Luminosity monitoring and measurement at CDF Cronin-Hennessy, D.; Beretvas, A.; Derwent, P.F.
Nuclear instruments & methods in physics research. Section A, Accelerators, spectrometers, detectors and associated equipment,
03/2000, Letnik:
443, Številka:
1
Journal Article
Recenzirano
Using two telescopes of beam–beam counters, CDF (Collider Detector at Fermilab) has measured the luminosity to an accuracy of 4.1% (3.6%) in run Ib (Ia). For run Ib (Ia) the average luminosity was
...9.1(3.3)×10
30
cm
−2
s
−1
. For a typical data set the integrated luminosity was
86.47
(19.65)
pb
−1
in run Ib (Ia) resulting in a total integrated luminosity of
106.1±4.1
pb
−1
. This paper shows how we have determined the accuracy of our results.
Here, a search for the exotic meson X(5568) decaying into the B$0\atop{s}$π± final state is performed using data corresponding to 9.6 fb-1 from $p\bar{p}$ collisions at $\sqrt{s}$ = 1960 GeV recorded ...by the Collider Detector at Fermilab. No evidence for this state is found and an upper limit of 6.7% at the 95% confidence level is set on the fraction of B$0\atop{s}$ produced through the X(5568)→B$0\atop{s}$π± process.
We present a search for the standard model Higgs boson produced in association with a Z boson, using up to 7.9 fb - 1 of integrated luminosity from p p i?12 collisions collected with the CDF II ...detector. We utilize several novel techniques, including multivariate lepton selection, multivariate trigger parametrization, and a multi-stage signal discriminant consisting of specialized functions trained to distinguish individual backgrounds. By increasing acceptance and enhancing signal discrimination, these techniques have significantly improved the sensitivity of the analysis above what was expected from a larger dataset alone. We observe no significant evidence for a signal, and we set limits on the ZH production cross section. For a Higgs boson with mass 115 GeV / c 2 , we expect (observe) a limit of 3.9 (4.8) times the standard model predicted value, at the 95% credibility level.
A search for a narrow Higgs boson resonance in the diphoton mass spectrum is presented based on data corresponding to 7.0 fb^-1 of integrated luminosity from p-pbar collisions at sqrt(s) = 1.96 TeV ...collected by the CDF experiment. No evidence of such a resonance is observed, and upper limits are set on the cross section times branching ratio of the resonant state as a function of Higgs boson mass. The limits are interpreted in the context of the standard model and one fermiophobic benchmark model where the data exclude fermiophobic Higgs bosons with masses below 114 GeV/c^2 at a 95% Bayesian credibility level.
We report the first observation of the baryonic flavor-changing neutral current decay Λb0→Λμ+μ- with 24 signal events and a statistical significance of 5.8 Gaussian standard deviations. This ...measurement uses a pp¯ collisions data sample corresponding to 6.8fb-1 at s=1.96TeV collected by the CDF II detector at the Tevatron collider. The total and differential branching ratios for Λb0→Λμ+μ- are measured. We find B(Λb0→Λμ+μ-)=1.73±0.42(stat)±(syst)×10-6. We also report the first measurement of the differential branching ratio of Bs0→ϕμ+μ-, using 49 signal events. In addition, we report branching ratios for B+→K+μ+μ-, B0→K0μ+μ-, and B→K*(892)μ+μ- decays.
A search has been performed for Bs0→μ+μ- and B0→μ+μ- decays using 7fb-1 of integrated luminosity collected by the CDF II detector at the Fermilab Tevatron collider. The observed number of B0 ...candidates is consistent with background-only expectations and yields an upper limit on the branching fraction of B(B0→μ+μ-)<6.0×10-9 at 95% confidence level. We observe an excess of Bs0 candidates. The probability that the background processes alone could produce such an excess or larger is 0.27%. The probability that the combination of background and the expected standard model rate of Bs0→μ+μ- could produce such an excess or larger is 1.9%. These data are used to determine B(Bs0→μ+μ-)=(1.8-0.9+1.1)×10-8 and provide an upper limit of B(Bs0→μ+μ-)<4.0×10-8 at 95% confidence level.
We report a study of the invariant mass distribution of jet pairs produced in association with a W boson using data collected with the CDF detector which correspond to an integrated luminosity of 4.3 ...fb^-1. The observed distribution has an excess in the 120-160 GeV/c^2 mass range which is not described by current theoretical predictions within the statistical and systematic uncertainties. In this letter we report studies of the properties of this excess.
We present a search for a new narrow, spin-1, high mass resonance decaying to $\mu^+\mu^- + X $, using a matrix element based likelihood and a simultaneous measurement of the resonance mass and ...production rate. In data with 4.6 fb$^{-1}$ of integrated luminosity collected by the CDF detector in $p\bar{p}$ collisions at $\sqrt{s}=1960$ GeV, the most likely signal cross section is consistent with zero at 16\% confidence level. We therefore do not observe evidence for a high mass resonance, and place limits on models predicting spin-1 resonances, including $M > 1071$ GeV/$c^2$ at 95\% confidence level for a $Z'$ boson with the same couplings to fermions as the $Z$ boson.
We report on a measurement of $b$-hadron lifetimes in the fully reconstructed decay modes B^+ -->J/Psi K+, B^0 --> J/Psi K*, B^0 --> J/Psi Ks, and Lambda_b --> J/Psi Lambda using data corresponding ...to an integrated luminosity of 4.3 ${\rm fb}^{-1}$, collected by the CDF II detector at the Fermilab Tevatron. The measured lifetimes are $\tau$B^+ = $1.639 \pm 0.009 ~({\rm stat}) \pm 0.009~{\rm (syst) ~ ps}$, $\tau$B^0 = $1.507 \pm 0.010 ~({\rm stat}) \pm 0.008~{\rm (syst) ~ ps}$ and $\tau$Lambda_b = $1.537 \pm 0.045 ~({\rm stat}) \pm 0.014~{\rm (syst) ~ ps}$. The lifetime ratios are $\tau$B^+/$\tau$B^0 = $1.088 \pm 0.009~({\rm stat})\pm 0.004~({\rm syst})$ and $\tau$Lambda_b/$\tau$B^0 = $1.020 \pm 0.030~({\rm stat})\pm 0.008~({\rm syst})$. These are the most precise determinations of these quantities from a single experiment.
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