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We try to motivate from QCD a pattern of production in various reactions of (non)exotic resonances. A higher penalty for extra q\bar{q} production in e^+ e^- collisions than in collisions with a nucleon target may explain the absence of…
Between 2004 until today many new resonances in the QCD spectrum have been added by the Particle Data Group. However, it is still possible that there are further states that have yet to be measured, as predicted by Lattice QCD calculations…
The proton mass arises from spontaneous breaking of chiral symmetry and the formation of constituent quarks. Their dynamics cannot be tested by proton tomography but only by studying excited baryons. However, the number of excited baryons…
We study the structure of the $\Lambda_c(2595)$ and $\Lambda_c(2625)$ resonances in the framework of an effective field theory consistent with heavy quark spin and chiral symmetries, that incorporates the interplay between…
Perturbative QCD-based models of parton production and equilibration in ultrarelativistic heavy ion collisions are reviewed with an emphasis on the treatment of quantum interference effects. Uncertainties in the initial parton production…
The complex patterns of the hadronic spectrum have puzzled physicists since the early discovery of the "particle zoo" in the 1960s. Today, the properties of these myriad particles are understood to be the result of quantum chromodynamics…
We consider the strong decays of the lowest-lying radially excited baryons, in SU(6) language the states comprising the first excited 56-plet. Assuming a single-quark decay approximation, and negligible configuration mixing, we make…
We consider the implications of the most general two-body quark-quark interaction Hamiltonian for the spin-flavor structure of the negative parity L=1 excited baryons. Assuming the most general two-body quark interaction Hamiltonian, we…
We study the baryonic fluctuations from second to eighth order involving electric charge, baryon number and strangeness below the quark-gluon plasma crossover and numerically known from lattice QCD calculations. By considering a particular…
Based on a thorough comparison of the nucleon and $\Delta$ excitation spectrum with models we show that parity doublets observed in the mass spectra do not entail the consequence that highly excited $N$ or $\Delta$ resonances are…
We study heavy baryons with exotic flavor quantum numbers formed by a heavy meson and a nucleon (DbarN and BN) with positive parity. One pion exchange interaction, providing a tensor force, dominates as a long range force to bind the DbarN…
We derive mass formulae for the ground state, J^P = 0^- and 1^-, and first excited even-parity, J^P = 0^+ and 1^+, charmed mesons including one loop chiral corrections and O(1/m_c) counterterms in heavy hadron chiral perturbation theory. We…
Positive-parity spin-1/2 excitations of the nucleon are explored in lattice QCD. The variational method is used in this investigation and several correlation matrices are employed. As our focus is on the utility and methodology of the…
We present the ground and excited state spectra of singly, doubly and triply charmed baryons by using dynamical lattice QCD. A large set of baryonic operators that respect the symmetries of the lattice and are obtained after subduction from…
Ongoing challenges in computing the spectrum of hadronic resonances and shallow bound-states from lattice QCD are reviewed. Since such states are identified as poles in the scattering matrix, nearby non-analyticities must be treated to…
We show that a remarkable compatibility exists between the results of a potential model with constituent quarks and the 1/Nc expansion mass formula for strange and nonstrange baryon resonances. Such compatibility brings support to the basic…
Exotic states have been predicted before and after the advent of QCD. In the last decades they have been observed at accelerator experiments in the sector with two heavy quarks, at or above the quarkonium strong decay threshold and called X…
I comment on progress of lattice QCD techniques and calculations. Recent results on pentaquark masses as well as of the spectrum of excited baryons are summarizned and interpreted. The present state of calculations of quantities related to…
The QCD equation of state at zero baryon chemical potential is the only element of the standard dynamical framework to describe heavy ion collisions that can be directly determined from first principles. Continuum extrapolated lattice QCD…
In Nature the excited states of the hadron spectrum appear as resonances. Consequently, there has been significant interest in studying the excited baryon spectrum using lattice QCD. With this in mind we perform spectroscopic calculations…