(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).A first measurement is presented of exclusive photoproduction of ... mesons associated with leading neutrons at HERA. The ...data were taken with the H1 detector in the years 2006 and 2007 at a centre-of-mass energy of ... GeV and correspond to an integrated luminosity of 1.16 pb... The ... mesons with transverse momenta ... GeV are reconstructed from their decays to charged pions, while leading neutrons carrying a large fraction of the incoming proton momentum, ..., are detected in the Forward Neutron Calorimeter. The phase space of the measurement is defined by the photon virtuality ... GeV..., the total energy of the photon-proton system ... GeV and the polar angle of the leading neutron ... mrad. The cross section of the reaction ... is measured as a function of several variables. The data are interpreted in terms of a double peripheral process, involving pion exchange at the proton vertex followed by elastic photoproduction of a ... meson on the virtual pion. In the framework of one-pion-exchange dominance the elastic cross section of photon-pion scattering, ..., is extracted. The value of this cross section indicates significant absorptive corrections for the exclusive reaction ...
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
Small and middle size surface detectors measuring extensive air showers (EAS) initiated by primary cosmic rays (PCR) incident on terrestrial atmosphere have been in operation for the last 50
years. ...Their main goal is to explore the “knee” in all particle spectrum to solve the problem of cosmic ray (CR) origin and acceleration. The recent achievements of atmospheric Cherenkov telescopes and X-ray space laboratories, establishing the supernova remnants (SNRs) as a source of hadronic cosmic rays, pose stringent conditions on the quality of EAS evidence. After establishing the existence of the “knee” itself, the most pronounced result from EAS studies is the rigidity dependent shift of the knee position to the highest energies. This feature was first observed by separation of the primary flux in different mass groups in MAKET-ANI, EAS-TOP and KASCADE experiments. The MAKET-ANI detector is placed on Mt. Aragats (Armenia) at 3200
m above the sea level (40°25′N, 44°15′E). More than 1.3
×
10
6 showers with size greater than 10
5 particles were registered in 1997–2004. The detector effectively collected the cores of EAS, initiated by primaries with energies of 10
14–10
17
eV. After proving that the quality of the EAS size and shape reconstruction was reasonably high, we present the lateral distribution function (LDF) for distances from 10 to 120
m from EAS core and EAS size spectra in 5 zenith angle intervals. We use CORSIKA simulations to present the energy spectra. The results from the MAKET-ANI experiment on the energy spectra of the “light”(p
+
He) and “heavy” (O
+
Si
+
Fe) nuclear groups are compared to the spectra obtained by balloon experiments and to other available spectra.
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).Measurements of normalised cross sections for the production of photons and neutrons at very small angles with respect to ...the proton beam direction in deep-inelastic ... scattering at HERA are presented as a function of the Feynman variable ... and of the centre-of-mass energy of the virtual photon-proton system ... The data are taken with the H1 detector in the years 2006 and 2007 and correspond to an integrated luminosity of ... The measurement is restricted to photons and neutrons in the pseudorapidity range ... and covers the range of negative four momentum transfer squared at the positron vertex ... GeV..., of inelasticity ... and of ...GeV. To test the Feynman scaling hypothesis the ... dependence of the ... dependent cross sections is investigated. Predictions of deep-inelastic scattering models and of models for hadronic interactions of high energy cosmic rays are compared to the measured cross sections.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
(ProQuest: ... denotes formulae and/or non-USASCII text omitted; see image).Inclusive ... double differential cross sections for neutral current deep inelastic scattering are measured with the H1 ...detector at HERA. The data were taken with a lepton beam energy of ... GeV and two proton beam energies of ... and 575 GeV corresponding to centre-of-mass energies of 225 and 252 GeV, respectively. The measurements cover the region of ... for ... GeV... up to ... The measurements are used together with previously published H1 data at ... GeV and lower ... data at ..., ... and ... GeV to extract the longitudinal proton structure function ... in the region ... GeV...
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
A measurement of the derivative (∂ lnF2/∂ lnx)Q2≡−λ(x,Q2) of the proton structure function F2 is presented in the low x domain of deeply inelastic positron–proton scattering. For 5×10−5⩽x⩽0.01 and ...Q2⩾1.5GeV2, λ(x,Q2) is found to be independent of x and to increase linearly with lnQ2.
The inclusive photoproduction of
D
∗
mesons and of
D
∗
-tagged dijets is investigated with the H1 detector at the
ep
collider HERA. The kinematic region covers small photon virtualities
Q
2
<2 GeV
2
...and photon–proton centre-of-mass energies of 100<
W
γp
<285 GeV. Inclusive
D
∗
meson differential cross sections are measured for central rapidities |
η
(
D
∗
)|<1.5 and transverse momenta
p
T
(
D
∗
)>1.8 GeV. The heavy quark production process is further investigated in events with at least two jets with transverse momentum
p
T
(jet)>3.5 GeV each, one containing the
D
∗
meson. Differential cross sections for
D
∗
-tagged dijet production and for correlations between the jets are measured in the range |
η
(
D
∗
)|<1.5 and
p
T
(
D
∗
)>2.1 GeV. The results are compared with predictions from Monte Carlo simulations and next-to-leading order perturbative QCD calculations.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The effect of α
2
-adrenoblocker mesedin (2-(2-methylamino-4-thiazolyl)-1,4-benzodioxane hydrochloride) on the content of oxidative stress biomarkers in the brain tissue was well studied in ischemic ...disorders. The aim of this study is to reveal the possible mechanisms of the antihypoxic effect of mesedin. The quantitative changes of the final product of lipid peroxidation (LP)—malondialdehyde (MDA) and carbonyl derivatives of proteins — aldehyde-dinitrophenylhydrazones of neutral character (ADNPuv), ketone-dinitro-phenylhydrazones of neutral character (KDNPuv), aldehyde-dinitrophenylhydrazones of basic character (ADNPvs) and ketone-dinitrophenylhydrazones of basic character (KDNPvs) were studied in the brain tissue of rats (
n
= 56) under the condition of experimental ischemia caused by the ligation of the right common carotid artery. The study showed that one of the possible mechanisms of antihypoxic action of mesedin is its ability to prevent the accumulation of malondialdehyde and to limit protein carbonylation in brain ischemia. The data received demonstrates that mesedin could serve as a potential medicine for the correction of cerebrovascular ischemic disorders, for the reason that along with improving cerebral blood flow and preventing the development of morphological shifts and neurobehavioral disturbances in brain local ischemia, the medicine also mitigates the aggressive action of oxidative stress while protecting the brain tissue from the consequences of hypoxia.
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