scholarly journals Sequential binary decay of highly excited 40Ar*

2019 ◽  
Vol 14 ◽  
pp. 53
Author(s):  
N. G. Nicolis
Keyword(s):  
Decay Process ◽  
Rate Equations ◽  
Final States ◽  
Intermediate Mass ◽  
Mass Distributions ◽  
Model Code ◽  
Alternative Description ◽  
Unbound States ◽  
Initial Excitation ◽  
Nucleon Emission

The sequential statistical binary decay of the highly excited compound nucleus 40Ar* is described with an extended evaporation formalism implemented in a Monte-Carlo multi-step statistical model code. Asymmetric mass splittings involving nucleon emission up to symmetric binary ones are treated within the evaporation formalism, in a unified manner. Emission of heavy fragments in their ground and excited (particle-bound or unbound) states is considered. The evolution of the final mass distributions from 40Ar* is studied as a function of the initial excitation energy, in the range from 45 up to 405 MeV. The population of final states originating from the decay of intermediate mass fragments in particle-bound and particle-unbound states (side-feeding) is discussed. Results are compared with an alternative description in which the time-dependent decay process is described by rate equations for the generation of different fragment species.

SEQUENTIAL BINARY DECAY OF HIGHLY EXCITED NUCLEI

2008 ◽  
Vol 17 (08) ◽  
pp. 1541-1556 ◽  
Author(s):  
N. G. NICOLIS
Keyword(s):  
Rate Equations ◽  
Stage Theory ◽  
Mass Distributions ◽  
Model Code ◽  
Decay Products ◽  
Final Mass ◽  
Initial Excitation ◽  
Nucleon Emission ◽  
Excited Nuclei ◽  
Complete Dissociation

The decay of highly excited nuclei is described as a sequence of binary processes involving emission of fragments in their ground, excited-bound and unbound states. Primary together with secondary decay products lead to the final mass distributions. Asymmetric mass splittings involving nucleon emission up to symmetric binary ones are treated according to a generalized Weisskopf evaporation formalism. This procedure is implemented in the Monte-Carlo multi-step statistical model code MECO (Multisequential Evaporation COde). We examine the evolution of the calculated final mass distributions in the decay of a light compound nucleus, as the initial excitation energy increases towards the limits of complete dissociation. Comparisons are made with the predictions of the transition-stage theory, as well as a consistent Weisskopf treatment in which the decay process is described by rate equations for the generation of different fragment species.

Hadron reactions study with the CMD-3 detector in e+e− collisions

2016 ◽  
Vol 31 (33) ◽  
pp. 1630038
Author(s):  
E. P. Solodov ◽  
A. N. Amirkhanov ◽  
A. V. Anisenkov ◽  
V. M. Aulchenko ◽  
V. S. Banzarov ◽  
...  
Keyword(s):  
Energy Range ◽  
Invariant Mass ◽  
Energy Dependence ◽  
Cross Section ◽  
Cross Sections ◽  
Final States ◽  
Preliminary Results ◽  
Mass Distributions ◽  
Electron Positron ◽  
Intermediate States

The CMD-3 detector has been taking data since December 2010 at the VEPP-2000 electron–positron collider. The collected data sample corresponds to about 60 inverse picobarn of integrated luminosity in the c.m. energy range from 0.32 GeV to 2.0 GeV. Preliminary results of the analysis of various hadronic cross-sections, in particular, [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], 3[Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] are presented. The processes with multi-hadron final states have several intermediate states which have to be taken into account to correctly describe the angular and invariant mass distributions, as well as cross-section energy dependence.

CORRELATED NUCLEON EMISSION IN PERIPHERAL RELATIVISTIC HEAVY ION COLLISIONS

1993 ◽  
Vol 08 (13) ◽  
pp. 2287-2296
Author(s):  
L. L. BARZ ◽  
A. F. R. de TOLEDO PIZA
Keyword(s):  
Cross Section ◽  
Born Approximation ◽  
Heavy Ion Collisions ◽  
Short Range ◽  
Heavy Ion ◽  
Relativistic Heavy Ion Collisions ◽  
Final States ◽  
Ion Collisions ◽  
Nucleon Emission ◽  
Short Range Correlations

The effects of short range correlations for two nucleon emission in peripheral relativistic heavy ion collisions are investigated. The cross section is calculated in Born approximation with properly orthogonalized initial and final states.

