We present data on charged kaons (K+-) and {\phi} mesons in Au(1.23A GeV)+Au collisions. It is the first simultaneous measurement of K and {\phi} mesons in central heavy-ion collisions below a kinetic beam energy of 10A GeV. The {\phi}/K- multiplicity ratio is found to be surprisingly high with a value of 0.52 +- 0.16 and shows no dependence on the centrality of the collision. Consequently, the different slopes of the K+ and K- transverse-mass spectra can be explained solely by feed- down, which substantially softens the spectra of K- mesons. Hence, in contrast to the commonly adapted argumentation in literature, the different slopes do not necessarily imply diverging freeze- out temperatures of K+ and K- mesons caused by different couplings to baryons.
Acceptance and efficiency corrected transverse-mass spectra around mid-rapidity.
$K^{+}$ signal and the corresponding background fit for the region covering mid-rapidity and $m_{t}−m_{0}$ between 25 and 50 $MeV/c^{2}$.
$K^{-}$ signal and the corresponding background fit for the region covering mid-rapidity and $m_{t}−m_{0}$ between 50 and 75 $MeV/c^{2}$.
The angular and energy distributions of pions produced by 650-MeV protons and pion-nucleon correlations were studied using a liquid hydrogen bubble chamber. The present investigation indicates that the experimental angular distributions of neutral and charged pions are consis- tent with the assumption of isotopic spin conservation. The contributions of rrN subsystem states with isospin T 11'N = 7' 2 and % are measured; the contribution of the latter is 72 ± 3%.
No description provided.
We present the analysis of the inclusive $K^{0}$ production in p+p and p+Nb collisions measured with the HADES detector at a beam kinetic energy of 3.5 GeV. Data are compared to the GiBUU transport model. The data suggest the presence of a repulsive momentum-dependent kaon potential as predicted by the Chiral Perturbation Theory (ChPT). For the kaon at rest and at normal nuclear density, the ChPT potential amounts to $\approx 35$ MeV. A detailed tuning of the kaon production cross sections implemented in the model has been carried out to reproduce the experimental data measured in p+p collisions. The uncertainties in the parameters of the model were examined with respect to the sensitivity of the experimental results from p+Nb collisions to the in-medium kaon potential.
The K0 production cross section in P P collisions.
The K0 production cross section in P + NB collisions. The uncertainty given on SIG(P NB --> K0 X) is the dominating absolute normalization uncertainty.
The fixed-target MIPP experiment, Fermilab E907, was designed to measure the production of hadrons from the collisions of hadrons of momenta ranging from 5 to 120 GeV/c on a variety of nuclei. These data will generally improve the simulation of particle detectors and predictions of particle beam fluxes at accelerators. The spectrometer momentum resolution is between 3 and 4%, and particle identification is performed for particles ranging between 0.3 and 80 GeV/c using $dE/dx$, time-of-flight and Cherenkov radiation measurements. MIPP collected $1.42 \times10^6$ events of 120 GeV Main Injector protons striking a target used in the NuMI facility at Fermilab. The data have been analyzed and we present here charged pion yields per proton-on-target determined in bins of longitudinal and transverse momentum between 0.5 and 80 GeV/c, with combined statistical and systematic relative uncertainties between 5 and 10%.
The production yields of PI+ and PI- and the ratio of these yields. The first uncertainty given on each value combines statistical uncertainties and systematic uncertainties from backgrounds.
