Date

Charged Hadron Production in $e^+ e^-$ Annihilation in the $\Upsilon$ and $\Upsilon^\prime$ Region

The LENA collaboration Niczyporuk, B. ; Zeludziewicz, T. ; Chen, K.W. ; et al.
Z.Phys.C 9 (1981) 1, 1981.
Inspire Record 164397 DOI 10.17182/hepdata.1354

Charged hadron production ine+e− annihilation is studied in the 7 to 10 GeV CM energy region and at the Υ (9.46) and Υ′ (10.01) resonances with the LENA detector at DORIS. The statistical moments of the charged multiplicities are studied. The data show KNO scaling behaviour and suggest the presence of long range correlations. An average charged multiplicityrise of Δn(Υ)=0.55±0.19 and Δn(Υ′)=1.26±0.29 over the continuum is observed for the Υ and Υ′ direct decays. The jet structure of the Υ and Υ′ direct decays is investigated using the charged particles. The polar angular distributions of the jet axis behave like 1+α(T) cos2θ with 〈α(T)〉Υ=0.7±0.3 and 〈α(T)〉Υ′=0.6±0.4. The 〈α(T)〉Υ value is in agreement with the QCD vector gluon assignment and excludes scalar gluons by more than four standard deviations.

3 data tables

No description provided.

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Precise Measurement of the Xi0 Magnetic Moment

Cox, P.T. ; Dworkin, J. ; Overseth, O.E. ; et al.
Phys.Rev.Lett. 46 (1981) 877-880, 1981.
Inspire Record 169860 DOI 10.17182/hepdata.20645

The magnetic moment of the Ξ0 hyperon has been measured to be μΞ0=−1.253±0.014 nuclear magnetons. A new measurement of μΛ is also reported.

1 data table

No description provided.


QUASIELASTIC OMEGA PHOTOPRODUCTION AT 50-GEV - 130-GEV

Breakstone, A.M. ; Cheng, D.C. ; Dorfan, D.E. ; et al.
Phys.Rev.Lett. 47 (1981) 1782-1785, 1981.
Inspire Record 173081 DOI 10.17182/hepdata.20625

A study of quasielastic ω photoproduction where the ω was detected in its π0γ decay mode is reported. The recoil proton's angle was detected with a nonmagnetic spectrometer allowing a full reconstruction of the final state. Differential cross sections for 0.1<|t|<1.2 GeV2 are presented, providing a test of the vector-meson dominance model over an extensive energy and momentum transfer range. The shape of the differential cross section agrees with that seen in both elastic γp and πp scattering as expected from this model.

4 data tables

No description provided.

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Elastic Photon Proton Scattering in the 50-{GeV} - 130-{GeV} Range

Breakstone, A.M. ; Cheng, D.C. ; Dorfan, D.E. ; et al.
Phys.Rev.Lett. 47 (1981) 1778-1781, 1981.
Inspire Record 173082 DOI 10.17182/hepdata.20627

In the tagged-photon beam at Fermilab, differential cross sections were measured for the elastic scattering of photons on a liquid-hydrogen target. The diffractive forward peak was measured for photon energies between 50 and 130 GeV and |t| values between 0.07 and 1.20 (GeV/c)2. The shape of the diffraction peak is similar to that seen in π−p scattering. The magnitude is that predicted by the optical theorem.

3 data tables

No description provided.

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Polarization of $\Sigma^+$ Hyperons Produced by 400 GeV Protons

Wilkinson, C. ; Handler, R. ; Lundberg, B. ; et al.
Phys.Rev.Lett. 46 (1981) 803-806, 1981.
Inspire Record 169869 DOI 10.17182/hepdata.20646

The polarization of 26 000 Σ+ hyperons produced by 400-GeV protons on Be has been measured. The polarizations of Σ+ and Λ hyperons have the opposite sign. The magnitude increases with momentum at 5-mrad production angle, and averages 22% over the momentum range 140 to 280 GeV/c.

2 data tables

No description provided.

