Bound state perturbation method via SVZ sum rules: A toponium addendum

1986 ◽  
Vol 36 (5) ◽  
pp. 655-658
Author(s):  
Š. Olejník
Keyword(s):  
Perturbation Method ◽  
Sum Rules ◽  
Bound State

scholarly journals Systematic errors of bound-state parameters obtained with SVZ sum rules

2007 ◽  
Author(s):  
Wolfgang Lucha ◽  
Dmitri Melikhov ◽  
Silvano Simula ◽  
Pietro Colangelo ◽  
Donato Creanza ◽  
...  
Keyword(s):  
Sum Rules ◽  
Systematic Errors ◽  
Bound State

THE MASS OF A QUARK–SQUARK BOUND STATE FROM QCD SUM RULES

1999 ◽  
Vol 14 (30) ◽  
pp. 4763-4780
Author(s):  
M. MEYER-HERMANN ◽  
A. SCHÄFER
Keyword(s):  
Sum Rules ◽  
Mass Range ◽  
Bound State ◽  
Higher Order ◽  
Qcd Sum Rules ◽  
Mass Effects ◽  
Squark Mass

We give an estimate of the expected mass range for a possible two-quark two-squark bound state, using QCD sum rules. The sum rules are modified, taking mass effects into account, so that a treatment of heavy squarks becomes justified. The influence of the higher-order mass corrections and the possibility of a bound state mass below the squark mass are discussed.

scholarly journals Extraction of bound-state parameters from dispersive sum rules

2010 ◽  
Vol 73 (10) ◽  
pp. 1770-1780 ◽  
Author(s):  
W. Lucha ◽  
D. I. Melikhov ◽  
S. Simula
Keyword(s):  
Sum Rules ◽  
Bound State

scholarly journals Accuracy of bound-state form factors extracted from dispersive sum rules

2009 ◽  
Vol 671 (4-5) ◽  
pp. 445-449 ◽  
Author(s):  
Wolfgang Lucha ◽  
Dmitri Melikhov ◽  
Silvano Simula
Keyword(s):  
Sum Rules ◽  
Form Factors ◽  
Bound State ◽  
State Form

Study of systematic errors of bound-state parameters in SVZ sum rules

2008 ◽  
Vol 71 (8) ◽  
pp. 1461-1469 ◽  
Author(s):  
W. Lucha ◽  
D. I. Melikhov ◽  
S. Simula
Keyword(s):  
Sum Rules ◽  
Systematic Errors ◽  
Bound State

scholarly journals Bound-state parameters from dispersive sum rules for vacuum-to-vacuum correlators

2010 ◽  
Vol 37 (3) ◽  
pp. 035003 ◽  
Author(s):  
Wolfgang Lucha ◽  
Dmitri Melikhov ◽  
Silvano Simula
Keyword(s):  
Sum Rules ◽  
Bound State

A Perturbation Theory for the Population of Atomic Energy Levels in Non-Lte Plasmas

1988 ◽  
Vol 102 ◽  
pp. 343-347
Author(s):  
M. Klapisch
Keyword(s):  
Perturbation Theory ◽  
Small Parameter ◽  
Classification Scheme ◽  
Sum Rules ◽  
Energy Levels ◽  
Natural Classification ◽  
Quantum Numbers ◽  
Formal Expansion ◽  
Atomic Energy Levels ◽  
As Effects

AbstractA formal expansion of the CRM in powers of a small parameter is presented. The terms of the expansion are products of matrices. Inverses are interpreted as effects of cascades.It will be shown that this allows for the separation of the different contributions to the populations, thus providing a natural classification scheme for processes involving atoms in plasmas. Sum rules can be formulated, allowing the population of the levels, in some simple cases, to be related in a transparent way to the quantum numbers.

CRYO-Electron Microscopy of the Acto-Myosin-ATP Complex

1990 ◽  
Vol 48 (1) ◽  
pp. 248-249
Author(s):  
John Trinickt ◽  
Howard White
Keyword(s):  
Electron Microscopy ◽  
Atp Hydrolysis ◽  
Myosin Head ◽  
Bound State ◽  
Cross Linking ◽  
Weakly Bound ◽  
Cryo Electron Microscopy ◽  
Myosin Subfragment 1 ◽  
Attached State ◽  
High Fraction

The primary force of muscle contraction is thought to involve a change in the myosin head whilst attached to actin, the energy coming from ATP hydrolysis. This change in attached state could either be a conformational change in the head or an alteration in the binding angle made with actin. A considerable amount is known about one bound state, the so-called strongly attached state, which occurs in the presence of ADP or in the absence of nucleotide. In this state, which probably corresponds to the last attached state of the force-producing cycle, the angle between the long axis myosin head and the actin filament is roughly 45°. Details of other attached states before and during power production have been difficult to obtain because, even at very high protein concentration, the complex is almost completely dissociated by ATP. Electron micrographs of the complex in the presence of ATP have therefore been obtained only after chemically cross-linking myosin subfragment-1 (S1) to actin filaments to prevent dissociation. But it is unclear then whether the variability in attachment angle observed is due merely to the cross-link acting as a hinge.We have recently found low ionic-strength conditions under which, without resorting to cross-linking, a high fraction of S1 is bound to actin during steady state ATP hydrolysis. The structure of this complex is being studied by cryo-electron microscopy of hydrated specimens. Most advantages of frozen specimens over ambient temperature methods such as negative staining have already been documented. These include improved preservation and fixation rates and the ability to observe protein directly rather than a surrounding stain envelope. In the present experiments, hydrated specimens have the additional benefit that it is feasible to use protein concentrations roughly two orders of magnitude higher than in conventional specimens, thereby reducing dissociation of weakly bound complexes.

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