Three-body hadronic structure of low-lying 1/2+1/2^+ Σ\Sigma and Λ\Lambda resonances

We discuss the dynamical generation of some low-lying $1/2^+$ $\Sigma$'s and $\Lambda$'s in two-meson one-baryon systems. These systems have been constructed by adding a pion in $S$-wave to the $\bar{K} N$ pair and its coupled channels, where the $1/2^-$ $\Lambda$(1405)-resonance gets dynamically generated. We solve Faddeev equations in the coupled-channel approach to calculate the $T$-matrix for these systems as a function of the total energy and the invariant mass of one of the meson-baryon pairs. This squared $T$-matrix shows peaks at the energies very close to the masses of the strangeness -1, $1/2^+$ resonances listed in the particle data book.Comment: Contribution to the NSTAR07 conferenc

Recent developments in chiral dynamics of hadrons and hadrons in a nuclear medium

In this talk I present recent developments in chiral dynamics of hadrons and hadrons in a medium addressing the following points: interaction of the octet of pseudoscalar mesons with the octet of baryons of the nucleon, showing recent experimental evidence on the existence of two $\Lambda(1405)$ states, the interaction of the octet of pseudoscalar mesons with the decuplet of baryons of the $\Delta$, with particular emphasis on the $\Lambda(1520)$ resonance, dynamically generated by this interaction. Then I review the interaction of kaons in a nuclear medium and briefly discuss the situation around the claims of deeply bound states in nuclei. The large renormalization of the $\Lambda(1520)$ in the nuclear medium is shown as another example of successful application of the chiral unitary techniques.Comment: Talk at the Fifth International Conference on Perspectives in Hadronic Physics: Particle-Nucleus and Nucleus-Nucleus Scattering at Relativistic Energies, Trieste, May 200

Chiral dynamics of baryon resonances and hadrons in a nuclear medium

In these lectures I make an introduction to chiral unitary theory applied to the meson baryon interaction and show how several well known resonances are dynamically generated, and others are predicted. Two very recent experiments are analyzed, one of them showing the existence of two $\Lambda(1405)$ states and the other one providing support for the $\Lambda(1520)$ resonance as a quasibound state of $\Sigma(1385) \pi$. The use of chiral Lagrangians to account for the hadronic interaction at the elementary level introduces a new approach to deal with the modification of meson and baryon properties in a nuclear medium. Examples of it for $\bar{K}$, $\eta$ and $\phi$ modification in the nuclear medium are presented.Comment: Lectures given in the Workshop on Hadron Physics, Puri (India), march 200

Baryon resonances and polarization transfer in hyperon photoproduction

A partial wave analysis is presented of data on photoproduction of hyperons including single and double polarization observables. The large spin transfer probability reported by the CLAS collaboration can be successfully described with an isobar partial wave analysis.Comment: 12 pages, 9 figure

Сравнительная оценка некоторых климатических характеристик станции Новолазаревская и аэродрома станции Новолазаревская

The results of a comparative analysis of the monthly mean of average, maximum and minimum values of air temperature, air humidity and wind speed calculated by daily data with one minute increment for the period from November 2006 to February 2012 during the months of operation of the meteorological station at the Novolazarevskaya airfield and directly at Novolazarevskaya station are given. The climatic parameters at two points of observation give high correlation index. The estimations of the trends in time series of climatic references at Novolazarevskaya station for the period 1961–2015 are also given.Приводятся результаты сравнительного анализа среднемесячных величин средних, максимальных и минимальных значений температуры воздуха, влажности воздуха и скорости ветра, рассчитанных по ежедневным данным с минутной дискретностью за период с ноября 2006 г. по февраль 2012 г. в месяцы работы метеостанции на аэродроме станции Новолазаревская и непосредственно на станции Новолазаревская. Наблюдается высокая корреляция между этими климатическими характеристиками в двух точках наблюдений. Приведены оценки тенденций временных рядов климатических характеристик на станции Новолазаревская за период 1961–2015 гг

The nature of the Lambda(1405)

We present here some results supporting the nature of the $\Lambda(1405)$ resonance as dynamically generated from the meson baryon interaction in coupled channels and resulting from the superposition of two close-by poles. We find support for this picture in the $K^- p \to \pi^0 \pi^0 \Sigma^0$ reaction, which shows a different shape than the one obtained from the $\pi ^- p \to K^0 \pi \Sigma$ reaction. We also call the attention to the $K^- p \to \gamma \pi \Sigma$ with $\pi \Sigma$ in the $\Lambda(1405)$ region, which shows a narrow peak in the calculations around 1420 MeV. We also report on recent calculations of the radiative decay of the two $\Lambda(1405)$ states and on reactions to obtain information on these decay modes. Finally, we present results for the $pp\to p K^+\Lambda(1405)$ reaction recently measured at ANKE/COSY and compare them with theoretical results.Comment: Talk given at the NSTAR2007 Workshop, Bonn September 200

Separable potential model for K−NK^{-}N interactions at low energies

The effective separable meson-baryon potentials are constructed to match the equivalent chiral amplitudes up to the second order in external meson momenta. We fit the model parameters (low energy constants) to the threshold and low energy $K^{-}p$ data. In the process, the $K^{-}$-proton bound state problem is solved exactly in the momentum space and the 1s level characteristics of the kaonic hydrogen are computed simultaneously with the available low energy $K^{-}p$ cross sections. The model is also used to describe the $\pi \Sigma$ mass spectrum and the energy dependence of the $K^{-}n$ amplitude.Comment: 31 pages, v2 - added corrections to make it compatible with the published versio

Penta-quark states with hidden charm and beauty

More and more hadron states are found to be difficult to be accommodated by the quenched quark models which describe baryons as 3-quark states and mesons as antiquark-quark states. Dragging out an antiquark-quark pair from the gluon field in hadrons should be an important excitation mechanism for hadron spectroscopy. Our recent progress on the penta-quark states with hidden charm and beauty is reviewed.Comment: Plenary talk at the 5th Asia-Pacific Conference on Few-Body Problems in Physics 2011 (APFB2011), 22-26 Aug., 2011, Seoul, Kore

The cusp effect in eta' --> eta pi pi decays

Strong final-state interactions create a pronounced cusp in eta' --> eta pi0 pi0 decays. We adapt and generalize the non-relativistic effective field theory framework developed for the extraction of pi pi scattering lengths from K --> 3 pi decays to this case. The cusp effect is predicted to have an effect of more than 8% on the decay spectrum below the pi+ pi- threshold.Comment: 11 pages, 8 figures; comment added, typos corrected, version published in Eur. Phys. J.