118430400
Supersymmetry Breaking and the Cosmological Constant
I review three attempts to explain the small value of the cosmological constant, and their connection to supersymmetry breaking. They are The String Landscape, Supersymmetric Large Extra Dimensions (SLED), and the Holographic Space–time Formalism invented by Fischler and myself.
124138605
String theory, holography and Quantum Gravity
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.
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.
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.
125302371
Cosmological SUSY Breaking and the Pyramid Scheme
3255120
Improved measurement of the positive-muon lifetime and determination of the Fermi constant.
The mean life of the positive muon has been measured to a precision of 11 ppm using a low-energy, pulsed muon beam stopped in a ferromagnetic target, which was surrounded by a scintillator detector array. The result, tau(micro)=2.197 013(24) micros, is in excellent agreement with the previous world average. The new world average tau(micro)=2.197 019(21) micros determines the Fermi constant G(F)=1.166 371(6)x10(-5) GeV-2 (5 ppm). Additionally, the precision measurement of the positive-muon lifetime is needed to determine the nucleon pseudoscalar coupling g(P).
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.
85463997
The low energy spectrum of TeO2 bolometers: results and dark matter perspectives for the CUORE-0 and CUORE experiments
We collected 19.4 days of data from four 750g TeO2 bolometers, and in three of them we were able to set the energy threshold around 3 keV using a new analysis technique. We found a background rate ranging from 25 cpd/keV/kg at 3 keV to 2 cpd/keV/kg at 25 keV, and a peak at 4.7 keV. The origin of this peak is presently unknown, but its presence is confirmed by a reanalysis of 62.7 kg.days of data from the finished CUORICINO experiment. Finally, we report the expected sensitivities of the CUORE-0 (52 bolometers) and CUORE (988 bolometers) experiments to a WIMP annual modulation signal.
41701681
Measurement of the 8B solar neutrino flux with the KamLAND liquid scintillator detector
We report a measurement of the neutrino-electron elastic scattering rate from ^8B solar neutrinos based on a 123 kton-day exposure of KamLAND. The background-subtracted electron recoil rate, above a 5.5-MeV analysis threshold is 1.49 ± 0.14(stat) ± 0.17(syst) events per kton-day. Interpreted as due to a pure electron flavor flux with a ^8B neutrino spectrum, this corresponds to a spectrum integrated flux of 2.77 ± 0.26(stat) ± 0.32(syst) ×10^6 cm^(−2_s^(−1). The analysis threshold is driven by ^(208)Tl present in the liquid scintillator, and the main source of systematic uncertainty is due to background from cosmogenic ^(11)Be. The measured rate is consistent with existing measurements and with standard solar model predictions which include matter-enhanced neutrino oscillation.
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%...