Ultra-High Energy Cosmic Rays

The origin of the ultra high energy cosmic rays (UHECR) with energies above E > 1017eV, is still unknown. The discovery of their sources will reveal the engines of the most energetic astrophysical accelerators in the universe. This is a written version of a series of lectures devoted to UHECR at the 2013 CERN-Latin-American School of High-Energy Physics. We present an introduction to acceleration mechanisms of charged particles to the highest energies in astrophysical objects, their propagation from the sources to Earth, and the experimental techniques for their detection. We also discuss some of the relevant observational results from Telescope Array and Pierre Auger Observatory. These experiments deal with particle interactions at energies orders of magnitude higher than achieved in terrestrial accelerators.Comment: 22 pages, contribution to the 2013 CERN - Latin-American School of High-Energy Physics, Arequipa, Peru, 6-19 Mar 201

Phenomenology of cosmic ray air showers

The properties of cosmic rays with energies above 1PeV have to be deduced from the spacetime structure and particle content of the air showers which they initiate. In this review, a summary of the phenomenology of these giant air showers is presented. We describe the hadronic interaction models used to extrapolate results from collider data to ultra high energies, an also the main electromagnetic processes that govern the longitudinal shower evolution as well as the lateral spread of particles.Comment: Invited talk at the Fifth International Workshop on New Worlds in Astroparticle Physics, 8-10 January 2005, Faro, Portugal (http://www.ualg.pt/fct/fisica/centra/a2005.html). Based on the review article Annals Phys. 314:145-207, 2004. Typo in the labelling of Fig.2 correcte

Sensitivities of one-prong tau branching fractions to tau neutrino mass, mixing, and anomalous charged current couplings

We analyse the sensitivities of exclusive one-prong tau branching fractions to: the tau neutrino mass; its mixing with a fourth generation neutrino; the weak charged current magnetic and electric dipole moments of the tau; and the Michel parameter $\eta$. Quantitative constraints are derived from current experimental data and the future constraints derivable from tau-charm factory measurements are estimated. The anomalous coupling constraints are used to constrain the tau compositeness scale and the allowed parameter space for Higgs doublet models.Comment: Invited talk at the Tau-Charm Workshop, 6-9 March 1999, SLAC, US

Determination of the Higgs boson spin with a linear e+e- collider

The energy dependence of the production cross section of a light Higgs boson is studied at threshold and compared to the expectations of several spin assumptions. Cross section measurements at three centre-of-mass energies with an integrated luminosity of 20 fb-1 allow the confirmation of the scalar nature of the Higgs Boson.Comment: 4 pages (Latex), 4 figures (Postscript

Massive relic neutrinos in the galactic halo and the knee in the cosmic ray spectrum

Despite many efforts to find a reasonable explanation, the origin of the "knee" in the cosmic ray spectrum at energy around 10**15.5 eV remains mysterious. In this letter we suggest that the "knee" may be due to a GZK-like effect of cosmic rays interacting with massive neutrinos in the galactic halo. Simple kinematics connects the location of the "knee" with the mass of the neutrinos, and, while the required interaction cross section is larger than that predicted by the Standard Model, it can be accommodated by a small neutrino magnetic dipole moment. The values for the neutrino parameters obtained from the analysis of existing experimental data are compatible with present laboratory bounds.Comment: 8 pages, 1 figure, uses RevTe

On the determination of CP-even and CP-odd components of a mixed CP Higgs boson at e+e^+ e−e^- collider

We present a method to investigate the CP quantum numbers of the Higgs boson in the process $e^+ e^- \to Z\phi$ at a future linear collider (LC), where $\phi$, a generic Higgs boson, is a mixture of CP-even and CP-odd states. The procedure consist of a comparison of the data with predictions obtained from Monte Carlo simulations corresponding to the productions of scalar and pseudoscalar Higgs and the interference term wich constitutes a distinctive signal of CP violation. We present estimates of the sensitivity of the method from Monte Carlo studies using hypothetical data samples with a full LC detector simulation taking into account the background signals.Comment: 5 pages, 4 figure

Never to return: migration and old age in Venezis’s “The State of Virginia”

This paper discusses Ilias Venezis’s short story “The State of Virginia” with special emphasis on the themes of migration and old age. Published in 1954, in the aftermath of WWII and the Greek Civil War, “The State of Virginia” captures the drama of an elderly woman victim of the Asia Minor Catastrophe, as she is migrating to Virginia, U.S.A. after thirty years of temporary residence in a refugee village in rural Attica. My analysis focuses on the protagonist’s reluctant migration as it emerges from the farewell scene between her and her life-long friend; their conversation on the irreversibility of their separation, the challenges facing elderly migrants, and the significance of native soil voices an insightful discourse on belonging and rootedness that transcends many socio-temporal limits

The Effect Of Age On Social Behaviour In Drosophila melanogaster And The Progeny of Aged Parents

Recent studies have linked neuropsychiatric disorders to older parents. These disorders often include changes in social behaviours like the social spacing between neighbouring individuals, which can be modeled in organisms such as Drosophila melanogaster. I investigated the effects of aging on the social space between neighbouring D. melanogaster and how aging impacts the next generation. To achieve this, I used the social space assay and found that individuals become less social with age and that this effect is passed on to the first generation only. Additionally, accelerating the physiological process of aging via increased rearing temperatures or exposure to oxidative stress resulted in individuals and their progeny that were less social. Finally, I found that only male progeny of old fathers were less social. Although it is unclear how aging affects gametes leading to changes in social behaviours, the powerful model system of Drosophila will allow us to identify the underlying mechanisms