Searcharxiv⌕ Search

arXiv · hep-ph/0310221

Exotic baryons and the large-Nc expansion

Abstract

The status of exotic baryons is analyzed in the limit of a large number of colors Nc. Several toy models reproducing the main features of the large-Nc QCD are studied in order to clarify the recent controversy concerning the consistency of various approaches to the 1/Nc-expansion for exotic baryons. The analysis reveals several difficulties of the rigid-rotator approximation including the problems of this approximation in the description of exotic baryons.

Explore related subjects

Keep this discovery

Explore connections, maps & timelines

BibTeXRIS

P. V. Pobylitsa. 2004-04-05. Exotic baryons and the large-Nc expansion. https://doi.org/10.1103/physrevd.69.074030

Cite the original work for its findings. Save a collection to share your selection of sources.

KEEP EXPLORING

Related papers

Pomeron Weights in QCD Processes at High Energy and the $S$-Matrix Unitarity Constraint

The pomeron topological cross-section is derived for the eikonal and the $U$-matrix unitarization schemes using a generalized representation of the scattering amplitude at high energy in an effort to examine pomeron characteristics, namely the multiplicity distribution, fluctuation, and correlation, and to reveal the impact of pomeron weights on the $pp$ multiplicity distribution. The results demonstrate that the $U$-matrix inherently incorporates a larger amount of diffraction production into the multi-pomeron vertices, yielding a larger pomerons' variability regardless of the energy range, while such fluctuations become significant only beyond a specific high-energy threshold in eikonal-like schemes. Most importantly, our findings indicate that within the $U$-matrix scheme, an increase in exchanged pomerons results in more pronounced pomeron correlations and that this correlated resummation plays a key role in enhancing multi-parton collisions. We argue that the choice of unitarization scheme is not arbitrary, as it directly dictates the statistical structure of multi-reggeon exchanges. By reflecting the composite nature of hadrons, rational alternatives to eikonal-like schemes, such as the $U$-matrix, offer a compelling theoretical foundation for modeling high-energy hadronic collisions, provided that specific formulations can be identified that strictly satisfy all mathematical and physical constraints.

hep-ph↗

Two-loop renormalisation of quark and gluon fields in the SMEFT

We compute the contributions of CP-conserving operators in the dimension-six SMEFT to the two-loop renormalisation constants of quark and gluon fields in the $\overline{\textrm{MS}}$-scheme. Specifically, we consider the top-quark chromomagnetic operator and the triple gluon operator. We work with the background-field method, which allows us to extract the contribution of these operators to the two-loop running of the top mass and the strong coupling constant. We discuss in detail the mixing with the unphysical operators required for the renormalisation, and we present analytic results for the renormalisation constants of all relevant operators.

hep-ph↗

Two-loop renormalisation of quark and gluon fields in the SMEFT in the on-shell scheme

We compute the contributions of CP-conserving dimension-six SMEFT operators to the two-loop renormalisation constants of quark and gluon fields in the on-shell scheme. Specifically, we consider the top-quark chromomagnetic operator and the triple gluon operator. We also compute the contribution of four-quark operators to the gluon renormalisation constant and discuss the implications for the running of the strong coupling constant.

hep-ph↗