4,394 research outputs found
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
Discrimination of SUSY breaking models using single-photon processes at future e+e- linear colliders
We examine the single-photon processes in the frame work of supersymmetric
models at future e+e- linear colliders. According to the recent experimental
achievement, the optimistic polarization degrees for both electron and positron
beams are taken into account to enhance the signal-to-noise ratio revealing the
observable difference between supersymmetry breaking models. The minimal
supergravity model and the minimal SU(5) grand unified model in gaugino
mediation have been examined as examples. We see that after several years of
accummulating data, the difference of the number of single-photon events
between the two models received from the collider would be in excess of three
times the statistical error, providing us the possibility to probe which model
would be realized in nature. The result is well suitable for the future running
of the International Linear Collider.Comment: 14 pages, 4 figures, version to be published in Mod. Phys. Lett.
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
Pion wave functions from holographic QCD and the role of infrared renormalons in photon-photon collisions
In this article, we calculate the contribution of the higher-twist Feynman
diagrams to the large- inclusive single pion production cross section in
photon-photon collisions in case of the running coupling and frozen coupling
approaches within holographic QCD. We compare the resummed higher-twist cross
sections with the ones obtained in the framework of the frozen coupling
approach and leading-twist cross section. Also, we show that in the context of
frozen coupling approach a higher-twist contribution to the photon-photon
collisions cross section is normalized in terms of the pion electromagnetic
form factor.Comment: 21 pages, 15 figures. arXiv admin note: text overlap with
arXiv:0709.2072 by other author
QED peripheral mechanism of pair production at colliders
Cross section of the processes of neutral pion production as well as pairs of
charged fermions and bosons in peripherical interaction of leptons, photons are
calculated in main logarithmical approximation. We investigate the phase
volumes and differential cross sections. The differential cross section of few
neutral pions and a few pairs production are written down explicitly.
Considering the academic problem of summation on the number of pairs for the
case of massless particles we reproduce the known results obtained in seventies
of last century. The possibility to construct the generator for Monte-Carlo
modeling of this processes basing of this results are discussed.Comment: 25 pages, 5 figure
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