The multiple-charm hierarchy in the statistical hadronization model

In relativistic nuclear collisions the production of hadrons with light (u,d,s) quarks is quantitatively described in the framework of the Statistical Hadronization Model (SHM). Charm quarks are dominantly produced in initial hard collisions but interact strongly in the hot fireball and thermalize. Therefore charmed hadrons can be incorporated into the SHM by treating charm quarks as ‘impurities’ with thermal distributions, while the total charm content of the fireball is fixed by the measured open charm cross section. We call this model SHMc and demonstrate that with SHMc the measured multiplicities of single charm hadrons in lead-lead collisions at LHC energies can be well described with the same thermal parameters as for (u,d,s) hadrons. Furthermore, transverse momentum distributions are computed in a blast-wave model, which includes the resonance decay kinematics. SHMc is extended to lighter collision systems down to oxygen-oxygen and includes doubly- and triply-charmed hadrons. We show predictions for production probabilities of such states exhibiting a characteristic and quite spectacular enhancement hierarchy.

Dynamical supersymmetry for the strange quark and ud antidiquark in the hadron mass spectrum

Speculating that the $ud$ diquark with spin 0 has a similar mass to the constituent $s$ quark, we introduce a symmetry between the $s$ quark and the $\overline{ud}$ diquark. Constructing an algebra for this symmetry, we regard a triplet of the $s$ quarks with spin up and down and the $\overline{ud}$ diquark with spin 0 as a fundamental representation of this algebra. We further build higher representations constructed by direct products of the fundamental representations. We propose assignments of hadrons to the multiples of this algebra. We find in particular that $\{D_{s}, D_{s}^{*}, \Lambda_{c}\}$, $\{\eta_{s}, \phi, \Lambda, f_{0}(1370)\}$, and $\{\Omega_{c}, T_{sc}\}$ form a triplet, a nonet, and a quintet, respectively, where $T_{sc}$ is a genuine tetraquark meson composed of $\overline{ud}sc$. We also find a mass relation between them by introducing symmetry breaking due to the mass difference between the $s$ quark and the $\overline{ud}$ diquark. The masses of the possible tetraquarks $\overline{ud}sc$ and $\overline{ud}sb$ are estimated from the symmetry breaking and the masses of $\Omega_{c}$ and $\Omega_{b}$ to be 2.942 GeV and 6.261 GeV, respectively.

The Quark Model

This chapter presents the quark model of hadrons. It discusses the quark description of the quark antiquark systems of c and b quarks. It then describes the structure of the lightest mesons and baryons as bound states of u, d, and s quarks.

Dalitz Decays of Unflavored Mesons in the Poincaré Covariant Quark Model

The procedure for obtaining the radiative decay constants of pseudoscalar and vector unflavored mesons in the point-form of PiQM is presented. Based on the obtained earlier parameters of the model for light (u, d, s) quarks, we obtain the remaining parameters from the experiments on the V → Py and P → Vy decays. As a result, the mixing angles for pseudoscalar and vector mesons and the behavior of the V → Pℓ+ℓ− decay constant are obtained in agreement with modern experimental data.

Medium effects and parity doubling of hyperons across the deconfinement phase transition

We analyse the behaviour of hyperons with strangeness S = –1,–2,–3 in the hadronic and quark gluon plasma phases, with particular interest in parity doubling and its emergence as the temperature grows. This study uses our FASTSUM anisotropic Nf = 2+1 ensembles, with four temperatures below and four above the deconfinement transition temperature, Tc. The positive-parity groundstate masses are found to be largely temperature independent below Tc, whereas the negative-parity ones decrease considerably as the temperature increases. Close to the transition, the masses are almost degenerate, in line with the expectation from chiral symmetry restoration. This may be of interest for heavy-ion phenomenology. In particular we show an application of this effect to the Hadron Resonance Gas model. A clear signal of parity doubling is found above Tc in all hyperon channels, with the strength of the effect depending on the number of s-quarks in the baryons.

NSIs in semileptonic rare decays of mesons induced by second generation of quarks (c-quark and s-quark)

We study rare decays [Formula: see text] and [Formula: see text] in the framework of nonstandard neutrino interactions (NSIs). We calculate branching ratios of these decays. We explore the possibility for second generation of quarks in NSIs just like leptonic contribution in [Formula: see text] and [Formula: see text]. We study the dependence of [Formula: see text] on [Formula: see text]. We show that there exists a possibility for [Formula: see text], also from this reaction and other two reactions, [Formula: see text] and [Formula: see text]. Three other processes, [Formula: see text] and [Formula: see text] are investigated with s quark in the loop for NSIs instead of d quark. Constraints on [Formula: see text] and [Formula: see text] are provided. We point out that constraints for both u and c quark are equal [Formula: see text] and similarly for d and s quarks the constraints are equal [Formula: see text].

MOMENTUM-SPACE FADDEEV CALCULATIONS FOR GROUND-STATE TRIPLY AND DOUBLY HEAVY BARYONS IN THE CONSTITUENT QUARK MODEL

In the framework of constituent quark model, mass spectra of the ground-state baryons consisting of three or two heavy (b or c) and one light (u, d or s) quarks are calculated by solving three-body Faddeev equations. The results imply that, it is possible to obtain a unified model to describe heavy baryons spectra, as well as meson and SU(3) octet and decuplet baryon spectra. We find that, when taking into account the relativistic correction quark–diquark approximation and three-body Faddeev approach tend to give similar predictions for heavy–light systems. We also study the spin splitting of JP = (1/2+) and JP = (3/2+).

HYBRID STARS WITH DELTA MATTER AND COLOR–FLAVOR LOCKED QUARK PHASE

The color–flavor locked (CFL) phase is believed to be the fundamental state of strange quark matter (SQM) at high densities. The CFL phase is a color superconductor composed of pairs of u, d and s quarks, with no electrons, forming a Bose condensate. In this work, we analyze a possible phase transition of hadronic matter made of nucleons, Δ–resonances, hyperons and leptons, to CFL superconducting quark matter. An equation of state taking into account this phase transition is employed to determine the characteristics of a hybrid star. The role of the color superconducting gap on the hybrid stars properties is also discussed.