119133202
Two Point Pade Approximants and Duality
We propose the use of two point Pade approximants to find expressions valid uniformly in coupling constant for theories with both weak and strong coupling expansions. In particular, one can use these approximants in models with a strong/weak duality, when the symmetries do not determine exact expressions for some quantity.
116990186
Essay: Supersymmetry, the Cosmological Constant, and a Theory of Quantum Gravity in Our Universe
There are many theories of quantum gravity, depending on asymptotic boundary conditions, and the amount of supersymmetry. The cosmological constant is one of the fundamental parameters that characterizes different theories. If it is positive, supersymmetry must be broken. A heuristic calculation shows that a cosmological constant of the observed size predicts superpartners in the TeV range. This mechanism for SUSY breaking also puts important constraints on low energy particle physics models.
119283684
Holographic Space-time and Newton's Law
We derive Newton's Law from the formalism of Holographic Space-Time (HST). More precisely, we show that for a large class of Hamiltonians of the type proposed previously for the HST description of a geodesic in Minkowski space, the eikonal for scattering of two massless particles at large impact parameter scales as expected with the impact parameter and the energies of the particles in the center of mass (CM) frame. We also discuss the criteria for black hole production in this collision, and find an estimate, purely within the HST framework, for the impact parameter at which it sets in, which coincides with the estimate based on general relativity.
118356346
HOLOGRAPHIC SPACE–TIME AND ITS PHENOMENOLOGICAL IMPLICATIONS
I briefly review the theory of holographic space–time and its relation to the cosmological constant problem, and the breaking of supersymmetry (SUSY). When combined with some simple phenomenological requirements, these ideas lead to a fairly unique model for Tera-scale physics, which implies direct gauge mediation of SUSY breaking and a model for dark matter as a hidden sector baryon, with nonzero magnetic dipole moment.
124138605
String theory, holography and Quantum Gravity
125302371
Cosmological SUSY Breaking and the Pyramid Scheme
54913753
Searching for Neutrinoless Double-Beta Decay of130Te with CUORE
Neutrinoless double-beta (0) decay is a hypothesized lepton-number-violating process that offers the only known means of asserting the possible Majorana nature of neutrino mass. The Cryogenic Underground Observatory for Rare Events (CUORE) is an upcoming experiment designed to search for 0 decay of 130Te using an array of 988 TeO2 crystal bolometers operated at 10 mK. The detector will contain 206 kg of 130Te and have an average energy resolution of 5 keV; the projected 0 decay half-life sensitivity after five years of livetime is 1.6 × 1026 y at 1 (9.5 × 1025 y at the 90% confidence level), which corresponds to an upper limit on the effective Majorana mass in the range 40–100 meV (50–130 meV). In this paper, we review the experimental techniques used in CUORE as well as its current status and anticipated physics reach.
73646575
Initial performance of the CUORE-0 experiment
CUORE-0 is a cryogenic detector that uses an array of tellurium dioxide bolometers to search for neutrinoless double-beta decay of $$\mathrm {^{130}Te}$$130Te. We present the first data analysis with $$7.1 \,\mathrm {kg\cdot y}$$7.1kg·y of total $$\mathrm {TeO_2}$$TeO2 exposure focusing on background measurements and energy resolution. The background rates in the neutrinoless double-beta decay region of interest (2.47 to $$2.57 \,\mathrm {MeV}$$2.57MeV) and in the $$\alpha $$α background-dominated region (2.70 to $$3.90\,\mathrm {MeV}$$3.90MeV) have been measured to be $${0.071\pm 0.011}$$0.071±0.011 and $${0.019\pm 0.002}\,\mathrm {counts/(keV\cdot kg\cdot y)}$$0.019±0.002counts/(keV·kg·y), respectively. The latter result represents a factor of 6 improvement from a predecessor experiment, Cuoricino. The results verify our understanding of the background sources in CUORE-0, which is the basis of extrapolations to the full CUORE detector. The obtained energy resolution (full width at half maximum) in the region of interest is $$5.7\,\mathrm {keV}$$5.7keV. Based on the measured background rate and energy resolution in the region of interest, CUORE-0 half-life sensitivity is expected to surpass the observed lower bound of Cuoricino with one year of live time.
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.
119144377
A circulating hydrogen ultra-high purification system for the MuCap experiment
Abstract The MuCap experiment is a high-precision measurement of the rate for the basic electroweak process of muon capture, μ − +p→n+ ν μ . The experimental approach is based on an active target consisting of a time projection chamber (TPC) operating with pure hydrogen gas. The hydrogen has to be kept extremely pure and at a stable pressure. A Circulating Hydrogen Ultra-high Purification System was designed at the Petersburg Nuclear Physics Institute (PNPI) to continuously clean the hydrogen from impurities. The system is based on an adsorption cryo pump to stimulate the hydrogen flow and on a cold adsorbent for the hydrogen cleaning. It was installed at the Paul Scherrer Institute (PSI) in 2004 and performed reliably during three experiment runs. During several months long operating periods the system maintained the hydrogen purity in the detector on the level of 20 ppb for moisture, which is the main contaminant, and of better than 7 and 5 ppb for nitrogen and oxygen, respectively. The pressure inside the TPC was stabilized to within 0.024% of 10 bar at a hydrogen flow rate of three standard liters per minute.
118695560
First results from the MuLan and MuCap experiments
MuLan and MuCap are ongoing experiments at the Paul Scherrer Institut, Switzerland, that use the muon lifetime to determine fundamental weak interaction parameters. The goal of MuLan is a 1 ppm measurement of the positive muon lifetime τμ+ to determine the Fermi constant GF to 0.5 ppm. The goal of MuCap is to make a 1% determination of the rate ΛS of the process of nuclear muon capture by the proton, μp→nν, by measuring the μ− disappearance rate in hydrogen gas to 10 ppm and subtracting the world average for the μ+ decay rate. A 1% determination of the capture rate ΛS is of interest because it would enable a 7% determination of gP, the induced pseudoscalar coupling of the nucleon. In 2007, both experiments published first results based upon data collected by each in 2004. MuLan reported an 11 ppm μ+ lifetime measurement, τμ+ = 2.197 013(24) μs, resulting in a new, 9.6 ppm world average, τμ+ = 2.197 019(21) μs, which determines the Fermi constant, GF = 1.166 371(6)×10−5 GeV−2, to 5 ppm. MuCap reported a 3%...