Date

Production of $\pi^0$ at Large Transverse Momentum in $\alpha \alpha$ and $\alpha p$ Collisions at the {CERN} Intersecting Storage Rings

Karabarbounis, A. ; Kourkoumelis, C. ; Resvanis, L.K. ; et al.
Phys.Lett.B 104 (1981) 75-78, 1981.
Inspire Record 165249 DOI 10.17182/hepdata.31047

Inclusive π 0 production has been measured at the CERN Intersecting Storage Rings in αα and α p collisions near 90°, for p T between 2 and 5 GeV/c. The differential cross sections show a slower exponential fall-off with p T than has been observed in pp collisions at the corresponding nucleon-nucleon centre-of-mass energies at large p T . The ratio of the π 0 production cross sections for αα collisions to those for pp collisions is observed to be larger than 16.

2 data tables

No description provided.

No description provided.


Measurement of $e^+ e^- \to e^+ e^-$ and $e^+ e^- \to \gamma \gamma$ at Energies Up to 36.7-{GeV}

The CELLO collaboration Behrend, H.J. ; Chen, C. ; Field, J. ; et al.
Phys.Lett.B 103 (1981) 148-152, 1981.
Inspire Record 165288 DOI 10.17182/hepdata.31169

The differential cross sections of the reactions e + e − → e + e − and e + e − → λλ are measured at energies between 33.0 and 36.7 GeV. The results agree with the predictions of quantum electrodynamics. A comparison with the standard model of electroweak interaction yields sin 2 θ W = 0.25 ± 0.13.

2 data tables

No description provided.

No description provided.


Inclusive $K^0$ Production in $e^+ e^-$ Annihilation for 9.3-{GeV} $<\sqrt{s}<$ 31.6-{GeV}

The PLUTO collaboration Berger, Christoph ; Genzel, H. ; Grigull, R. ; et al.
Phys.Lett.B 104 (1981) 79-83, 1981.
Inspire Record 165122 DOI 10.17182/hepdata.6716

Results on inclusive K s 0 production in e + e − annihilation at mean center-of-mass energies of 9.4, 12.0 and 30 GeV are presented. The ratio R (K 0 ) = 2 σ (K s 0 )/ σ μμ rises from 3.10 ± 0.75 at √ s = 9.4 GeV to 5.6 ± 1.2 at √ s = 30 GeV, corresponding to an approximately constant K 0 /charged-particle ratio of 0.12 ± 0.02. A similar ratio for K 0 / charged particle is observed for direct hadronic decays of the ϒ.

7 data tables

SYSTEMATIC ERROR INCLUDED.

NUMBER OF K0 PER HADRONIC EVENT. AUTHORS ALSO USE MULTIPLICITY TO ESTIMATE NUMBER OF K0 PER CHARGED PARTICLE.

INCLUDING EARLIER DATA.

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A Study of the Reaction $\pi^- p \to \phi \phi n$ at 16-{GeV}/$c$

The Aachen-Bari-Bonn-CERN-Glasgow-Liverpool-Milan collaboration Armstrong, T.A. ; Baccari, B. ; Booth, P.S.L. ; et al.
Nucl.Phys.B 196 (1982) 176-188, 1982.
Inspire Record 165251 DOI 10.17182/hepdata.34217

The reaction π − p → φφ n has been isolated at 16 GeV/ c and its cross section determined to be 40 ± 10 nb. The φφ mass spectrum shows a threshold enhancement between 2.1 and 2.5 GeV. A successful description of the angular content of the φφ system requires two interferingss J P = 2 + states.

2 data tables

No description provided.

SLOPE OF DIFFERENTIAL TP(P=3,P=2) DISTRIBUTION.


Evidence for a High Mass Enhancement in $K^+ K^-$ Photoproduction

The Bonn-CERN-Ecole Poly-Glasgow-Lancaster-Manchester-Orsay-Paris-Rutherford-Sheffield collaboration Aston, D. ; Atkinson, M. ; Bailey, R. ; et al.
Phys.Lett.B 104 (1981) 231-234, 1981.
Inspire Record 165081 DOI 10.17182/hepdata.31068

The reaction γ p → K + K − p has been investigated with tagged photons in the energy range of 20 < E γ < 70 GeV. A structure in the 1.7 GeV mass region is observed and interpreted in terms of a recurrence of the ø.

1 data table

No description provided.


