Fast calculation of HELAS amplitudes using graphics processing unit (GPU)

We use the graphics processing unit (GPU) for fast calculations of helicity amplitudes of physics processes. As our first attempt, we compute $u\bar{u}\to n\gamma$ ($n=2$ to 8) processes in $pp$ collisions at $\sqrt{s} = 14$TeV by transferring the MadGraph generated HELAS amplitudes (FORTRAN) into newly developed HEGET ({\bf H}ELAS {\bf E}valuation with {\bf G}PU {\bf E}nhanced {\bf T}echnology) codes written in CUDA, a C-platform developed by NVIDIA for general purpose computing on the GPU. Compared with the usual CPU programs, we obtain 40-150 times better performance on the GPU.Comment: 14 pages, 8 figure

Fast computation of MadGraph amplitudes on graphics processing unit (GPU)

Continuing our previous studies on QED and QCD processes, we use the graphics processing unit (GPU) for fast calculations of helicity amplitudes for general Standard Model (SM) processes. Additional HEGET codes to handle all SM interactions are introduced, as well assthe program MG2CUDA that converts arbitrary MadGraph generated HELAS amplitudess(FORTRAN) into HEGET codes in CUDA. We test all the codes by comparing amplitudes and cross sections for multi-jet srocesses at the LHC associated with production of single and double weak bosonss a top-quark pair, Higgs boson plus a weak boson or a top-quark pair, and multisle Higgs bosons via weak-boson fusion, where all the heavy particles are allowes to decay into light quarks and leptons with full spin correlations. All the helicity amplitudes computed by HEGET are found to agree with those comsuted by HELAS within the expected numerical accuracy, and the cross sections obsained by gBASES, a GPU version of the Monte Carlo integration program, agree wish those obtained by BASES (FORTRAN), as well as those obtained by MadGraph. The performance of GPU was over a factor of 10 faster than CPU for all processes except those with the highest number of jets.Comment: 37 pages, 12 figure

Weak boson fusion production of supersymmetric particles at the LHC

We present a complete calculation of weak boson fusion production of colorless supersymmetric particles at the LHC, using the new matrix element generator SUSY-MadGraph. The cross sections are small, generally at the attobarn level, with a few notable exceptions which might provide additional supersymmetric parameter measurements. We discuss in detail how to consistently define supersymmetric weak couplings to preserve unitarity of weak gauge boson scattering amplitudes to fermions, and derive sum rules for weak supersymmetric couplings.Comment: 24 p., 3 fig., 9 tab., published in PRD; numbers in Table IV corrected to those with kinematic cuts cite

Monte Carlo integration on GPU

We use a graphics processing unit (GPU) for fast computations of Monte Carlo integrations. Two widely used Monte Carlo integration programs, VEGAS and BASES, are parallelized on GPU. By using $W^{+}$ plus multi-gluon production processes at LHC, we test integrated cross sections and execution time for programs in FORTRAN and C on CPU and those on GPU. Integrated results agree with each other within statistical errors. Execution time of programs on GPU run about 50 times faster than those in C, and more than 60 times faster than the original FORTRAN programs.Comment: 6 pages, 2 figure

Fig Pollinating Wasp Transfers Nematodes Into Figs of Ficus Racemosa in Sumatra, Indonesia

The fruits (figs) of fig trees (Ficus spp, known as ‘bak ara\u27 in Aceh), are the source of food for many species of faunas in the forest, including birds, monkeys, orangutans, etc. Pollination within the figs totally depends on female fig wasps that belong to family Agaonidae. Fig trees and their pollinating wasps rely on each other to survive. Female fig wasps are known to transport nematodes into receptive figs when the wasps enter the figs to lay eggs. An investigation on the nematodes carried by female pollinating wasps Ceratosolen fusciceps Mayr into figs of Ficus racemosa was conducted in Sumatra, Indonesia. The figs on the trees were regularly sampled to determine the presence of nematodes and infer their ecology. The Baermann funnel method was employed to extract the nematodes from the figs. Eight species of nematodes were recorded from the figs, two of which are still unidentified. The species found were (1) Teratodiplogaster fignewmani, (2) Teratodiplogaster sp., (3) Parasitodiplogaster sp., (4) Schistonchus sp1., (5) Schistonchus sp2., (6) Mononchoides sp., (7) and (8) two undescribed Diplogastridae species (‘umbrella-like\u27 species 1 and species 2). This is the most diverse fig nematode community recorded. The highest nematode populations were routinely found in D-phase figs, when the new generations of wasps were about to emerge. Details of the ecology of each nematode species are likely to differ, but as a group they did not seem to significantly affect seed and wasp development in F. racemosa fig

