10 research outputs found
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
Measurements of higher-order cumulants of multiplicity and net-electric charge distributions in inelastic proton-proton interactions by NA61/SHINE
International audienceThis paper presents the energy dependence of multiplicity and net-electric charge fluctuations in interactions at beam momenta 20, 31, 40, 80, and 158 GeV/. Results are corrected for the experimental biases and quantified with the use of cumulants and factorial cumulants. Data are compared with the Epos1.99 and FTFP-BERT model predictions
Measurements of higher-order cumulants of multiplicity and net-electric charge distributions in inelastic proton-proton interactions by NA61/SHINE
This paper presents the energy dependence of multiplicity and net-electric charge fluctuations in interactions at beam momenta 20, 31, 40, 80, and 158 GeV/. Results are corrected for the experimental biases and quantified with the use of cumulants and factorial cumulants. Data are compared with the Epos1.99 and FTFP-BERT model predictions
Measurements of , , , , and production in 120 GeV/ p + C interactions
International audienceThis 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
Search for the critical point of strongly-interacting matter in Ar + Sc collisions at 150A GeV/c using scaled factorial moments of protons
International audienceThe critical point of dense, strongly interacting matter is searched for at the CERN SPS in Ar + Sc collisions at 150A GeV/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 critical proton pairs and the power of the correlation function is obtained based on a comparison with the Power-law Model developed for this purpose
Search for a critical point of strongly-interacting matter in central Ar +Sc collisions at 13-75 GeV/ beam momentum
International audienceThe critical point of strongly interacting matter is searched for at the CERN SPS by the NA61/SHINE experiment in central Ar +Sc collisions at 13, 19, 30, 40, and 75 GeV/. The dependence of the second-order scaled factorial moments of proton multiplicity distributions on the number of subdivisions in transverse momentum space is measured. The intermittency analysis uses statistically independent data sets for every subdivision in transverse and cumulative-transverse momentum variables. The results obtained do not indicate the searched intermittent pattern. An upper limit on the fraction of correlated protons and the intermittency index is obtained based on a comparison with the Power-law Model
meson production in inelastic p+p interactions at 31, 40 and 80 GeV/c beam momentum measured by NA61/SHINE at the CERN SPS
Measurements of meson production via its decay mode in inelastic interactions at incident projectile momenta of 31, 40 and 80 GeV/ ( and GeV, respectively) are presented. The data were recorded by the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. Double-differential distributions were obtained in transverse momentum and rapidity. The mean multiplicities of mesons were determined to be at 31 GeV/, at 40 GeV/ and at 80 GeV/. The results on production are compared with model calculations (Epos1.99, SMASH 2.0 and PHSD) as well as with published data from other experiments
meson production in inelastic p+p interactions at 31, 40 and 80 GeV/c beam momentum measured by NA61/SHINE at the CERN SPS
International audienceMeasurements of meson production via its decay mode in inelastic interactions at incident projectile momenta of 31, 40 and 80 GeV/ ( and GeV, respectively) are presented. The data were recorded by the NA61/SHINE spectrometer at the CERN Super Proton Synchrotron. Double-differential distributions were obtained in transverse momentum and rapidity. The mean multiplicities of mesons were determined to be at 31 GeV/, at 40 GeV/ and at 80 GeV/. The results on production are compared with model calculations (Epos1.99, SMASH 2.0 and PHSD) as well as with published data from other experiments