We study the processes $e^+ e^-\to K_S^0 K_L^0 \gamma$, $K_S^0 K_L^0 \pi^+\pi^-\gamma$, $K_S^0 K_S^0 \pi^+\pi^-\gamma$, and $K_S^0 K_S^0 K^+K^-\gamma$, where the photon is radiated from the initial state, providing cross section measurements for the hadronic states over a continuum of center-of-mass energies. The results are based on 469 fb$^{-1}$ of data collected with the BaBar detector at SLAC. We observe the $\phi(1020)$ resonance in the $K_S^0 K_L^0$ final state and measure the product of its electronic width and branching fraction with about 3% uncertainty. We present a measurement of the $e^+ e^-\to K_S^0 K_L^0 $ cross section in the energy range from 1.06 to 2.2 GeV and observe the production of a resonance at 1.67 GeV. We present the first measurements of the $e^+ e^-\to K_S^0 K_L^0 \pi^+\pi^-$, $K_S^0 K_S^0 \pi^+\pi^-$, and $K_S^0 K_S^0 K^+K^-$ cross sections, and study the intermediate resonance structures. We obtain the first observations of \jpsi decay to the $K_S^0 K_L^0 \pi^+\pi^-$, $K_S^0 K_S^0 \pi^+\pi^-$, and $K_S^0 K_S^0 K^+K^-$ final states.
Cross section measurement for PHI(1020).
Mass measurement for PHI(1020).
Measurement of the PHI(1020) width.
The process e+e- --> p anti-p gamma is studied using 469 fb-1 of integrated luminosity collected with the BABAR detector at the PEP-II collider, at an e+e- center-of-mass energy of 10.6 GeV. From the analysis of the p anti-p invariant mass spectrum, the energy dependence of the cross section for e+e- --> p anti-p is measured from threshold to 4.5 GeV. The energy dependence of the ratio of electric and magnetic form factors, |G_E/G_M|, and the asymmetry in the proton angular distribution are measured for p anti-p masses below 3 GeV. We also measure the branching fractions for the decays J/psi --> p anti-p and psi(2S) --> p anti p.
Measurement of the cross section as a function of the invariant mass of the PBAR-P system and the effective form factor for the reaction E+ E- --> PBAR P. The contributions from J/PSI and PSI(25) decaying to PBAR-P have been subtracted. The form factor error is the combined statistical and systematic.
Ilford G-5 emulsions were exposed to an external, 3.5 GeY proton beam of the Berkeley Bevatron. A total of 1200 nuclear interactions of beam protons was located, of which 128 were identified as protonproton collisions. Multiple scattering, blob density, range and angle measurements were employed to determine the cross-sections for elastic and inelastic interactions as well as the identities and center-of-mass system momenta and scattering angles of secondaries from inelastic proton-proton interactions. This analysis indicates a cross-section of (8.0±2.4) mb for elastic events, (24.1±2.9) mb for two-prong inelasitc events, (7.9±1.4)mb for four-prong events and (0.6±0.3) mb for sixprong events. The mean charged pion multiplicity in inelastic interactions is 1.5±0.2 and corresponds to an average degree of inelasticity of 0.45 ±0.06. Center-of-mass system angular distributions of charged secondaries from inelastic events display a peaking for small scattering angles which is most pronounced for protons and pions from events with low secondary multiplicity. Momentum and transverse momentum distributions of secondary protons and pions from inelastic events are presented and compared with the results at other energies. The angular distribution of elastically scattered protons is found to be in fair agreement with that predicted by a uniform optical model of radius 1.25-10-13 cm and opacity 0.66.
No description provided.
A precise measurement of the cross section of the process $e^+e^-\to\pi^+\pi^-(\gamma)$ from threshold to an energy of 3GeV is obtained with the initial-state radiation (ISR) method using 232fb$^{-1}$ of data collected with the BaBar detector at $e^+e^-$ center-of-mass energies near 10.6GeV. The ISR luminosity is determined from a study of the leptonic process $e^+e^-\to\mu^+\mu^-(\gamma)\gamma_{\rm ISR}$, which is found to agree with the next-to-leading-order QED prediction to within 1.1%. The cross section for the process $e^+e^-\to\pi^+\pi^-(\gamma)$ is obtained with a systematic uncertainty of 0.5% in the dominant $\rho$ resonance region. The leading-order hadronic contribution to the muon magnetic anomaly calculated using the measured $\pi\pi$ cross section from threshold to 1.8GeV is $(514.1 \pm 2.2({\rm stat}) \pm 3.1({\rm syst}))\times 10^{-10}$.
