Natural Inflation with Hidden Scale Invariance

We propose a new class of natural inflation models based on a hidden scale invariance. In a very generic Wilsonian effective field theory with an arbitrary number of scalar fields, which exhibits scale invariance via the dilaton, the potential necessarily contains a flat direction in the classical limit. This flat direction is lifted by small quantum corrections and inflation is realised without need for an unnatural fine-tuning. In the conformal limit, the effective potential becomes linear in the inflaton field, yielding to specific predictions for the spectral index and the tensor-to-scalar ratio, being respectively: $n_s-1\approx -0.025\left(\frac{N_{\star}}{60}\right)^{-1}$ and $r\approx 0.0667\left(\frac{N_{\star}}{60}\right)^{-1}$, where $N_{\star}\approx 30-65$ is a number of efolds during observable inflation. This predictions are in reasonable agreement with cosmological measurements. Further improvement of the accuracy of these measurements may turn out to be critical in falsifying our scenario.Comment: 8 pages, minor revision, to be published in PL

A cometary ion mass spectrometer

The development of flight suitable analyzer units for that part of the GIOTTO Ion Mass Spectrometer (IMS) experiment designated the High Energy Range Spectrometer (HERS) is discussed. Topics covered include: design of the total ion-optical system for the HERS analyzer; the preparation of the design of analyzing magnet; the evaluation of microchannel plate detectors and associated two-dimensional anode arrays; and the fabrication and evaluation of two flight-suitable units of the complete ion-optical analyzer system including two-dimensional imaging detectors and associated image encoding electronics

Composition of the hot plasma near geosynchronous altitude

Although there were no direct measurements of the composition of the hot (keV) plasma at geosynchronous altitudes, the combination of other observations leads to the conclusion that, at least during geomagnetically disturbed periods, there are significant fluxes of ions heavier than protons in this region. Ion composition measurements below 8000 km altitude show upward streaming fluxes of both O(+) and H(+) ions in the L-region of the geosynchronous orbit. These observations are consistent with the conclusion that at least a portion of the total ion fluxes observed at geosynchronous altitude to be highly peaked near the magnetic field lines are heavier than protons and originate in the ionosphere

Exotic Lepton Searches via Bound State Production at the LHC

Heavy long-lived multi-charged leptons (MCLs) are predicted by various new physics models. These hypothetical MCLs can form bound states, due to their high electric charges and long life times. In this work, we propose a novel strategy of searching for MCLs through their bound state productions and decays. By utilizing LHC-8 TeV data in searching for resonances in the diphoton channel, we exclude the masses of isospin singlet heavy leptons with electric charge $|q|\geq 6$ (in units of electron charge) lower than $\sim$1.2 TeV, which are much stronger than the corresponding 8 TeV LHC bounds from analysing the high ionisation and the long time-of-flight of MCLs. By utilising the current 13 TeV LHC diphoton channel measurements the bound can further exclude MCL masses up to $\sim$1.6 TeV for $|q|\geq 6$. Also, we demonstrate that the conventional LHC limits from searching for MCLs produced via Drell-Yan processes can be enhanced by including the contribution of photon fusion processes.Comment: 9 pages, 3 figures, Updated to match PL

Blackpentecostal Breath: The Aesthetics of Possibility

A book review is presented for Ashon T. Crawley, Blackpentecostal Breath: The Aesthetics of Possibility. New York: Fordham University Press, 2017. 320 pp

Higher Ground: Rev. Dr. William Barber II and the Political Content of Prophetic Form

This essay argues that Rev. Dr. William J. Barber’s message on “Higher Ground,” a speech delivered at a massive 2014 protest rally, reveals his intentional problematization of distinctions between the sacred and the secular. As Barber’s articulation of what Ashon Crawley calls “Blackpentecostal breath” spill over the boundaries posited by conventional categories—they are too ecstatic to be ordinary speeches, and too political to be traditional sermons—these plural expressions identify themselves as sounds that come from another world. If both content and form are understood as thought, it becomes apparent that these prophetic utterances critique the oppression wrought by contemporary social orders, announcing the reality of live-giving, just forms of social life. In place of the world that seems natural, Barber’s incantations presence a world to-come, a higher ground. Thus, while Barber’s sound is familiar as a signature of black Christian contexts, his public ministry asserts that aesthetic practices such as these contain a surplus, a transformative and collectivizing capacity. Barber’s ecstatic preaching, then, functions as a technology of transcendence which refuses putative divisions between the sacred and the secular, advancing in their place a moral worldview