2,814 research outputs found
Improving bounds on flavor changing vertices in the two Higgs doublet model from mixing
We find some constraints on the flavor changing vertices of the two Higgs
doublet model, from the \Delta M_{B_{d}} measurement. Although bounds from this
observable have already been considered, this paper takes into account the role
of a new operator not included previously, as well as the vertices \xi_{bb},
\xi_{tc} and \xi_{sb}. Using the Cheng-Sher parametrization, we found that for
a relatively light charged Higgs boson (200-300 GeV), we get that \lambda
_{tt}<1, while the parameter \lambda_{bb} could have values up to about 50. In
addition, we use bounds for \lambda_{tt} and \lambda_{bb} obtained from
B^{0}->X_{s}\gamma at next to leading order, and studied the case where the
only vanishing vertex factors are the ones involving quarks from the first
family. We obtained that \Delta M_{B_{d}} is not sensitive to the change of the
parameter \lambda_{sb}, while \lambda_{tc}<1Comment: 4 pages, 1 figure, LaTeX2
Symmetric discrete coherent states for n qubits
We put forward a method of constructing discrete coherent states for n
qubits. After establishing appropriate displacement operators, the coherent
states appear as displaced versions of a fiducial vector that is fixed by
imposing a number of natural symmetry requirements on its Q-function. Using
these coherent states we establish a partial order in the discrete phase space,
which allows us to picture some n-qubit states as apparent distributions. We
also analyze correlations in terms of sums of squared Q-functions.Comment: Published in J. Phys. A. Special issue on Coherent State
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Post harvest losses of rice in the Dominican Republic
A national survey of post-harvest losses of rice was conducted in the Dominican Republic during the period March· November 1979. Quantitative and qualitative losses during harvesting, milling and storage of rice were studied and an attempt was made to assess their economic value. Recorded losses due to inefficient harvesting and threshing practices totalled 18.1 per cent. At the rice mills significant breakage of grains occurred when sun dried rice was milled. lt was estimated that millers using this drying method were losing, on average, 9.75 per cent of the value of the product because of the lower grade obtained. The milling process itself appeared to cause no significant losses of quantity or quality. An average weight loss of 0.35 per cent, recorded during storage at government warehouses, was attributable mainly to spillage and handling. No insect losses were observed. The loss during storage is small, but the total annual loss is estimated to be 680 metric tons
Delta rho pi interaction leading to N* and Delta* resonances
We have performed a calculation for the three body system
by using the fixed center approximation to Faddeev equations, taking the
interaction between and , and, and and
from the chiral unitary approach. We find several peaks in the modulus
squared of the three-body scattering amplitude, indicating the existence of
resonances, which can be associated to known and and baryon states.Comment: Presented at the 21st European Conference on Few-Body Problems in
Physics, Salamanca, Spain, 30 August - 3 September 201
A column-store meets the point clouds
Dealing with LIDAR data in the context of database management
systems calls for a re-assessment of their functionality, performance,
and storage/processing limitations. The territory for efficient and
scalable processing of LIDAR repositories using GIS enabled database
systems is still largely unexplored. Bringing together hard core
database management experts and GIS application developers is a
sine qua non to advance the state of the art. In particular to assess
the relative merits of both traditional row-based database engines
and the modern column-oriented database engines
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Experience with a double-compensating beam calorimeter
In an experiment to measure the D(t,..cap alpha..)n cross section at beam energies of 10 to 120 keV, we have developed a double-compensating beam calorimeter, based on a Swiss design to measure the partical beam intensity. A Faraday cup is not useful because of considerable charge exchange in the target gas at such low beam energies. We calibrated the calorimeter both with 10- and 3-MeV protons (comparing with a Faraday-cup measurement of the beam flux) and with the heat generated in a precision resistor. Both methods agree and give a calibration accurate to +- 0.08% over a range of 10 to 800 mW beam power. Beam powers as low as 5 mW may be used, but with less accuracy. The beam energy must be known in order to calculate the particle intensity. Some difficulties with and peculiarities of the device are discussed
Very Low Temperature Tunnelling Spectroscopy in the heavy fermion superconductor PrOsSb
We present scanning tunnelling spectroscopy measurements on the heavy fermion
superconductor PrOsSb. Our results show that the superconducting gap
opens over a large part of the Fermi surface. The deviations from isotropic BCS
s-wave behavior are discussed in terms of a finite distribution of values of
the superconducting gap.Comment: 4 pages, 4 figure
Perturbations of anti-de Sitter black holes
I review perturbations of black holes in asymptotically anti-de Sitter space.
I show how the quasi-normal modes governing these perturbations can be
calculated analytically and discuss the implications on the hydrodynamics of
gauge theory fluids per the AdS/CFT correspondence. I also discuss phase
transitions of hairy black holes with hyperbolic horizons and the dual
superconductors emphasizing the analytical calculation of their properties.Comment: 25 pages, 4 figures, prepared for the proceedings of the 5th Aegean
Summer School "From Gravity to Thermal Gauge Theories: the AdS/CFT
Correspondence," Milos, Greece, September 2009
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