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
Δ
P
T
,
N
,
Σ
P
T
,
N
and
Φ
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
U
r
qmd
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.
The critical point of dense, strongly interacting matter is searched for at the CERN SPS in
40
Ar +
45
Sc collisions at 150
A
Ge V /
c
. The dependence of second-order scaled factorial moments of ...proton multiplicity distribution on the number of subdivisions of transverse momentum space is measured. The intermittency analysis is performed using both transverse momentum and cumulative transverse momentum. For the first time, statistically independent data sets are used for each subdivision number. The obtained results do not indicate any statistically significant intermittency pattern. An upper limit on the fraction of correlated proton pairs and the power of the correlation function is obtained based on a comparison with the Power-law Model developed for this purpose.
Measurements of multiplicity fluctuations of identified hadrons produced in inelastic p+p interactions at 31, 40, 80, and 158 Formula omitted beam momentum are presented. Three different measures of ...multiplicity fluctuations are used: the scaled variance Formula omitted and strongly intensive measures Formula omitted and Formula omitted. These fluctuation measures involve second and first moments of joint multiplicity distributions. Data analysis is preformed using the Identity method which corrects for incomplete particle identification. Strongly intensive quantities are calculated in order to allow for a direct comparison to corresponding results on nucleus-nucleus collisions. The results for different hadron types are shown as a function of collision energy. A comparison with predictions of string-resonance Monte-Carlo models: Epos, Smash and Venus, is also presented.
Abstract
The measurement of
$$K^{*}(892)^0$$
K
∗
(
892
)
0
resonance production via its
$$K^{+}\pi ^{-}$$
K
+
π
-
decay mode in inelastic p+p collisions at beam momentum 158
$$\text{ Ge }\text{ V ...}\!/\!c$$
Ge
V
/
c
(
$$\sqrt{s_{NN}}=17.3$$
s
NN
=
17.3
$$\text{ Ge }\text{ V }$$
Ge
V
) is presented. The data were recorded by the NA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The
template
method was used to extract the
$$K^{*}(892)^0$$
K
∗
(
892
)
0
signal and double-differential transverse momentum and rapidity spectra were obtained. The full phase-space mean multiplicity of
$$K^{*}(892)^0$$
K
∗
(
892
)
0
mesons was found to be
$$(78.44 \pm 0.38 \mathrm {(stat)} \pm 6.0 \mathrm {(sys)) \cdot 10^{-3}}$$
(
78.44
±
0.38
(
stat
)
±
6.0
(
sys
)
)
·
10
-
3
. The NA61/SHINEresults are compared with the
Epos1.99
and Hadron Resonance Gas models as well as with world data from p+p and nucleus–nucleus collisions.
The T2K long-baseline neutrino oscillation experiment in Japan needs precise predictions of the initial neutrino flux. The highest precision can be reached based on detailed measurements of hadron ...emission from the same target as used by T2K exposed to a proton beam of the same kinetic energy of 30GeV. The corresponding data were recorded in 2007–2010 by the NA61/SHINE experiment at the CERN SPS using a replica of the T2K graphite target. In this paper details of the experiment, data taking, data analysis method and results from the 2007 pilot run are presented. Furthermore, the application of the NA61/SHINE measurements to the predictions of the T2K initial neutrino flux is described and discussed.
The offline software framework of the Pierre Auger Observatory Argirò, S.; Barroso, S.L.C.; Gonzalez, J. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2007, Letnik:
580, Številka:
3
Journal Article
Recenzirano
Odprti dostop
The Pierre Auger Observatory is designed to unveil the nature and the origins of the highest energy cosmic rays. The large and geographically dispersed collaboration of physicists and the ...wide-ranging collection of simulation and reconstruction tasks pose some special challenges for the offline analysis software. We have designed and implemented a general purpose framework which allows collaborators to contribute algorithms and sequencing instructions to build up the variety of applications they require. The framework includes machinery to manage these user codes, to organize the abundance of user-contributed configuration files, to facilitate multi-format file handling, and to provide access to event and time-dependent detector information which can reside in various data sources. A number of utilities are also provided, including a novel geometry package which allows manipulation of abstract geometrical objects independent of coordinate system choice. The framework is implemented in
C
++
, and takes advantage of object oriented design and common open source tools, while keeping the user side simple enough for
C
++
novices to learn in a reasonable time. The distribution system incorporates unit and acceptance testing in order to support rapid development of both the core framework and contributed user code.
