Single Z' production at CLIC based on e^- gamma collisions

We analyze the potential of CLIC based on e- gamma collisions to search for new $Z'$ gauge boson. Single Z' production at e-gamma colliders in two SU(3)_C X SU(3)_L X U(1)_N models: the minimal model and the model with right-handed (RH) neutrinos is studied in detail. Results show that new Z' gauge bosons can be observed at the CLIC, and the cross sections in the model with RH neutrinos are bigger than those in the minimal one.Comment: 11 pages, 4 figures, To appear in JET

The T7 flavor symmetry in 3-3-1 model with neutral leptons

We construct a 3-3-1 model based on non-Abelian discrete symmetry $T_7$ responsible for the fermion masses. Neutrinos get masses from only anti-sextets which are in triplets $\underline{3}$ and $\underline{3}^*$ under $T_7$. The flavor mixing patterns and mass splitting are obtained without perturbation. The tribimaximal form obtained with the breaking $T_7 \rightarrow Z_3$ in charged lepton sector and both $T_7 \rightarrow Z_3$ and $Z_3 \rightarrow \{\mathrm{Identity}\}$ must be taken place in neutrino sector but only apart in breakings $Z_3 \rightarrow \{\mathrm{Identity}\}$ (without contribution of \si'), and the upper bound on neutrino mass $\sum_{i=1}^3m_i$ at the level is presented. The Dirac CP violation phase $\delta$ is predicted to either $\frac{\pi}{2}$ or $\frac{3\pi}{2}$ which is maximal CP violation. From the Dirac CP violation phase we obtain the relation between Euler's angles which is consistent with the experimental in PDG 2012. On the other hand, the realistic lepton mixing can be obtained if both the direction for breakings $T_7 \rightarrow Z_3$ and $Z_3 \rightarrow \{\mathrm{Identity}\}$ are taken place in neutrino sectors. The CKM matrix is the identity matrix at the tree-level.Comment: 39 pages, 16 figures. arXiv admin note: substantial text overlap with arXiv:1312.5034; and text overlap with arXiv:1304.0921, arXiv:1306.4138, arXiv:1311.6729, arXiv:1310.4614 by other author

The dynamical fate of planetary systems in young star clusters

We carry out N-body simulations to examine the effects of dynamical interactions on planetary systems in young open star clusters. We explore how the planetary populations in these star clusters evolve, and how this evolution depends on the initial amount of substructure, the virial ratio, the cluster mass and density, and the initial semi-major axis of the planetary systems. The fraction of planetary systems that remains intact as a cluster member, fbps, is generally well-described by the functional form fbps=f0(1+[a/a0]^c)^-1, where (1-f0) is the fraction of stars that escapes from the cluster, a0 the critical semi-major axis for survival, and c a measure for the width of the transition region. The effect of the initial amount of substructure over time can be quantified as fbps=A(t)+B(D), where A(t) decreases nearly linearly with time, and B(D) decreases when the clusters are initially more substructured. Provided that the orbital separation of planetary systems is smaller than the critical value a0, those in clusters with a higher initial stellar density (but identical mass) have a larger probability of escaping the cluster intact. These results help us to obtain a better understanding of the difference between the observed fractions of exoplanets-hosting stars in star clusters and in the Galactic field. It also allows us to make predictions about the free-floating planet population over time in different stellar environments.Comment: 14 pages, 9 figures, accepted for publication in MNRA

What’s the Difference: A Study of the Nature and Extent of Racism in Rugby League

At the start of the 1993/4 season the Commission for Racial Equality (CRE) and the Professional Footballers' Association launched the 'Let's Kick Racism Out of Football' campaign which subsequently gained the support of the Football Association, the FA Premier, the Endsleigh League and the Football Trust (CRE/PFA, 1994). That campaign led to discussions between the Rugby Football League (RFL), Leeds City Council and the Commission for Racial Equality (CRE) with a view to taking action to address racism in rugby league. Some sports though have become renowned as being sites for racialist confrontations, most notably football, as recorded in Hill's (1989) account of John Barnes' experiences and Holland's (1994) work on the terraces at Newcastle, Leeds and Bolton. General impressions suggested that the position in rugby league was not as bad as in football, but racist abuse and occasional incidents of banana throwing and monkey chants have all been recorded at rugby league matches. Concern about racism at matches has also been expressed recently in the letters pages of the rugby league press and players have talked about their own experiences on television. Since we live in a racist society it would be remarkable if there was no evidence of racism in sport. Nonetheless, as the National Governing Body of the sport, the RFL recognised that this was not a reason for taking no action if it were demonstrated that there are cases of racism in rugby league. However, before embarking on direct action it was decided that information was needed on the nature and extent of racism within the game. To that end Leeds Metropolitan University was asked to survey attitudes and it was agreed that this investigation should have three main components: a) the attitudes of the clubs b) the attitudes of (black and white) players c) the attitudes of spectators At this stage we have been concerned only with the professional game, thou