Heavy quarkonium: progress, puzzles, and opportunities

A golden age for heavy quarkonium physics dawned a decade ago, initiated by the confluence of exciting advances in quantum chromodynamics (QCD) and an explosion of related experimental activity. The early years of this period were chronicled in the Quarkonium Working Group (QWG) CERN Yellow Report (YR) in 2004, which presented a comprehensive review of the status of the field at that time and provided specific recommendations for further progress. However, the broad spectrum of subsequent breakthroughs, surprises, and continuing puzzles could only be partially anticipated. Since the release of the YR, the BESII program concluded only to give birth to BESIII; the $B$-factories and CLEO-c flourished; quarkonium production and polarization measurements at HERA and the Tevatron matured; and heavy-ion collisions at RHIC have opened a window on the deconfinement regime. All these experiments leave legacies of quality, precision, and unsolved mysteries for quarkonium physics, and therefore beg for continuing investigations. The plethora of newly-found quarkonium-like states unleashed a flood of theoretical investigations into new forms of matter such as quark-gluon hybrids, mesonic molecules, and tetraquarks. Measurements of the spectroscopy, decays, production, and in-medium behavior of c\bar{c}, b\bar{b}, and b\bar{c} bound states have been shown to validate some theoretical approaches to QCD and highlight lack of quantitative success for others. The intriguing details of quarkonium suppression in heavy-ion collisions that have emerged from RHIC have elevated the importance of separating hot- and cold-nuclear-matter effects in quark-gluon plasma studies. This review systematically addresses all these matters and concludes by prioritizing directions for ongoing and future efforts.Comment: 182 pages, 112 figures. Editors: N. Brambilla, S. Eidelman, B. K. Heltsley, R. Vogt. Section Coordinators: G. T. Bodwin, E. Eichten, A. D. Frawley, A. B. Meyer, R. E. Mitchell, V. Papadimitriou, P. Petreczky, A. A. Petrov, P. Robbe, A. Vair

Improved Measurement of Branching Fractions for pipi Transitions among Upsilon(nS)States

Using samples of (5.93 +/- 0.10) x 10^6 Upsilon(3S) decays and (9.11 +/- 0.14) x 10^6 Upsilon(2S) decays collected with the CLEO detector, we report improved measurements of the branching fractions for the following five transitions: B(Upsilon(3S)-->Upsilon(1S) pi^+ pi^-) = (4.46 +/- 0.01 +/- 0.13)%, B(Upsilon(2S)-->Upsilon(1S) pi^+ pi^-) = (18.02 +/- 0.02 +/- 0.61)%, B(Upsilon(3S)-->Upsilon(1S) pi^0 pi^0) = (2.24 +/- 0.09 +/- 0.11)%, B(Upsilon(2S)-->Upsilon(1S) pi^0 pi^0) = (8.43 +/- 0.16 +/- 0.42)% and B(Upsilon(3S)-->Upsilon(2S) pi^0 pi^0) = (1.82 +/- 0.09 +/- 0.12)%. In each case the first uncertainty reported is statistical, while the second is systematic.Comment: 11 pages, available at http://www.lns.cornell.edu/public/CLNS/, Accepted for Publication in Phys. Rev.

Enzymatic and transport studies in cholesterol-fed Guinea Pigs using Intestinal Brush Border Membrane Vesicles

The intestinal absorptive and digestive functions using the brush border membrane (BBM) vesicles were evaluated in guinea pigs receiving cholesterol-supplemented diet for 12 weeks. The Na+-gradient-dependent transport of D-glucose (p < 0.001), L-alanine and L-phenylalanine (p < 0.01) was decreased significantly the BBM of cholesterol-fed animals. The maximal velocity (Vmax) value of the sucrase and leucine aminopeptidase was decreased without any change in the affinity constant (Km) value, demonstrating that the enzyme contents were reduced in response to cholesterol-rich diet. However, both the Km and Vmax values of the alkaline phosphatase decreased markedly, suggesting that a new enzyme of increased substrate affinity had been formed due to intestinal adaptation of cholesterol load in diet. The present study demonstrated that cholesterol feeding caused a significant alteration in nutrients absorption, membrane enzymes and chemical composition of the small intestine