Production and detection of doubly charmed tetraquarks

The feasibility of tetraquark detection is studied. For the cc\bar{u}\bar{d} tetraquark we show that in present (SELEX, Tevatron, RHIC) and future facilities (LHCb, ALICE) the production rate is promising and we propose some detectable decay channels.Comment: 6 pages, 5 figure

Are there compact heavy four-quark bound states?

We present an exact method to study four-quark systems based on the hyperspherical harmonics formalism. We apply it to several physical systems of interest containing two heavy and two light quarks using different quark-quark potentials. Our conclusions mark the boundaries for the possible existence of compact, non-molecular, four-quark bound states. While $QQ\bar n \bar n$ states may be stable in nature, the stability of $Q\bar Qn \bar n$ states would imply the existence of quark correlations not taken into account by simple quark dynamical modelsComment: 10 pages, 1 figure. Accepted for publication in Phys. Rev.

Exotic mesons with double charm and bottom flavor

We study exotic mesons with double charm and bottom flavor, whose quark configuration is \bar{Q}\bar{Q}qq. This quark configuration has no annihilation process of quark and antiquark, and hence is a genuinely exotic states. We take a hadronic picture by considering the molecular states composed of a pair of heavy mesons, such as DD, DD* and D*D* for charm flavor, and BB, BB* and B*B* for bottom flavor. The interactions between heavy mesons are derived from the heavy quark effective theory. All molecular states are classified by I(J^P) quantum numbers, and are systematically studied up to the total angular momentum J \leq 2. By solving the coupled channel Schrodinger equations, due to the strong tensor force of one pion exchanging, we find bound and/or resonant states of various quantum numbers.Comment: 24 pages, 3 figure

Possible interpretation of the ZbZ_b(10610) and ZbZ_b(10650) in a chiral quark model

Motivated by the two charged bottomonium-like resonances $Z_b$(10610) and $Z_b$(10650) newly observed by the Belle collaboration, the possible molecular states composed of a pair of heavy mesons, $B\bar{B}, B\bar{B}^*, B^*\bar{B}^*, B_s\bar{B}$, etc (in S-wave), are investigated in the framework of chiral quark models by the Gaussian expansion method. The bound states $B\bar{B}^*$ and $B^*\bar{B}^*$ with quantum numbers $I(J^{PC})=1(1^{+-})$, which are good candidates for the $Z_b(10610)$ and $Z_b(10650)$ respectively, are obtained. Other three bound states $B\bar{B}^*$ with $I(J^{PC})=0(1^{++})$, $B^*\bar{B}^*$ with $I(J^{PC})=1(0^{++}), 0(2^{++})$ are predicted. These states may be observed in open-bottom or hidden-bottom decay channel of highly excited $\Upsilon$. When extending directly the quark model to the hidden color channel of the multi-quark system, more deeply bound states are found. Future experimental search of those states will cast doubt on the validity of applying the chiral constituent quark model to the hidden color channel directly.Comment: 13 pages, 1 figure, title and some arguments in the abstract and section 5 are revised, results unchange

Non-Abelian dynamics and heavy multiquarks, Steiner-tree confinement in hadron spectroscopy

A brief review is first presented of attempts to predict stable multiquark states within current models of hadron spectroscopy. Then a model combining flip-flop and connected Steiner trees is introduced and shown to lead to stable multiquarks, in particular for some configurations involving several heavy quarks and bearing exotic quantum numbers.Comment: 8 pages, 5 figures, Invited talk at the 21st European Conference on Few-Body Problems in Physics, Salamanca, Spain, August 29th--September 3rd, 2010, to appear in the Proceedings, ed.~A.~Valcarce et al., to appear in Few-Body Syste

