Effects of mesonic correlations in the QCD phase transition

The finite temperature phase transition of strongly interacting matter is studied within a nonlocal chiral quark model of the NJL type coupled to a Polyakov loop. In contrast to previous investigations which were restricted to the mean-field approximation, mesonic correlations are included by evaluating the quark-antiquark ring sum. For physical pion masses, we find that the pions dominate the pressure below the phase transition, whereas above T_c the pressure is well described by the mean-field approximation result. For large pion masses, as realized in lattice simulations, the meson effects are suppressed.Comment: 11 pages, 4 figures; version accepted for publication in Yad. Fiz., text extended, 1 figure adde

rho(omega)-> pi^0 pi^0 gamma, rho(omega) -> eta pi^0 gamma decays in the local quark Nambu--Jona-Lasinio model

The branching ratios and photon spectra of the rare processes rho(omega)-> pi^0 pi^0 gamma, rho(omega) -> eta pi^0 gamma are calculated in the framework of the standard local quark Nambu--Jona-Lasinio (NJL) model. Three types of diagrams are considered: the quark box and the pole diagrams with scalar (sigma,a_0(980)) and vector (rho,omega) mesons. The obtained estimations for the widths of the processes rho(omega)-> pi^0 pi^0 gamma are in satisfactory agreement with existing experimental data. Predictions are made for the widths of the processes rho(omega) -> eta pi^0 gamma.Comment: 6 pages, 5 figure

Phase diagrams in nonlocal PNJL models constrained by Lattice QCD results

Based on lattice QCD-adjusted SU(2) nonlocal Polyakov--Nambu--Jona-Lasinio (PNJL) models, we investigate how the location of the critical endpoint in the QCD phase diagram depends on the strenght of the vector meson coupling, as well as the Polyakov-loop (PL) potential and the form factors of the covariant model. The latter are constrained by lattice QCD data for the quark propagator. The strength of the vector coupling is adjusted such as to reproduce the slope of the pseudocritical temperature for the chiral phase transition at low chemical potential extracted recently from lattice QCD simulations. Our study supports the existence of a critical endpoint in the QCD phase diagram albeit the constraint for the vector coupling shifts its location to lower temperatures and higher baryochemical potentials than in the case without it.Comment: 23 pages, 10 figures. Version accepted in Phys. Part. Nucl. Lett. (to appear), references adde

CarotidSCORE.RU — risk stratification for complications after carotid endarterectomy

Aim. To demonstrate the first Russian computer program (carotidscore.ru) for risk stratification of postoperative complications of carotid endarterectomy (CE).Material and methods. The present study is based on the analysis of a multicenter Russian database including 25812 patients after CE operated on from January 1, 2010 to April 1, 2022. The following types of CE were implemented: conventional CE with patch angioplasty — 6814 patients; eversion CE — 18998 patients. Following postoperative complications were assessed during the study: death, stroke, myocardial infarction (MI), composite endpoint (death + stroke + MI).Results. During inhospital postoperative period, 0,18% of participants died, while 0,14% had MI, 0,35% — stroke. The composite endpoint was recorded in 0,68%. For each factor present in patients, a predictive coefficient was estimated. The predictive coefficient was considered as a numerical parameter reflecting the strength of the effect of each factor on the development of postoperative complications. Based on this equation, predictive coefficients were calculated for each factor present in patients in our study. The total contribution of these factors was reflected as a percentage and denoted the risk of postoperative complications with a minimum of 0% and a maximum of 100%. On the basis of obtained calculations, a CarotidSCORE program was created. Its graphical interface is based on the QT framework. It is possible not only to estimate the risk of a complication, but also to save all data about a patient in JSON format. The CarotidSCORE program contains 47 patient parameters, including clinical, demographic, anamnestic and angiographic characteristics. It makes it possible to choose one of the four CE types, which will provide an accurate stratification of the complication risk for each of them.Conclusion. CarotidSCORE (carotidscore.ru) may determine the probability of postoperative complications in patients undergoing CE

Ten-year long-term outcomes of conventional and eversion carotid endarterectomy. Multicenter study

