Performing heritage: the use of live 'actors' in heritage presentations

This paper investigates the phenomenon of 'living history' presentations of heritage, using live 'actors' to portray historical characters. Its aim is to discuss these presentations in the context of what may be understood as 'heritage', and of the nature of 'performance'. Four case studies of heritage sites, each important as a tourist attraction, have been selected for detailed study, together with a number of other examples of heritage performance. It is clear from the empirical work that different performance strategies are employed within the heritage industry and by individual 'actors'. Most of the performers take part as a leisure activity, and many do not consider themselves to be 'performing' at all. The greatest concern of participants lies in the degree of authenticity of the performance. Through 'living history', the 'actors' are drawn into an experience of heritage which has real meaning for them, and which may contribute both to a sense of identity and to an enhanced understanding of society, past and present. The popularity of such presentations with visitors also indicates that similar benefits are perceived by the 'audience'

Collider signals from slow decays in supersymmetric models with an intermediate-scale solution to the mu problem

The problem of the origin of the mu parameter in the Minimal Supersymmetric Standard Model can be solved by introducing singlet supermultiplets with non-renormalizable couplings to the ordinary Higgs supermultiplets. The Peccei-Quinn symmetry is broken at a scale which is the geometric mean between the weak scale and the Planck scale, yielding a mu term of the right order of magnitude and an invisible axion. These models also predict one or more singlet fermions which have electroweak-scale masses and suppressed couplings to MSSM states. I consider the case that such a singlet fermion, containing the axino as an admixture, is the lightest supersymmetric particle. I work out the relevant couplings in several of the simplest models of this type, and compute the partial decay widths of the next-to-lightest supersymmetric particle involving leptons or jets. Although these decays will have an average proper decay length which is most likely much larger than a typical collider detector, they can occasionally occur within the detector, providing a striking signal. With a large sample of supersymmetric events, there will be an opportunity to observe these decays, and so gain direct information about physics at very high energy scales.Comment: 24 pages, LaTeX, 4 figure

An Extended Technicolor Model With QCD-like Symmetry Breaking

We present a one-doublet extended technicolor model, with all fermions in fundamental representations. The bare lagrangian has no explicit mass terms but generates masses through gauge symmetry breaking by purely QCD-like dynamics. The model generates three families of quarks and leptons and can accommodate the observed third family mass spectrum (including a large top mass and light neutrinos). In addition, we show how the model may be extended to incorporate a top color driven top mass without the need for a strong U(1) interaction. We discuss the compatiblity of the model with experimental constraints and its possible predicitive power with respect to first and second family masses.Comment: 25 pages, latex, 7 figure

Particle Physics Approach to Dark Matter

We review the main proposals of particle physics for the composition of the cold dark matter in the universe. Strong axion contribution to cold dark matter is not favored if the Peccei-Quinn field emerges with non-zero value at the end of inflation and the inflationary scale is superheavy since, under these circumstances, it leads to unacceptably large isocurvature perturbations. The lightest neutralino is the most popular candidate constituent of cold dark matter. Its relic abundance in the constrained minimal supersymmetric standard model can be reduced to acceptable values by pole annihilation of neutralinos or neutralino-stau coannihilation. Axinos can also contribute to cold dark matter provided that the reheat temperature is adequately low. Gravitinos can constitute the cold dark matter only in limited regions of the parameter space. We present a supersymmetric grand unified model leading to violation of Yukawa unification and, thus, allowing an acceptable b-quark mass within the constrained minimal supersymmetric standard model with mu>0. The model possesses a wide range of parameters consistent with the data on the cold dark matter abundance as well as other phenomenological constraints. Also, it leads to a new version of shifted hybrid inflation.Comment: 32 pages including 6 figures, uses svmult.cls, some clarifications added, lectures given at the Third Aegean Summer School "The Invisible Universe: Dark Matter and Dark Energy", 26 September-1 October 2005, Karfas, Island of Chios, Greece (to appear in the proceedings

