HEPData Search

Showing 10 of 3488 results

Production of $\psi$ and $\psi^\prime$ Mesons in $\pi^- N$ Scattering at 150-{GeV}/$c$

Abolins, M.A. ; Barate, R. ; Bareyre, P. ; et al.

Phys.Lett.B 82 (1979) 145, 1979.

Inspire Record 133175 DOI 10.17182/hepdata.27333

In a large-acceptance spectrometer, muon pairs and associated hadrons were observed with μμ masses up to 10 GeV/ c 2 and ΔM M = 0.015 resolution. We report here on the production of 4000 J/ ψ and 80 ψ ′ mesons.

4 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

More…

Measurement of Hadronic Production of the $\chi$ 1++ (3507) and the $\chi$ 2++ (3553) Through Their Radiative Decay to $J/\psi$

Lemoigne, Y. ; Barate, R. ; Bareyre, P. ; et al.

Phys.Lett.B 113 (1982) 509, 1982.

Inspire Record 176731 DOI 10.17182/hepdata.30918

The χ 1 ++ (3507) and the χ 2 ++ (3553) states have been observed in the Goliath spectrometer at the CERN SPS in 185 GeV/ c π − -Be collisions. Their radiative decays contribute 27.7% (for the χ 1 ++ ) and 12.8% (for the χ 2 ++ ) to J ϕ production. At this energy, their cross sections are 65±19 nb and 96±29 nb, respectively

1 data table match query

Table 1

No description provided.

The Reaction pi- p --> eta n Up to rho* (eta) = 450-MeV/c: Experimental Results and Partial Wave Analysis

Feltesse, J. ; Ayed, R. ; Bareyre, P. ; et al.

Nucl.Phys.B 93 (1975) 242-260, 1975.

Inspire Record 99411 DOI 10.17182/hepdata.32003

An accurate measurement of d σ d Ω (π − p → η n ) at 1531 MeV total energy (expanded) up to l = 4 Legendre polynomials) requires reconsideration of previous angular distribution fits which were expanded only up to l = 2 and of subsequent partial-wave analysis. An energy-dependent partial-wave analysis has been performed here for p η ∗ up to 450 MeV/ c . In addition to the well-known S 11 (1520 MeV) resonance, either the P 11 (1532 MeV) or the P 13 (1530 MeV) resonance is found to be strongly coupled to the η-n channel. In both cases, the P 11 (1729 MeV) resonance is needed as is the weakly coupled D 13 (1525 MeV) resonance. The decay states in the ηn channelare compared to the SU(3) and SU(6) W predictions.

2 data tables match query

Table 1

No description provided.

Table 2

No description provided.

Measurement of b anti-b correlations at the CERN p anti-p collider

The UA1 collaboration Albajar, C. ; Ankoviak, K. ; Bartha, S. ; et al.

Z.Phys.C 61 (1994) 41-52, 1994.

Inspire Record 359461 DOI 10.17182/hepdata.14368

We report on measurements of correlated$b\bar b$ production in$p\bar p$ collisions at$\sqrt s = 630GeV$, using dimuon data to tag both theb and$\bar b$ quarks. Starting from an inclusive dimuon sample we obtain improved cross-sections for single inclusive beauty production and confirm our earlier results on$B^0 - \bar B^0$ mixing. From a study of$b\bar b$ correlations we derive explicit cross-sections for semi-differential$b\bar b$ production. We compare the measured cross-sections and correlations to$\mathcal{O}\left( {\alpha _s^3 } \right)$ QCD predictions and find good quantitative agreement. From the measured angular distributions we establish a size-able contribution from higher order QCD processes with a significance of about seven standard deviations. A large nonperturbative contribution to these higher order corrections is excluded.

17 data tables match query

Table 1

The first error is PT-dependent, and the second is PT-independent. Dimuons from different b-quarks.

Table 2

The first error is PT-dependent, and the second is PT-independent. Dimuons from b chain decays (b --> c + mu, c --> mu).

Table 3

Total cross-section for single b-quark production in the restricted rapidity range.

More…

Production of High Mass Muon Pairs in $\pi^-$ Be Collisions at 150-{GeV}/$c$ and 175-{GeV}/$c$

Barate, R. ; Bareyre, P. ; Bonamy, P. ; et al.