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Measurement of the Polarization in Large Angle $\pi^- P$ Elastic Scattering at 2.93-{GeV}/c and 3.25-{GeV}/c

Auer, I.P. ; Bridges, D. ; Droege, T. ; et al.
Phys.Rev.D 24 (1981) 1771-1784, 1981.
Inspire Record 172691 DOI 10.17182/hepdata.24055

We have measured the polarization for elastic scattering in the reaction π−p→π−p at 2.93 and 3.25 GeV/c using a polarized proton target and multiwire proportional chambers (MWPC's) with emphasis on large-angle scattering. Events were selected by fast scintillation-counter logic. Beam trajectories were measured with four MWPC's and the scattered-particle angles were measured with one or two MWPC's; elastic events were determined by coplanarity and angle-angle correlations. The polarization is in agreement with previous measurements below |t|=2.0 (GeV/c)2, and crosses from negative to positive near the secondary dip in the differential cross section dσdt. In the backward region, an energy dependence appears with the polarization being large and negative at 2.93 GeV/c and consistent with zero at 3.25 GeV/c.

2 data tables

No description provided.

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Search for Narrow Resonances in $e^+ e^-$ Annihilation at $c$.m. Energies Between 33.0-{GeV} and 36.72-{GeV}

The JADE collaboration Bartel, W. ; Cords, D. ; Dittmann, P. ; et al.
Phys.Lett.B 100 (1981) 364-366, 1981.
Inspire Record 164319 DOI 10.17182/hepdata.45224

A search for narrow resonances in e + e − annihilation between 33.00 and 36.72 GeV is reported. No evidence is found for the existence of such states. The 90% confidence upper limit on the integrated resonance cross section is determined to be 28 nb MeV, a value significantly below that expected for the lowest t t bound state.

2 data tables

AVERAGE R VALUE THROUGHOUT ENERGY RANGE. SYSTEMATIC ERROR IS CONSERVATIVE AND WILL BE IMPROVED.

R VALUES AT 20 MEV STEPS. DATA TAKEN FROM TABLE IN THE PREPRINT.


The Effective Energy Dependence of the Charged Particle's Multiplicity in $P / \pi^+ / K^+$ Interactions on Protons at 147 GeV/c

Brick, D. ; Rudnicka, H. ; Shapiro, A.M. ; et al.
Phys.Lett.B 103 (1981) 241-246, 1981.
Inspire Record 170358 DOI 10.17182/hepdata.6707

The energy dependence of the average of the charged multiplicity and its dispersion in π + /K + /p interaction on protons at 147 GeV/ c is found to be the same as in e + e − annihilations if an “effective energy” variable is used instead of the total energy. The effective energy S eff is defined as the invariant mass of all secondaries left after the two leading particles have been removed. Fitting the expression aS eff b to the average charge multiplicity 〈 n ch 〉, we find the power b to be in good agreement with the value of 0.25 predicted by Fermi's statistical model and by Landau's hydrodynamical model.

6 data tables

BINS IN WEFF SELECTED SO AS TO YIELD 200 EVENTS IN EACH BIN.

200 EVENTS IN EACH BIN IN WEFF.

50 EVENTS IN EACH BIN IN WEFF.

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A Measurement of the Cross-Section for Four Pion Production in gamma gamma Collisions at SPEAR

Burke, D.L. ; Abrams, G.S. ; Alam, M.S. ; et al.
Phys.Lett.B 103 (1981) 153-156, 1981.
Inspire Record 165016 DOI 10.17182/hepdata.31168

We present a measurement of the cross section for the reaction e + e − → e + e − π + π − π + π − at SPEAR. This channel is found to be large and dominated by the process γγ → ϱ 0 ϱ 0 → π + π − π + π − . The cross section, which is small just above the four-pion threshold, exhibits a large enhancement near the ϱ 0 ϱ 0 threshold.

1 data table

Axis error includes +- 0.0/0.0 contribution (THE QUOTED ERRORS INCLUDE VARIOUS SYSTEMATIC ERRORS ADDED QUADRATICALLY).


Evidence for Planar Events and a Forward Double Jet Structure in Deep Inelastic Muon Scattering

The European Muon collaboration Aubert, J.J. ; Bassompierre, G. ; Becks, K.H. ; et al.
Phys.Lett.B 100 (1981) 433-438, 1981.
Inspire Record 164536 DOI 10.17182/hepdata.31213

The final states of charged hadrons produced in 280 GeV μp scattering are analysed with respect to their planarity and jet structure. Distributions of p ⊥ 2 in and p ⊥ out 2 are presented. A two jet structure in the forward hemisphere is observed for events with high p ⊥ tracks are predicted by QCD models.

2 data tables

PTIN**2 is the sum of the PTIN components squared.

PTOUT**2 is the sum of the PTOUT components squared.