Nonleptonic Hyperon Decays with QCD Sum Rules

Despite measurements which date more than 20 years ago, no straightforward solution of the ratio of the parity-conserving (P-wave) to parity- violating (S-wave) decays of the hyperons has been obtained. Here we use two 2-point methods in QCD sum rules to examine the problem. We find that resonance contributions are needed to fit the data, similar to a chiral perturbation theory treatment.Comment: 17 pages, 8 figure

Semileptonic D decay into scalar mesons: a QCD sum rule approach

Semileptonic decays of D-mesons into scalar hadronic states are investigated. Two extreme cases are considered: a) the meson decays directly into an uncorrelated scalar state of two two mesons and b) the decay proceeds via resonance formation. QCD sum rules including instanton contributions are used to calculate total and differential decay rates under the two assumptions.Comment: 18 pages, 9 figures, e-mail: [email protected]

The coupling constant gρσγ_{\rho\sigma\gamma} as derived from QCD sum rules

We employ QCD sum rules to calculate the coupling constant g$_{\rho\sigma\gamma}$ by studying the three point ${\rho\sigma\gamma}$-correlation function. Our results is consistent with the value of this coupling constant obtained using vector meson dominance of the electromagnetic current and the experimental $\rho^0$-photoproduction data.Comment: 10 pages RevTex, 3 postscript figure

Non-Perturbative QCD Treatment of High-Energy Hadron-Hadron Scattering

Total cross-sections and logarithmic slopes of the elastic scattering cross-sections for different hadronic processes are calculated in the framework of the model of the stochastic vacuum. The relevant parameters of this model, a correlation length and the gluon condensate, are determined from scattering data, and found to be in very good agreement with values coming from completely different sources of information. A parameter-free relation is given between total cross-sections and slope parameters, which is shown to be remarkably valid up to the highest energies for which data exist.Comment: 60 pages, Heidelberg preprin

The Pion-Nucleon Form Factor From QCD Sum Rules

QCD sum rules are used to calculate the $q^2$ dependence of the $\pi NN$ coupling $g_{\pi NN} (q^2)$ in the spacelike region 0.5 \ {\mbox{GeV}}^2 \lesssim q^2 \lesssim 1.5\ {\mbox{GeV}}^2. We study the Borel sum rule for the three point function of one pseudoscalar and two nucleon currents up to order four in the operator product expansion. The Borel transform is performed with respect to the nucleon momenta, whereas the momentum $q^2$ of the pseudoscalar vertex is kept fixed at spacelike values. The results can be well fitted using a monopole form with a cutoff mass of about $\Lambda_\pi \approx 800 \ {\mbox{MeV}}.Comment: 13 pages (REVTEX), 6 figures as 5 postscript files (as fig.uu tarred, compressed, uudecoded

The Proton Spin and Flavor Structure in the Chiral Quark Model

After a pedagogical review of the simple constituent quark model and deep inelastic sum rules, we describe how a quark sea as produced by the emission of internal Goldstone bosons by the valence quarks can account for the observed features of proton spin and flavor structures. Some issues concerning the strange quark content of the nucleon are also discussed.Comment: 59 pages with table of contents, Lecture delivered at the Schladming Winter School (March 1997), to be published by Springer-Verlag under the title "Computing Particle Properties" (eds. C. B. Lang and H. Gausterer

DsD_s decays into ϕ\phi and f0(980)f_0(980) mesons

We consider the nonleptonic and semileptonic decays of $D_s$-mesons into $\phi$ and $f_0(980)$ mesons. QCD sum rules are used to calculate the form factors associated with these decays, and the correspondig decay rates. On the basis of data on $D_s^+\to\pi^+\pi^+\pi^-$, which goes dominantly via the transition $D_s^+\to \pi^+f_0(980)$, we conclude that there is space for a sizeable light quark component on $f_0(980)$.Comment: 14 pages, RevTeX4 including 5 figures in ps file

Probing exotic phenomena at the interface of nuclear and particle physics with the electric dipole moments of diamagnetic atoms: A unique window to hadronic and semi-leptonic CP violation

The current status of electric dipole moments of diamagnetic atoms which involves the synergy between atomic experiments and three different theoretical areas -- particle, nuclear and atomic is reviewed. Various models of particle physics that predict CP violation, which is necessary for the existence of such electric dipole moments, are presented. These include the standard model of particle physics and various extensions of it. Effective hadron level combined charge conjugation (C) and parity (P) symmetry violating interactions are derived taking into consideration different ways in which a nucleon interacts with other nucleons as well as with electrons. Nuclear structure calculations of the CP-odd nuclear Schiff moment are discussed using the shell model and other theoretical approaches. Results of the calculations of atomic electric dipole moments due to the interaction of the nuclear Schiff moment with the electrons and the P and time-reversal (T) symmetry violating tensor-pseudotensor electron-nucleus are elucidated using different relativistic many-body theories. The principles of the measurement of the electric dipole moments of diamagnetic atoms are outlined. Upper limits for the nuclear Schiff moment and tensor-pseudotensor coupling constant are obtained combining the results of atomic experiments and relativistic many-body theories. The coefficients for the different sources of CP violation have been estimated at the elementary particle level for all the diamagnetic atoms of current experimental interest and their implications for physics beyond the standard model is discussed. Possible improvements of the current results of the measurements as well as quantum chromodynamics, nuclear and atomic calculations are suggested.Comment: 46 pages, 19 tables and 16 figures. A review article accepted for EPJ

Elliptic hypergeometry of supersymmetric dualities II. Orthogonal groups, knots, and vortices