Phys.Rev.Lett. 43 (1979) 1541, 1979.

Inspire Record 142156 DOI 10.17182/hepdata.20768

This paper presents production and decay characteristics of 500 high-mass, high-resolution μ+μ− pairs produced in π− Be collisions at 150 and 175 GeV/c. The data do not agree with a simple Drell-Yan production mechanism, but indicate that higher-order quantum-chromodynamic corrections must be included.

2 data tables match query

Table 1

No description provided.

Table 2

No description provided.

rivet Analysis
QCD analyses and determinations of alpha(s) in e+ e- annihilation at energies between 35-GeV and 189-GeV.

The JADE & OPAL collaborations Pfeifenschneider, P. ; Biebel, O. ; Movilla Fernandez, P.A. ; et al.

Eur.Phys.J.C 17 (2000) 19-51, 2000.

Inspire Record 513337 DOI 10.17182/hepdata.12882

We employ data taken by the JADE and OPAL experiments for an integrated QCD study in hadronic e+e- annihilations at c.m.s. energies ranging from 35 GeV through 189 GeV. The study is based on jet-multiplicity related observables. The observables are obtained to high jet resolution scales with the JADE, Durham, Cambridge and cone jet finders, and compared with the predictions of various QCD and Monte Carlo models. The strong coupling strength, alpha_s, is determined at each energy by fits of O(alpha_s^2) calculations, as well as matched O(alpha_s^2) and NLLA predictions, to the data. Matching schemes are compared, and the dependence of the results on the choice of the renormalization scale is investigated. The combination of the results using matched predictions gives alpha_s(MZ)=0.1187+{0.0034}-{0.0019}. The strong coupling is also obtained, at lower precision, from O(alpha_s^2) fits of the c.m.s. energy evolution of some of the observables. A qualitative comparison is made between the data and a recent MLLA prediction for mean jet multiplicities.

80 data tables match query

Table 1

Overall result for ALPHAS at the Z0 mass from the combination of the ln R-matching results from the observables evolved using a three-loop running expression. The errors shown are total errors and contain all the statistics and systematics.

Table 2

Weighted mean for ALPHAS at the Z0 mass determined from the energy evolutions of the mean values of the 2-jet cross sections obtained with the JADE and DURHAMschemes and the 3-jet fraction for the JADE, DURHAM and CAMBRIDGE schemes evaluted at a fixed YCUT.. The errors shown are total errors and contain all the statistics and systematics.

Table 3

Combined results for ALPHA_S from fits of matched predicitions. The first systematic (DSYS) error is the experimental systematic, the second DSYS error isthe hadronization systematic and the third is the QCD scale error. The values of ALPHAS evolved to the Z0 mass using a three-loop evolution are also given.

More…

Measurement of $J/\psi$ and $\psi^\prime$ Real Photoproduction on $^{6}$Li at a Mean Energy of 90-{GeV}

The NA14 collaboration Barate, R. ; Bareyre, P. ; Bloch, D. ; et al.

Z.Phys.C 33 (1987) 505, 1987.

Inspire Record 235579 DOI 10.17182/hepdata.15814

Inelastic and elasticJ/ψ (3097) photoproduction on Li6 are measured at a mean γ energy of 90 GeV in an open spectrometer. TheJ/ψ are identified by their decays intoμ+μ− ore+e−. A signal of ψ′(3685) intoμ+μ− andJ/ψπ+π− is also seen. The inelastic cross-section withZ=Eψ/Eγ<0.9 is compared in shape and magnitude with the colour singlet model of photon-gluon fusion.

2 data tables match query

Table 1

DIMUON TRIGGER, INELASTIC MEANS Z < 0.9.

Table 2

ELECTRON TRIGGER, INELASTIC MEANS Z < 0.9.

J / psi and psi-prime production at the CERN p anti-p collider

The UA1 collaboration Albajar, C. ; Albrow, M.G. ; Allkofer, O.C. ; et al.

Phys.Lett.B 256 (1991) 112-120, 1991.

