Inclusive doubly differential cross sections d super(2) s sub(pA )/dx sub(F ) dp sub(T ) super(2) as a function of Feynman-x (x sub(F )) and transverse momentum (p sub(T )) for the production of K ...sub(S ) super(0) , and $\bar{\varLambda}$ in proton-nucleus interactions at 920 GeV are presented. The measurements were performed by HERA-B in the negative x sub(F )range (-0.12<x sub(F )<0.0) and for transverse momenta up to p sub(T )=1.6 GeV/c. Results for three target materials: carbon, titanium and tungsten are given. The ratios of production cross sections are presented and discussed. The Cronin effect is clearly observed for all three V super(0) species. The atomic number dependence is parameterized as s sub(pA )=s sub(pN ); A super(a )where s sub(pN )is the proton-nucleon cross section. The measured values of a are all near one. The results are compared with EPOS 1.67 and PYTHIA 6.3. EPOS reproduces the data to within -20% except at very low transverse momentum.
Inclusive doubly differential cross sections d2σpA/dxF dpT2 as a function of Feynman-x (xF) and transverse momentum (pT) for the production of KS0, Λ and \(\bar{\varLambda}\) in proton-nucleus ...interactions at 920 GeV are presented. The measurements were performed by HERA-B in the negative xF range (−0.12<xF<0.0) and for transverse momenta up to pT=1.6 GeV/c. Results for three target materials: carbon, titanium and tungsten are given. The ratios of production cross sections are presented and discussed. The Cronin effect is clearly observed for all three V0 species. The atomic number dependence is parameterized as σpA=σpN⋅Aα where σpN is the proton-nucleon cross section. The measured values of α are all near one. The results are compared with EPOS 1.67 and PYTHIA 6.3. EPOS reproduces the data to within ≈20% except at very low transverse momentum.
In this paper we describe the operation and performance of the HERA-B Outer Tracker, a 112
674 channel system of planar drift tube layers. The performance of the HERA-B Outer Tracker system ...fullfilled all requirements for stable and efficient operation in a hadronic environment, thus confirming the adequacy of the honeycomb drift tube technology and of the front-end readout system. The detector was stably operated with a gas gain of
3
×
10
4
in an
Ar
/
CF
4
/
CO
2
(65:35:5) gas mixture, yielding a good efficiency for triggering and track reconstruction, larger than 95% for tracks with momenta above
5
GeV
/
c
. The hit resolution of the drift cells was 300–
320
μ
m
and the relative momentum resolution can be described as:
σ
(
p
)
/
p
%
=
(
1.61
±
0.02
)
+
(
0.0051
±
0.0006
)
·
p
GeV
/
c
. At the end of the HERA-B running no aging effects in the Outer Tracker cells were observed.
The inclusive production cross sections of the strange vector mesons K*0, K̄*0, and φ have been measured in interactions of 920 GeV protons with C, Ti, and W targets with the HERA-B detector at the ...HERA storage ring. Differential cross sections as a function of rapidity and transverse momentum have been measured in the central rapidity region and for transverse momenta up to pT = 3.5 GeV/c. The atomic number dependence is parametrised as σpA=σpN*Aα, where σpN is the proton–nucleon cross section. Within the phase space accessible, α(K*0)=0.86±0.03, α(K̄*0)=0.87±0.03, and α(φ)=0.96±0.02. The total proton–nucleon cross sections, determined by extrapolating the differential measurements to full phase space, are σpN→K*0=(5.06±0.54) mb, σpN→K̄*0=(4.02±0.45) mb, and σpN→φ=(1.17±0.11) mb. For all resonances the Cronin effect is observed; compared to the measurements of Cronin et al. for K± mesons, the measured values of α for φ mesons coincide with those of K+ mesons for all transverse momenta, while the enhancement for K*0/K̄*0 mesons is smaller.
A statistical-dynamical downscaling procedure is applied for an investigation into the availability of wind power over a region of 80 × 87 km which covers flat and hilly terrain. The approach is ...based on the statistical coupling of a regionally representative wind climate with a numerical atmospheric mesoscale model. The large-scale wind climatology is calculated by a cluster-analysis of a time series of radiosonde data over 12 years. Any of the resulting 143 clusters represents a particular combination of geostrophic wind components and vertical temperature gradient. For each cluster, a highly resolved steady-state wind field is simulated with a non-hydrostatic mesoscale model. These wind fields are statistically evaluated by weighting them with the corresponding cluster frequency. The resulting three-dimensional wind field and the frequency distributions of windspeed and direction are compared with observations at synoptic stations.
The translational diffusion of the integral membrane sialoglycoprotein from erythrocyte membranes, glycophorin, incorporated into bilayer membranes of dimyristoyl-phosphatidylcholine at a ...protein/lipid molar ratio of 1:4500 was examined by using the fluorescence redistribution after photobleaching technique. A plot of the diffusion coefficient vs. temperature shows a sharp decrease in the rate of diffusion at about 15 degrees C. This sharp diffusion transition is at a temperature some 9 degrees C lower than the calorimetrically measured lipid gel-liquid crystalline phase transition temperature of the system. The difference between the diffusion transition temperature and the lipid phase transition temperature is attributed toi a localized fluidizing effect of the protein upon the gel phase lipid. The value of the diffusion coefficient above 15 degrees C was found to be (1-2) x 10(-8) cm(2)s(-1), and below 15 degrees C it was lower than about 5 x 10(-11)cm(2)s(-1). The fluorescence recovery in the bleached area as a consequence of diffusional redistribution appeared to be due to a single diffusing species at temperatures above 15 degrees C and due to more than one diffusing species below this temperature.
Using the ARGUS detector at the
e
+
e
− storage ring DORIS II at DESY, we have found evidence for the production of the excited charmed baryon state
Λ
c
(2593)
+ in the channel
Λ
c
+
π
+
π
−. Its ...mass was determined to be (2594.6±0.9±0.4) MeV/c
2, and the natural width measured to be Γ = (2.9
−2.1−1.4
+2.9+1.8) MeV. The production cross section times the branching ratios of
σ(
e
+
e
− →
Λ
c
(2593)
+
X) ×
Br(
Λ
c
(2593)
+ →
Λ
c
+
π
+
π
−) ×
Br(
Λ
c
+ →
pK
−
π
+) was measured to be (0.25
−0.13
+0.24 ±0.13) pb. The fractions of
Λ
c
(2593)
+ decays proceeding through the
Σ
c
0
π
+ and
Σ
c
++
π
− channels were determined to be 0.29±0.10±0.11 and 0.37±0.12±0.13, respectively.
Using the ARGUS detector at the
e
+
e
− storage ring DORIS II, we have measured the Michel parameters
ρ,
ξ, and
ξδ for
τ
±→l
±ν
ν
̄
decays in
τ-pair events produced at center of mass energies in the ...region of the
ϒ resonances. Using
τ
∓→
ρ
∓
ν as spin analyzing tags, we find
ρ
e
=0.68±0.04±0.08,
ξ
e
=1.12±0.20±0.09,
ξδ
e
=0.57±0.14±0.07,
ρ
μ
=0.69±0.06±0.08,
ξ
μ
=1.25±0.27±0.14 and
ξδ
μ
=0.72±0.18±0.10. In addition, we report the combined ARGUS results on
ρ,
ξ, and
ξδ using this work und previous measurements.
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