New Quark Relations for Hadron Masses and Magnetic Moments - A Challenge for Explanation from QCD

The recent measurement by CDF M(Sigma_b)-M(Lambda_b)=192 MeV is in striking agreement with our theoretical prediction M(Sigma_b)-M(Lambda_b) = 194 MeV. In addition, the measured splitting M(Sigma_b*)-M(Sigma_b) = 21 MeV agrees well with the predicted splitting of 22 MeV. We point out the connection between these predictions and an effective supersymmetry between mesons and baryons related by replacing a light antiquark by a light diquark. We discuss the theoretical framework ...

In this contribution I will try to give an overview of what has been achieved in constituent quark models of mesons and baryons by a comparison of some selected results from various ansaetze with experimental data. In particular I will address the role of relativistic covariance, the nature of the effective quark forces, the status of results on electromagnetic and strong-decay observables beyond the mere mass spectra, as well as some unresolved issues in hadron spectroscopy.

In this work, we compute masses and magnetic moments of the heavy baryons and tetraquarks with one and two open heavy flavors in a unified framework of MIT bag model. Using the parameters of MIT bag model, we confirm that an extra binding energy, which is supposed to exist between heavy quarks ($c$ and $b$) and between heavy and strange quarks in literatures, is required to reconcile light hadrons with heavy hadrons. Numerical calculations are made for all light mesons, heavy...

Magnetic moments of the octet baryons are computed using lattice QCD in background magnetic fields, including the first treatment of the magnetically coupled Sigma-Lambda system. Although the computations are performed for relatively large values of the up and down quark masses, we gain new insight into the symmetries and relations between magnetic moments by working at a three-flavor mass-symmetric point. While the spin-flavor symmetry in the large Nc limit of QCD is shared ...

Excited state mass spectra of the low lying single charmed baryons with non strangeness have been calculated in a hypercentral approach. The six-dimensional hyperradial Schr\"{o}dinger equation is solved by applying a simple variational method. We extend our scheme to predict the magnetic moments and the $ \frac{3}{2}^+ \rightarrow \frac{1}{2}^+ $ transition magnetic moments of $ \Sigma_{c} $ and $ \Lambda_{c} $ state baryons. A comparison of our results with the experimental...

Quark model with potentials derived from QCD, including the quark-diquark model for excited hadrons gives mass formulae in very good agreement with experiment and goes a long way in explaining the approximate symmetries and supersymmetries of the hadronic spectrum, including the symmetry breaking mechanism.

A dynamically broken hadron supersymmetry appears to exist as a consequence of QCD. The reasons for the supersymmetry appear most transparently in the framework of the constituent quark model with a diquark approximation to two quarks. Applications of the supersymmetry have led to relations between meson and baryon masses and to predictions that certain kinds of exotic hadrons should not be observed. I summarize the successful applications and discuss possible future directio...

Using phenomenological formulae, we deduce the masses and quantum numbers of the quarks from two elementary quarks ($\epsilon_{u}$ and $\epsilon_{d}$) first. Then using the sum laws and a binding energy formula, in terms of the qqq baryon model and SU(4), we deduce the masses and quantum numbers of the important baryons from the deduced quarks. At the same time, using the sum laws and a binding energy formula, in terms of the quark-antiquark bound state meson model, we deduce...

In the present work, we have studied the masses and magnetic moments of spin$-{\frac{1}{2}}^+$ and spin$-{\frac{3}{2}}^+$ singly and doubly charmed baryons in the strange hadronic medium at finite temperature using the chiral SU(3) quark mean field model. The properties of baryons within the framework of chiral SU(3) mean field model are defined in terms of constituent quark masses and energies, which are modified through the exchange of scalar fields $\sigma$, $\zeta$ and $\...

Hadron masses under strong magnetic fields are studied. In the presence of strong magnetic fields exceeding the QCD energy scale $ eB \gg \Lambda^2_{\rm QCD} $, ${\rm SU(3)}_{\rm flavor} \otimes {\rm SU(2)}_{\rm spin}$ symmetry of hadrons is explicitly broken so that the quark components of hadrons differ from those with zero or weak magnetic fields $ eB \lesssim \Lambda^2_{\rm QCD} $. Also, squeezing of hadrons by strong magnetic fields affects the hadron mass spectrum. We d...