Bare cross-section $e^+e^-\rightarrow\pi^+\pi^-(\gamma)$ The cross section values (nb) for 337 CM energy intervals (GeV) from 0.3 to 3 GeV. The cross section is bare (excluding vacuum polarization) and includes the emission of final state photons. ***WARNING*** The quoted errors are from the diagonal elements of the statistical covariance matrix (reported on the Table titled "Bare cross-section statistical covariance") and added quadratically with the systematic uncertainties (reported in the Table titled "Bare cross-section systematic uncertainties"). These errors can be used when plotting the results as they are representative of the precision achieved. However, any calculation involving the cross section over some energy range MUST use, to be meaningful, the full statistical covariance matrix and the proper correlations of the systematic uncertainties. ***WARNING*** The Bare cross-section statistical covariance is reported as additional resource in YAML, since its size exceeds the maximum size of 10 MB for the library hepdata_lib. It is a statistical covariance matrix, for 337x337 CM energy intervals (GeV), from 0.3 to 3 GeV, matching the ones of this table.
Bare cross-section $e^+e^-\rightarrow\pi^+\pi^-(\gamma)$ systematic uncertainties contributions and total systematic uncertainties, for 337 CM energy intervals (GeV), from 0.3 to 3 GeV. All systematics contributions are each 100% correlated in all energy bins.
Bare cross-section $e^+e^-\rightarrow\pi^+\pi^-(\gamma)$ statistical covariance matrix, for 337x337 CM energy intervals (GeV), from 0.3 to 3 GeV.
We study the processes e+e- --> K+ K- pi+pi-gamma, K+ K- pi0pi0gamma, and K+ K- K+ K-gamma, where the photon is radiated from the initial state. About 84000, 8000, and 4200 fully reconstructed events, respectively, are selected from 454 fb-1 of BaBar data. The invariant mass of the hadronic final state defines the \epem center-of-mass energy, so that the K+ K- pi+pi- data can be compared with direct measurements of the e+e- --> K+ K- pi+pi- reaction. No direct measurements exist for the e+e- --> K+ K-pi0pi0 or e+e- --> K+ K-K+ K- reactions, and we present an update of our previous result with doubled statistics. Studying the structure of these events, we find contributions from a number of intermediate states, and extract their cross sections. In particular, we perform a more detailed study of the e+e- --> phi(1020)pipigamma reaction, and confirm the presence of the Y(2175) resonance in the phi(1020) f0(980) and K+K-f0(980) modes. In the charmonium region, we observe the J/psi in all three final states and in several intermediate states, as well as the psi(2S) in some modes, and measure the corresponding product of branching fraction and electron width.
The cross section for the reaction E+ E- --> K+ K- PI+ PI- measured with ISR data. Statistical errors only.
Cross section measurements for the reaction E+ E- --> K*(892)0 K- PI+. Statistical errors only.
Cross section measurements for the reaction E+ E- --> PHI PI+ PI-. Statistical errors only.
A comprehensive survey of event-by-event fluctuations of charged hadron multiplicity in relativistic heavy ions is presented. The survey covers Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV, and Cu+Cu collisions sqrt(s_NN) = 22.5, 62.4, and 200 GeV. Fluctuations are measured as a function of collision centrality, transverse momentum range, and charge sign. After correcting for non-dynamical fluctuations due to fluctuations in the collision geometry within a centrality bin, the remaining dynamical fluctuations expressed as the variance normalized by the mean tend to decrease with increasing centrality. The dynamical fluctuations are consistent with or below the expectation from a superposition of participant nucleon-nucleon collisions based upon p+p data, indicating that this dataset does not exhibit evidence of critical behavior in terms of the compressibility of the system. An analysis of Negative Binomial Distribution fits to the multiplicity distributions demonstrates that the heavy ion data exhibit weak clustering properties.
Additional information containing number of events which were used to reconstruct the numvers matching to Figure 1 and 2.
Additional information containing number of events which were used to reconstruct the numvers matching to Figure 1 and 2.
Additional information containing number of events which were used to reconstruct the numvers matching to Figure 1 and 2.
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