Sum rule for a difference of proton and neutron total photoproduction cross-sections

Starting from very high energy inelastic electron-nucleon scattering with a production of a hadronic state $X$ to be moved closely to the direction of the initial nucleon, then utilizing analytic properties of parts of forward virtual Compton scattering amplitudes on proton and neutron, one obtains the relation between nucleon form factors and a difference of proton and neutron differential electroproduction cross-sections. In particular, for the case of small transferred momenta, one finally derives sum rule, relating Dirac proton mean square radius and anomalous magnetic moments of proton and neutron to the integral over a difference of the total proton and neutron photoproduction cross-sections.Comment: LaTeX2e, 7 pages, 1 eps figure (revised version

Process 3 -> 3 and crossing symmetry violation

Using the Sudakov technique we sum the perturbation series for the process $3\to 3$ and obtain the compact analytical expression for the amplitude of this process, which takes into account all possible Coulomb interactions between colliding particles. Compare it with the amplitude of the lepton pair production in heavy ion collision i.e. in the process $2\to 4$, we show that crossing symmetry between this processes holds only if one neglects the interaction of produced pair with ions (i.e. in the approximation $Z_{1,2}\alpha \ll 1$).Comment: LaTeX2e, 10 pages, 5 eps figure

New sum rules for nucleon and trinucleon total photoproduction cross-sections

Two new sum rules are derived relating Dirac radii and anomalous magnetic moments of the considered strongly interacting fermions with the convergent integral over a difference of the total proton and neutron, as well as $He^3$ and $H^3$, photoproduction cross-sections.Comment: 1 eps figure. Contribution presented at the PHOTON'03, April 7-11, 2003, Frascati (Roma), Ital

The lowest order inelastic QED processes at polarized photon-electron high energy collisions

The compact expressions for cross sections of photoproduction of a pair of charged particles $\mathrm{e}^+,\mathrm{e}^-$; $\mu^+,\mu^-$; $\pi^+,\pi^-$ as well as the double Compton scattering process are given. The explicit analytic expressions for the case of polarized photon and the initial electron in the kinematics when all the particles can be considered as a massless ones are presented. The photon polarization is described in the terms of Stokes parameters.Comment: LaTeX2e, 9 page

Radiative corrections to muon decay in leading and next to leading approximation for electron spectrum

We have noted that the electron spectrum of muon decay in the leading logarithmic approximation calculated in two lowest orders of the perturbation theory in the paper of Berman (1958), can be reproduced by the parton language. This fact permits one to generalize the result to all orders of the perturbation theory using the structure function method.Comment: 4 pages, 1 figur

Adjusting for Publication Bias in JASP and R: Selection Models, PET-PEESE, and Robust Bayesian Meta-Analysis

Meta-analyses are essential for cumulative science, but their validity can be compromised by publication bias. In order to mitigate the impact of publication bias, one may apply publication bias adjustment techniques such as PET-PEESE and selection models. Implemented in JASP & R, these methods allow researchers without programming experience to conduct state-of-the-art publication bias adjusted meta-analysis. In this tutorial, we demonstrate how to conduct a publication bias adjusted meta-analysis in JASP & R and interpret the results. First, we explain two frequentist bias correction methods: PET-PEESE and selection models. Second, we introduce robust Bayesian meta-analysis (RoBMA), a Bayesian approach that simultaneously considers both PET-PEESE and selection models. We illustrate the methodology on an example data set, provide instructional video (https://bit.ly/pubbias), R-markdown script (https://osf.io/uhaew/), and discuss the interpretation of the results. Finally, we include concrete guidance on reporting the meta-analytic results in an academic article

Recoil proton distribution in high energy photoproduction processes

For high energy linearly polarized photon--proton scattering we have calculated the azimuthal and polar angle distributions in inclusive on recoil proton experimental setup. We have taken into account the production of lepton and pseudoscalar meson charged pairs. The typical values of cross sections are of order of hundreds of picobarn. The size of polarization effects are of order of several percents. The results are generalized for the case of electroproduction processes on the proton at rest and for high energy proton production process on resting proton.Comment: LaTeX2e, 4 pages, 3 figure

Platelet Counts and Risk of Severe Retinopathy of Prematurity: A Bayesian Model-Averaged Meta-Analysis

Background: We aimed to conduct a systematic review and Bayesian model-averaged meta-analysis (BMA) on the association between platelet counts and severe retinopathy of prematurity (ROP). Methods: We searched for studies reporting on platelet counts (continuous variable) or thrombocytopenia (categorical variable) and severe ROP or aggressive posterior ROP (APROP). The timing of platelet counts was divided into Phase 1 (<2 weeks) and Phase 2 (around ROP treatment). BMA was used to calculate Bayes factors (BFs). The BF10 is the ratio of the probability of the data under the alternative hypothesis (H1) over the probability of the data under the null hypothesis (H0). Results: We included 21 studies. BMA showed an association between low platelet counts and severe ROP. The evidence was strong (BF10 = 13.5, 7 studies) for phase 1 and very strong (BF10 = 51.0, 9 studies) for phase 2. Thrombocytopenia (<100 × 109/L) in phase 2 was associated with severe ROP (BF10 = 28.2, 4 studies). Following adjustment for publication bias, only the association of severe ROP with thrombocytopenia remained with moderate evidence in favor of H1 (BF10 = 4.30). Conclusions: Thrombocytopenia is associated with severe ROP. However, the evidence for this association was tempered when results were adjusted for publication bias