Symplectic structure and monopole strength in 12C

The relation between the monopole transition strength and existence of cluster structure in the excited states is discussed based on an algebraic cluster model. The structure of $^{12}$C is studied with a 3$\alpha$ model, and the wave function for the relative motions between $\alpha$ clusters are described by the symplectic algebra $Sp(2,R)_z$, which corresponds to the linear combinations of $SU(3)$ states with different multiplicities. Introducing $Sp(2,R)_z$ algebra works well for reducing the number of the basis states, and it is also shown that states connected by the strong monopole transition are classified by a quantum number $\Lambda$ of the $Sp(2,R)_z$ algebra.Comment: Phys. Rev. C in pres

Multimedia broadcast and internet satellite system design and user trial results

The EU funded project, System for Advanced Multimedia Broadcast and IT Services (SAMBITS), has created an enhanced and synchronised, multimedia terminal for merging satellite broadcast and internet telecommunication services in a way that efficiently combines the large bandwidth of the broadcast channel and the interactivity of the internet. This paper proposes a novel broadcast and internet service concept, illustrates this concept with two service scenarios and develops a system architecture to demonstrate the range of key benefits provided by these new technologies. It then describes the interactive multimedia terminal that was used for consuming this new service concept. Finally, the results of the user trials on the terminal are presented and discussed

Application of the generalized two-center cluster model to 10Be

A generalized two-center cluster model (GTCM), including various partitions of the valence nucleons around two alpha-cores, is proposed for studies on the exotic cluster structures of Be isotopes. This model is applied to the 10Be = alpha + alpha + n + n system and the adiabatic energy surfaces for alpha-alpha distances are calculated. It is found that this model naturally describes the formation of the molecular orbitals as well as that of asymptotic cluster states dependeing on their relative distance. In the negative-parity state, a new type of the alpha + 6He cluster structure is also predicted.Comment: 5 pages, 3 figure

A massive star origin for an unusual helium-rich supernova in an elliptical galaxy

The unusual helium-rich (type Ib) supernova SN 2005E is distinguished from any supernova hitherto observed by its faint and rapidly fading light curve, prominent calcium lines in late-phase spectra and lack of any mark of recent star formation near the supernova location. These properties are claimed to be explained by a helium detonation in a thin surface layer of an accreting white dwarf (Perets et al. 2010). Here we report on observations of SN 2005cz appeared in an elliptical galaxy, whose observed properties resemble those of SN 2005E in that it is helium-rich and unusually faint, fades rapidly, shows much weaker oxygen emission lines than those of calcium in the well-evolved spectrum. We argue that these properties are best explained by a core-collapse supernova at the low-mass end ($8-12 M_{\odot}$) of the range of massive stars that explode (Smartt 2009). Such a low mass progenitor had lost its hydrogen-rich envelope through binary interaction, having very thin oxygen-rich and silicon-rich layers above the collapsing core, thus ejecting a very small amount of radioactive $^{56}$Ni and oxygen. Although the host galaxy NGC 4589 is an elliptical, some studies have revealed evidence of recent star-formation activity (Zhang et al. 2008), consistent with the core-collapse scenario.Comment: Accepted by Nature (24 March 2010), 32 pages including Supplementary Informatio

Rapid prototyping and fast user trial of multimedia broadcast and cellular services

This paper presents the results of fast user trial of multimedia services that are enabled when a mobile terminal has access to converged services over digital broadcast and mobile telecommunications networks. It first describes the motivations behind developing this system and describes the service scenarios that benefit most from it. It then provides an overview of the service components of the test case scenario. Finally, it presents the results of fast user trials on end users of the services that were developed. This work was conducted as part of the EU-funded CISMUNDUS project