We report the first observation of diffractive $J/\psi(\to \mu^+\mu^-)$ production in $\bar pp$ collisions at $\sqrt{s}$=1.8 TeV. Diffractive events are identified by their rapidity gap signature. In a sample of events with two muons of transverse momentum $p_T^{\mu}>2$ GeV/$c$ within the pseudorapidity region $|\eta|<$1.0, the ratio of diffractive to total $J/\psi$ production rates is found to be $R_{J/\psi}= [1.45\pm 0.25]%$. The ratio $R_{J/\psi}(x)$ is presented as a function of $x$-Bjorken. By combining it with our previously measured corresponding ratio $R_{jj}(x)$ for diffractive dijet production, we extract a value of $0.59\pm 0.15$ for the gluon fraction of the diffractive structure function of the proton.
Diffractive to total J/psi production ratio.
Ratio of diffractive to total J/psi rate, per unit of the fractional momentum loss of the leading (anti)proton, and as a function of x-Bjorken of the struck parton of the (anti)proton adjacent to the rapidity gap and participating in the J/psi production.
Gluon fraction of the diffractive structure function of the (anti)proton.
We have measured the polarization of J/Psi and Psi(2S) mesons produced in p\bar{p} collisions at \sqrt{s} = 1.8 TeV, using data collected at CDF during 1992-95. The polarization of promptly produced J/Psi [Psi(2S)] mesons is isolated from those produced in B-hadron decay, and measured over the kinematic range 4[5.5] < P_T < 20 GeV/c and |y| < 0.6. For P_T \gessim 12 GeV/c we do not observe significant polarization in the prompt component.
Polarization for prompt J/PSIs (Q=PROMPT) and for J/PSI from B meson decays(NAME=BEAUTY).
Polarization for prompt PSI(2S) (NAME=PROMPT) and for PSI(2S) from B meson decays (NAME=B).
We present a study of J/ψ and ψ(2S) production in pp¯ collisions, at s=1.8TeV with the CDF detector at Fermilab. The J/ψ and ψ(2S) mesons are reconstructed using their μ+μ− decay modes. We have measured the inclusive production cross section for both mesons as a function of their transverse momentum in the central region, |η|<0.6. We also measure the fraction of these events originating from b hadrons. We thus extract individual cross sections for J/ψ and ψ(2S) mesons from b-quark decays and prompt production. We find a large excess (approximately a factor of 50) of direct ψ(2S) production compared with predictions from the color singlet model.
Integrated cross sections.
Differential cross section times branching ratio for J/PSI's originating from b hadron decays.
Differential cross section times branching ratio for PSI(2S) originating from b hadron decays.
We have measured the fraction of J/ψ mesons originating from χc meson decays in pp¯ collisions at s=1.8TeV. The fraction, for PTJ/ψ>4.0GeV/c and |ηJ/ψ|<0.6, not including contributions from b flavored hadrons, is 29.7%±1.7%(stat)±5.7%(syst). We have determined the cross sections for J/ψ mesons originating from χc decays and for directly produced J/ψ mesons. We have found that direct J/ψ production is in excess of the prediction of the color singlet model by the same factor found for direct ψ(2S) production.
Fraction of J/PSI mesons from CHI/C decays, excluding the the contributions from b-hadron decay.
Differential cross section for J/PSI's directly produced (ie excluding CHI/C and PSI/(25) decay contribution to the prompt production cross section). RE = PBAR P --> J/PSI X.
Differential cross section for J/PSI's produced in CHI/C decays.
We report on a measurement of the branching fraction of the Cabibbo-suppressed decay Bu+→J/ψπ+, where J/ψ→μ+μ−. The data were collected by the Collider Detector at Fermilab during 1992–1995 and correspond to an integrated luminosity of 110pb−1 in p¯p collisions at s=1.8TeV. A signal of 28−9+10 events is observed and we determine the ratio of branching fractions B(Bu+→J/ψπ+)/B(Bu+→J/ψK+) to be [5.0−1.7+1.9(stat)±0.1(syst)]%. Using the world average value for B(Bu+→J/ψK+), we calculate the branching fraction B(Bu+→J/ψπ+) to be (5.0−1.9+2.1)×10−5. We also search for the decay Bc+→J/ψπ+ and report a 95% confidence level limit on σ(Bc+)B(Bc+→J/ψπ+)/σ(Bu+)B(Bu+→J/ψK+) as a function of the Bc+ lifetime.
The ratio of the cross sections times the branching fraction.
The decay Λb0→J/ψ Λ is observed in 110 pb−1 of pp¯ collisions taken at s=1.8 TeV. These data are used to measure a Λb0 mass of 5621±4(stat)±3(syst) MeV/c2, and a mass difference between the Λb0 and the B0 of 340±5(stat)±1(syst) MeV/c2. The production cross-section times branching fraction for the decay Λb0→J/ψ Λ relative to that for the decay B0→J/ψ KS0 has been measured to be 0.27±0.12(stat)±0.05(syst).
No description provided.
We report a measurement of the ratios of the decay rates of the B~+, B~0 and B~0_s mesons into exclusive final states containing a J/psi meson. The final states were selected from 19.6 pb~{-1} of p-pbar collisions recorded by the Collider Detector at Fermilab. These data are interpreted to determine the bquark fragmentation fractions f_u, f_d and f_s. We also determine the branching fractions for the decay modes B~+ --> J/psi K~+, B~+ --> J/psi K~*(892)~+, B~0 --> J/psi K~0, B~0 --> J/psi K~*(892)~0 and B_s~0 --> J/psi phi(1020). We discuss the implications of these measurements to B meson decay models.
Charge conjugated states are implied. FD is considered as a quark fragmentation fraction.
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