Meson mass spectrum in QCD_2 ’t Hooft model

We study the spectrum of meson masses in large N_c QCD_2 governed by the renowned ‘t Hooft integral equation. In [https://arxiv.org/abs/2409.11324] we generalize non-perturbative analytical methods proposed by Fateev, Lukyanov and Zamolodchikov to the case of arbitrary, but equal quark masses m_1 = m_2. Furthermore, we have also successfully solved the most general case of the 't Hooft model with two flavors, allowing for arbitrary m_{1}, m_{2} (this paper is being prepared for publication). Our results include analytical expressions for spectral sums and systematic large-n expansion. Additionally, we examine the behavior of these non-perturbative results in various limiting regimes, including the chiral, heavy-quark, and heavy-light limits, and establish their full consistency with known analytical and numerical results obtained through other approaches.