We consider Seiberg electric-magnetic dualities for 4d $\mathcal{N}=1$ SYM theories with SO(N) gauge group. For all such known theories we construct superconformal indices (SCIs) in terms of elliptic hypergeometric integrals. Equalities of these indices for dual theories lead both to proven earlier special function identities and new conjectural relations for integrals. In particular, we describe a number of new elliptic beta integrals associated with the s-confining theories with the spinor matter fields. Reductions of some dualities from SP(2N) to SO(2N) or SO(2N+1) gauge groups are described. Interrelation of SCIs and the Witten anomaly is briefly discussed. Possible applications of the elliptic hypergeometric integrals to a two-parameter deformation of 2d conformal field theory and related matrix models are indicated. Connections of the reduced SCIs with the state integrals of the knot theory, generalized AGT duality for (3+3)d theories, and a 2d vortex partition function are described.Comment: Latex, 58 pages; paper shortened, to appear in Commun. Math. Phy

ОСТРЫЕ НАРУШЕНИЯ МОЗГОВОГО КРОВООБРАЩЕНИЯ ВО ВРЕМЯ БЕРЕМЕННОСТИ, РОДОВ И В ПОСЛЕРОДОВОМ ПЕРИОДЕ

Background: Acute cerebrovascular accidents are rare and serious complication of pregnancy, labor and puerperium, leading to an increase in maternal and perinatal morbidity and mortality. More than 12% of maternal mortality is related to stroke. Aim: To assess the impact of pregnancy on the incidence of stroke, as well as the impact of cerebrovascular disorders on pregnancy, labor and puerperium. Materials and methods: We retrospectively and prospectively analyzed the course of pregnancy, labor and puerperium in 136 female patients with strokes of various etiologies. The diagnosis of stroke and cerebrovascular disorders was verified with magnetic resonance imaging, angiography, conventional and multiaxial computerized tomography, ophthalmoscopy, electroencephalography, electrocardiography and echocardiography (trans-thoracic and trans-esophageal), 24-hour blood pressure monitoring and electrocardiogram monitoring, ultrasound assessment of extra and intracranial vasculature with duplex scanning, cerebral angiography and laboratory assessments. Results: The analysis of 92 strokes that occurred during pregnancy, labor and postpartum showed that 38% of the cases (n=35) were caused by various cerebrovascular abnormalities. In 18.5% of the cases (n=17), acute cerebrovascular accidents occurred in patients with preeclampsia/eclampsia. Most often (84.8%, or 78/97 of cases) strokes or other cerebrovascular accidents developed in II and III trimesters. The most severe cases were patients with intracranial hemorrhages (n=31). In this group, there were 5  deaths of mothers, 1  antenatal and 1  neonatal fetal deaths. In 90% of these cases (28/31), intracranial hemorrhage in pregnancy was related to manifestation of intracerebral vascular abnormality (arteriovenous malformations, arterial aneurysms, cavernomas). We observed a 4-fold rate of arteriovenous malformation ruptures during pregnancy (21 cases vs. 5). The rates of arterial aneurysm and cavernoma ruptures during pregnancy and in the past history were comparable (6 and 8 cases and 4 and 6 cases, respectively). Conclusion: An acute cerebrovascular accident is a hazardous complication of pregnancy, which increases maternal and perinatal morbidity and mortality. Pregnancy increases the risk of manifestation of brain arteriovenous malformations. Актуальность. Острое нарушение мозгового кровообращения (ОНМК)  – редкое, грозное осложнение беременности, родов и  послеродового периода, приводящее к повышению материнской и  перинатальной заболеваемости и смертности. Инсульт составляет более 12% материнской смертности. Цель  – оценить влияние беременности на частоту ОНМК, а  также воздействие цереброваскулярной патологии на течение беременности, родов и послеродового периода. Материал и методы. Проведен ретроспективный и проспективный анализ течения беременности, родов и  послеродового периода у  136  пациенток с  ОНМК различной этиологии. Для верификации диагноза ОНМК и  цереброваскулярной патологии использовали магнитно-резонансную томографию и  ангиографию, компьютерную томографию, мультиспиральную компьютерную томографию, офтальмоскопию, электроэнцефалографию, электрокардиографию и  эхокардиографию (трансторакальную и  чреспищеводную), суточное мониторирование артериального давления и  электрокардиограммы, ультразвуковое исследование экстра- и  интракраниальных сосудов с дуплексным сканированием, церебральную ангиографию, лабораторные методы исследования. Результаты. Анализ 92 случаев ОНМК во время беременности, родов и  послеродового периода показал, что в  38%  случаев (n=35) причиной этого осложнения была различная цереброваскулярная патология. В  18,5%  наблюдений (n=17) ОНМК было на фоне преэклампсии/эклампсии. Чаще всего – в 84,8% случаев (78 из 97) – ОНМК или другие проявления цереброваскулярной патологии развивались во II и  III триместрах беременности. Наиболее тяжелую группу составили пациентки с внутричерепным кровоизлиянием (n=31). В  этой группе было 5  летальных исходов для матерей, 1  антенатальная и  1  неонатальная гибель плодов. В  90%  случаев (28  из 31) причиной внутричерепного кровоизлияния у  беременных стал манифест внутримозговой сосудистой патологии (артериовенозные мальформации, артериальные аневризмы, каверномы). Отмечено увеличение частоты разрыва артериовенозных мальформаций во время беременности в  4  раза по сравнению с аналогичным показателем в анамнезе (21 случай против  5). При этом частота разрывов артериальных аневризм и  каверном во время беременности и в анамнезе была сопоставима (6 и 8 случаев и 4 и 6 случаев соответственно). Заключение. ОНМК  – грозное осложнение беременности, приводящее к  увеличению материнской и  перинатальной заболеваемости и смертности. Беременность способствует повышению частоты манифеста артериовенозных мальформаций головного мозга