14227515
Black Crunch
We study the growth of fluctuations in collapsing cosmologies, extending old work of Lifschitz and Khalatnikov. As examples of systems where the fluctuations have a different composition than the background we study scalar fields with general improvement terms. Fluctuations always grow, and often dominate the homogeneous background. We argue that even for very dilute fluctuations, scattering processes inevitably lead to a dense gas of black holes. This leads us to hypothesize that the generic final state of a Big Crunch is described by a collapsing p = ρ FRW cosmology. We conjecture that the black hole fluid is invariant under the conformal Killing symmetry of this metric, so that the final state is in fact stationary.
14227515
Black Crunch
We study the growth of fluctuations in collapsing cosmologies, extending old work of Lifschitz and Khalatnikov. As examples of systems where the fluctuations have a different composition than the background we study scalar fields with general improvement terms. Fluctuations always grow, and often dominate the homogeneous background. We argue that even for very dilute fluctuations, scattering processes inevitably lead to a dense gas of black holes. This leads us to hypothesize that the generic final state of a Big Crunch is described by a collapsing p = ρ FRW cosmology. We conjecture that the black hole fluid is invariant under the conformal Killing symmetry of this metric, so that the final state is in fact stationary.
31219852
Remodeling the Pentagon After the Events of 2/23/06
The meta-stable SUSY breaking mechanism of Intriligator Seiberg and Shih can be used to simplify the Pentagon model of TeV scale physics. The simplified model has only a single scalar field and no troublesome low energy axion. One significant signature is $l^+ l^- X$ plus missing energy, where $X$ might be the two photons of gauge mediated models, but is likely to be different. There is a new strongly interacting sector with a scale around 1.5 TeV. The penta-hadrons of this sector have masses of order 6 TeV or more. Dark matter is probably the pseudo-goldstone boson of spontaneously broken penta-baryon number. This can be a viable dark matter candidate if an appropriate asymmetry in penta-baryon number is generated in the early universe. The pseudo-Goldstone particle has a mass of $\sim 1$ eV and is produced predominantly in flavor changing charged current decays of ordinary particles. The model solves the flavor problems of SUSY, but has two low energy CP violating phases, whose value is strongly constrained by experiment.
118441175
Lectures on Holographic Space Time
Summary of three talks on the Holographic Space Time models of early universe cosmology, particle physics, and the asymptotically de Sitter final state of our universe.
15705008
Breaking SUSY on the Horizon
I present a heuristic calculation of the critical exponent relating the gravitino mass to the cosmological constant in a de Sitter universe. The ingredients for the calculation are the area law for entropy, an R symmetry of the low energy effective Lagrangian, and a crude picture of the degenerate levels of the cosmological horizon.
125302371
Cosmological SUSY Breaking and the Pyramid Scheme
42385898
Production of Radioactive Isotopes through Cosmic Muon Spallation in KamLAND
Radioactive isotopes produced through cosmic muon spallation are a background for rare-event detection in ν detectors, double-β-decay experiments, and dark-matter searches. Understanding the nature of cosmogenic backgrounds is particularly important for future experiments aiming to determine the pep and CNO solar neutrino fluxes, for which the background is dominated by the spallation production of ^(11)C. Data from the Kamioka liquid-scintillator antineutrino detector (KamLAND) provides valuable information for better understanding these backgrounds, especially in liquid scintillators, and for checking estimates from current simulations based upon MUSIC, FLUKA, and GEANT4. Using the time correlation between detected muons and neutron captures, the neutron production yield in the KamLAND liquid scintillator is measured to be Y_n=(2.8±0.3)×10^(-4) μ^(-1) g^(-1) cm^2. For other isotopes, the production yield is determined from the observed time correlation related to known isotope lifetimes. We find some yields are inconsistent with extrapolations based on an accelerator muon beam experiment.
28501467
CUORE crystal validation runs: Results on radioactive contamination and extrapolation to CUORE background
The CUORE Crystal Validation Runs (CCVRs) have been carried out since the end of 2008 at the Gran Sasso National Laboratories, in order to test the performance and the radiopurity of the TeO2 crystals produced at SICCAS (Shanghai Institute of Ceramics, Chinese Academy of Sciences) for the CUORE experiment. In this work the results of the first 5 validation runs are presented. Results have been obtained for bulk contaminations and surface contaminations from several nuclides. An extrapolation to the CUORE background has been performed. (C) 2012 Elsevier B.V. All rights reserved.
55546545
Validation of techniques to mitigate copper surface contamination in CUORE
In this article we describe the background challenges for the CUORE experiment posed by surface contamination of inert detector materials such as copper, and present three techniques explored to mitigate these backgrounds. Using data from a dedicated test apparatus constructed to validate and compare these techniques we demonstrate that copper surface contamination levels better than 10(-7)- 10(-8) Bq/cm(2) are achieved for U-238 and Th-232. If these levels are reproduced in the final CUORE apparatus the projected 90% C.L. upper limit on the number of background counts in the region of interest is 0.02-0.03 counts/keV/kg/y depending on the adopted mitigation technique. (C) 2013 Elsevier B.V. All rights reserved.
14554475
Measurement of muon capture on the proton to 1% precision and determination of the pseudoscalar coupling gP.
The MuCap experiment at the Paul Scherrer Institute has measured the rate Λ(S) of muon capture from the singlet state of the muonic hydrogen atom to a precision of 1%. A muon beam was stopped in a time projection chamber filled with 10-bar, ultrapure hydrogen gas. Cylindrical wire chambers and a segmented scintillator barrel detected electrons from muon decay. Λ(S) is determined from the difference between the μ(-) disappearance rate in hydrogen and the free muon decay rate. The result is based on the analysis of 1.2 × 10(10) μ(-) decays, from which we extract the capture rate Λ(S) = (714.9 ± 5.4(stat) ± 5.1(syst)) s(-1) and derive the proton's pseudoscalar coupling g(P)(q(0)(2) = -0.88 m(μ)(2)) = 8.06 ± 0.55.
1335841
ODYSSEUS: A DYNAMIC STRONG-STRONG BEAM-BEAM SIMULATION FOR STORAGE RINGS
We have developed a simulation of the beam-beam interaction in e+/estorage ring colliders which is specifically intended to reveal the dynamic collective behavior of the colliding beams. This program is a true 6-dimensional strongstrong simulation in which the electromagnetic fields of longitudinal slices of the colliding beams are recalculated for each slice collision. Broadband wake fields are included and no constraints are placed on the distribution of particles in the beams. Information on tests of the code will be shown. Results will be presented including limiting beambeam parameters for round and flat beams, deviations from the Gaussian distribution, effects of the beam-beam parameter on head-tail instability thresholds, and Landau damping rates. Possibilities for further improvements will be discussed.