scholarly journals PION-NUCLEON SCATTERING WITHIN A GAUGED LINEAR SIGMA MODEL WITH PARITY-DOUBLED NUCLEONS

2007 ◽  
Vol 16 (07n08) ◽  
pp. 2388-2393 ◽  
Author(s):  
SUSANNA WILMS ◽  
FRANCESCO GIACOSA ◽  
DIRK H. RISCHKE

We compute pion-nucleon scattering at tree-level within a gauged linear sigma model which contains the nucleon and its chiral partner. Such an investigation in principle allows to make definite predictions as to whether the main contribution to the nucleon mass comes from the chiral condensate or from the mixing with its chiral partner. We find that there seems to be no set of model parameters that allows for a simultaneous description of all experimentally measured scattering lengths and range parameters. This indicates the need to improve the dynamical ingredients of the model.

2009 ◽  
Vol 80 (11) ◽  
Author(s):  
Amir H. Fariborz ◽  
N. W. Park ◽  
Joseph Schechter ◽  
M. Naeem Shahid

2021 ◽  
Vol 2021 (10) ◽  
Author(s):  
Kang Zhou

Abstract We generalize the unifying relations for tree amplitudes to the 1-loop Feynman integrands. By employing the 1-loop CHY formula, we construct differential operators which transmute the 1-loop gravitational Feynman integrand to Feynman integrands for a wide range of theories, including Einstein-Yang-Mills theory, Einstein-Maxwell theory, pure Yang-Mills theory, Yang-Mills-scalar theory, Born-Infeld theory, Dirac-Born-Infeld theory, bi-adjoint scalar theory, non-linear sigma model, as well as special Galileon theory. The unified web at 1-loop level is established. Under the well known unitarity cut, the 1-loop level operators will factorize into two tree level operators. Such factorization is also discussed.


2009 ◽  
Vol 2009 (11) ◽  
pp. 007-007 ◽  
Author(s):  
William D Linch ◽  
Brenno Carlini Vallilo

2010 ◽  
Vol 25 (01) ◽  
pp. 25-33 ◽  
Author(s):  
MYUNG-KI CHEOUN ◽  
C. Y. RYU

We evaluate mass differences between a neutron and a proton, and between a charged and a neutral meson by using a gauged linear sigma model retaining the chiral SU (2) L × SU (2) R × U (1)V symmetry. Masses of nucleons and relevant mesons are generated through the spontaneous and the explicit chiral symmetry breaking. Since our Lagrangian includes explicitly SU(2) isospin symmetry breaking term, it enables us to simultaneously consider the mass differences of a neutron and a proton, and a charged meson and a neutral one. Their reciprocal relations of the mass differences are also derived, where radiative corrections due to electromagnetic interactions are deliberately taken into account to exactly obtain the isospin symmetry breaking effect in the particle mass differences.


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