1,101 research outputs found
Relativistic corrections to \eta_c-pair production in high energy proton-proton collisions
On the basis of perturbative QCD and the relativistic quark model we
calculate relativistic corrections to the double meson production in
proton-proton interactions at LHC energies. Relativistic terms in the
production amplitude connected with the relative motion of heavy quarks and the
transformation law of the bound state wave functions to the reference frame of
moving charmonia are taken into account. For the gluon and quark propagators
entering the amplitude we use a truncated expansion in relative quark momenta
up to the second order. Relativistic corrections to the quark bound state wave
functions are considered by means of the Breit-like potential. It turns out
that the examined effects decrease total nonrelativistic cross section more
than two times and on 20 percents in the rapidity region of LHCb detector.Comment: 12 pages, 3 figure
Pair double heavy diquark production in high energy proton-proton collisions
On the basis of perturbative QCD and relativistic quark model we calculate
relativistic and bound state corrections in the production processes of a pair
of double heavy diquarks. Relativistic factors in the production amplitude
connected with the relative motion of heavy quarks and the transformation law
of the bound state wave function to the reference frame of the moving S-wave
diquark bound states are taken into account. For the gluon and quark
propagators entering the amplitudes we use a truncated expansion in relative
quark momenta up to the second order. Relativistic corrections to the
quark-quark bound state wave functions in the rest frame are considered by
means of the Breit-like potential. It turns out that the examined effects
significantly decrease nonrelativistic cross sections.Comment: 20 pages, 5 figure
Determining the size of the proton
A measurement of the Lamb shift of 49,881.88(76) GHz in muonic hydrogen in
conjunction with theoretical estimates of the proton structure effects was
recently used to deduce an accurate but rather small radius of the proton. Such
an important shift in the understanding of fundamental values needs
reconfirmation. Using a different approach with electromagnetic form factors of
the proton, we obtain a new expression for the transition energy, , in muonic hydrogen and deduce
a proton radius, fm.Comment: 20 pages LaTe
Self-energy correction to the bound-electron g factor in H-like ions
The one-loop self-energy correction to the 1s electron g factor is evaluated
to all orders in Z\alpha with an accuracy, which is essentially better than
that of previous calculations of this correction. As a result, the uncertainty
of the theoretical prediction for the bound-electron g factor in H-like carbon
is reduced by a factor of 3. This improves the total accuracy of the recent
electron-mass determination [Beier et al. Phys. Rev. Lett. 88, 011603 (2002)].
The new value of the electron mass is found to be m_e = 0.000 548 579 909 3(3)
u
Nucleus polarizability contribution to the hydrogen-deuterium isotope shift
The correction to the hydrogen-deuterium isotope shift due to the proton and
deuteron polarizability is evaluated on the basis of modern experimental data
on the structure functions of inelastic lepton-nucleus scattering. The
numerical value of this contribution is equal 63\pm 12 Hz.Comment: 5 page
Development of enterprise reputation management in the sphere of medical services
Topicality of the theme is determined by the increased role and influence of patients on the formation of the reputation of healthcare organisations in the conditions of active use of social networks by patients as a source of information when choosing a doctor. The purpose of the article was to identify the specificity and stages of the process of development of enterprise reputation management in the sphere of medical services. In the process of achieving this purpose there were used such scientific research methods as logic generalisation, comparative analysis, synthesis, graphical method as well. For gathering the feedback from the patients, the survey method based on quantitative analysis of responses and net promoter score was used. The specifics of medical services and their types were substantiated as the main results of the research, as well as elements that determine the value of medical services for the consumers. The features and trends of reputation management in the field of medical services have been considered and the stages of the process of development of reputation management of the healthcare organisation have been substantiated. As a result of the propositions, considered in the article, it has become possible to solve the reputational contradictions at enterprises in the field of medical services. With the purpose of improving reputational management the algorithm for the application of Search engine reputation management technology elements was developed for the work with consumers’ feedback. Practical meaning of the results is in increasing the effectiveness of reputational management and its development due to the implementation of elaborated algorithm into the process of everyday work with clients of healthcare organisation. It can be the basis for planning changes in business processes and operational management as well as for optimisation of the use of resource
A spectral characterization of skeletal maps
We prove that a map between two realcompact spaces is skeletal if and only if it is homeomorphic to the limit map of a skeletal morphism between ω-spectra with surjective limit projections
- …