اشترك بالحزمة الذهبية واحصل على وصول غير محدود شمرا أكاديميا
تسجيل مستخدم جديدX-ray energies of circular transitions and electrons screening in kaonic atoms
97
0
0.0
(
0
)
تأليف
J.P. Santos
اسأل ChatGPT حول البحث
ﻻ يوجد ملخص باللغة العربية
The QED contribution to the energies of the circular (n,l=n-1), 2 ≤ n ≤ 19 transitions have been calculated for several kaonic atoms throughout the periodic table, using the current world average kaon mass. Calculations were done in the framework of the Klein-Gordon equation, with finite nuclear size and all-order Uelhing vacuum polarization corrections, as well as Kallen and Sabry and Wichmann and Kroll corrections. These energy level values are compared with other computed values. The circular transition energies are compared with available measured and theoretical transition energy. Electron screening is evaluated using a Dirac-Fock model for the electronic part of the wave function. The effect of electronic wavefunction correlation is evaluated for the first time.
قيم البحث
اقرأ أيضاً
Photoabsorption by and fluorescence of the K{alpha} transitions in highly charged iron ions are essential mechanisms for X-ray radiation transfer in astrophysical environments. We study photoabsorption due to the main K{alpha} transitions in highly c
harged iron ions from heliumlike to fluorinelike (Fe 24+...17+) using monochromatic X-rays around 6.6 keV at the PETRA III synchrotron photon source. Natural linewidths were determined with hitherto unattained accuracy. The observed transitions are of particular interest for the understanding of photoexcited plasmas found in X-ray binaries and active galactic nuclei.
The X-ray transition yields of kaonic atoms produced in Kapton polyimide (C22H10N2O5) were measured for the first time in the SIDDHARTA experiment. X-ray yields of the kaonic atoms with low atomic numbers (Z = 6, 7, and 8) and transitions with high p
rincipal quantum numbers (n = 5-8) were determined. The relative yield ratios of the successive transitions and those of carbon-to-nitrogen (C:N) and carbon-to-oxygen (C:O) were also determined. These X-ray yields provide important information for understanding the capture ratios and cascade mechanisms of kaonic atoms produced in a compound material, such as Kapton.
We study the screening of a homogeneous oscillating external electric field $E_0$ in noble-gas atoms using atomic many-body calculations. At zero frequency of the oscillations ($omega=0$) the screened field $E(r)$ vanishes at the nucleus, $E(0)=0$. H
owever, the profile of the field $E(r)$ is complicated, with the magnitude of the field exceeding the external field $E_0$ at certain points. For $omega >0$ the field $E(r,omega)$ strongly depends on $omega$ and at some points may exceed the external field $E_0$ many times. The field at the nucleus is not totally screened and grows with $omega$ faster than $omega^2$. It can even be enhanced when $omega$ comes close to resonance with a frequency of an atomic transition. This field interacts with CP-violating nuclear electric dipole moments creating new opportunities for studying them. The screening of the external field by atomic electrons may strongly suppress (or enhance near an atomic resonance) the low energy nuclear electric dipole transitions.
We measured the $K$-series X-rays of the $K^{-}p$ exotic atom in the SIDDHARTA experiment with a gaseous hydrogen target of 1.3 g/l, which is about 15 times the $rho_{rm STP}$ of hydrogen gas. At this density, the absolute yields of kaonic X-rays, wh
en a negatively charged kaon stopped inside the target, were determined to be 0.012$^{+0.004}_{-0.003}$ for $K_{alpha}$ and 0.043$^{+0.012}_{-0.011}$ for all the $K$-series transitions $K_{tot}$. These results, together with the KEK E228 experiment results, confirm for the first time a target density dependence of the yield predicted by the cascade models, and provide valuable information to refine the parameters used in the cascade models for the kaonic atoms.
The onset of antiprotonic X-ray transitions at high principal quantum numbers and the occurence of electronic X-rays in antiprotonic argon, krypton, and xenon has been analyzed with the help of Multiconfiguration Dirac-Fock calculations. The shell-by
-shell ionisation by Auger electron emission, characterised by appearance and disappearance of X-ray lines, is followed through the antiprotonic cascade by considering transition and binding energies of both the antiproton and the remaining electrons. Electronic lines could be attributed partly to specific states of the antiprotonic atom de-excitation.
سجل دخول لتتمكن من نشر تعليقات
التعليقات
جاري جلب التعليقات
سجل دخول لتتمكن من متابعة معايير البحث التي قمت باختيارها
