STUDIES OF Λ(1405) WITH K-MESIC ATOMS

2011 ◽  
Vol 26 (03n04) ◽  
pp. 402-407
Author(s):  
SŁAWOMIR WYCECH
Keyword(s):  
Binding Energy ◽  
Atomic Hydrogen ◽  
Scattering Amplitude ◽  
Absorptive Part ◽  
Experimental Tests ◽  
P Wave ◽  
Subthreshold Region ◽  
Radiative Transitions ◽  
Mesic Atom

Experimental tests of the Λ(1405) properties are suggested. These could reflect the position and shape of this state in the [Formula: see text] channel. The first test consists in precise determinations of the level widths in the highest accessible K -mesic atom states. One needs to study the dependence of these widths on the binding energy of the valence protons in the involved nuclei. The second test consists in the measurement of radiative transitions from the P-wave atomic hydrogen levels to the Λ(1405) state. In both cases one can study the absorptive part of [Formula: see text] scattering amplitude in the subthreshold region.

scholarly journals Influence of a quasi-molecular mechanism of recombination on the formation of hydrogen in the early Universe

2020 ◽  
Vol 501 (1) ◽  
pp. 1160-1167
Author(s):  
Tamaz Kereselidze ◽  
Irakli Noselidze ◽  
John F Ogilvie
Keyword(s):  
Hydrogen Atom ◽  
Binding Energy ◽  
Molecular Mechanism ◽  
Early Universe ◽  
Ground State ◽  
Atomic Hydrogen ◽  
Molecular Approach ◽  
Evolution Of The Universe ◽  
Radiative Transitions ◽  
The Universe

ABSTRACT In the framework of a quasi-molecular approach, the formation of hydrogen atom in the pre-recombination period of evolution of the Universe is analysed quantitatively. Calculations in an adiabatic multilevel representation enable estimates of probabilities of radiative transitions. The quasi-molecular mechanism of recombination allows the formation of hydrogen molecular ion, ${\mathrm{ H}_2}^+$, in its ground state. The probability of this process is comparable with the probability of the creation of atomic hydrogen. The participation of a second proton in the recombination increases the binding energy of an electron and decreases the rate of recombination of hydrogen.

scholarly journals Converting copper sulfide to copper with surface sulfur for electrocatalytic alkyne semi-hydrogenation with water

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yongmeng Wu ◽  
Cuibo Liu ◽  
Changhong Wang ◽  
Yifu Yu ◽  
Yanmei Shi ◽  
...  
Keyword(s):  
Binding Energy ◽  
Noble Metal ◽  
Atomic Hydrogen ◽  
Copper Sulfide ◽  
Low Cost ◽  
Water Electrolysis ◽  
Metal Free ◽  
Copper Nanowire

AbstractElectrocatalytic alkyne semi-hydrogenation to alkenes with water as the hydrogen source using a low-cost noble-metal-free catalyst is highly desirable but challenging because of their over-hydrogenation to undesired alkanes. Here, we propose that an ideal catalyst should have the appropriate binding energy with active atomic hydrogen (H*) from water electrolysis and a weaker adsorption with an alkene, thus promoting alkyne semi-hydrogenation and avoiding over-hydrogenation. So, surface sulfur-doped and -adsorbed low-coordinated copper nanowire sponges are designedly synthesized via in situ electroreduction of copper sulfide and enable electrocatalytic alkyne semi-hydrogenation with over 99% selectivity using water as the hydrogen source, outperforming a copper counterpart without surface sulfur. Sulfur anion-hydrated cation (S2−-K+(H2O)n) networks between the surface adsorbed S2− and K+ in the KOH electrolyte boost the production of active H* from water electrolysis. And the trace doping of sulfur weakens the alkene adsorption, avoiding over-hydrogenation. Our catalyst also shows wide substrate scopes, up to 99% alkenes selectivity, good reducible groups compatibility, and easily synthesized deuterated alkenes, highlighting the promising potential of this method.

scholarly journals Elastic I=3/2 p -wave nucleon-pion scattering amplitude and the Δ(1232) resonance from Nf=2+1 lattice QCD

2018 ◽  
Vol 97 (1) ◽  
Author(s):  
Christian Walther Andersen ◽  
John Bulava ◽  
Ben Hörz ◽  
Colin Morningstar
Keyword(s):  
Lattice Qcd ◽  
Scattering Amplitude ◽  
P Wave ◽  
Pion Scattering

scholarly journals MORE ABOUT THE WILSONIAN ANALYSIS ON THE PIONLESS NEFT

2009 ◽  
Vol 24 (16n17) ◽  
pp. 3191-3225 ◽  
Author(s):  
KOJI HARADA ◽  
HIROFUMI KUBO ◽  
ATSUSHI NINOMIYA
Keyword(s):  
Fixed Points ◽  
Scattering Amplitude ◽  
Flow Equation ◽  
Effective Field ◽  
P Wave ◽  
P Waves ◽  
S Waves ◽  
Partial Waves ◽  
The One ◽  
Power Divergence

We extend our Wilsonian renormalization group (RG) analysis on the pionless nuclear effective field theory in the two-nucleon sector in two ways; on the one hand, (1) we enlarge the space of operators up to including those of [Formula: see text] in the S waves, and, on the other hand, (2) we consider the RG flows in higher partial waves (P and D waves). In the larger space calculations, we find, in addition to nontrivial fixed points, two "fixed lines" and a "fixed surface" which are related to marginal operators. In the higher partial wave calculations, we find similar phase structures to that of the S waves, but there are two relevant directions in the P waves at the nontrivial fixed points and three in the D waves. We explain the physical meaning of the P-wave phase structure by explicitly calculating the low-energy scattering amplitude. We also discuss the relation between the Legendre flow equation which we employ and the RG equation by Birse, McGovern and Richardson, and possible implementation of power divergence subtraction in higher partial waves.

scholarly journals Hα Absorption in Transiting Exoplanet Atmospheres

2013 ◽  
Vol 8 (S299) ◽  
pp. 281-282
Author(s):  
Duncan Christie ◽  
Phil Arras ◽  
Zhi-Yun Li
Keyword(s):  
Impact Parameter ◽  
Atomic Hydrogen ◽  
State Level ◽  
Atomic Layer ◽  
Ionization Rate ◽  
Upper Atmosphere ◽  
Theoretical Understanding ◽  
Radiative Transitions ◽  
Order Of Magnitude ◽  
Specific Impact

AbstractRecent observations by Jensen et al. of Hα absorption by the upper atmosphere of HD189733b have motivated the need for a theoretical understanding of the distribution of n=2 hydrogen within hot Jupiter atmospheres. With this in mind, we model the n=2 state of atomic hydrogen in a hydrostatic atmosphere in thermal and photoionization equilibrium. Both collisional and radiative transitions are included in the calculation of the n = 2 state level population. In our model, the Hα absorption is dominated by a τ ~ 1 shell composed of metastable 2s hydrogen located within the neutral atomic layer, with the contribution coming roughly uniformly throughout the layer instead of from a specific impact parameter. An ionization rate an order of magnitude over the expected value can reproduce the observed transit depth.

Sign in / Sign up

Export Citation Format

Share Document