Validity of the kink approximation to the tunneling action
Coleman tunneling in a general scalar potential with two non-degenerate minima is known to have an approximation in terms of a piecewise linear triangular-shaped potential with sharp 'kinks' at the place of the local minima. This approximate potential has a regime where the existence of the bounce solution needs the scalar field to 'wait' for some amount of Euclidean time at one of the 'kinks'. We discuss under which conditions a kink approximation of locally smooth 'cap' regions provides a good estimate for the bounce action.

title: Gauge unification in extra dimensions: power corrections vs. higher dimension operators
abstract: Power-like loop corrections to gauge couplings are a generic feature of higher-dimensional field theories. In supersymmetric grand unified theories in d = 5 dimensions, such corrections arise only in the presence of a vacuum expectation value of the adjoint scalar of the gauge multiplet. We show that, using the analysis of the exact quantum effective action by Intriligator, Morrison and Seiberg, these power corrections can be understood as the effect of higher dimension operators. Such operators, both classical and quantum, are highly constrained by gauge symmetry and supersymmetry. As a result, even non-perturbatively large contributions to gauge coupling unification can be unambiguously determined within 5d low-energy effective field theory. Since no massive hypermultiplet matter exists in 6 dimensions, the predictivity is further enhanced by embedding the 5d model in a 6d gauge theory relevant at smaller distances. Thus, large and quantitatively controlled power-law contributions to gauge couplings arise naturally and can, in the most extreme case, lead to calculable TeV-scale power law unification. We identify a simple 5d SU(5) model with one massless 10 in the bulk where the power-law effect is exactly MSSM-like.

title: Power Spectrum of Inflationary Attractors
abstract: Inflationary attractors predict the spectral index and tensor-to-scalar ratio to take specific values that are consistent with Planck. An example is the universal attractor for models with a generalised non-minimal coupling, leading to Starobinsky inflation. In this paper we demonstrate that it also predicts a specific relation between the amplitude of the power spectrum and the number of e-folds. The length and height of the inflationary plateau are related via the non-minimal coupling: in a wide variety of examples, the observed power normalisation leads to at least 55 flat e-foldings. Prior to this phase, the inflationary predictions vary and can account for the observational indications of power loss at large angular scales.

title: Evading the Lyth Bound in Hybrid Natural Inflation
abstract: Generically, the gravitational-wave or tensor-mode contribution to the primordial curvature spectrum of inflation is tiny if the field-range of the inflaton is much smaller than the Planck scale. We show that this pessimistic conclusion is naturally avoided in a rather broad class of small-field models. More specifically, we consider models where an axion-like shift symmetry keeps the inflaton potential flat (up to non-perturbative cosine-shaped modulations), but inflation nevertheless ends in a waterfall-regime, as is typical for hybrid inflation. In such hybrid natural inflation scenarios (examples are provided by Wilson line inflation and fluxbrane inflation), the slow-roll parameter ǫ can be sizable during an early period (relevant for the CMB spectrum). Subsequently, ǫ quickly becomes very small before the tachyonic instability eventually terminates the slow-roll regime. In this scenario, one naturally generates a considerable tensor-mode contribution in the curvature spectrum, collecting nevertheless the required amount of e-foldings during the final period of inflation. While non-observation of tensors by Planck is certainly not a problem, a discovery in the medium to long term future is realistic.

title: $R^2\log R$ quantum corrections and the inflationary observables
abstract: We study a model of inflation with terms quadratic and logarithmic in the Ricci scalar, where the gravitational action is $f(R)=R+\alpha R^2+\beta R^2 \ln R$. These terms are expected to arise from one loop corrections involving matter fields in curved space-time. The spectral index $n_s$ and the tensor to scalar ratio yield $10^{-4}\lesssim r\lesssim0.03$ and $0.94\lesssim n_s \lesssim 0.99$. i.e. $r$ is an order of magnitude bigger or smaller than the original Starobinsky model which predicted $r\sim 10^{-3}$. Further enhancement of $r$ gives a scale invariant $n_s\sim 1$ or higher. Other inflationary observables are $d n_s/d\ln k \gtrsim -5.2 \times 10^{-4},\, \mu \lesssim 2.1 \times 10^{-8} ,\, y \lesssim 2.6 \times 10^{-9}$. Despite the enhancement in $r$, if the recent BICEP2 measurement stands, this model is disfavoured.

