213 research outputs found

    Production of para-- and orthopositronium at relativistic heavy ion colliders

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    We consider the ortho-- and parapositronium production in the process AAAA+AA \to AA+ Ps where A is a nucleus with the charge number Z. The inclusive cross section and the energy distribution of the relativistic Ps are calculated which are of primary interest from the experimental point of view. The accuracy of the corresponding cross sections is given by omitting terms (Zα)2/L2\sim (Z\alpha )^2/L^2 for the para--Ps and (Zα)2/L\sim (Z\alpha)^2/L for the ortho--Ps production where L=lnγ29L=\ln{\gamma^2} \approx 9 and 16 for the RHIC and the LHC. Within this accuracy the multiphoton (Coulomb) corrections are taken into account. We show that the RHIC and the LHC will be Ps factories with a productions rate of about 105÷10810^5 \div 10^8 relativistic Ps per day. The fraction of the ortho--Ps is expected to be of the same order as that of the para--Ps for Au--Au and Pb--Pb collisions.Comment: 22 pages, 5 figures, RevTeX, misprint correcte

    Russia’s Eurasian past, present and future: rival international societies and Moscow’s place in the post-cold war world

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    The failure of post-Soviet Russia to integrate into the West became evident with the 2014 Ukraine crisis, leading Moscow to accelerate its declared “pivot to the East”. However, the increased dependence on China carries its own risks, such as the danger of becoming Beijing’s junior partner. For an erstwhile superpower that continues to declare and prize its autonomy in international affairs, this is a particularly unappealing prospect. Thus, it remains to be seen whether a genuinely balanced partnership can exist between both countries. This article uses insights from Adam Watson’s pendulum theory to explore Russia’s post-2014 Eurasian predicament. We argue that the rapid rightward swing of the pendulum in the Euro-Atlantic order following the end of the Cold War has proven indigestible for Moscow. The article then moves to discuss the Sino-Russian relationship in the context of the emerging Eurasian space. It concludes that the growing disillusionment of Russian leaders with the West since the 2000s, along with the normative convergence between Moscow and Beijing, has led to a closer partnership between the two. Yet the partnership is also riddled with a number of insecurities on Moscow’s side that could undermine the long-term prospects for cooperation between Russia and China

    1989 as a mimetic revolution: Russia and the challenge of post-communism

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    Various terms have been used to describe the momentous events of 1989, including Jürgen Habermas’s ‘rectifying revolution,’ and my own notion of 1989 as a type of ‘anti-revolution’: repudiating not only what had come before, but also denying the political logic of communist power, as well as the emancipatory potential of revolutionary socialism in its entirety. In the event, while the negative agenda of 1989 has been fulfilled, it failed in the end to transcend the political logic of the systems that collapsed at that time. This paper explores the unfulfilled potential of 1989. Finally, 1989 became more of a counter- rather than an anti-revolution, replicating in an inverted form the practices of the mature state socialist regimes. The paucity of institutional and intellectual innovation arising from 1989 is striking. The dominant motif was ‘returnism,’ the attempt to join an established enterprise rather than transforming it. Thus, 1989 can be seen as mimetic revolution, in the sense that it emulated systems that were not organically developed in the societies in which they were implanted. For Eastern Europe ‘returning’ to Europe appeared natural, but for Russia the civilizational challenge of post-communism was of an entirely different order. There could be no return, and instead of a linear transition outlined by the classic transitological literature, Russia’s post-communism demonstrated that the history of others could not be mechanically transplanted from one society to another

    Hadron production in gamma-gamma collisions as a background for e+e- linear colliders

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    Drees and Godbole have proposed that, at the interaction point of an e+e- linear collider, one expects a high rate of hadron production by gamma-gamma collisions, providing an additional background to studies in e+e- annihilation. Using a simplified model of the gamma-gamma cross section with soft and jet-like components, we estimate the expected rate of these hadronic events for a variety of realistic machine designs. The final background rates are quite small, and they become smaller still when viewed with a realistic detector simulation.Comment: PHYZZX, 39 pages, including 3 tables; 14 figures are not included but are available upon reques

    Creative suburbia: Rethinking urban cultural policy - the Australian case

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    This article considers the question of whether creative workers demonstrate a preference for inner cities or suburbs, drawing upon research findings from the ‘Creative Suburbia’ project undertaken by a team of Australian researchers over 2008–2010 in selected suburban areas of Brisbane and Melbourne. Locating this question in wider debates about the relationship of the suburbs to the city, as well as the development of new suburban forms such as master-planned communities, the article finds that the number of creative industries workers located in the suburbs is significant, and those creative workforce members living and working in suburban areas are generally happy with this experience, locating in the suburbs out of personal choice rather than economic necessity. This runs counter to the received wisdom on creative cities, which emphasize cultural amenity in inner city areas as a primary driver of location decisions for the ‘creative class’. The article draws out some implications of the findings for urban cultural policy, arguing that the focus on developing inner urban cultural amenity has been overplayed, and that more attention should be given to how to better enable distributed knowledge systems through high-speed broadband infrastructure
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