arXiv subjects

M. D. Scadron

Publications and source records attributed to M. D. Scadron.

At least 19 recordsLinked to original sources

arXiv2007

Predictive pion-quark BCS relation and Thornber-Feynman high-Tc gap

A pion-quark pairing temperature is defined by a BCS-like relation identified from a quark-level Goldberger-Treiman relation with a Nambu scalar mass "gap parameter" taken in the low-mass limit. This intuitive relation predicts the associated "experimental" lattice-gauge pairing temperature. The opposite high-mass limit predicts the sigma mass, and notably has a predictive analog in high-Tc superconductivity in the stable nondispersive energy gap as defined by Thornber-Feynman polaron dynamics.

hep-ph↗

arXiv2007

Constituent and current quark masses at low chiral energies

Light constituent quark masses and the corresponding dynamical quark masses are determined by data, the Quark-Level Linear $σ$ Model, and infrared QCD. This allows to define effective nonstrange and strange current quark masses which reproduce the experimental pion and kaon masses very accurately, by simple additivity. Moreover, the masses of the light scalar mesons $σ(600)$ and $κ(800)$ can be obtained straightforwardly from the constituent quark masses. In contrast, the usual nonstrange and strange current quark masses employed by Chiral Perturbation Theory do not allow a simple quantitative explanation of the pion and kaon masses.

hep-ph↗

arXiv2006

Constituent Quark Masses and the Electroweak Standard Model

Constituent quark masses can be determined quite well from experimental data in several ways and one can obtain fairly accurate values for all six $m_q$. The strong quark-meson coupling $g=2π/\sqrt{3}$ arises from the quark-level linear $σ$ model, whereas $e$ and $\sinθ_w$ arise from weak interactions when the heavy $M_W$ and $M_Z$ are regarded as resonances in analogy with the strong KSFR relation. The Higgs boson mass, tied to null expectation value of charged Higgs components, is found to be around 317 GeV. Finally, the experimental CPV phase angle $δ$ and the three CKM angles $Θ_c, Θ_2, Θ_3$ are successfully deduced from the 6 constituent quark masses following Fritzsch's approach.

hep-ph↗

arXiv2005

Circumventing the axial anomalies and the strong CP problem

Many meson processes are related to the U_A(1) axial anomaly, present in the Feynman graphs where fermion loops connect axial vertices with vector vertices. However, the coupling of pseudoscalar mesons to quarks does not have to be formulated via axial vertices. The pseudoscalar coupling is also possible, and this approach is especially natural on the level of the quark substructure of hadrons. In this paper we point out the advantages of calculating these processes using (instead of the anomalous graphs) the graphs where axial vertices are replaced by pseudoscalar vertices. We elaborate especially the case of the processes related to the Abelian axial anomaly of QED, but we speculate that it seems possible that effects of the non-Abelian axial anomaly of QCD can be accounted for in an analogous way.

hep-ph↗

arXiv2005

Bypassing the axial anomalies

Many meson processes are related to the U_A(1) axial anomaly, present in the Feynman graphs where fermion loops connect axial vertices with vector vertices. However, the coupling of pseudoscalar mesons to quarks does not have to be formulated via axial vertices. The pseudoscalar coupling is also possible, and this approach is especially natural on the level of the quark substructure of hadrons. In this paper we point out the advantages of calculating these processes using (instead of the anomalous graphs) the Feynman graphs where axial vertices are replaced by pseudoscalar vertices. We elaborate especially the case of the processes related to the Abelian axial anomaly of QED, but we speculate that it seems possible that effects of the non-Abelian axial anomaly of QCD can be accounted for in an analogous way.

hep-ph↗

arXiv2005

The kaon electromagnetic form factor

We use recent data on K^+ -> pi^+ e^+ e^-, together with known values for the pion form factor, to derive experimental values for the kaon electromagnetic form factor for 0 < q^2 < 0.125 (GeV/c)^2. The results are then compared with the predictions of the Vector Meson Dominance model, which gives a good fit to the experimental results.

hep-ph↗

arXiv2005

Chiral symmetry breaking via constituent quarks for qbarq pseudoscalar mesons

We base our chiral symmetry approach on the quark-level linear sigma model Lagrangian. Then we review the Nambu--Goldstone theorem with vanishing pi, K, eta_8 masses. Next we dynamically generate the pi, K, eta_8 masses away from the chiral limit. Then we study pion and kaon Goldberger-Treiman relations. Finally we extend this qbarq scheme to scalar and vector mesons. We also show the above qbarq meson scheme fits the higher mass octet baryon qqq pattern as well.

hep-ph↗

arXiv2005

The pion and kaon electromagnetic form factors

We use recent data on K^+ -> pi^+e^+e^-, together with known values for the pion form factor, to derive the kaon electromagnetic form factor for 0 <q^2 <0.125 (GeV/c)^2. The results are then compared with predictions of the Linear sigma Model, a quark-triangle model and Vector Meson Dominance. The first two models describe the data at least qualitatively, but the simple Vector Meson Dominance picture gives a detailed quantitative fit to the experimental results.