title: Study of the neutron quantum states in the gravity field
abstract: We have studied neutron quantum states in the potential well formed by the earth’s gravitational field and a horizontal mirror. The estimated characteristic sizes of the neutron wave functions in the two lowest quantum states correspond to expectations with an experimental accuracy. A position-sensitive neutron detector with an extra-high spatial resolution of $\sim 2 \mathrm{\mu} $m was developed and tested for this particular experiment, to be used to measure the spatial density distribution in a standing neutron wave above a mirror for a set of some of the lowest quantum states. The present experiment can be used to set an upper limit for an additional short-range fundamental force. We studied methodological uncertainties as well as the feasibility of improving further the accuracy of this experiment.

title: Response of the BP-1 phosphate glass detector to relativistic heavy ions
abstract: We report on a systematic study of the response of the novel phosphate glass track-etch detector BP-1 to relativistic heavy ions. Using 197Au beams with energies of 0.5, 0.7, and 11.4 AGeV, we demonstrate that the BP-1 detector can measure ionic charge with an unprecedented resolution above thresholds that can be set by proper choice of the chemical etchants after irradiation. These remarkable advantages have made it possible to use BP-1 to explore a number of interesting topics in high-energy heavy-ion physics and cosmic-ray astrophysics.

title: Energy loss of relativistic heavy ions in matter
abstract: We have investigated the theory of energy loss of charged particles in matter due to ionization of the medium, integrating the work of other authors over several decades. We describe the most important corrections to standard energy-loss formulae. We compare our calculations to an improved measurement of the range of 1 A GeV U ions and to other codes and tabulations. We show that calculations based on the theory of ionization energy loss are at least as accurate as tabulations extrapolated from empirical data for the stopping of uranium ions in matter. We have made available the computer code resulting from our investigations.

title: Amanda South Pole neutrino detector
abstract: High energy neutrino radiation provides us with a tomographic tool to scan the Universe. Sites shielded by a few hundred grams of matter are not revealed by light, whatever its wavelength. High energy neutrinos are decay products of pions and therefore are a signature of the most energetic cosmic processes. It is proposed to instrument the polar ice cap as a low‐noise particle detector sensing the Cherenkov light from neutrino‐induced muons. This paper describes the successful operation of a prototype string of optical modules that were deployed on January 17, 1992 at the South Pole. The advantages of the method are intriguing. The ice has good optical transmission and provides a mechanical structure to support the instrument. Ice is a quiet, sterile medium where photomultiplier tubes experience low background counting rates. The low background allows us to develop electronics and triggering schemes that are simple and can be installed at the surface and thus remain accessible after deployment of the PMTs...

title: AMANDA: Antarctic Muon And Neutrino Detector Array
abstract: Enormous detectors with unprecedented sensitivity will be required to search for astrophysical sources of neutrinos. If the transparency of deep polar ice is similar to that measured in the laboratory, then AMANDA (Antarctic Muon And Neutrino Detector Array) may be the most cost-effective way to reach the detector volumes required to search for astrophysical sources of high energy neutrinos or WIMP annihilation within the sun.