Calculation of HELAS amplitudes for QCD processes using graphics processing unit (GPU)

We use a graphics processing unit (GPU) for fast calculations of helicity amplitudes of quark and gluon scattering processes in massless QCD. New HEGET ({\bf H}ELAS {\bf E}valuation with {\bf G}PU {\bf E}nhanced {\bf T}echnology) codes for gluon self-interactions are introduced, and a C++ program to convert the MadGraph generated FORTRAN codes into HEGET codes in CUDA (a C-platform for general purpose computing on GPU) is created. Because of the proliferation of the number of Feynman diagrams and the number of independent color amplitudes, the maximum number of final state jets we can evaluate on a GPU is limited to 4 for pure gluon processes ($gg\to 4g$), or 5 for processes with one or more quark lines such as $q\bar{q}\to 5g$ and $qq\to qq+3g$. Compared with the usual CPU-based programs, we obtain 60-100 times better performance on the GPU, except for 5-jet production processes and the $gg\to 4g$ processes for which the GPU gain over the CPU is about 20

Generic User Process Interface for Event Generators

Generic Fortran common blocks are presented for use by High Energy Physics event generators for the transfer of event configurations from parton level generators to showering and hadronization event generators.Comment: Physics at TeV Colliders II Workshop, Les Houches, France, May 2001 14 pages, 6 figure

Prospects for the Search for a Standard Model Higgs Boson in ATLAS using Vector Boson Fusion

The potential for the discovery of a Standard Model Higgs boson in the mass range m_H < 2 m_Z in the vector boson fusion mode has been studied for the ATLAS experiment at the LHC. The characteristic signatures of additional jets in the forward regions of the detector and of low jet activity in the central region allow for an efficient background rejection. Analyses for the H -> WW and H -> tau tau decay modes have been performed using a realistic simulation of the expected detector performance. The results obtained demonstrate the large discovery potential in the H -> WW decay channel and the sensitivity to Higgs boson decays into tau-pairs in the low-mass region around 120 GeV.Comment: 20 pages, 13 ps figures, uses EPJ style fil

Antagonistic action of Agrobacterium tumefaciens and essential oils against Aspergillus flavus isolates from Bertholletia excelsa (brasil-nuts).

The chestnut-do-brasil (Bertholletia excelsa) is a tree found in the Amazon region, whose fruit called ?the Brazil nut? has an important role in regional economy. Such seeds are affected by the growth of several fungi that produce mycotoxins. The fungus Aspergillus flavus is the main producer of aflatoxins, compromising the nuts. The main objective of this study was study the growth inhibitory action of A. flavus by essential oils of rosemary, anise, beta-caryophyllene, cinnamon, lemongrass, clove, eucalyptus, limonene, mint-citrata and thyme. The culture medium used was the LB, and the incubation was performed at 28°C for 48 hours in the presence of 10&#956;L of the respective oils. Simultaneously, were tested the Agrobacterium tumefaciens and yeasts as possible agents for controlling A. flavus. The results point to a more effective inhibitory activity of essential oils of rosemary, anise, mint-citrata, eucaliptus, lemongrass, thyme, beta-caryophylelene and limonene. Cinnamon and clove oils were unable to inhibit the growth of A. flavus strains. The A. tumefaciens was able to inhibit 16 of 70 A. flavus strains, but is not recorded any inhibition by yeasts

Constraints on neutrino oscillation parameters from the measurement of day-night solar neutrino fluxes at Super-Kamiokande

A search for day-night variations in the solar neutrino flux resulting from neutrino oscillations has been carried out using the 504 day sample of solar neutrino data obtained at Super-Kamiokande. The absence of a significant day-night variation has set an absolute flux independent exclusion region in the two neutrino oscillation parameter space.Comment: 11 pages, 3 figures, submitted to PRL, single-spacin