English

Cutting the Coon Amplitude

High Energy Physics - Theory 2023-07-05 v2 Complex Variables

Abstract

The Coon amplitude is a qq-deformed generalization of the Veneziano amplitude exhibiting a semi-infinite sequence of poles that converge on an accumulation point, from which a branch cut emerges. A number of recent papers have provided compelling evidence that the residues of this amplitude satisfy the positivity requirements imposed by unitarity. This paper investigates whether positivity is also satisfied along the branch cut. It is found that positivity violations occur in a region of the branch cut exponentially close to the accumulation point according to a scale set by qq. The closing section of the paper discusses possible interpretations of this fact and strategies for excising negativity from the partial wave coefficients. An appendix presents derivations of instrumental identities relating the qq-gamma and qq-polygamma functions to the Weierstrass elliptic and quasiperiodic functions.

Keywords

Cite

@article{arxiv.2303.02149,
  title  = {Cutting the Coon Amplitude},
  author = {Christian Baadsgaard Jepsen},
  journal= {arXiv preprint arXiv:2303.02149},
  year   = {2023}
}

Comments

v2: fixed typo in equation (55), fixed Figure 1, added two references, made the summary of section 2 in the introduction more precise, edited discussion in second bullet point in section 3,

R2 v1 2026-06-28T09:00:27.390Z