title: Comparison of the oxidation state of Fe in comet 81P/Wild 2 and chondritic-porous interplanetary dust particles
abstract: Comparison of the oxidation state of Fe in comet 81P/Wild 2 and chondritic-porous interplanetary dust particles R.C. Ogliore a, ⁎ , A.L. Butterworth a , S.C. Fakra b , Z. Gainsforth a , M.A. Marcus b , A.J. Westphal a a b Space Sciences Laboratory, University of California at Berkeley, Berkeley, CA 94720, USA Advanced Light Source, Lawrence Berkeley National Laboratory, Berkeley, CA 94720, USA a r t i c l e i n f o a b s t r a c t The fragile structure of chondritic-porous interplanetary dust particles (CP-IDPs) and their minimal parent- body alteration have led researchers to believe these particles originate in comets rather than asteroids where aqueous and thermal alterations have occurred. The solar elemental abundances and atmospheric entry speed of CP-IDPs also suggest a cometary origin. With the return of the Stardust samples from Jupiter- family comet 81P/Wild 2, this hypothesis can be tested. We have measured the Fe oxidation state of 15 CP- IDPs and 194 Stardust fragments using a synchrotron-based x-ray microprobe. We analyzed ∼ 300 ng of Wild 2 material — three orders of magnitude more material than other analyses comparing Wild 2 and CP-IDPs. The Fe oxidation state of these two samples of material are N2σ different: the CP-IDPs are more oxidized than the Wild 2 grains. We conclude that comet Wild 2 contains material that formed at a lower oxygen fugacity than the parent-body, or parent bodies, of CP-IDPs. If all Jupiter-family comets are similar, they do not appear to be consistent with the origin of CP-IDPs. However, comets that formed from a different mix of nebular material and are more oxidized than Wild 2 could be the source of CP-IDPs.  comet 81P/Wild 2 interplanetary dust particles XANES Jupiter-family comets 1.  Chondritic-porous interplanetary dust particles (CP-IDPs), collect- ed in the stratosphere by high-altitude aircraft, are widely thought to originate in comets (Schramm et al., 1989; Bradley, 1994). The collisional history of asteroids makes it unlikely that these particles (fragile, porous aggregates of small grains) are asteroidal (Brownlee, 1985). The atmospheric entry speed of CP-IDPs, as deduced from thermal release proﬁles of solar wind He (Nier and Schlutter, 1992), is consistent with cometary, rather than asteroidal, orbits (Brownlee et al., 1995). Infrared and electron beam studies of IDPs show that those consisting of mostly anhydrous minerals are usually chondritic- porous, whereas IDPs rich in phyllosilicates are usually chondritic- smooth (Sandford and Walker, 1985; Bradley and Brownlee, 1986). The presence of GEMS (glass with embedded metal and sulﬁdes) in IDPs indicates a lack of thermal alteration (Bradley, 1994). CP-IDPs, therefore, show very little parent-body alteration and must originate from either anhydrous objects or hydrous objects that have been kept at very low temperature — again, consistent with cometary origin. Nevertheless, a cometary origin of CP-IDPs is not universally accepted (Flynn, 1992; Thomas et al., 1995). With the return of samples from comet 81P/Wild 2 by NASA's Stardust mission (Brownlee et al., 2006), it is now possible to compare CP-IDPs with material from this Jupiter- ⁎ Corresponding author. E-mail address: ogliore@ssl.berkeley.edu (R.C. Ogliore). family comet. We seek to prove or disprove, with a known level of conﬁdence, the hypothesis that CP-IDPs originate from parent bodies with the composition of comet Wild 2. The oxidation state of Fe is a clear mineralogic indicator of the oxidation state of meteorites (Rubin et al., 1988). Meteorite groups are in fact distinguished from each other by their differing Fe oxidation states, as Urey and Craig ﬁrst reported more than ﬁfty years ago (Urey and Craig, 1953). Parent-body processing can drastically change the Fe oxidation state of some of the meteorite groups, obscuring information about the original oxidation state the material acquired in the solar nebula (Rubin et al., 1988). Carbonates and Fe-bearing crystalline silicates, possible products of aqueous alteration on asteroids (Krot et al., 1995), are found alongside anhydrous minerals in the same Stardust track (Flynn, 2008), and therefore co-existed in one large aggregate in comet Wild 2. No phyllosilicates have been unambiguously identiﬁed in the Stardust samples (Zolensky et al., 2008). With these and other pieces of evidence, Wooden (2008) argues that instead of selective aqueous alteration on submicron scales in the comet itself, grains which formed in different regions of the solar nebula under varying reduction–oxidation conditions (e.g. Mg- and Fe-rich crystalline silicates) migrated, aggregated, and formed comet Wild 2. Likewise, the oxidation state of anhydrous CP-IDPs was unaffected by parent- body processing (Schramm et al., 1989; Zolensky and Thomas, 1995), so a comparison of the Fe oxidation state of comet Wild 2 with anhydrous CP-IDPs yields insight into the nebular environment in which they formed.