3,761 research outputs found
Higher Twist Effects in Proton-Proton Collisions
In this article, we investigate the contribution of the high twist Feynman
diagrams to the large- pion production cross section in proton-proton
collisions and we present the general formulae for the high and leading twist
differential cross sections. The pion wave function where two non-trivial
Gegenbauer coefficients and have been extracted from the CLEO data,
two other pion model wave functions, , , the asymptotic and the
Chernyak-Zhitnitsky wave functions are used in the calculations. The results of
all the calculations reveal that the high twist cross sections, the ratios ,
, the dependence transverse momentum and the rapidity of pion in
the wave function case is very close to the
asymptotic wave function case. It is shown that the high twist
contribution to the cross section depends on the choice of the meson wave
functions.Comment: 28 pages 18 figures RevTex
Scintillation Light Detection with MAPD-3NK and MPPC-S12572-010P Readout
The linearity and energy resolution of two different solid-state photomultipliers (SiPMs) has been studied with reading out the LFS-8 scintillator (3x3x10 mm3). First SiPM (MAPD-3NK) from Zecotek Photonics consists of deeply burned pixels (cells) and has an active area of 3.7x3.7 mm2. The second one (MPPC-S12572-010P) from Hamamatsu has a surface cell structure and an active area of 3x3 mm2. Both SiPMs have the same pixel density of 10000 mm−2. Energy resolution and linearity of the SiPMs has been studied in the energy range of 59.6-1275 keV. It is found that both SiPMs demonstrate good linearity of signal amplitude as a function of the gamma ray energy in the studied energy range. The detector based on the MAPD-3NK provides significantly good energy resolution in comparison to the detector based on the MPPC-S12572-010P
Investigation of the nuetralino pair production at LHC
In this article, we investigate the Drell-Yan process of the light neutralino
pair () productions
at proton-proton collisions and we present the general formulate for the
differential cross sections. We conduct an extensive examination of the
dependence of the total cross section of the subprocesses on the beam energy, on the mass
of the squarks and also on the gaugino for the three extremely different
scenarios. For all three cases, the outcomes are as follows. The dependence of
the total cross section of the subprocesses on the beam energy is dominated by one of
the subprocesses, . On the other hand, the dependence of the total cross section of
the subprocesses
on the mass of the squarks is dominated by one of the subprocesses, . We derive there from that
our findings may lead to new insights relating to experimental investigations
and these dependencies may be used as bases of an experimental research for the
neutralino pair at LHC.Comment: 38pp, 22 figures, ReVTeX4, (Baku State University, Azerbaijan, and
Erciyes University, Kayseri, Turkey
The Meson Production in Proton-Proton Collisions in Next-To-Leading Order and Infrared Renormalons
In this article, we investigate the next-to-leading order contribution of the
higher-twist Feynman diagrams to the large- inclusive pion production
cross section in proton-proton collisions and present the general formulae for
the higher-twist differential cross sections in the case of the running
coupling and frozen coupling approaches. We compared the resummed
next-to-leading order higher-twist cross sections with the ones obtained in the
framework of the frozen coupling approach and leading-twist cross section. The
structure of infrared renormalon singularities of the higher twist subprocess
cross section and it's resummed expression (the Borel sum) are found. It is
shown that the resummed result depends on the choice of the meson wave
functions used in the calculations. We discuss the phenomenological
consequences of possible higher-twist contributions to the meson production in
proton-proton collisions in next-to-leading order at RHIC.Comment: 33 pages, 15 figures, 4 table
Portable neutron/gamma scintillation detector for status monitoring of accelerator-driven neutron source IREN
Accelerator-driven system (ADS) facilities world-wide opens new opportunities
for nuclear physics investigations, so that a high flux of neutrons through
spallation reactions can be produced at these facilities. It is known that the
measurement, continuous monitoring and optimization of the particle accelerator
beam intensity are among the most important actions in the operation of such
facilities. Considering this point of view, this paper presents a neutron/gamma
counter based on a micropixel avalanche photodiode (MAPD) and a plastic
scintillator that monitors the status of the accelerator-driven intense
resonance neutron source (IREN) facility by measuring the neutron-gamma
intensity in the target hall. The electronics of the modular neutron counter
has been designed and developed, including a bias voltage source (up to 130 V),
a preamplifier (36 gain) and discriminator (>10 mV) circuit. The last product
of MAPD (operation voltage- 55 V, PDE- 33 %, total number of pixels- 136900)
was used as a photon readout from a plastic scintillator. The sensitive area of
MAPD was 3.7*3.7 mm2 and the size of the plastic scintillator 3.7*3.7*30 mm3.
The measurement was carried out in the IREN target hall, where it was necessary
to monitor not only high neutron fluxes, but also gamma quanta. The
experimental results demonstrated a dependence between the count rate of the
detector and the frequency of the accelerator, which ranges from 2 to 50 Hz.Comment: 8 pages, 7 figure
Production of pair in electron-positron annihilation in the Nambu-Jona-Lasinio model
The process is described in the framework of the
expanded NJL model in the energy region from 0.9 GeV to 1.5 GeV. The
contribution of intermediate state with vector mesons , and , where is the first radial
excitation of - meson was taken into account. Results obtained are in
satisfactory agreement with experimental data.Comment: 5 pages, 1 figure, 1 tabl
Fuzzy Expert System for Rectal Cancer Based on Possibility Measure
Intestinal infections in common and colorectal cancer in particular are quite widely spread and affect modern population in a significant manner. Therefore, they have been objects of intensive scientific research for quite a long time. It is known that the colorectal cancer’s diagnostics can face some difficulties caused by the uncertainties in patients’ health status and disease data. The uncertainty, in common, can be classified as probabilistic or possibilistic (fuzzy). The goal of this chapter is to analyze a fuzzy-rule-based medical expert system for the colorectal cancer’s diagnostics. In the modeling, fuzzy inference based on possibility measure and knowledge extraction based on fuzzy clustering are applied. During the initial stage of the system’s modeling, the applied parameters of colorectal cancer were defined by using clinical data. During the next stage, the soft-computing-based evaluation of the cancer’s factors is performed. During the third stage, the applied fuzzy inference, based on possibility measure, is introduced and supported by the examples. The knowledge base of the modeled system consists of the case data obtained from 100 patients in the course of 3 years by the National Center of Oncology. The effectiveness of the modeled system was checked on the testing subset of 30 diagnoses, and 22 predictions by the expert system were defined as correct
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