72 research outputs found
Young-type interference in projectile-electron loss in energetic ion-molecule collisions
Under certain conditions an electron bound in a fast projectile-ion,
colliding with a molecule, interacts mainly with the nuclei and inner shell
electrons of atoms forming the molecule. Due to their compact localization in
space and distinct separation from each other these molecular centers play in
such collisions a role similar to that of optical slits in light scattering
leading to pronounced interference in the spectra of the electron emitted from
the projectile.Comment: 4 pages, 3 figure
Imaging Molecules from Within: Ultra-fast, {\AA}ngstr\"om Scale Structure Determination of Molecules via Photoelectron Holography using Free Electron Lasers
A new scheme based on (i) upcoming brilliant X-ray Free Electron Laser (FEL)
sources, (ii) novel energy and angular dispersive, large-area electron imagers
and (iii) the well-known photoelectron holography is elaborated that provides
time-dependent three-dimensional structure determination of small to medium
sized molecules with {\AA}ngstr\"om spatial and femtosecond time resolution.
Inducing molecular dynamics, wave-packet motion, dissociation, passage through
conical intersections or isomerization by a pump pulse this motion is
visualized by the X-ray FEL probe pulse launching keV photoelectrons within few
femtoseconds from specific and well-defined sites, deep core levels of
individual atoms, inside the molecule. On their way out the photoelectrons are
diffracted generating a hologram on the detector that encodes the molecular
structure at the instant of photoionization, thus providing 'femtosecond
snapshot images of the molecule from within'. Detailed calculations in various
approximations of increasing sophistication are presented and three-dimensional
retrieval of the spatial structure of the molecule with {\AA}ngstr\"om spatial
resolution is demonstrated. Due to the large photo-absorption cross sections
the method extends X-ray diffraction based, time-dependent structure
investigations envisioned at FELs to new classes of samples that are not
accessible by any other method. Among them are dilute samples in the gas phase
such as aligned, oriented or conformer selected molecules, ultra-cold ensembles
and/or molecular or cluster objects containing mainly light atoms that do not
scatter X-rays efficiently.Comment: 18 pages, 11 figure
Ion-lithium collision dynamics studied with an in-ring MOTReMi
We present a novel experimental tool allowing for kinematically complete
studies of break-up processes of laser-cooled atoms. This apparatus, the
'MOTReMi', is a combination of a magneto-optical trap (MOT) and a Reaction
Microscope (ReMi). Operated in an ion-storage ring, the new setup enables to
study the dynamics in swift ion-atom collisions on an unprecedented level of
precision and detail. In first experiments on collisions with 1.5 MeV/amu
O-Li the pure ionization of the valence electron as well as
ionization-excitation of the lithium target has been investigated
The effect of Polygonum hyrcanicum Rech. f. hydroalcoholic extract on oxidative stress and nephropathy in alloxan-induced diabetic mice
Diabetic nephropathy, characterized by inflammation and oxidative stress, poses a management challenge. This study investigates the effect of Polygonum hyrcanicum extract on diabetic nephropathy in alloxan-induced diabetic mice. In this experimental animal study, the P. hyrcanicum extract was prepared using continuous macerations. Thirty male Albino mice, divided into five groups, were induced with alloxan-induced diabetes. They received intraperitoneal injections of the plant extract (100 and 200 mg/kg) and metformin (300 mg/kg) for four weeks. Kidney and blood samples were collected to assess protein carbonyl, glutathione, lipid peroxidation, TNF-α and IL-6 levels. The amount of total flavonoid and phenolic content in the hydroalcoholic extract of P. hyrcanicum were 7.5 ± 0.3 mg of quercetin and 88.2 ± 1.3 mg gallic acid per gram of extract respectively. The antioxidant activity level of the hydroalcoholic extract was determined to be 1.78 ± 0.51 mM equivalent per gram of extract. Alloxan administration resulted in a significant reduction in glutathione levels and a significant increase in protein carbonyl, lipid peroxidation, TNF-α, and IL-6 levels. Hydroalcoholic extract of P. hyrcanicum effectively reduced oxidative stress markers and inflammatory cytokines (TNF-α, IL-6), indicating its potential in mitigating diabetic nephropathy. However, no significant difference in efficacy was observed between the 100 mg/kg and 200 mg/kg doses in terms of reducing these toxicities
Bound-bound pair production in relativistic collisions
Electron-positron pair production is considered in the relativistic collision
of a nucleus and an anti-nucleus, in which both leptons are created in bound
states of the corresponding nucleus-lepton system. Compared to free and
bound-free pair production this process is shown to display a qualitatively
different dependency both on the impact energy and charged of the colliding
particles. Interestingly, at high impact energies the cross section for this
process is found to be larger than that for the analogous atomic process of
non-radiative electron capture although the latter does not involve the
creation of new particles.Comment: 4 pages, 3 figure
Polarization and Interference Effects in Ionization of Li by Ion Impact
We present initial-state selective fully differential cross sections for ionization of lithium by 24 MeV O8+ impact. The data for ionization from the 2s and 2p states look qualitatively different from each other and from 1s ionization of He. For ionization from the 2p state, to which in our study the mL=-1 substate predominantly contributes, we observe orientational dichroism and for 2s ionization pronounced interference which we trace back to the nodal structure of the initial-state wave function
Ion-Lithium Collision Dynamics Studied with a Laser-Cooled In-Ring Target
We present a novel experimental tool allowing for kinematically complete studies of break-up processes of laser-cooled atoms. This apparatus, the \u27MOTReMi,\u27 is a combination of a magneto-optical trap (MOT) and a reaction microscope (ReMi). Operated in an ion-storage ring, the new setup enables us to study the dynamics in swift ion-atom collisions on an unprecedented level of precision and detail. In the inaugural experiment on collisions with 1.5MeV/amu O8 +-Li the pure ionization of the valence electron as well as the ionization-excitation of the lithium target was investigated
The CLIC Potential for New Physics
The Compact Linear Collider (CLIC) is a mature option for the future of high
energy physics. It combines the benefits of the clean environment of
colliders with operation at high centre-of-mass energies, allowing to probe
scales beyond the reach of the Large Hadron Collider (LHC) for many scenarios of new physics. This places the CLIC project at a privileged spot in between the precision and energy frontiers, with capabilities that will significantly extend knowledge on both fronts at the end of the LHC era. In this report we review and revisit the potential of CLIC to search, directly and indirectly, for physics beyond the Standard Model
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