We present results from the FUNK experiment in the search for hidden-photon dark matter. Near the surface of a mirror, hidden photons may be converted into ordinary photons. These photons are emitted ...perpendicularly to the surface and have an energy equal to the mass of the dark matter hidden photon. Our experimental setup consists of a large, spherical mirror with an area of more than 14 m2, which concentrates the emitted photons into its central point. Using a detector sensitive to visible and near-UV photons, we can exclude a kinetic-mixing coupling of stronger than χ ≈ 10−12 in the mass range of 2.5 to 7 eV, assuming hidden photons comprise all of the dark matter. The experimental setup and analysis used to obtain this limit are discussed in detail.
We report a measurement of the energy spectrum of cosmic rays for energies above 2.5 × 1018 eV based on 215,030 events recorded with zenith angles below 60°. A key feature of the work is that the ...estimates of the energies are independent of assumptions about the unknown hadronic physics or of the primary mass composition. The measurement is the most precise made hitherto with the accumulated exposure being so large that the measurements of the flux are dominated by systematic uncertainties except at energies above 5 × 1019 eV. The principal conclusions are (1) The flattening of the spectrum near 5 × 1018 eV, the so-called "ankle," is confirmed. (2) The steepening of the spectrum at around 5 × 1019 eV is confirmed. (3) A new feature has been identified in the spectrum: in the region above the ankle the spectral index γ of the particle flux ( ∝ E−γ ) changes from 2.51 ± 0.03 ( stat ) ± 0.05 ( syst ) to 3.05 ± 0.05 ( stat ) ± 0.10 ( syst ) before changing sharply to 5.1 ± 0.3 ( stat ) ± 0.1 ( syst ) above 5 × 1019 eV. (4) No evidence for any dependence of the spectrum on declination has been found other than a mild excess from the Southern Hemisphere that is consistent with the anisotropy observed above 8 × 1018 eV.
The Pierre Auger Cosmic Ray Observatory Aab, A.; Abreu, P.; Aglietta, M. ...
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
10/2015, Letnik:
798, Številka:
C
Journal Article
Recenzirano
Odprti dostop
The Pierre Auger Observatory, located on a vast, high plain in western Argentina, is the world׳s largest cosmic ray observatory. The objectives of the Observatory are to probe the origin and ...characteristics of cosmic rays above 1017eV and to study the interactions of these, the most energetic particles observed in nature. The Auger design features an array of 1660 water Cherenkov particle detector stations spread over 3000km2 overlooked by 24 air fluorescence telescopes. In addition, three high elevation fluorescence telescopes overlook a 23.5km2, 61-detector infilled array with 750m spacing. The Observatory has been in successful operation since completion in 2008 and has recorded data from an exposure exceeding 40,000km2sryr. This paper describes the design and performance of the detectors, related subsystems and infrastructure that make up the Observatory.
We report a measurement of the energy spectrum of cosmic rays above 2.5 × 1018 eV based on 215 030 events. New results are presented: at about 1.3 × 1019 eV , the spectral index changes from 2.51 ± ...0.03 (stat) ± 0.05 (syst) to 3.05 ± 0.05 (stat) ± 0.10 (syst), evolving to 5.1 ± 0.3 (stat) ± 0.1 (syst) beyond 5 × 1019 eV, while no significant dependence of spectral features on the declination is seen in the accessible range. These features of the spectrum can be reproduced in models with energy-dependent mass composition. The energy density in cosmic rays above 5 × 1018 eV is 5.66 ± 0.03 (stat) ± 1.40 (syst) × 1053 erg Mpc−3.
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