Static Properties of Quark Solitons

It has been conjectured that at distances smaller than the confinement scale but large enough to allow for nonperturbative effects, QCD is described by an effective $SU(N_c {\times} N_f)_L\times SU(N_c {\times} N_f)_R$ chiral Lagrangian. The soliton solutions of such a Lagrangian are extended objects with spin ${1\over 2}$. For $N_c{=}3$, $N_f{=}3$ they are triplets of color and flavor and have baryon number ${1\over3}$, to be identified as constituent quarks. We investigate in detail the static properties of such constituent-quark solitons for the simplest case $N_f{=}1, N_c{=}3$. The mass of these objects comes from the energy of the static soliton and from quantum effects, described semiclassically by rotation of collective coordinates around the classical solution. The quantum corrections tend to be large, but can be controlled by exploring the Lagrangian's parameter space so as to maximize the inertia tensor. We comment on the acceptable parameter space and discuss the model's further predictive power.Comment: 8 pages + 1 PostScript figure; plain LaTe

Colour chiral solitons in low energy QCD

We derive an effective colour chiral action with a background gauge field. The action describes configurations of soliton-skyrmion type. Kinetic term constant $f_0^2$, analogue of $f_\pi ^2$, is a phenomenological dimensional parameter of the model; $d=4$ terms are unique up to the choice of background gauge field. The case of SU(2) colour group is discussed in detail. We study an isolated configuration, i.e. a configuration in a background field which is the vacuum field forming the gluon condensate. Thereby we introduce the condensate energy as a second parameter and scale. Compared with the case of flavor skyrmion configuration, the colour chiral action contains a piece with slowly decreasing terms coming from the background vacuum field. Asymptotic behaviour at large distances shows exponential decrease for the case of chromomagnetic condensates and periodic otherwise . This defines a stability region for a colour soliton. The mass is given by the positive definite integrand for a soliton of purely bosonization origin. Contribution from the Yang-Mills action of the background colour field has the sign opposite to bosonization part. The baryon number current is not influenced by the background field and leads to the standard baryon number $B=N_F/N_C$ . For $B=1/3$ we evaluated the estimate from above $M\approx 460$ $Mev$ .Comment: 12 pages, Latex, Discussion of the confining potential between colour solitons and journal reference are adde

Quark Solitons from Effective Action of QCD

We derive an effective low energy action for QCD in 4 dimensions. The low energy dynamics is described by chiral fields transforming non-trivially under both color and flavor. We use the method of anomaly integration from the QCD action. The solitons of the theory have the quantum numbers of quarks. They are expected to be the constituent quarks of hadrons. In two dimensions our result is exact, namely the bosonic gauged action of WZW.Comment: 19 pages (phyzzx macropackage) WIS-93/110/Nov-PH, TAUP 2117-93. Some sign changes, one sentence added following eq(3.9), and one ref. [23] adde

The Constitutent Quark as a Topological Soliton

Recently it was proposed that the constituent quark is a topological soliton. I investigate this soliton, calculating its mass, radius, magnetic moment, color magnetic moment, and spin structure function. Within the approximations used, the magnetic moments and spin structure function cannot simultaneously be made to agree with the constituent quark model. Some discussion of what to expect from better approximations is included.Comment: 21 pages, LBL-3510

Determination of αs\alpha_s and the Nucleon Spin Decomposition Using Recent Polarized Structure Function Data

New data on polarized $\mu-p$ and $e-p$ scattering permit a first determination of $\alpha_s$ using the Bjorken sum rule, as well as higher precision in determining the nucleon spin decomposition. Using perturbative QCD calculations to $O(\alpha_s^4)$ for the non-singlet combination of structure functions, we find $\alpha_s(2.5 GeV^2) = 0.375^{+0.062}_{-0.081}$, corresponding to $\alpha_s(M_Z^2) =0.122^{+0.005}_{-0.009}$, and using calculations to $O(\alpha_s^3)$ for the singlet combination we find $\Delta u = 0.83 \pm 0.03$, $\Delta d= -0.43 \pm 0.03$, $\Delta s =-0.10 \pm 0.03$, \Delta \Sigma \equiv \Delta u + \Delta d + \Ds = 0.31 \pm 0.07, at a renormalization scale $Q^2=10 GeV^2$. Perturbative QCD corrections play an essential role in reconciling the interpretations of data taken using different targets. We discuss higher-twist uncertainties in these determinations. The $\Delta q$ determinations are used to update predictions for the couplings of massive Cold Dark Matter particles and axions to nucleons.Comment: 15 pages (LateX) + 5 postscript figures appended after the text; CERN-TH-7324/94, TAUP-2178-9

A Top Quark Soliton and its Anomalous Chromomagnetic Moment

We show that under the assumption of dynamical symmetry breaking of electro weak interactions by a top quark condensate, motivated by the Top Mode Standard Model, the top quark in this effective theory can be considered then as chiral color soliton (qualiton). This is realized in an effective four-fermion interaction with chiral $SU(3)_c$ as well as $SU(2)_L\otimes U_Y(1)$ symmetry. In the pure top sector the qualiton consists of a top valence quark and a Dirac sea of top and anti-top quark coupled to a color octet of Goldstone pions. The mass spectra, isoscalar quadratic radii and the anomalous chromomagnetic moment due to a non-trivial color form factor are calculated with zero and finite current top masses and effects at the Hadron Colliders are discussed. The anomalous chromomagnetic moment turns out to have a value consistent with the top production rates of the D0- and CDF-measurements.Comment: LaTeX, using RevTeX.sty and aps.sty, without figures, 16 pages, to be published in Physical Review D. Full postscript version and figures available on request or via ftp://hadron.tp2.ruhr-uni-bochum.de/preprint.tp2/1995/08-95.tar.g