123338629
IceCube: A Multipurpose Neutrino Telescope
IceCube is a new high-energy neutrino telescope which will be coming online in the near future. IceCube will be capable of measuring fluxes of all three flavors of neutrino, and its peak neutrino energy sensitivity will be in the TeV–PeV range. Here, after a brief description of the detector, we describe its anticipated performance with a selection of physics topics: supernovae, extraterrestrial diffuse and point sources of neutrinos, gamma-ray bursts, neutrinos from WIMP annihilation, and cosmic ray composition.
124471126
The 3rd generation Front-End cards of the Pierre Auger surface detectors: Test results and performance in the field
The surface detector array of the Pierre Auger Observatory comprises 1600 water Cherenkov detectors distributed over an area of 3000 km 2 . The Cherenkov light is detected by three 9-in. photo-multiplier tubes from which the signals of the anode and last dynode are digitized by 10 bit 40 MHz FADCs. An Altera Cyclone FPGA is employed to generate different local triggers and to handle the data transfer to a communication board. After briefly discussing the design of the cards we present an autonomous test-bench, which has been set up in order to test the large number of boards prior to installation in the field. The qualification procedure and the results obtained in the laboratory are presented. Up to three years of operation in the field demonstrate a very good performance and reliability of the Front-End cards.
210155517
The IceCube Neutrino Observatory VI: Neutrino Oscillations, Supernova Searches, Ice Properties
IceCube DeepCore can study atmospheric neutrino oscillations through a combination of its low energy reach, as low as about 10 GeV, and its unprecedented statistical sample, of about 150,000 triggered atmospheric muon neutrinos per year. With the diameter of the earth as a baseline, the muon neutrino disappearance minimum and tau neutrino appearance maximum are expected at about 25 GeV, which is considerably lower energy than typical IceCube neutrino events, but higher than the energies at which accelerator-based experiments have detected oscillations. νμ disappearance and ντ appearance from neutrino oscillation can be measured in IceCube DeepCore. We present here the status of the newly developed low energy reconstruction algorithms, the expected experimental signatures, and the proposed approach for such neutrino oscillation measurements. Corresponding authors: Sebastian Euler (seuler@icecube.wisc.edu), Laura Gladstone(gladstone@icecube.wisc.edu), Jason Koskinen(koskinen@psu.edu), Donglian Xu(dxu@crimson.ua.edu) III. Physikalisches Institut, RWTH Aachen University, D-52056 Aachen, Germany Dept. of Physics, University of Wisconsin, Madison, WI 53706, USA Dept. of Physics, Pennsylvania State University, University Park, PA 16802, USA Dept. of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487, USA
118125996
Moduli Stabilization and String Geometry
I describe recent progress in using conformal field theory techniques to describe the stabilization of moduli fields arising in compactifications of type IIB string theory to four dimensions.
7411732
A note on fluxes in six-dimensional string theory backgrounds
Abstract We study the structure of warped compactifications of type IIB string theory to six space–time dimensions. We find that the most general four-manifold describing the internal dimensions is conformal to a Kahler manifold, in contrast with the heterotic case where the four-manifold must be conformally Calabi–Yau.
2844671
Graviton scattering amplitudes in M theory
We compute graviton scattering amplitudes in M theory using Feynman rules for a scalar particle coupled to gravity in eleven dimensions. The processes that we consider describe the single graviton exchange and the double graviton exchange, that in M(atrix) theory correspond to the v^4/r^7 and v^6/r^14 term, respectively. We argue that the v^6/r^14 term appearing in M(atrix) theory at two loops can be obtained from the covariant eleven-dimensional four-graviton amplitude. Finally, we calculate the v^8/r^18 term appearing at two loops in M(atrix) theory. It has been previously conjectured that this term is related to a four graviton scattering amplitude involving the R^4 vertex of M theory.
14845456
In the realm of the geometric transitions
Abstract We complete the duality cycle by constructing the geometric transition duals in the type IIB, type I and heterotic theories. We show that in the type IIB theory the background on the closed string side is a Kahler deformed conifold, as expected, even though the mirror type IIA backgrounds are non-Kahler (both before and after the transition). On the other hand, the type I and heterotic backgrounds are non-Kahler. Therefore, on the heterotic side these backgrounds give rise to new torsional manifolds that have not been studied before. We show the consistency of these backgrounds by verifying the torsional equation.
119498787
M-theory inflation from multi M5-brane dynamics
Abstract We derive inflation from M-theory on S 1 / Z 2 via the non-perturbative dynamics of N M5-branes. The open membrane instanton interactions between the M5-branes give rise to exponential potentials which are too steep for inflation individually but lead to inflation when combined together. The resulting type of inflation, known as assisted inflation, facilitates considerably the requirement of having all moduli, except the inflaton, stabilized at the beginning of inflation. During inflation the distances between the M5-branes, which correspond to the inflatons, grow until they reach the size of the S 1 / Z 2 orbifold. At this stage the M5-branes will reheat the universe by dissolving into the boundaries through small instanton transitions. Further flux and non-perturbative contributions become important at this late stage, bringing inflation to an end and stabilizing the moduli. We find that with moderate values for N, one obtains both a sufficient amount of e-foldings and the right size for the spectral index.