The Cosmology of Composite Inelastic Dark Matter

Composite dark matter is a natural setting for implementing inelastic dark matter - the O(100 keV) mass splitting arises from spin-spin interactions of constituent fermions. In models where the constituents are charged under an axial U(1) gauge symmetry that also couples to the Standard Model quarks, dark matter scatters inelastically off Standard Model nuclei and can explain the DAMA/LIBRA annual modulation signal. This article describes the early Universe cosmology of a minimal implementation of a composite inelastic dark matter model where the dark matter is a meson composed of a light and a heavy quark. The synthesis of the constituent quarks into dark mesons and baryons results in several qualitatively different configurations of the resulting dark matter hadrons depending on the relative mass scales in the system.Comment: 31 pages, 4 figures; references added, typos correcte

Knowledge transfer in agriculture and websites – an example of web data mining

Celem artykułu jest określenie znaczenia i wykorzystania przez użytkowników internetowych serwisów instytucji, będących źródłem wiedzy dla rolników. Zagadnienie to przedstawiono w kontekście transferu wiedzy. Możliwość pozyskania i wykorzystana informacji, która może być przekształcona w wiedzę, nie zawsze musi przekładać się na zachowanie użytkowników w zakresie korzystania z określonych źródeł wiedzy. Opracowanie koncentruje się na randze serwisów z perspektywy ich użytkowania. Zagadnienie to przeanalizowano na podstawie rankingu Alexa. W wyniku przeprowadzonych badań stwierdzono, że z perspektywy użytkowników najważniejsze serwisy internetowe to portale rolnicze oraz portale należące do uczelni wyższych. W zakresie czasu spędzanego przez użytkowników na stronach internetowych instytucje rządowe (centralne) osiągają słabe rezultaty, w odróżnieniu od głównych portali rolniczych. Uwagę użytkowników najlepiej przyciągają te serwisy, które oferują możliwość pozyskania większych zasobów tzw. wiedzy nieskodyfikowanej.This paper discusses selected aspects concerning the actual use of websites representing different groups of institutions that are considered potential sources of knowledge for farmers. It should be stressed that the potential to acquire and use information, which can be then converted into knowledge, will not necessarily translate into actual behaviour in terms of taking advantage of these sources. Given the above, this study focus on the actual use of those websites. This aspect was studied using data from the Alexa Ranking. It should be noted that most of the leading websites belong to the category of portals and universities. In terms of user time on site, governmental institutions achieve poor results, in stark contrast to the major portals. In terms of attracting user attention, those website that offer greater resources of uncodified knowledge (less accessible and transferable) are more successful

Level of Farmers’ Educational Attainment in Poland – Spatial and Temporal Analysis

Rolnicy kojarzeni są zazwyczaj z niskim poziomem wykształcenia, wykorzystania nowoczesnych technologii – stają się niejako synonimem grupy osób o niskim poziomie wiedzy. Takie przekonanie można powiązać z tym, że często wiejskie (silnie związane z rolnictwem) rynki pracy nie wykazują (nie wykazywały) dużego zapotrzebowania na wysoko wykwalifikowanych pracowników. Jednak współczesne kierunki rozwoju rolnictwa, związane z coraz intensywniejszym wykorzystaniem nowoczesnych technologii i umiejętnością podejmowania szybkich, ryzykownych decyzji odnośnie do produkcji rolnej wiążą się z koniecznością posiadania konkretnych (niemałych) zasobów wiedzy. Stawia to istotne wyzwania przed prowadzącymi działalność rolniczą, szczególnie gdy ma ona być podstawowym źródłem ich utrzymania.The aim of the present study is to show the changes in the level of farmers’ educational attainment in Poland in recent years and studying the education’s attitudes of farmers on acquisition of the farm. The work was based on data collected during the Agricultural Censuses in 1996, 2002 and 2010 and results of a survey realized in the spring of 2014 among 2,411 farmers from 60 municipalities in the country. The presented data show that the education of farmers in Poland in recent years has changed significantly in terms of shares of the various types of education, while in the case of spatial distribution only slightly, as a result of historical and contemporary socio-economic relations