18 research outputs found
NA61/SHINE L\'evy HBT Measurements in Be+Be Collisions at 150 GeV/c
The program of NA61/SHINE allows for the investigation of the phase diagram
of strongly interacting matter. The nature of the quark-hadron transition can
be studied through analyzing the space-time structure of the hadron emission
source via the measurement of Bose-Einstein momentum correlations. These can be
described by correlation functions based on Levy-distributed sources. This
report presents the performance plots of Bose-Einstein correlation analysis in
Be+Be collisions at 150A GeV/c beam momentum. The transverse mass dependence of
the Levy source parameters and their possible interpretations are discussed.Comment: 6 pages, 3 figures, proceedings of the XIII Workshop on Particle
Correlations and Femtoscopy (WPCF 2018), Cracow, Poland, May 22-26, 2018,
submitted to Acta Physica Polonica
Measurements of , , , , and production in 120 GeV/ p + C interactions
This paper presents multiplicity measurements of charged hadrons produced in
120 GeV/ proton-carbon interactions. The measurements were made using data
collected at the NA61/SHINE experiment during two different data-taking
periods, with increased phase space coverage in the second configuration due to
the addition of new subdetectors. Particle identification via was
employed to obtain double-differential production multiplicities of ,
, , , and . These measurements are presented as a
function of laboratory momentum in intervals of laboratory polar angle covering
the range from 0 to 450 mrad. They provide crucial inputs for current and
future long-baseline neutrino experiments, where they are used to estimate the
initial neutrino flux
Measurements of , , and spectra in Ar+Sc collisions at 13 to 150 GeV/
The NA61/SHINE experiment at the CERN Super Proton Synchrotron studies the
onset of deconfinement in strongly interacting matter through a beam energy
scan of particle production in collisions of nuclei of varied sizes. This paper
presents results on inclusive double-differential spectra, transverse momentum
and rapidity distributions and mean multiplicities of , ,
and produced in Ar+Sc collisions at beam momenta of
13, 19, 30, 40, 75 and 150 GeV/. The analysis uses the 10%
most central collisions, where the observed forward energy defines centrality.
The energy dependence of the / ratios as well as of inverse
slope parameters of the transverse mass distributions are placed in
between those found in inelastic + and central Pb+Pb collisions. The
results obtained here establish a system-size dependence of hadron production
properties that so far cannot be explained either within statistical (SMES,
HRG) or dynamical (EPOS, UrQMD, PHSD, SMASH) models
Search for the critical point of strongly-interacting matter in Ar + Sc collisions at 150A Ge V /c using scaled factorial moments of protons
The critical point of dense, strongly interacting matter is searched for at the CERN SPS in Ar + Sc collisions at 150A 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 two-pion HBT correlations in Be+Be collisions at 150A GeV/c beam momentum, at the NA61/SHINE experiment at CERN
International audienceThis paper reports measurements of two-pion Bose-Einstein (HBT) correlations in Be+Be collisions at a beam momentum of 150A\,\mbox{GeV}/\textit{c} by the \mbox{NA61/SHINE} experiment at the CERN SPS accelerator. The obtained momentum space correlation functions can be well described by a Lévy distributed source model. The transverse mass dependence of the Lévy source parameters is presented, and their possible theoretical interpretations are discussed. The results show that the Lévy exponent is approximately constant as a function of , and far from both the Gaussian case of or the conjectured value at the critical endpoint, . The radius scale parameter shows a slight decrease in , which can be explained as a signature of transverse flow. Finally, an approximately constant trend of the intercept parameter as a function of was observed, different from measurement results at RHIC
Excess of charged over neutral meson production in high-energy collisions of atomic nuclei
Collisions of atomic nuclei at relativistic velocities produce new particles, predominantly mesons containing one valence quark and one valence anti-quark. These particles are produced in strong interactions, which preserve an approximate symmetry between up () and down () quarks. In the case of meson production, if this symmetry were exact, it would result in equal numbers of charged ( and ) and neutral ( and ) mesons in the final state. In this Letter, we report a measurement of the relative abundance of charged over neutral meson production in collisions of argon and scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We find that production of and mesons at mid-rapidity displays a significant excess of relative to that of the neutral mesons. The origin of this unexpected excess remains to be elucidated.Collisions of atomic nuclei at relativistic velocities produce new particles, predominantly mesons containing one valence quark and one valence anti-quark. These particles are produced in strong interactions, which preserve an approximate symmetry between up () and down () quarks. In the case of meson production, if this symmetry were exact, it would result in equal numbers of charged ( and ) and neutral ( and ) mesons in the final state. In this Letter, we report a measurement of the relative abundance of charged over neutral meson production in collisions of argon and scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We find that production of and mesons at mid-rapidity displays a significant excess of relative to that of the neutral mesons. The origin of this unexpected excess remains to be elucidated
Excess of charged over neutral meson production in high-energy collisions of atomic nuclei
International audienceCollisions of atomic nuclei at relativistic velocities produce new particles, predominantly mesons containing one valence quark and one valence anti-quark. These particles are produced in strong interactions, which preserve an approximate symmetry between up () and down () quarks. In the case of meson production, if this symmetry were exact, it would result in equal numbers of charged ( and ) and neutral ( and ) mesons in the final state. In this Letter, we report a measurement of the relative abundance of charged over neutral meson production in collisions of argon and scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We find that production of and mesons at mid-rapidity displays a significant excess of relative to that of the neutral mesons. The origin of this unexpected excess remains to be elucidated