Antideuteron production in proton-proton and proton-nucleus collisions

The experimental data of the antideuteron production in proton-proton and proton-nucleus collisions are analyzed within a simple model based on the diagrammatic approach to the coalescence model. This model is shown to be able to reproduce most of existing data without any additional parameter.Comment: To appear in Eur. Phys. J A (2002

A New Constraint for the Coupling of Axion-like particles to Matter via Ultra-Cold Neutron Gravitational Experiments

We present a new constraint for the axion monopole-dipole coupling in the range of 1 micrometer to a few millimeters, previously unavailable for experimental study. The constraint was obtained using our recent results on the observation of neutron quantum states in the Earth's gravitational field. We exploit the ultimate sensitivity of ultra-cold neutrons (UCN) in the lowest gravitational states above a material surface to any additional interaction between the UCN and the matter, if the characteristic interaction range is within the mentioned domain. In particular, we find that the upper limit for the axion monopole-dipole coupling constant is (g_p g_s)/(\hbar c)<2 x 10^{-15} for the axion mass in the ``promising'' axion mass region of ~1 meV.Comment: 5 pages 3 figure

Gravitational resonance spectroscopy with an oscillating magnetic field gradient in the GRANIT flow through arrangement

Gravitational resonance spectroscopy consists in measuring the energy spectrum of bouncing ultracold neutrons above a mirror by inducing resonant transitions between different discrete quantum levels. We discuss how to induce the resonances with a flow through arrangement in the GRANIT spectrometer, excited by an oscillating magnetic field gradient. The spectroscopy could be realized in two distinct modes (so called DC and AC) using the same device to produce the magnetic excitation. We present calculations demonstrating the feasibility of the newly proposed AC mode

Frequency shifts in gravitational resonance spectroscopy

Quantum states of ultracold neutrons in the gravitational field are to be characterized through gravitational resonance spectroscopy. This paper discusses systematic effects that appear in the spectroscopic measurements. The discussed frequency shifts, which we call Stern-Gerlach shift, interference shift, and spectator state shift, appear in conceivable measurement schemes and have general importance. These shifts have to be taken into account in precision experiments

Quasi-specular albedo of cold neutrons from powder of nanoparticles

We predicted and observed for the first time the quasi-specular albedo of cold neutrons at small incidence angles from a powder of nanoparticles. This albedo (reflection) is due to multiple neutron small-angle scattering. The reflection angle as well as the half-width of angular distribution of reflected neutrons is approximately equal to the incidence angle. The measured reflection probability was equal to ~30% within the detector angular size that corresponds to 40-50% total calculated probability of quasi-specular reflection

Nanoparticles as a possible moderator for an ultracold neutron source

Ultracold and very cold neutrons (UCN and VCN) interact strongly with nanoparticles due to the similarity of their wavelengths and nanoparticles sizes. We analyze the hypothesis that this interaction can provide efficient cooling of neutrons by ultracold nanoparticles at certain experimental conditions, thus increasing the density of UCN by many orders of magnitude. The present analytical and numerical description of the problem is limited to the model of independent nanoparticles at zero temperature. Constraints of application of this model are discussed

Storage of very cold neutrons in a trap with nano-structured walls

We report on storage of Very Cold Neutrons (VCN) in a trap with walls containing powder of diamond nanoparticles. The efficient VCN reflection is provided by multiple diffusive elastic scattering of VCN at single nanoparticles in powder. The VCN storage times are sufficiently long for accumulating large density of neutrons with complete VCN energy range of up to a few times 10(-4) eV. Methods for further improvements of VCN storage times are discussed

Antiproton-deuteron annihilation at low energies

Recent experimental studies of the antiproton-deuteron system at low energies have shown that the imaginary part of the antiproton-deuteron scattering length is smaller than the antiproton-proton one. Two- and three-body systems with strong annihilation are investigated and a mechanism explaining this unexpected relation between the imaginary parts of the scattering lengths is proposed.Comment: 6 pages, 3 figures, to be published in The European Physical Journal

Centrifugal quantum states of neutrons

We propose a method for observation of the quasi-stationary states of neutrons, localized near the curved mirror surface. The bounding effective well is formed by the centrifugal potential and the mirror Fermi-potential. This phenomenon is an example of an exactly solvable "quantum bouncer" problem that could be studied experimentally. It could provide a promising tool for studying fundamental neutron-matter interactions, as well as quantum neutron optics and surface physics effects. We develop formalism, which describes quantitatively the neutron motion near the mirror surface. The effects of mirror roughness are taken into account.Comment: 13 pages, 10 figure

Postoperative Cardiac Ischemic Complications in Lung Cancer Patients

Background. Perioperative myocardial ischemia often complicates extracardiac surgery. The problems of its prediction, diagnostics, treatment and prevention are not solved. Frequency, structure and clinical features of cardiac ischemic complications of surgical treatment of lung cancer are not well understood.The aim of the study was to investigate the frequency of postoperative myocardial infarction and myocardial ischemia in the surgical treatment of patients with non-small cell lung cancer.Methods. The frequency (%) of myocardial infarction (MI) with and without ST segment elevation of electrocardiogram, acute myocardial ischemia in a complete sample of cancer patients (n = 2051) who underwent treatment for non-small cell lung cancer for the last 10 years was calculated. By comparing the relative indicators and calculating the Odds Ratio (OR), we studied the relationship between the cardiac ischemic events with age, type of surgery, prevalence and localization of the tumour. The clinical manifestations and pathomorphology of postoperative myocardial infarction were analysed.Results. Cardiac ischemic complications of thoracotomy for lung cancer occurred in 2.73 % (95% CI 1.98–3.48) cases. Myocardial infarction with ST segment elevation was recorded in 1.07 % (95% CI 0.58–1.57) patients, MI without ST segment elevation – in 0.54 % (95% CI 0.17–0.9), myocardial ischemia – in 1.12 % (95% CI 0.62–1.63). An increase in the frequency of ischemic events after pneumonectomy was observed compared with lobectomy (OR 6.5, 95% CI 3.5–12.2) and after right-sided pneumonectomy compared with left-sided one (OR 3.2, 95% CI 1.6–6.3), and also the age over 70. Hospital mortality from MI was 39.3 %. According to autopsies of patients who died of МI, coronary atherothrombosis was detected in 2 of 22 cases.Conclusion. In the surgical treatment of non-small cell lung cancer, cardiac ischemic events develop in 2.73 % of patients. The greatest risk is associated with right-sided pneumonectomy