119217520
Moduli stabilisation in early superstring cosmology
We study the cosmological evolution induced by the free energy of a string gas at finite temperature. We first consider the maximally supersymmetric heterotic string in the weak coupling regime in dimension D ≥ 4. The free energy develops local minima associated to some gauge symmetry enhancement induced by perturbative states. This can stabilize all heterotic moduli except the dilaton. By string-string S-dualities, it follows that the dual type I moduli can be stabilized by either non perturbative D-string states or perturbative open string states. We next consider the type II string compactified on Calabi-Yau three-folds, which has = 2 supersymmetry in D = 4. The moduli space has singular loci where the Calabi-Yau space undergoes extremal transitions, accompanied with either conifold transitions or certain gauge symmetry enhancement. Also the free energy reaches local minima due to the emergence of extra non perturbative massless modes. Consequently, the type II moduli are attracted to these singular loci. Using the type II/heterotic string duality, we can stabilize the dual heterotic moduli, and in particular it is possible to stabilize the heterotic dilaton.
119221894
Holographic renormalization in no-boundary quantum cosmology
Recent results of Hartle-Hawking wave functions on asymptotic dS boundaries show non-normalizability, while the bulk origin is not clear. This paper attempts to addresse this problem by studying (Kerr-)dS_3 cosmology in Einstein gravity deformed by a minimally coupled scalar field. Various saddle-point contributions exp[i(saddle-point action)] to the Hartle-Hawking wave functions are computed with mini-superspace formalism. The saddle-point actions are first obtained in the spacetime bulks by direct computation, then on the asymptotic dS boundary by holographic renormalization. It is found that the imaginary part of the saddle-point actions, as functions of scalar field deformation, are generally bounded in the bulk, but can diverge to -infty on the boundary. This can probably be a source of the scalar field-related non-normalizability of the boundary Hartle-Hawking wave functions. For Kerr-dS_3 cosmology, some saddle-point actions have imaginary parts diverging to -infty both in the bulk and on the boundary, when the boundary T^2 is stretched to infinitely long. This can be an origin of non-normalizability of the boundary Hartle-Hawking wave functions related to temperature divergence. Finally the holographic renormalization is extended to scalar-deformed dS_{d+1} (d>= 3) cosmologies for the imaginary part of the saddle-point actions. The result is tested on a 5d example, and saddle points leading to divergent contribution to the boundary Hartle-Hawking wave function are shown to exist.
118658408
Massless D-strings and moduli stabilization in type I cosmology
We consider the cosmological evolution induced by the free energy F of a gas of maximally supersymmetric heterotic strings at finite temperature and weak coupling in dimension D ≥ 4. We show that F, which plays the role of an effective potential, has minima associated to enhanced gauge symmetries, where all internal moduli can be attracted and dynamically stabilized. Using the fact that the heterotic/type I S-duality remains valid at finite temperature and can be applied at each instant of a quasi-static evolution, we find in the dual type I cosmology that all internal NS-NS and RR moduli in the closed string sector and the Wilson lines in the open string sector can be stabilized. For the special case of D = 6, the internal volume modulus remains a flat direction, while the dilaton is stabilized. An essential role is played by light D-string modes wrapping the internal manifold and whose contribution to the free energy cannot be omitted, even when the type I string is at weak coupling. As a result, the order of magnitude of the internal radii expectation values on the type I side is $ \sqrt {{{\lambda_{\text{I}}}{\alpha^{\prime}}}} $, where λI is the ten-dimensional string coupling. The non-perturbative corrections to the type I free energy can alternatively be described as effects of “thermal E1-instantons”, whose worldsheets wrap the compact Euclidean time cycle.
119388877
Energy absorption problem of a brane-world black hole
We have studied the wave dynamics and the energy absorption problem for the scalar field as well as the brane-localized gravitational field in the background of a brane-world black hole. Comparing our results with the four-dimensional Schwarzschild black hole, we have observed the signature of the extra dimension in the energy absorption spectrum.
7670434
Transverse momentum spectra of charged particles in proton-proton collisions at sqrt(s) = 900 GeV with ALICE at the LHC
The inclusive charged particle transverse momentum distribution is measured in proton-proton collisions at $\sqrt{s} = 900$~GeV at the LHC using the ALICE detector. The measurement is performed in the central pseudorapidity region $(|\eta|_{\rm INEL}=0.483\pm0.001$~(stat.)~$\pm0.007$~(syst.)~GeV/$c$ and $\left_{\rm NSD}=0.489\pm0.001$~(stat.)~$\pm0.007$~(syst.)~GeV/$c$, respectively. The data exhibit a slightly larger $\left$ than measurements in wider pseudorapidity intervals. The results are compared to simulations with the Monte Carlo event generators PYTHIA and PHOJET
120902364
A NUMERICAL STUDY OF IMPROVED WILSON QUARK ACTIONS ON ANISOTROPIC LATTICES
Tadpole improved Wilson quark actions with clover terms on anisotropic lattices are studied numerically. Using asymmetric lattice volumes, the pseudo-scalar meson dispersion relations are measured for 8 lowest lattice momentum modes with quark mass values ranging from the strange to the charm quark with various values of the gauge coupling β and 3 different values of the bare speed of light parameter ν. These results can be utilized to extrapolate or interpolate to obtain the optimal value for the bare speed of light parameter νopt(m) at a given gauge coupling for all bare quark mass values m. In particular, the optimal values of ν at the physical strange and charm quark mass are given for various gauge couplings. The lattice action with these optimized parameters can then be used to study physical properties of hadrons involving either light or heavy quarks.
13915263
A NUMERICAL STUDY OF IMPROVED QUARK ACTIONS ON ANISOTROPIC LATTICES
Tadpole improved Wilson quark actions with clover terms on anisotropic lattices are studied numerically. Using asymmetric lattice volumes, the pseudoscalar meson dispersion relations are measured for eight lowest lattice momentum modes with quark mass values ranging from the strange to the charm quark with various values of the gauge coupling β and three different values of the bare speed of light parameter ν. These results can be utilized to extrapolate or interpolate to obtain the optimal value for the bare speed of light parameter νopt(m) at a given gauge coupling for all bare quark mass values m. In particular, the optimal values of ν at the physical strange and charm quark mass are given for various gauge couplings. The lattice action with these optimized parameters can then be used to study physical properties of hadrons involving either light or heavy quarks.
117982666
Relics Theory of Dark Matter in quantum evaporating Black Hole
We introduce first a new road to quantize the Schwarzschild black hole. Then we find that the ground state or relic of the quantum evaporating black hole can be identified as dark matter.
121633455
The quantized Schwarzschild Black Hole and the possible origin of Dark Matter