4.13), so that one can simply calculate a reduced amplitude, with the dependence on the pion form factors fully factorized. Further, in the solution of Roy-Steiner equations, a MO representation similar to (4.13) is often required for the low-energy region only, in order to match to some known high-energy input, and to this end a finite matching point is introduced [55,[132][133][134][135]. In case the amplitudes are assumed to vanish above the matching point, it effectively acts as a cutoff both in (4.13) and in the Omnès function.…”

Section: Jhep04(2017)161mentioning

confidence: 99%

Dispersion relation for hadronic light-by-light scattering: two-pion contributions

Colangelo

Hoferichter

Procura

et al. 2017

J. High Energ. Phys.

Self Cite

374

257

View full text Add to dashboard Cite

In this third paper of a series dedicated to a dispersive treatment of the hadronic light-by-light (HLbL) tensor, we derive a partial-wave formulation for two-pion intermediate states in the HLbL contribution to the anomalous magnetic moment of the muon (g − 2) µ , including a detailed discussion of the unitarity relation for arbitrary partial waves. We show that obtaining a final expression free from unphysical helicity partial waves is a subtle issue, which we thoroughly clarify. As a by-product, we obtain a set of sum rules that could be used to constrain future calculations of γ * γ * → ππ. We validate the formalism extensively using the pion-box contribution, defined by two-pion intermediate states with a pion-pole left-hand cut, and demonstrate how the full known result is reproduced when resumming the partial waves. Using dispersive fits to high-statistics data for the pion vector form factor, we provide an evaluation of the full pion box, a π-box µ = −15.9(2)×10 −11 . As an application of the partial-wave formalism, we present a first calculation of ππ-rescattering effects in HLbL scattering, with γ * γ * → ππ helicity partial waves constructed dispersively using ππ phase shifts derived from the inverse-amplitude method. In this way, the isospin-0 part of our calculation can be interpreted as the contribution of the f 0 (500) to HLbL scattering in (g − 2) µ . We argue that the contribution due to charged-pion rescattering implements corrections related to the corresponding pion polarizability and show that these are moderate. Our final result for the sum of pion-box contribution and its S-wave rescattering corrections reads a π-box µ + a ππ,π-pole LHC µ,J=0 = −24(1) × 10 −11 .

show abstract

Section: Jhep04(2017)161mentioning

confidence: 99%

Dispersion relation for hadronic light-by-light scattering: two-pion contributions

Colangelo

Hoferichter

Procura

et al. 2017

J. High Energ. Phys.

Self Cite

374

257

View full text Add to dashboard Cite

show abstract

“…We perform renormalization using the EOMS scheme such that the power counting violating terms are dealt with properly. The S-and P -wave phase shifts are extracted from the manifestly Lorentz invariant amplitudes and then fitted to the phase shifts obtained from the recent Roy-Steiner (RS) equation analysis of πN scattering [17] such that all involved LECs are determined. Based on the obtained LECs, we predict the D-and F -wave phase shifts and compare them with the results of the George Washington University (GWU) group analysis [45].…”

Section: Jhep05(2016)038mentioning

confidence: 99%

“…Unfortunately, none of these groups provide uncertainties of their results. Therefore, we prefer to perform fits to the phase shifts generated by the recent Roy-Steiner-equation analysis (RS) of the πN scattering [17], where both the central values and the errors of results are given by Schenklike or conformal parameterizations. Note that this analysis also includes the most up-todate experimental information on the pion-nucleon scattering lengths.…”

Section: Fitting Proceduresmentioning

confidence: 99%

See 1 more Smart Citation

Pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit Delta resonances

Yao

Siemens

Bernard

et al. 2016

J. High Energ. Phys.

Self Cite

102

View full text Add to dashboard Cite

We present the results of a third order calculation of the pion-nucleon scattering amplitude in a chiral effective field theory with pions, nucleons and delta resonances as explicit degrees of freedom. We work in a manifestly Lorentz invariant formulation of baryon chiral perturbation theory using dimensional regularization and the extended on-mass-shell renormalization scheme. In the delta resonance sector, the on mass-shell renormalization is realized as a complex-mass scheme. By fitting the low-energy constants of the effective Lagrangian to the S-and P -partial waves a satisfactory description of the phase shifts from the analysis of the Roy-Steiner equations is obtained. We predict the phase shifts for the D and F waves and compare them with the results of the analysis of the George Washington University group. The threshold parameters are calculated both in the delta-less and delta-full cases. Based on the determined low-energy constants, we discuss the pion-nucleon sigma term. Additionally, in order to determine the strangeness content of the nucleon, we calculate the octet baryon masses in the presence of decuplet resonances up to next-to-next-to-leading order in SU(3) baryon chiral perturbation theory. The octet baryon sigma terms are predicted as a byproduct of this calculation.

show abstract

“…Its empirical number, deduced from low-energy pion-nucleon data, has for a long time been in the range σ N (45 ± 8) MeV [52]. A recent advanced analysis [53] arrives at a significantly larger value: σ N (59.1 ± 3.5) MeV, while lattice QCD [54] suggests a smaller value, σ N = 38 ± 3(stat.) ± 3(syst.)…”

mentioning

confidence: 99%

Functional renormalization group studies of nuclear and neutron matter

Drews

Weise

2017

Progress in Particle and Nuclear Physics

View full text Add to dashboard Cite

Functional renormalization group (FRG) methods applied to calculations of isospinsymmetric and asymmetric nuclear matter as well as neutron matter are reviewed. The approach is based on a chiral Lagrangian expressed in terms of nucleon and meson degrees of freedom as appropriate for the hadronic phase of QCD with spontaneously broken chiral symmetry. Fluctuations beyond mean-field approximation are treated solving Wetterich's FRG flow equations. Nuclear thermodynamics and the nuclear liquid-gas phase transition are investigated in detail, both in symmetric matter and as a function of the proton fraction in asymmetric matter. The equations of state at zero temperature of symmetric nuclear matter and pure neutron matter are found to be in good agreement with advanced ab-initio many-body computations. Contacts with perturbative many-body approaches (in-medium chiral perturbation theory) are discussed. As an interesting test case, the density dependence of the pion mass in the medium is investigated. The question of chiral symmetry restoration in nuclear and neutron matter is addressed. A stabilization of the phase with spontaneously broken chiral symmetry is found to persist up to high baryon densities once fluctuations beyond mean-field are included. Neutron star matter including beta equilibrium is discussed under the aspect of the constraints imposed by the existence of two-solar-mass neutron stars.

show abstract

Roy–Steiner-equation analysis of pion–nucleon scattering

Cited by 244 publications

References 494 publications

Dispersion relation for hadronic light-by-light scattering: two-pion contributions

Dispersion relation for hadronic light-by-light scattering: two-pion contributions

Pion-nucleon scattering in covariant baryon chiral perturbation theory with explicit Delta resonances

Functional renormalization group studies of nuclear and neutron matter

Contact Info

Product

Resources

About