Formation of antihydrogen in the ground state

2007 ◽  
Vol 85 (4) ◽  
pp. 393-399
Author(s):  
V S Kulhar
Keyword(s):  
Cross Sections ◽  
Ground State ◽  
Time Reversal ◽  
Exchange Process ◽  
Hydrogen Charge ◽  
High Energy ◽  
High Energy Region ◽  
Charge Exchange Process ◽  
State Approximation ◽  
Reversal Invariance

Cross sections for antihydrogen formation in the ground state for the process [Formula: see text] + Ps(nlm) → [Formula: see text](1s) + e– have been calculated using charge conjugation and time reversal invariance. Calculations are based on a two-state approximation method, used by the author earlier for positron–hydrogen charge -exchange process (e+ – H → Ps(nlm) + p). Cross-section results are reported in the intermediate- and high-energy region (20 keV – 500 keV). PACS No.: 36.10.Dr

Excited states of positronium in positron–hydrogen charge exchange

1978 ◽  
Vol 56 (5) ◽  
pp. 565-570 ◽  
Author(s):  
V. S. Kulhar ◽  
C. S. Shastry
Keyword(s):  
Excited States ◽  
Charge Exchange ◽  
Cross Sections ◽  
Ground State ◽  
Born Approximation ◽  
Energy Region ◽  
Hydrogen Charge ◽  
Positronium Formation ◽  
State Approximation ◽  
Higher Excited States

The two state approximation method for the study of the rearrangement collisions is applied to the process of positronium formation in excited states for positron–hydrogen charge exchange collisions. Differential and integrated cross sections are computed for positronium formation in 2S, 2P, and 3S excited states. The results obtained in the energy region 2 to 10 Ry are compared with positronium formation cross sections in ground state. Total positronium formation cross sections including the contributions of capture into all the higher excited states of positronium are also computed in the first Born approximation and the two state approximation in the energy region considered.

scholarly journals Upgrade of the MAGNEX spectrometer toward the high-intensity phase of NUMEN

2021 ◽  
Vol 252 ◽  
pp. 03003
Author(s):  
Manuela Cavallaro ◽  
Clementina Agodi ◽  
Giuseppe A. Brischetto ◽  
Salvatore Calabrese ◽  
Daniela Calvo ◽  
...  
Keyword(s):  
Cross Sections ◽  
Exchange Process ◽  
Reaction Cross ◽  
Target System ◽  
Charge Exchange Process ◽  
Double Charge Exchange ◽  
Detection Systems ◽  
Superconducting Cyclotron ◽  
Plane Detector ◽  
Double Charge

The NUMEN experimental activity with accelerated beams is performed at INFN–Laboratori Nazionali del Sud (LNS) in Catania using the Superconducting Cyclotron and the MAGNEX magnetic spectrometer. The scientific motivation of NUMEN is to extract experiment-driven information on the nuclear matrix elements entering in the expression of the 0νββ decay half-life. The reaction cross sections involved, especially for the double charge exchange process, are very low, thus limiting the present exploration to a few selected isotopes of interest in the context of typically low-yield experimental runs. In order to make feasible a systematic study of all the candidate nuclei, a major upgrade of the LNS facility is foreseen to increase the experimental yield by more than two orders of magnitude. To this purpose, frontier technologies are being developed for the accelerator and the detection systems. An updated description of the choices derived from the recent R&D activity on the target system and MAGNEX focal plane detector is given.

SEMIEMPIRICAL FORMULAS FOR CALCULATION OF L SUBSHELL IONIZATION CROSS SECTIONS

1994 ◽  
Vol 04 (04) ◽  
pp. 217-230 ◽  
Author(s):  
I. ORLIĆ ◽  
C.H. SOW ◽  
S.M. TANG
Keyword(s):  
Experimental Data ◽  
Cross Sections ◽  
High Energy ◽  
Universal Function ◽  
High Energy Region ◽  
Ionization Cross ◽  
Section Data ◽  
Data Points ◽  
Ionization Cross Sections ◽  
Similar Paper

Presented are new parameters for the calculation of L subshell ionization cross sections for proton impact using a semiempirical expression. A similar paper was published by our group in early 1993 but the fitting parameters were obtained by using only 2295 experimental L shell cross section data. Since then a large number of experimental data have become available and therefore a new fitting has been performed employing more than 5000 data points. All available data were fitted separately for L1, L2 and L3 subshells. For targets with low atomic numbers (14≤Z≤42), only coefficients for L tot were obtained. Because of the slight Z dependence of the universal function, data were also devised into five sub-groups according to their atomic numbers and fitted separately within each group for L1, L2 and L3 subshells. To extend the energy range of validity of the new fitting function theoretical values were used in the high energy region where experimental data were lacking. Results are compared with ECPSSR predictions and discussed.

Relativistic effects in the photoionization of hydrogenic ions

1983 ◽  
Vol 61 (2) ◽  
pp. 198-204 ◽  
Author(s):  
S. P. Goldman ◽  
G. W. F. Drake
Keyword(s):  
Cross Sections ◽  
Energy Region ◽  
Neutral Hydrogen ◽  
Relativistic Effects ◽  
High Energy ◽  
Basis Set ◽  
High Energy Region ◽  
High Energies ◽  
Hydrogenic Ions ◽  
Good Agreement

Accurate relativistic calculations of the oscillator strength densities and photoeffect cross sections for neutral hydrogen and hydrogenic lead (Z = 82) are performed up to the high energy region. Relativistically induced Cooper minima are found in the partial wave contributions at high energies. The results are in good agreement with calculations in which the scattering continuum is represented by a discrete relativistic variational basis set.

scholarly journals Diffusive-like redistribution in state-changing collisions between Rydberg atoms and ground state atoms

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Philipp Geppert ◽  
Max Althön ◽  
Daniel Fichtner ◽  
Herwig Ott
Keyword(s):  
Quantum Number ◽  
Ground State ◽  
Rydberg Atoms ◽  
Principal Quantum Number ◽  
Exchange Process ◽  
Final States ◽  
Initial State ◽  
Charge Exchange Process ◽  
Wide Range ◽  
A Charge

AbstractExploring the dynamics of inelastic and reactive collisions on the quantum level is a fundamental goal in quantum chemistry. Such collisions are of particular importance in connection with Rydberg atoms in dense environments since they may considerably influence both the lifetime and the quantum state of the scattered Rydberg atoms. Here, we report on the study of state-changing collisions between Rydberg atoms and ground state atoms. We employ high-resolution momentum spectroscopy to identify the final states. In contrast to previous studies, we find that the outcome of such collisions is not limited to a single hydrogenic manifold. We observe a redistribution of population over a wide range of final states. We also find that even the decay to states with the same angular momentum quantum number as the initial state, but different principal quantum number is possible. We model the underlying physical process in the framework of a short-lived Rydberg quasi-molecular complex, where a charge exchange process gives rise to an oscillating electric field that causes transitions within the Rydberg manifold. The distribution of final states shows a diffusive-like behavior.

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