Lepton Flavor Violation and the Origin of the Seesaw Mechanism

The right--handed neutrino mass matrix that is central to the understanding of small neutrino masses via the seesaw mechanism can arise either (i) from renormalizable operators or (ii) from nonrenormalizable or super-renormalizable operators, depending on the symmetries and the Higgs content of the theory beyond the Standard Model. In this paper, we study lepton flavor violating (LFV) effects in the first class of seesaw models wherein the \nu_R Majorana masses arise from renormalizable Yukawa couplings involving a B-L = 2 Higgs field. We present detailed predictions for \tau -> \mu + \gamma and \mu -> e + \gamma branching ratios in these models taking the current neutrino oscillation data into account. Focusing on minimal supergravity models, we find that for a large range of MSSM parameters suggested by the relic abundance of neutralino dark matter and that is consistent with Higgs boson mass and other constraints, these radiative decays are in the range accessible to planned experiments. We compare these predictions with lepton flavor violation in the second class of models arising entirely from the Dirac Yukawa couplings. We study the dependence of the ratio r \equiv B(\mu -> e+\gamma)/B(\tau ->\mu +\gamma) on the MSSM parameters and show that measurement of r can provide crucial insight into the origin of the seesaw mechanism.Comment: 20 pages, Revtex, 7 figure

A measurement of the tau mass and the first CPT test with tau leptons

We measure the mass of the tau lepton to be 1775.1+-1.6(stat)+-1.0(syst.) MeV using tau pairs from Z0 decays. To test CPT invariance we compare the masses of the positively and negatively charged tau leptons. The relative mass difference is found to be smaller than 3.0 10^-3 at the 90% confidence level.Comment: 10 pages, 4 figures, Submitted to Phys. Letts.

Measurement of the B0 Lifetime and Oscillation Frequency using B0->D*+l-v decays

The lifetime and oscillation frequency of the B0 meson has been measured using B0->D*+l-v decays recorded on the Z0 peak with the OPAL detector at LEP. The D*+ -> D0pi+ decays were reconstructed using an inclusive technique and the production flavour of the B0 mesons was determined using a combination of tags from the rest of the event. The results t_B0 = 1.541 +- 0.028 +- 0.023 ps, Dm_d = 0.497 +- 0.024 +- 0.025 ps-1 were obtained, where in each case the first error is statistical and the second systematic.Comment: 17 pages, 4 figures, submitted to Phys. Lett.

First Measurement of Z/gamma* Production in Compton Scattering of Quasi-real Photons

We report the first observation of Z/gamma* production in Compton scattering of quasi-real photons. This is a subprocess of the reaction e+e- to e+e-Z/gamma*, where one of the final state electrons is undetected. Approximately 55 pb-1 of data collected in the year 1997 at an e+e- centre-of-mass energy of 183 GeV with the OPAL detector at LEP have been analysed. The Z/gamma* from Compton scattering has been detected in the hadronic decay channel. Within well defined kinematic bounds, we measure the product of cross-section and Z/gamma* branching ratio to hadrons to be (0.9+-0.3+-0.1) pb for events with a hadronic mass larger than 60 GeV, dominated by (e)eZ production. In the hadronic mass region between 5 GeV and 60 GeV, dominated by (e)egamma* production, this product is found to be (4.1+-1.6+-0.6) pb. Our results agree with the predictions of two Monte Carlo event generators, grc4f and PYTHIA.Comment: 18 pages, LaTeX, 5 eps figures included, submitted to Physics Letters

Search for Higgs Bosons in e+e- Collisions at 183 GeV

The data collected by the OPAL experiment at sqrts=183 GeV were used to search for Higgs bosons which are predicted by the Standard Model and various extensions, such as general models with two Higgs field doublets and the Minimal Supersymmetric Standard Model (MSSM). The data correspond to an integrated luminosity of approximately 54pb-1. None of the searches for neutral and charged Higgs bosons have revealed an excess of events beyond the expected background. This negative outcome, in combination with similar results from searches at lower energies, leads to new limits for the Higgs boson masses and other model parameters. In particular, the 95% confidence level lower limit for the mass of the Standard Model Higgs boson is 88.3 GeV. Charged Higgs bosons can be excluded for masses up to 59.5 GeV. In the MSSM, mh > 70.5 GeV and mA > 72.0 GeV are obtained for tan{beta}>1, no and maximal scalar top mixing and soft SUSY-breaking masses of 1 TeV. The range 0.8 < tanb < 1.9 is excluded for minimal scalar top mixing and m{top} < 175 GeV. More general scans of the MSSM parameter space are also considered.Comment: 49 pages. LaTeX, including 33 eps figures, submitted to European Physical Journal