The limits to growth then and now

In this paper the indications of the 1972 report of the club of Rome about the relationship between environment and economic growth are reviewed and compared to the ideas debated nowadays on the same topic. The implications of the stages of growth approach and of the economic growth models are considered. Market failure has a central role when the environment is considered. Hence the main problems of policy design and evaluation and their implications for international cooperation, as studied in a burgeoning literature, are presented.

And how experiments begin: the international prototype kilogram and the Planck constant

The artefact that has defined the kilogram since 1889 is to be retired and the kilogram will instead be defined by fixing the value of the Planck constant. In this paper, I detail some of the elements of this reform, believing that the case study should prompt philosophers to reassess the role scientific standards play in the progress of the physical sciences. A metrological account of scientific standards should explain metrology’s more theoretical motivations and also acknowledge its empirical contribution to the physical sciences. I present three theses towards this end. I develop a more thoroughgoing and yet much weaker version of Bridgman’s operational attitude. I present a picture of the physical sciences united by metrology. Finally, I present the case for a quiet form of realism that attempts to accommodate both the more theoretical and the more pragmatic motivations of the metrologist

Challenges in Double Beta Decay

After nearly 80 years since the first guess on its existence, neutrino still escapes our insight: the mass and the true nature (Majorana or Dirac) of this particle is still unknown. In the past ten years, neutrino oscillation experiments have finally provided the incontrovertible evidence that neutrinos mix and have finite masses. These results represent the strongest demonstration that the Standard Model of electroweak interactions is incomplete and that new Physics beyond it must exist. None of these experimental efforts could however shade light on some of the basic features of neutrinos. Indeed, absolute scale and ordering of the masses of the three generations as well as charge conjugation and lepton number conservation properties are still unknown. In this scenario, a unique role is played by the Neutrinoless Double Beta Decay searches: these experiments can probe lepton number conservation, investigate the Dirac/Majorana nature of the neutrinos and their absolute mass scale (hierarchy problem) with unprecedented sensitivity. Today Neutrinoless Double Beta Decay faces a new era where large scale experiments with a sensitivity approaching the so-called degenerate-hierarchy region are nearly ready to start and where the challenge for the next future is the construction of detectors characterized by a tonne-scale size and an incredibly low background, to fully probe the inverted-hierarchy region. A number of new proposed projects took up this challenge. These are based either on large expansions of the present experiments or on new ideas to improve the technical performance and/or reduce the background contributions. n this paper, a review of the most relevant ongoing experiments is given. The most relevant parameters contributing to the experimental sensitivity are discussed and a critical comparison of the future projects is proposed.Comment: 70 pages, 16 figures, 6 tables. arXiv admin note: text overlap with arXiv:1109.5515, arXiv:hep-ex/0501010, arXiv:0910.2994 by other author

Searches for Long Lived Neutral Particles

An intriguing possibility for TeV scale physics is the existence of neutral long lived particles (LOLIPs) that subsequently decay into SM states. Such particles are many cases indistinguishable from missing transverse energy (MET) at colliders. We propose new methods to search for these particles using neutrino telescopes. We study their detection prospects, assuming production either at the LHC or through dark matter (DM) annihilations in the Sun and the Earth. We find that the sensitivity for LOLIPs produced at the LHC is limited by luminosity and detection energy thresholds. On the other hand, in the case of DM annihilation into LOLIPs, the sensitivity of neutrino telescopes is promising and may extend beyond the reach of upcoming direct detection experiments. In the context of low scale hidden sectors weakly coupled to the SM, such indirect searches allow to probe couplings as small as 10^-15.Comment: 22 pages, 6 figure

Visible Light Driven Carbon Dioxide Conversion into Methanol Using Metal Doped Titanium Dioxide

Increasing energy crisis and declining climate caused by the excessive utilization of fossil fuel have increase exponentially on the research activities about Carbon Dioxide (CO2) capture, storage and utilization. Artificial photosynthesis that uses Ultraviolet light (UV-light) and solar light energy to convert CO2 to form value added chemical and renewable fuels such as methanol and methane has drawn the attention worldwide. It not only reduces the greenhouse effects caused by CO2 emission but as well produce value added chemicals for renewable energy. Titanium dioxide, (TiO2) nanoparticles were synthesized using Triton X-100 as surfactant. Copper (Cu) was doped into the TiO2 nanoparticles via wet impregnation method in order for the photocatalyst to absorb the light from UV region to visible region. In this experiment, 0-5wt% Cu was used to determine the optimum amount of Cu with 40ml of distilled water. From the result, 3wt% Cu/TiO2 shows significant result on the formation of methanol which give 2.574 ml. This report provides a brief information about the principles of artificial photosynthesis of CO2, method and materials needed for preparing the photocatalyst as well as the progress in exploring more efficient photocatalyst for the photoreduction process

Fully General Relativistic Simulations of Core-Collapse Supernovae with An Approximate Neutrino Transport

We present results from the first generation of multi-dimensional hydrodynamic core-collapse simulations in full general relativity (GR) that include an approximate treatment of neutrino transport. Using a M1 closure scheme with an analytic variable Eddington factor, we solve the energy-independent set of radiation energy and momentum based on the Thorne's momentum formalism. To simplify the source terms of the transport equations, a methodology of multiflavour neutrino leakage scheme is partly employed. Our newly developed code is designed to evolve the Einstein field equation together with the GR radiation hydrodynamic equations. We follow the dynamics starting from the onset of gravitational core-collapse of a 15 $M_{\odot}$ star, through bounce, up to about 100 ms postbounce in this study to study how the spacial multi-dimensionality and GR would affect the dynamics in the early postbounce phase. Our 3D results support the anticipation in previous 1D results that the neutrino luminosity and average neutrino energy of any neutrino flavor in the postbounce phase increase when switching from SR to GR hydrodynamics. This is because the deeper gravitational well of GR produces more compact core structures, and thus hotter neutrino spheres at smaller radii. By analyzing the residency timescale to the neutrino-heating timescale in the gain region, we show that the criterion to initiate neutrino-driven explosions can be most easily satisfied in 3D models, irrespective of SR or GR hydrodynamics. Our results suggest that the combination of GR and 3D hydrodynamics provides the most favorable condition to drive a robust neutrino-driven explosion.Comment: 50pages, 20 figures, Accepted by ApJ. Latest version with following the referee's suggestions and comment

A facility to Search for Hidden Particles (SHiP) at the CERN SPS

A new general purpose fixed target facility is proposed at the CERN SPS accelerator which is aimed at exploring the domain of hidden particles and make measurements with tau neutrinos. Hidden particles are predicted by a large number of models beyond the Standard Model. The high intensity of the SPS 400~GeV beam allows probing a wide variety of models containing light long-lived exotic particles with masses below ${\cal O}$(10)~GeV/c$^2$, including very weakly interacting low-energy SUSY states. The experimental programme of the proposed facility is capable of being extended in the future, e.g. to include direct searches for Dark Matter and Lepton Flavour Violation.Comment: Technical Proposa