6 research outputs found
Multiplicity and transverse momentum fluctuations in inelastic proton-proton interactions at the CERN Super Proton Synchrotron
Measurements of multiplicity and transverse momentum fluctuations of charged
particles were performed in inelastic p+p interactions at 20, 31, 40, 80 and
158 GeV/c beam momentum. Results for the scaled variance of the multiplicity
distribution and for three strongly intensive measures of multiplicity and
transverse momentum fluctuations \$\Delta[P_{T},N]\$, \$\Sigma[P_{T},N]\$ and
\$\Phi_{p_T}\$ are presented. For the first time the results on fluctuations
are fully corrected for experimental biases. The results on multiplicity and
transverse momentum fluctuations significantly deviate from expectations for
the independent particle production. They also depend on charges of selected
hadrons. The string-resonance Monte Carlo models EPOS and UrQMD do not describe
the data. The scaled variance of multiplicity fluctuations is significantly
higher in inelastic p+p interactions than in central Pb+Pb collisions measured
by NA49 at the same energy per nucleon. This is in qualitative disagreement
with the predictions of the Wounded Nucleon Model. Within the statistical
framework the enhanced multiplicity fluctuations in inelastic p+p interactions
can be interpreted as due to event-by-event fluctuations of the fireball energy
and/or volume.Comment: 18 pages, 12 figure
Measurement of Production Properties of Positively Charged Kaons in Proton-Carbon Interactions at 31 GeV/c
Spectra of positively charged kaons in p+C interactions at 31 GeV/c were
measured with the NA61/SHINE spectrometer at the CERN SPS. The analysis is
based on the full set of data collected in 2007 with a graphite target with a
thickness of 4% of a nuclear interaction length. Interaction cross sections and
charged pion spectra were already measured using the same set of data. These
new measurements in combination with the published ones are required to improve
predictions of the neutrino flux for the T2K long baseline neutrino oscillation
experiment in Japan. In particular, the knowledge of kaon production is crucial
for precisely predicting the intrinsic electron neutrino component and the high
energy tail of the T2K beam. The results are presented as a function of
laboratory momentum in 2 intervals of the laboratory polar angle covering the
range from 20 up to 240 mrad. The kaon spectra are compared with predictions of
several hadron production models. Using the published pion results and the new
kaon data, the K+/\pi+ ratios are computed.Comment: 10 pages, 11 figure
Theta_13: phenomenology, present status and prospect
The leptonic mixing angle theta_13 is currently a high-priority topic in the
field of neutrino physics, with five experiments under way, searching for
neutrino oscillations induced by this angle. We review the phenomenology of
theta_13 and discuss the information from present global oscillation data. A
description of the upcoming reactor and accelerator experiments searching for a
non-zero value of theta_13 is given, and we evaluate the sensitivity reach
within the next few years.Comment: Topical review, 55 pages, 23 figures, v2: various minor improvements,
references added, new section 6, matches version to appear in J. Phys.
Two-particle correlations in azimuthal angle and pseudorapidity in inelastic p + p interactions at the CERN Super Proton Synchrotron
Results on two-particle ΔηΔϕ correlations in inelastic p + p interactions at 20, 31, 40, 80, and 158 GeV/c are presented. The measurements were performed using the large acceptance NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The data show structures which can be attributed mainly to effects of resonance decays, momentum conservation, and quantum statistics. The results are compared with the Epos and UrQMD models
Production of Lambda-hyperons in inelastic p plus p interactions at 158 GeV/c
Inclusive production of Lambda-hyperons was measured with the large
acceptance NA61/SHINE spectrometer at the CERN SPS in inelastic p+p
interactions at beam momentum of 158 GeV/c. Spectra of transverse
momentum and transverse mass as well as distributions of rapidity and
x(F) are presented. The mean multiplicity was estimated to be
0.120+/-0.006 (stat.) +/-0.010 (sys.). The results are compared with
previous measurements and predictions of the EPOS, URQMD and FRITIOF
models
Measurements of production properties of K-S(0) mesons and Lambda hyperons in proton- carbon interactions at 31 GeV/c
Spectra of K-S(0) mesons and Lambda hyperons were measured in p + C
interactions at 31 GeV/c with the large acceptance NA61/SHINE
spectrometer at the CERN SPS. The data were collected with an isotropic
graphite target with a thickness of 4% of a nuclear interaction length.
Interaction cross sections, charged pion spectra, and charged kaon
spectra were previously measured using the same data set. Results on
K-S(0) and Lambda production in p + C interactions serve as a reference
for the understanding of the enhancement of strangeness production in
nucleus-nucleus collisions. Moreover, they provide important input for
the improvement of neutrino flux predictions for the T2K long baseline
neutrino oscillation experiment in Japan. Inclusive production cross
sections for K-S(0) and Lambda are presented as a function of laboratory
momentum in intervals of the laboratory polar angle covering the range
from 0 up to 240 mrad. The results are compared with predictions of
several hadron production models. The K-S(0) mean multiplicity in
production processes < n(KS0)> and the inclusive cross section for
K-S(0) production sigma(KS0) were measured and amount to 0.127 +/- 0.005
(stat) +/- 0.022 (sys) and 29.0 +/- 1.6 (stat) +/- 5.0 (sys) mb,
respectively