Goldstone Boson Scattering with a Light Composite Scalar

• Main Authors: Appelquist, T, Brower, R. C, Cushman, K. K, Fleming, G. T, Gasbarro, A, Hasenfratz, A, Ingoldby, J, Jin, X. Y, Kiskis, J, Neil, E. T, Osborn, J. C, Rebbi, C, Rinaldi, E, Schaich, D, Vranas, P, Weinberg, E, Witzel, O
• Format: Journal Article
• Language: English
• Published: 04-03-2022
• Subjects: Physics - High Energy Physics - Lattice; Physics - High Energy Physics - Phenomenology
• DOI: 10.48550/arxiv.2106.13534

The appearance of a light composite $0^+$ scalar resonance in nearly
conformal gauge-fermion theories motivates further study of the low energy
structure of these theories. To this end, we present a nonperturbative lattice
calculation of s-wave scattering of Goldstone bosons in the maximal-isospin
channel in SU(3) gauge theory with $N_f=8$ light, degenerate flavors. The
scattering phase shift is measured both for different values of the underlying
fermion mass and for different values of the scattering momentum. We examine
the effect of a light flavor-singlet scalar (reported in earlier studies) on
Goldstone boson scattering, employing a dilaton effective field theory (EFT) at
the tree level. The EFT gives a good description of the scattering data,
insofar as the magnitude of deviations between EFT and lattice data are no
larger than the expected size of next-to-leading order corrections in the EFT.