Glueballs, Hybrids, Multiquarks. Experimental facts versus QCD inspired concepts

This review presents the fundamental theoretical concepts concerning the photogalvanic effect (PGE)—the phenomenon of appearance of a direct current in a homogeneous medium under uniform illumination. This effect can occur in all media lacking a center of symmetry, in particular, in ferroelectrics, piezoelectrics, gyrotropic crystals, and in gases and liquid possessing natural optical activity. The starting point of a systematic microscopic theory is the asymmetry of the elementary electronic processes—their noninvariance with respect to spatial reflection. Within the framework of the theory, we study the most important mechanisms of the PGE in the regions of impurity, interband, and intraband light absorption. Possible observable manifestations of the PGE are discussed. Theoretical results are compared with experimental data.

https://iopscience.iop.org/article/10.1070/PU1980v023n03ABEH004703/pdf

The photogalvanic effect in media lacking a center of symmetry

Study of K pi Scattering Using the Reactions K+- p ---> K+- pi+ n and K+- p ---> K+- pi- Delta++ at 13-GeV/c

Diffractive production mechanisms

Resonances in Coupled Channels in Nuclear and Particle Physics

We present a partial-wave analysis of the K$sup +-$$pi$$sup +$$pi$$sup - $ system in K$sup +-$p $Yields$ K$sup +-$$pi$$sup +$$pi$$sup -$p at 13 GeV. Evidence is given for the existence of two J/sup P/ = 1$sup +$ mesons: one at approx. 1300 MeV(GAMMA approx. 200 MeV), coupling principally to rhoK, and the other at approx. 1400 MeV (GAMMA approx. 160 MeV), coupling principally to K*$pi$. (AIP)

/pdf/observation-of-two-strangeness-one-axial-vector-mesons-4ux03m3m1t.pdf

Observation of Two Strangeness-One Axial-Vector Mesons

The J/subP/=0/sup -/ partial waves of the K..pi pi.. system in the reactions K/sup plus-or-minus/p..-->..K/sup plus-or-minus/..pi../sup +/..pi../sup -/p at 13 GeV are presented. Structure in intensities and relative phase variations suggest the existence of a pseudoscalar resonance, the K', with a mass of approx.1400 MeV and a width of approx.250 MeV decaying predominantly into epsilonK. (AIP)

/pdf/evidence-for-a-new-strangeness-one-pseudoscalar-meson-2r5j6tcw66.pdf

Evidence for a New Strangeness-One Pseudoscalar Meson

The momentum transfer (t') dependence of the J/sup p/ = 1/sup +/ K*..pi.. and pK partial waves in the K/sup + -/..pi../sup +/..pi../sup -/ system is presented. The production of the Q/sub 1/ meson (m approx. 1300 MeV), which has a large rhoK decay mode, obeys approximate s-channel helicity conservation. In contrast, the production of the Q/sub 2/ meson (m approx. 1400 MeV), which decays predominantly to K*..pi.., satisfies approximate t-channel helicity conservation. Furthermore, the Q/sub 1//sup + -/ production distributions are virtually identical, whereas the Q/sub 2//sup + -/ distributions exhibit a distinct crossover for abs. value t' approx. = 0.18 GeV/sup 2/. (AIP)

G.W. Brandenburg

Papers

Observation of Two Strangeness-One Axial-Vector Mesons

Evidence for a New Strangeness-One Pseudoscalar Meson

Production properties of Q mesons in K$sup +-$p$Yields$K$sup +-$/$pi$$sup +$$pi$$sup -$p at 13 GeV

Analysis of K−K+ and π−π+ final states in 13 GeV K−p interactions

Determination of the K∗(1800) spin parity☆