Aim. To analyze the immediate and long-term outcomes of eversion and conventional carotid endarterectomy (CE) with patch angioplasty.Material and methods. For the period from February 1, 2006 to September 1, 2021, the present retrospective multicenter open comparative study included 25106 patients who underwent CE. Depending on the technique of operation, the following groups were formed: group 1 (n=18362) — eversion CE; group 2 (n=6744) — conventional CE with patch angioplasty. The long-term follow-up period was 124,7±53,8 months.Results. In the hospital postoperative period, the groups were comparable in incidence of all complications: lethal outcome (group 1: 0,19%, n=36; group 2: 0,17%, n=12; p=0,89; odds ratio (OR) =1,1; 95% confidence interval (CI) =0,57- 2,11); myocardial infarction (MI) (group 1: 0,15%, n=28; group 2: 0,13%, n=9; p=0,87; OR=1,14; 95% CI=0,53-2,42); stroke (group 1: 0,33%, n=62; group 2: 0,4%, n=27; p=0,53; OR=0,84; 95% CI=0,53-1,32); bleeding with hematoma formation (group 1: 0,39%, n=73; group 2: 0,41%, n=28; p=0,93; OR=0,95; 95% CI=0,61-1,48); internal carotid artery (ICA) thrombosis (group 1: 0,05%, n=11; group 2: 0,07%, n=5, p=0,9; OR=0,8; 95% CI=0,28-2,32). In the long-term follow-up, the groups were comparable only in MI incidence: group 1: 0,56%, n=103; group 2: 0,66%, n=45; p=0,37; OR=0,84; 95% CI=0,59-1,19. All other complications were more frequent after conventional CE with patch angioplasty: all-cause death (group 1: 2,7%, n=492; group 2: 9,1%, n=616; p<0,0001; OR=0,27; 95% CI=0,24-0,3); lethal ischemic stroke (group 1: 1,0%, n=180; group 2: 5,5%, n=371; p<0,0001; OR=0,17; 95% CI=0,14-0,21); non-lethal ischemic stroke (group 1: 0,62%, n=114; group 2: 7,0%, n=472; p<0,0001; OR=0,08; 95% CI=0,06-0,1); ICA restenosis >60%, requiring re-revascularization (group 1: 1,6%, n=296; group 2: 12,6%, n=851; p<0,0001; OR=0,11; 95% CI=0,09-0,12). Thus, the composite endpoint (lethal ischemic stroke + non-lethal ischemic stroke + MI) after conventional CE with patch angioplasty was more than 6 times higher than this parameter of eversion CE: group 1: 2,2%, n=397; group 2: 13,2%, n=888; p<0,0001; OR=0,14; 95% CI=0,12-1,16.Conclusion. Conventional CE with patch angioplasty is not prefer for cerebral revascularization in the presence of hemodynamically significant ICA stenosis due to the high prevalence of deaths, stroke, and ICA restenosis in the long-term follow-up

The anomalous magnetic moment of the muon in the Standard Model

194 pages, 103 figures, bib files for the citation references are available from: https://muon-gm2-theory.illinois.eduWe review the present status of the Standard Model calculation of the anomalous magnetic moment of the muon. This is performed in a perturbative expansion in the fine-structure constant $\alpha$ and is broken down into pure QED, electroweak, and hadronic contributions. The pure QED contribution is by far the largest and has been evaluated up to and including $\mathcal{O}(\alpha^5)$ with negligible numerical uncertainty. The electroweak contribution is suppressed by $(m_\mu/M_W)^2$ and only shows up at the level of the seventh significant digit. It has been evaluated up to two loops and is known to better than one percent. Hadronic contributions are the most difficult to calculate and are responsible for almost all of the theoretical uncertainty. The leading hadronic contribution appears at $\mathcal{O}(\alpha^2)$ and is due to hadronic vacuum polarization, whereas at $\mathcal{O}(\alpha^3)$ the hadronic light-by-light scattering contribution appears. Given the low characteristic scale of this observable, these contributions have to be calculated with nonperturbative methods, in particular, dispersion relations and the lattice approach to QCD. The largest part of this review is dedicated to a detailed account of recent efforts to improve the calculation of these two contributions with either a data-driven, dispersive approach, or a first-principle, lattice-QCD approach. The final result reads $a_\mu^\text{SM}=116\,591\,810(43)\times 10^{-11}$ and is smaller than the Brookhaven measurement by 3.7$\sigma$. The experimental uncertainty will soon be reduced by up to a factor four by the new experiment currently running at Fermilab, and also by the future J-PARC experiment. This and the prospects to further reduce the theoretical uncertainty in the near future-which are also discussed here-make this quantity one of the most promising places to look for evidence of new physics