Inspire Record 300862 DOI 10.17182/hepdata.26999

We have measured the production cross-section times branching ratio for J/ψ→μ + μ − in pp̄ interactions at √ s = 630 GeV in the kinematic range |y|<2.0 and p T >5 GeV /c, BR ( J /ψ→μ + μ − )σ( p p ̄ → J /ψ)=6.18±0.24±0.81 nb . The data sample collected in 1988 and 1989 for an integrated luminosity of 4.7 pb −1 represents a fivefold improvement over the statistics in our earlier study of the J / ψ production process, and the p T distribution which is measured extends to 28 GeV / c . Using event topology we show that the rate for the direct production of J / ψ , via radiative decays of χ states, is larger than that for production via B-hadrons. Production of ψ′ is also studied using the decay modes < ψ ′→ μ + μ − and ψ ′→ J / ψπ + ψ − .

4 data tables match query

Table 1

Numerical values supplied by Nick Ellis.

Table 2

Table 3

More…

Measurement of the ratio R = sigma(w) Br (W) ---> mu neutrino) / sigma(Z) Br (Z ---> mu mu) and gamma(W) total at the CERN proton - anti-proton collider

The UA1 collaboration Albajar, C. ; Albrow, M.G. ; Allkofer, O.C. ; et al.

Phys.Lett.B 253 (1991) 503-510, 1991.

Inspire Record 300863 DOI 10.17182/hepdata.29508

An analysis of W and Z boson production at UA1, using 4.66 pb −1 of data from the 1988 and 1989 CERN p p Collider runs at s =0.63 TeV , yields R ≡ σ W Br(W→ μ v)/ σ z Br( Z → μμ )=10.4 −1.5 +1.8 stat.±0.8(syst.) We find R =9.5 −1.0 +1.1 (stat.+syst.) when combining all available UA1 data, in both the electron and muon channel, taken in the period 1983–1989. In the framework of the standard model, the value of R is used to infer the total width of the W boson, Γ W tot =2.18 −0.24 +0.26 (exp.)±0.04(theory) GeV/ c 2 .

1 data table match query

Table 1

No description provided.

High-energy Photoproduction of Large Transverse Momentum $\pi^0$ Mesons: A Quantitative Test of {QCD}

The NA14 collaboration Auge, E. ; Barate, R. ; Bloch, D. ; et al.

Phys.Lett.B 168 (1986) 163-169, 1986.

Inspire Record 227057 DOI 10.17182/hepdata.30278

The first results on inclusive photoproduction of π 0 at transverse momenta up to 4 GeV/ c , using incident γ energies between 50 and 150 GeV are presented. A comparison is made with inclusive π 0 production obtained, in the same experiment, with incident π − . Using the π − data to parametrize the hadronic behaviour of the photon, significant differences are observed in quantitative agreement with QCD Compton scattering and corrections thereof.

2 data tables match query

Table 1

FC,IC,BC REFER TO FORWARD,INTERMEDIATE AND BACKWARD CALORIMETERS.

Table 2

FC,IC,BC REFER TO FORWARD,INTERMEDIATE AND BACKWARD CALORIMETERS.

Date

Collaboration

Subject_areas

Phrases

Reactions

Observables

CM Energies (GeV)

Authors Reset

Production of $\psi$ and $\psi^\prime$ Mesons in $\pi^- N$ Scattering at 150-{GeV}/$c$

Measurement of Hadronic Production of the $\chi$ 1++ (3507) and the $\chi$ 2++ (3553) Through Their Radiative Decay to $J/\psi$

The Reaction pi- p --> eta n Up to rho* (eta) = 450-MeV/c: Experimental Results and Partial Wave Analysis

Measurement of b anti-b correlations at the CERN p anti-p collider

Production of High Mass Muon Pairs in $\pi^-$ Be Collisions at 150-{GeV}/$c$ and 175-{GeV}/$c$

rivet Analysis
QCD analyses and determinations of alpha(s) in e+ e- annihilation at energies between 35-GeV and 189-GeV.

Measurement of $J/\psi$ and $\psi^\prime$ Real Photoproduction on $^{6}$Li at a Mean Energy of 90-{GeV}

J / psi and psi-prime production at the CERN p anti-p collider

Measurement of the ratio R = sigma(w) Br (W) ---> mu neutrino) / sigma(Z) Br (Z ---> mu mu) and gamma(W) total at the CERN proton - anti-proton collider

High-energy Photoproduction of Large Transverse Momentum $\pi^0$ Mesons: A Quantitative Test of {QCD}