Determination of the Quark Density Ratio $d(x)/u(x)$ in the Proton

The Aachen-Bonn-CERN-Munich-Oxford collaboration Allen, P. ; Grassler, H. ; Lanske, D. ; et al.
Phys.Lett.B 103 (1981) 71-74, 1981.
Inspire Record 10562 DOI 10.17182/hepdata.31204

Data from an exposure of BEBC filled with hydrogen to a wideband neutrino beam are analysed to yield the structure function F v p 2 ( x ) for x > 0.2. Using our results in combination with data from electron-proton and muon-proton scattering, the quark density ratio d/u is determined as a function of x . The dominance u at large x is clearly seen. The results are compared with theoretical predictions.

6 data tables

No description provided.

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No description provided.

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Experimental Study of Electroweak Parameters at {PETRA} Energies (12-{GeV} $< E_{CMS} <$ 36.7-{GeV})

The MARK-J collaboration Barber, D.P. ; Becker, U. ; Bei, G.D. ; et al.
Phys.Rev.Lett. 46 (1981) 1663, 1981.
Inspire Record 164675 DOI 10.17182/hepdata.3303

We have performed a high-statistics measurement of Bhabha scattering and of the production of hadrons in electron-positron annihilation at PETRA energies (12 GeV<~s<~36.7 GeV). Combining the results with measurements of μ+μ− and τ+τ− production enables us to compare our results with electroweak theory. We find sin2θw=0.27±0.08. This is in good agreement with the value obtained from neutrino experiments which were carried out in entirely different kinematic regions.

5 data tables

No description provided.

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ASYMMETRY WAS USED.

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Measurement of the Ratio of Total and Differential Cross-sections on Neutron and Proton for Charged Current Neutrino Events

The BEBC TST Neutrino collaboration Armenise, N. ; Calicchio, M. ; Erriquez, O. ; et al.
Phys.Lett.B 102 (1981) 374-380, 1981.
Inspire Record 164906 DOI 10.17182/hepdata.31183

Charged-current neutrino interactions have been analysed in a sample of pictures from BEBC equipped with a TST. Using a method independent of both the neutrino flux and nuclear interaction corrections, the ratio R = σ n / σ p has been measured. The result is R =1.98±0.19 for the ratio of total cross sections. Bjorken x distributions for proton and neutron targets and for u and d quarks are compared.

3 data tables

No description provided.

No description provided.

No description provided.


A Determination of Quark Weak Couplings at {PETRA} Energies

The JADE collaboration Bartel, W. ; Cords, D. ; Dittmann, P. ; et al.
Phys.Lett.B 101 (1981) 361, 1981.
Inspire Record 164812 DOI 10.17182/hepdata.31227

Data on hadron production by e + e − annihilation at c.m. energies between 12 and 36.6 GeV have been collected using the JADE detector. They have been analysed in terms of single-photon and weak neutral-current exchange assuming production of quark-antiquark pairs with only d, u, s, c and b quarks to produce values for the quark weak neutral-current couplings. A further analysis in terms of the Glashow-Salam-Weinberg theory produced the result, sin 2 θ W = 0.22 ± 0.08 . The theory has therefore been tested in a new energy domain and within the context of the neutral weak couplings of the first, second and third generation quarks.

2 data tables

No description provided.

WIDTH(Z) = 2.5 GEV WAS ASSUMED. CONST(N=SIN2TW) WAS DETERMINED FROM RATIO(HADRONS/MU). FIRST ORDER QCD.


The Reaction $\gamma p \to p \pi^+ \pi^- \pi^+ \pi^-$ for Photon Energies From 25-{GeV} to 70-{GeV}

The Bonn-CERN-Ecole Poly-Glasgow-Lancaster-Manchester-Orsay-Paris-Rutherford-Sheffield collaboration Aston, D. ; Atkinson, M. ; Bailey, R. ; et al.
Nucl.Phys.B 189 (1981) 15-39, 1981.
Inspire Record 164533 DOI 10.17182/hepdata.34258

Measurements of the reaction γ p → p π + π − π + π − are presented, in which π + π − π + π − systems with masses up to 3 GeV are produced from fragmentation of the incident photon. The reaction is dominated by production of the large peak of the ϱ′(1600) meson and, at higher masses ≳2 GeV, y production of jet-like 4 π systems. The ϱ′(1600) meson is produced by a predominantly s -channel helicity conserving mechanism. At higher masses there are also indications of ϱπ peaks, of masses 1.3 GeV (the A 2 meson) and 1.75 GeV, produced with a recoiling π meson by a mechanism consistent with the Deck effect.

1 data table

CORRECTED FOR TAILS OF BREIT-WIGNER RESONANCE USED IN FIT AND ALLOWING FOR 10 PCT BACKGROUND.