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An extensive generalization of the ordinary and quasi-eikonal methods is presented for the $pp$ and $\bar pp$ elastic scattering amplitudes, which takes into account in a phenomenological way all intermediate multiparticle states involving…

High Energy Physics - Phenomenology · Physics 2009-01-07 P. Desgrolard , M. Giffon , E. Martynov , E. Predazzi

Within the framework of chiral effective field theory, perturbative calculation for $NN$ scattering is carried out in partial waves with orbital angular momentum $L \geqslant 1$. The primary goal is to identify the lowest angular momenta at…

Nuclear Theory · Physics 2019-02-26 Shaowei Wu , Bingwei Long

The longest-range part of the nuclear force due to the one-pion exchange governs the energy dependence of the scattering amplitude in the near-threshold region and imposes correlations between the coefficients in the effective range…

Nuclear Theory · Physics 2015-07-15 V. Baru , E. Epelbaum , A. A. Filin , J. Gegelia

We identify a redundancy between two- and three-nucleon contact interactions at the fourth and fifth order of the chiral expansion respectively. In particular we show that tensor-type and spin-orbit three-nucleon contact interactions…

Nuclear Theory · Physics 2021-01-04 L. Girlanda , A. Kievsky , L. E. Marcucci , M. Viviani

I discuss low-energy pion-nucleon scattering in the framework of chiral perturbation theory. I argue that using this theoretical method one is able to handle the in some cases tremendous experimental accuracy (for the low partial waves). I…

High Energy Physics - Phenomenology · Physics 2007-05-23 Ulf-G. Meißner

Assuming the existence of a local, analytic, unitary UV completion in a Poincar\'{e} invariant scalar field theory with a mass gap, we derive an infinite number of positivity requirements using the known properties of the amplitude at and…

High Energy Physics - Theory · Physics 2017-11-01 Claudia de Rham , Scott Melville , Andrew J. Tolley , Shuang-Yong Zhou

Positivity bounds are powerful tools to constrain effective field theories. Utilizing the partial wave expansion in the dispersion relation and the full crossing symmetry of the scattering amplitude, we derive several sets of generically…

High Energy Physics - Theory · Physics 2023-01-11 Andrew J. Tolley , Zi-Yue Wang , Shuang-Yong Zhou

Weak interactions in two-nucleon system at low energies are explored in the framework of effective field theory. We review our recent calculations of parity-violating observables in radiative neutron capture on a proton at threshold where…

Nuclear Theory · Physics 2011-03-28 Shung-ichi Ando , Chang Ho Hyun , Jae Won Shin

Effective field theory of the in-medium nucleon-nucleon interaction is considered. The effective range parameters are found to be of a natural scale. The low density limit is discussed both in perturbative and nonperturbative situations. In…

High Energy Physics - Phenomenology · Physics 2007-05-23 B. Krippa

We match the results for the subthreshold parameters of pion-nucleon scattering obtained from a solution of Roy-Steiner equations to chiral perturbation theory up to next-to-next-to-next-to-leading order, to extract the pertinent low-energy…

Nuclear Theory · Physics 2015-11-09 Martin Hoferichter , Jacobo Ruiz de Elvira , Bastian Kubis , Ulf-G. Meißner

We derive positivity bounds for scattering amplitudes of particles with arbitrary spin using unitarity, analyticity and crossing symmetry. The bounds imply the positivity of certain low-energy coefficients of the effective action that…

High Energy Physics - Theory · Physics 2017-03-08 Brando Bellazzini

The scale-dependence of the nucleon-nucleon interaction, which in recent years has been extensively analysed within the context of chiral effective field theory, is, in fact, inherent in any potential models constrained by a fit to…

Nuclear Theory · Physics 2019-03-28 Omar Benhar

A new tool which combines chiral perturbation theory and unitarity in coupled channels is applied with success to the study of the meson-meson interaction, extending the theoretical predictions up to sqrt{s} = 1.2 GeV, hence improving…

High Energy Physics - Phenomenology · Physics 2007-05-23 E. Oset , J. A. Oller , J. R. Peláez , Chiang Huan Ching , M. J. Vicente Vacas

Previous representations of pion pair production amplitudes by two real photons at low energy, which combine dispersion theoretical constraints with elastic unitariy, chiral symmetry and soft photon constraints are generalized to the case…

High Energy Physics - Phenomenology · Physics 2015-06-15 B. Moussallam

The analysis of hadronic interactions with effective field theory techniques is complicated by the appearance of a large number of low-energy constants, which are usually fitted to data. On the other hand, the large-$N_c$ limit imposes…

High Energy Physics - Phenomenology · Physics 2015-01-12 T. Ledwig , J. Nieves , A. Pich , E. Ruiz Arriola , J. Ruiz de Elvira

A cartoon is drawn how and why to define and extract the energy dependence of the nucleon polarisabilities from low energy Compton scattering on the nucleon. The information dynamical polarisabilities contain about the low energy degrees of…

Nuclear Theory · Physics 2017-08-23 Harald W. Griesshammer

Chiral perturbation theory is nowadays a well-established approach to incorporate the chiral constraints from QCD. Nevertheless, for systems involving one baryon, the power counting which dictates the chiral order of observables is not as…

Nuclear Theory · Physics 2014-11-20 Renato Higa

Third order chiral perturbation theory accounts for the $\pi-N$ scattering phase shift data out to energies slightly below the position of the $\Delta$ resonance. The low energy constants are not accurately determined. Explicit inclusion of…

Nuclear Theory · Physics 2017-08-23 P. J. Ellis

The effective field theory approach is applied to the three-nucleon process of $S=1/2$ neutron-deuteron scattering in the S-wave, including the effective range parameters summed at all orders. This is achieved through a modification of the…

Nuclear Theory · Physics 2007-05-23 F. Gabbiani

We discuss the current status of chiral effective field theory in the three-nucleon sector and present selected results for nucleon-deuteron scattering observables based on semilocal momentum-space-regularized chiral two-nucleon potentials…