Mean proton and alpha-particle reduced widths of the Porter-Thomas distribution and astrophysical applications

The Porter-Thomas distribution is a key prediction of the Gaussian orthogonal ensemble in random matrix theory. It is routinely used to provide a measure for the number of levels that are missing in a given resonance analysis. The Porter-Thomas distribution is also of crucial importance for estimates of thermonuclear reaction rates where the contributions of certain unobserved resonances to the total reaction rate need to be taken into account. In order to estimate such contributions by randomly sampling over the Porter-Thomas distribution, the mean value of the reduced width must be known. We present mean reduced width values for protons and α particles of compound nuclei in the A = 28–67 mass range. The values are extracted from charged-particle elastic scattering and reaction data that weremeasured at the riangle Universities Nuclear Laboratory over several decades. Our new values differ significantly from those previously reported that were based on a preliminary analysis of a smaller data set. As an example for the application of our results, we present new thermonuclear rates for the 40Ca(α,γ)44Ti reaction, which is important for 44Ti production in core-collapse supernovae, and compare with previously reported results.Peer ReviewedPostprint (published version

Effect of photoions on the line shapes of the F\"orster resonance and microwave transitions in cold rubidium Rydberg atoms

Experiments on the spectroscopy of the F\"orster resonance Rb(37P)+Rb(37P) -> Rb(37S)+Rb(38S) and microwave transitions nP -> n'S, n'D between Rydberg states of cold Rb atoms in a magneto-optical trap have been performed. Under ordinary conditions, all spectra exhibited a 2-3 MHz line width independently of the interaction time of atoms with each other or with microwave radiation, although the ultimate resonance width should be defined by the inverse interaction time. Analysis of the experimental conditions has shown that the main source of the line broadening was the inhomogeneous electric field of cold photoions appeared at the excitation of initial Rydberg nP states by broadband pulsed laser radiation. Using an additional pulse of the electric field, which rapidly removed the photoions after the laser pulse, lead to a substantial narrowing of the microwave and F\"orster resonances. An analysis of various sources of the line broadening in cold Rydberg atoms has been conducted.Comment: 10 pages, 6 figure

Hemodynamic criteria of the circulatory system in ethnic groups of students with different types of autonomic regulation of the heart rate

Under physiological conditions, the first years of university studies of the students of Arabic and African subgroups with MPAR and PPAR HR were characterized by toughness, low effectiveness of the system of blood circulation, increased peripheral vascular resistance, vascular TSC; Indian and Latino-American subgroups with MPAR HR revealed the weakness and low efficiency of the circulatory system, the optimal GPBC and cardiovascular TSC were revealed in Indian and Latino-American subgroups with MPAR HR, and subgroups with PPAR HR showed high endurance of the circulatory syste

Comparative analysis of habitus and behavioral responses in birds in desynchronosis conditions

The dynamics of behavioral reactions is studied. Habit, live weight of roosters in artificially created models of desynchronosis: acute, due to three-day inversion of the light regime, and chronic, due to crowding - increased placing density. An assessment of the behavior, habitus, feed intake, feather cover and molting conditions in combination with the glycemia level, which together provide an objective assessment of the effect of desynchronosis on the functional state of birds and their adaptation to acute and chronic stres

Health ecology: factors of spread and consequences of viral hepatitis manifestation

The features of viral hepatitis B (HB) and C (HC) in the initial making of these diagnoses in three age groups of men and women (25-30, 31-55 years old for women and 31-60 years old for men, over 55 for women and 60 years old for men) were studied. High levels of bilirubin in the blood serum in all groups indicated damage of the functions of hepatocytes, especially in men with hepatitis B, in women with hepatitis C. The high ALT activity indicated an increase in cytolytic processes in liver hepatocytes in all groups with viral HB and HC, especially in men of the younger group, in women of the younger and middle-aged grou

Mean proton and α -particle reduced widths of the Porter-Thomas distribution and astrophysical applications

The Porter-Thomas distribution is a key prediction of the Gaussian orthogonal ensemble in random matrix theory. It is routinely used to provide a measure for the number of levels that are missing in a given resonance analysis. The Porter-Thomas distribution is also of crucial importance for estimates of thermonuclear reaction rates where the contributions of certain unobserved resonances to the total reaction rate need to be taken into account. In order to estimate such contributions by randomly sampling over the Porter-Thomas distribution, the mean value of the reduced width must be known. We present mean reduced width values for protons and α particles of compound nuclei in the A = 28–67 mass range. The values are extracted from charged-particle elastic scattering and reaction data that weremeasured at the riangle Universities Nuclear Laboratory over several decades. Our new values differ significantly from those previously reported that were based on a preliminary analysis of a smaller data set. As an example for the application of our results, we present new thermonuclear rates for the 40Ca(α,γ)44Ti reaction, which is important for 44Ti production in core-collapse supernovae, and compare with previously reported results