hep-ph↗

arXiv2003

The pion nucleon coupling constant and the Goldberger-Treiman relation

The latest $πN$ elastic scattering data are re-analysed to determine the coupling constant $g_c$ of the charged pion, using the dispersion relation for the invariant amplitude $B^{(+)}$. Depending on the choice of data-base, values $g^2_c/4π= 13.80$ to 13.65 are obtained with errors of $\pm 0.12$. We re-examine the well known discrepancy with the Goldberger-Treiman relation. After allowing for the mass dependence of the pion decay constant $f_π$, a (2-3)% discrepancy is predicted, hence $g^2_c/4π= 13.74 \pm 0.10$ in the prior case. The mass difference between charge states of $Δ(1232)$ is $M^0 -M^{++} = 2.0 \pm 0.4$ MeV, close to twice the mass difference between neutron and proton. The difference in widths on resonance is $Γ^0 - Γ^{++} =3.8 \pm 1.0$ MeV. One may account for a width difference of 4.5 MeV from phase space for decays and the extra channel $Δ^0 \to γn$.

hep-ph↗

arXiv2003

Kaon CP violation and radiative corrections

This paper has been withdrawn by the author, because a profoundly overhauled and improved version, also with a new title and two more authors, has now been submitted to the arXiv, with no. hep-ph/0310059. In view of the elapsed time and the very substantial changes in the original paper, a new e-print was judged more appropriate than just a replacement.

hep-ph↗

arXiv2003

SU(3) Mass Splittings for $\bar{q}q$ Mesons and $qqq$ Baryons

By comparing SU(3)-breaking scales of linear mass formulae, it is shown that the lowest vector, axial-vector, and scalar mesons all have a $\bar{q}q$ configuration, while the ground-state octet and decuplet baryons are $qqq$. Also, the quark-level linear $σ$ model is employed to predict similar $\bar{q}q$ and $qqq$ states. Finally, the approximate mass degeneracy of the scalar $a_0$(980) and $f_0$(980) mesons is demonstrated to be accidental.

hep-ph↗

arXiv2002

Nucleon strangeness and spin crisis?

We summarize three alternative extensions of the quark-valence picture of nucleon strangeness and spin, including (1) gluon spin in QCD, (2) Bjorken sum rule and QCD, (3) D--E meson mixing and tadpole leakage. All three approaches suggest that ~40% of the nucleon's spin (as well as its momentum) resides with quarks, but that less than 6% is due to strange quarks.

hep-ph↗

arXiv2002

Consistently computing the K -> pi long distance weak transition

First we extract the long-distance (LD) weak matrix element from certain data and give compatible theoretical estimates. We also link this LD scale to the single-quark-line (SQL) transition scale and then test the latter SQL scale against the decuplet weak decay amplitude ratio. Finally, we study LD decay. All of these experimental and theoretical values are in good agreement. We deduce an average value from eleven experimental determinations compared to the theoretical SQL values average.

hep-ph↗

arXiv2002

Footprints of a Broad $σ$(600) in Weak-Interaction Processes

We explore how chiral-symmetry constraints on weak-interaction matrix elements suggest the existence of an intermediate state sigma in several different weak-interaction processes. Particular attention is directed toward recent evidence for a sigma within three-body nonleptonic weak decays.

hep-ph↗

arXiv2002

Large Nc means Nc=3

We show that the nonperturbative solution of the SU(2) linear sigma model field theory requires color number Nc=3. Also, we show that the three-point and four-point functions bootstrap (or nonperturbatively ``shrink'') in the chiral limit to the tree amplitudes. Independently, we show that a chiral phase transition for Nf=2 requires Tc=180 MeV, consistent with the computer lattice value (173 +/- 8 MeV).

hep-ph↗

arXiv2002

On the amelioration of quadratic divergences

Once massless quadratically divergent tadpole diagrams are discarded, because they contain no intrinsic scale, it is possible to convert other divergences into logarithmic form, using partial fraction identities; this includes the case of quadratic divergences, as has been applied to the linear sigma model. However the procedure must be carried out with due care, paying great attention to correct numerator factors.

hep-ph↗

arXiv2001

Chiral Phase Transitions

We show that melting the quark mass, the scalar $σ$ mass and the quark condensate leads uniquely to the quark-level SU(2) linear $σ$ model field theory. Upon thermalization, the chiral phase transition curve requires $T_c =2f^{CL}_π\approx 180 MeV$ when $μ= 0$, while the critical chemical potential is $μ_c =m_q\approx 325 MeV$. Transition to the superconductive phase occurs at $T^{(SC)}_c=Δ/πe^{-γ_E}$. Coloured diquarks suggest $T_c^{(SC)}<180 MeV$.

hep-th↗

arXiv2001

On polarization of strange baryons in reactions p + p -> p + Lambda^0 + K^+ and p + p -> p + Sigma^0 + K^+ near thresholds

Polarization properties of strange baryons produced in pp reactions, p + p -> p + Lambda^0 + K^+ and p + p -> p + Sigma^0 + K^$, near thresholds of the final states (p Lambda^0 K^+) and (p Sigma^0 K^+) are analysed relative to polarizations of colliding protons. The cross sections for pp reactions are calculated within the effective Lagrangian approach accounting for strong pp rescattering in the initial state of colliding protons with a dominant contribution of the one-pion exchange and strong final-state interaction of daughter hadrons (Eur. Phys. J. A 9, 425 (2000)).

nucl-th↗