Mass perturbation theory in the 2-flavor Schwinger model with opposite masses with a review of the background

Journal of High Energy Physics

Regular Article - Theoretical Physics

Howard Georgi¹ 

[1] Center for the Fundamental Laws of Nature, Jefferson Physical Laboratory, Harvard University, 02138, Cambridge, MA, USA;Physics Department, Harvard University, 17 Oxford St, 02138, Cambridge, MA, USA;

关键词: Field Theories in Lower Dimensions;    Scale and Conformal Symmetries;    Integrable Field Theories;   

DOI  :  10.1007/JHEP10(2022)119

 received in 2022-08-04, accepted in 2022-10-04,  发布年份 2022

来源: Springer

【 摘 要 】

I discuss the 2-flavor Schwinger model with θ = 0 and small equal and opposite fermion masses (or θ = π with equal masses). The massless model has an unparticle sector with unbroken conformal symmetry. I argue that this special mass term modifies the conformal sector without breaking the conformal symmetry. I show in detail how mass-perturbation-theory works for correlators of flavor-diagonal fermion scalar bilinears. The result provides quantitative evidence that the theory has no mass gap for small non-zero fermion masses. The massive fermions are bound into conformally invariant unparticle stuff. I show how the long-distance conformal symmetry is maintained when small fermion masses are turned on and calculate the relevant scaling dimensions for small mass. I calculate the corrections to the 2- and 4-point functions of the fermion-bilinear scalars to leading order in perturbation theory in the fermion mass and describe a straightforward procedure to extend the calculation to all higher scalar correlators. I hope that this model is a useful and non-trivial example of unparticle physics, a sector with unbroken conformal symmetry coupled to interacting massive particles, in which we can analyze the particle physics in a consistent approximation.

【 授权许可】

Unknown   
© The Author(s) 2022