None
THE RATIO SIG(RHO0)/SIG(OMEGA) IS FREE PARAMETER.
THE RATIO SIG(RHO0)/SIG(OMEGA)=1. AND FIXED.
No description provided.
The focus of this experiment is on dimuons at low M T but the mass range up to the J ψ is also covered. Dimuons are measured over a wide rapidity interval, ranging from nearly central to very forward rapidities. We present the experimental results in different kinematic regions and as a function of charged multiplicity. The observed dimuon spectra are also compared to conventional sources of lepton pairs production.
No description provided.
No description provided.
No description provided.
The focus of this experiment is on dimuons at low M T but the mass range up to the J ψ is also covered. Dimuons are measured over a wide rapidity interval, ranging from nearly central to very forward rapidities. Experimental results concerning the vector meson production in p-W and S-W interactions at 200 GeV/c/A as a function of the charged multiplicity are presented together with a comparison of the observed invariant mass spectra with the dimuon conventional sources in the mass region between the φ and J ψ mesons. The observed large difference in the shape and absolute value of p-W and S-W dimuon spectra cannot be explained in terms of a direct extrapolation of the p-p results.
No description provided.
No description provided.
Inclusive ϕ meson production has been measured for 100 GeV/c and 200 GeV/c incident π−,\(\bar p\) andK−, and for 120 GeV/c and 200 GeV/c incident π+,p andK+, using a Be target. A total of 630,000 ϕ mesons has been recorded in the kinematic range 0<xF<0.4. Presented are the differential cross sectionsdσ/dxF anddσ/dpT2. The longitudinal momentum distributions show that the strange valence quarks of the incidentK mesons play an important role in ϕ meson production, even at smallxF. The decay angular distribution of the ϕ meson is evaluated in the Gottfried-Jackson frame and is expressed in the elements of the density matrix. There is a small but significant cos2θGJ dependence for smallpT, which decreases for increasingpT.
Note that the data is plotted in fig. 5 a factor 5 too large. The numbers here are correct.
Note that the data is plotted in fig 5 a factor of 5 too large. The numbers here are correct.
Note that the data is plotted in fig. 5 a factor of 5 too large. CT = The numbers here are correct.
We report the measurements of the inclusive μ-pair production by 150-GeV protons and π+ mesons on beryllium. Absolute cross sections as well as the Feynman-x and PT dependence are presented in the mass region between 0.211 and 3.5 GeV/c2. Upper limits are also given for the inclusive production of η and ρ′(1600) mesons.
DATA OBTAINED FROM FIGURE BY A.A. LEBEDEV.
DATA OBTAINED FROM FIGURE BY A.A. LEBEDEV.
No description provided.
The inclusive production cross sections of the strange vector mesons K*0, K*0bar, and phi have been measured in interactions of 920 GeV protons with C, Ti, and W targets with the HERA-B detector at the HERA storage ring. Differential cross sections as a function of rapidity and transverse momentum have been measured in the central rapidity region and for transverse momenta up to pT=3.5 GeV/c. The atomic number dependence is parametrised as sigma(pA) = sigma(pN)*A**alpha, where sigma(pN) is the proton-nucleon cross section. Within the phase space accessible, alpha(K*0) = 0.86+/-0.03, alpha(K*0bar) = 0.87+/-0.03, and alpha(phi) = 0.96+/-0.02. The total proton-nucleon cross sections, determined by extrapolating the differential measurements to full phase space, are sigma(pN->K*0) = 5.06+/-0.54 mb, sigma(pN->K*0bar) = 4.02+/-0.45 mb, and sigma(pN->phi) = 1.17+/-0.11 mb. The Cronin effect is observed for the first time for vector mesons containing strange quarks/ compared to the measurements of Cronin et al. for K+- mesons, the measured values of alpha for phi mesons coincide with those of K- mesons for all transverse momenta, while the enhancement for K*0 / K*0bar mesons is smaller.
Measured rapidity distribution for K*0 production in the accessible phase space.
Measured rapidity distribution for K*BAR0 production in the accessible phase space.
Measured rapidity distribution for PHI production in the accessible phase space.
We have measured the invariant cross section for inclusive ϕ production in proton-nucleus collisions at 400 GeV/c near Feynman x=0. For transverse momenta in the range between 0.8 and 3.5 GeV/c the ratio of ϕ to π− rises from 1 to 7%. We also report on correlations with particles opposite the ϕ in the center-of-mass system as they relate to the Okubo-Zweig-Iizuka rule.
No description provided.
We present our first results on φ and ϱ+ω production in pW and SW collisions at 200 GeV/nucleon, obtained using the HELIOS/3 muon spectrometer, which measures dimuons in a large acceptance in transverse momentum and rapidity. The data show a clear increase of the ratio φ/(ϱ+ω) going from pW to SW collisions and a slight increase from peripheral to central SW collisions. This the case for low (p t ≤ 0.6GeV/c) and high (p t > 0.6 GeV/c) transverse momentum. The rise is due to an increase in the number of produced φ mesons.
No description provided.
No description provided.
Muon pair production is studied in p - W and S U collisions at 200 GeV per nucleon, as a function of transverse momentum P Tμμ . The inclusive ϱ + ω and Φ differential cross-sections dσ dP T are measured in the dimuon decay channel, for P T ≥ 0.6 GeV/c, in the central rapidity region, 3.0≤ y ≤ 4.0. Assuming the power law A-dependence σ = σ 0 ( A beam · A target ) α , the study of the integrated cross-sections for p - W and S U collisions leads to α ϱ + ω = 1.00±0.02±0.07 and α Φ = 1.23±0.03±0.05, showing clear evidence of Φ enhancement in S U interactions as compared to p - W collisions.
Statistical errors only.
Statistical errors only.
Statistical errors only.
The inclusive production of omega and phi mesons is studied in the backward region of the interaction of 12 GeV protons with polyethylene, carbon, and copper targets. The mesons are measured in e^+ e^- decay channels. The production cross sections of the mesons are presented as functions of rapidity y and transverse momentum p_T. The nuclear mass number dependences (A dependences) are found to be A^{0.710 +/- 0.021(stat) +/- 0.037(syst)} for omega mesons and A^{0.937 +/- 0.049(stat) +/- 0.018(syst)} for phi mesons in the region of 0.9 < y < 1.7 and p_T < 0.75 GeV/c.
Differential cross section as a function of rapidity (YRAP) for OMEGA production.
Differential cross section as a function of rapidity (YRAP) for PHI production.
Differential cross section as a function of transverse momentum (PT) for OMEGA production.