Production of neutron-unbound states in intermediate-mass fragments fromN14+Ag reactions atE/A=35 MeV

1991 ◽  
Vol 43 (5) ◽  
pp. 2318-2335 ◽  
Author(s):  
L. Heilbronn ◽  
A. Galonsky ◽  
C. K. Gelbke ◽  
W. G. Lynch ◽  
T. Murakami ◽  
...  
Keyword(s):  
Intermediate Mass ◽  
Unbound States

scholarly journals Sequential binary decay of light nuclear systems: An assessment of statistical model codes

2020 ◽  
Vol 15 ◽  
pp. 83
Author(s):  
N. G. Nicolis
Keyword(s):  
Monte Carlo ◽  
Statistical Model ◽  
Sequential Decay ◽  
Model Code ◽  
Charge Distributions ◽  
Final Mass ◽  
Nuclear Systems ◽  
Nucleon Emission ◽  
Excited Nuclei ◽  
Complete Dissociation

The sequential decay of excited nuclei is described as a succession of binary processes involving fragments in their ground, excited-bound and unbound states. Primary together with secondary decays lead to the final mass and charge distributions. Asymmetric mass splittings involving nucleon emission up to symmetric binary ones are treated within the Weisskopf evaporation formalism, in a unified manner. This procedure was imple- mented in the Monte-Carlo multi-step statistical model code MECO (Multisequential Evaporation COde). We study the evolution of the calculated final mass and charge distributions from 40Ar* as a function of the excitation energy, up to complete dissociation. Our results are compared with the predictions of statistical evaporation codes based on different assumptions for the compound nucleus decay.

scholarly journals Searching in 2-Dimensional mass space for final states with 2 invisible particles

2021 ◽  
Vol 2021 (7) ◽  
Author(s):  
G. Anagnostou
Keyword(s):  
Dark Matter ◽  
Search Method ◽  
Final States ◽  
Missing Energy ◽  
Final State ◽  
True Nature ◽  
Mass Distributions ◽  
Bump Hunting ◽  
Related Distribution ◽  
Proof Of Principle

Abstract A method to search for particles of unknown masses in final states with two invisible particles is presented. Searching for final states with missing energy is a challenging task usually performed in the tail of a missing energy related distribution. The search method proposed is based on a 2-Dimensional mass reconstruction of the final state with two invisible particles. Thus, a bump hunting is possible, allowing a stronger signal versus background discrimination. Parameters of the new theory can be extracted from the mass distributions, a valuable step towards understanding its true nature. The proof of principle is based on the existing SM top pairs in their dilepton final state. The method is applicable in many interesting searches at the LHC, including dark matter candidates or heavy top partners.

Dielectronic Recombination in the Average-Atom Model

1988 ◽  
Vol 102 ◽  
pp. 215
Author(s):  
R.M. More ◽  
G.B. Zimmerman ◽  
Z. Zinamon
Keyword(s):  
Detailed Balance ◽  
Systematic Errors ◽  
Dielectronic Recombination ◽  
Rate Equations ◽  
Strong Correlations ◽  
Dense Plasmas ◽  
Atom Model ◽  
New Feature ◽  
Average Atom Model ◽  
Attachment Process

Autoionization and dielectronic attachment are usually omitted from rate equations for the non–LTE average–atom model, causing systematic errors in predicted ionization states and electronic populations for atoms in hot dense plasmas produced by laser irradiation of solid targets. We formulate a method by which dielectronic recombination can be included in average–atom calculations without conflict with the principle of detailed balance. The essential new feature in this extended average atom model is a treatment of strong correlations of electron populations induced by the dielectronic attachment process.

On the interpretation of dislocation-loop growth during in-situ high-voltage Electron Microscopy

1990 ◽  
Vol 48 (4) ◽  
pp. 532-533
Author(s):  
E. Holzäpfel ◽  
F. Phillipp ◽  
M. Wilkens
Keyword(s):  
Point Defect ◽  
Rate Equations ◽  
Rate Theory ◽  
Dislocation Loops ◽  
High Voltage Electron Microscopy ◽  
Vacancy Migration ◽  
Voltage Electron ◽  
Reaction Rate Theory ◽  
Defect Reactions

During in-situ radiation damage experiments aiming on the investigation of vacancy-migration properties interstitial-type dislocation loops are used as probes monitoring the development of the point defect concentrations. The temperature dependence of the loop-growth rate v is analyzed in terms of reaction-rate theory yielding information on the vacancy migration enthalpy. The relation between v and the point-defect production rate P provides a critical test of such a treatment since it is sensitive to the defect reactions which are dominant. If mutual recombination of vacancies and interstitials is the dominant reaction, vαP0.5 holds. If, however, annihilation of the defects at unsaturable sinks determines the concentrations, a linear relationship vαP is expected.Detailed studies in pure bcc-metals yielded vαPx with 0.7≾×≾1.0 showing that besides recombination of vacancies and interstitials annihilation at sinks plays an important role in the concentration development which has properly to be incorporated into the rate equations.

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