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Observation of Planar Three Jet Events in e+ e- Annihilation and Evidence for Gluon Bremsstrahlung

The JADE collaboration Bartel, W. ; Canzler, T. ; Cords, D. ; et al.
Phys.Lett.B 91 (1980) 142-147, 1980.
Inspire Record 143985 DOI 10.17182/hepdata.6339

Topological distributions of charged and neutral hadrons from the reaction e + e − → multihadrons are studied at √ s of about 30 GeV. An excess of planar events is observed at a rate which cannot be explained by statistical fluctuations in the standard two-jet process. The planar events, mostly consisting of a slim jet on one side and a broader jet on the other, are shown actually to possess three-jet structure by demonstrating that the broader jet itself consists of two collinear jets in its own rest system. Detailed agreement between data and predictions is obtained if the process e + e − →q q ̄ g is taken into account. This strongly suggests gluon bremsstrahlung as the origin of the planar three-jet events. By comparison of the data with the qq̄g-model we obtain a value for the strong coupling constant of α S ( q 2 = 0.17 ± 0.04.

2 data tables
Table 1

THRUST AND PLANARITY DISTRIBUTIONS. FINAL (BETTER) THRUST DISTRIBUTIONS WITH DETECTOR CORRECTIONS TO BE PUBLISHED LATER.

Table 2

No description provided.


Measurement of the Spin Correlation Parameters a(00kk), a(00ks) and a(00ss) in the p p Elastic Scattering Between 400-MeV and 600-MeV

Aprile, E. ; Hausammann, R. ; Heer, E. ; et al.
Phys.Rev.D 28 (1983) 21-39, 1983.
Inspire Record 162345 DOI 10.17182/hepdata.23773

We have measured the spin-correlation parameters A00kk, A00ks, and A00ss in p−p scattering between 400 and 600 MeV using a longitudinally polarized beam and a butanol target polarized in the horizontal plane. Owing to the restrictive geometrical acceptance of the target, the polarization axis of the target was oriented at an angle α with respect to beam direction. The parameters A00kk and A00ks were therefore measured as a linear combination at 577, 536, 514, 494, and 445 MeV. These experiments were extended to the measurement of A00ks and A00ss by using a transversely polarized beam. We present the results, which are compared with phase-shift predictions.

5 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.

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Observation of the $\rho^-$prime (1600) in the Channel $\gamma p \to \pi^+ \pi^- p$

The Bonn-CERN-Ecole Poly-Glasgow-Lancaster-Manchester-Orsay-Paris-Rutherford-Sheffield collaboration Aston, D. ; Atkinson, M. ; Bailey, R. ; et al.
Phys.Lett.B 92 (1980) 215-218, 1980.
Inspire Record 152747 DOI 10.17182/hepdata.27241

A dipion enhancement of mass 1.59 GeV and width 0.23 GeV is observed in the channel γp→π + π − p. The spin-parity of the enhancement is consistent with being 1 − .

1 data table
Table 1

No description provided.


Search for Narrow Resonances in $e^+ e^-$ Annihilation at c.m. Energies Between 29.90-{GeV} and 31.46-{GeV}

The JADE collaboration Bartel, W. ; Cords, D. ; Dittmann, P. ; et al.
Phys.Lett.B 91 (1980) 152-154, 1980.
Inspire Record 152290 DOI 10.17182/hepdata.27258

A search for narrow resonances in e + e − annihilation at c.m. energies between 29.90 and 31.46 GeV provides no evidence for the existence of such states. The 90% confidence upper limit on the integrated resonance cross section is 38 nb MeV, significantly below the value expected for the lowest (t,t̄) bound state.

1 data table
Table 1

No description provided.


CROSS-SECTIONS FOR PI- + P ---> N + (K) PI0 (K = 1 TO 5) AND PI- + P ---> N + ETA0 (ETA0 ---> 2 GAMMA) FOR INCIDENT PION MOMENTA BETWEEN 1.3-GEV/C AND 3.8-GEV/C

Crouch, H.R. ; Hargraves, R. ; Lanou, R.E. ; et al.
Phys.Rev.D 21 (1980) 3023-3058, 1980.
Inspire Record 158169 DOI 10.17182/hepdata.4334

This paper presents the results of a study of the dominant neutral final states from π−p interactions. The data were obtained in an experiment performed at the Brookhaven National Laboratory Alternating Gradient Synchrotron, using a set of steel-plate optical spark chambers surrounding a liquid-hydrogen target. We present differential and total cross sections for the reactions (1) π−p→n+π0 and (2) π−p→n+η0(η0→2γ) and total cross sections for the reactions (3) π−p→n+kπ0 (k=2, 3, 4, and 5) and (4) π−p→all neutrals for eighteen values of beam momentum in the interval 1.3 to 4.0 GeV/c. The angular distributions for (1) and (2) have been analyzed in terms of expansions in Legendre polynomials, the coefficients for which are also given.

41 data tables
Table 1

No description provided.

Table 2

SIG = 4*PI*LEG(L=0).

Table 3

FORWARD DIFFERENTIAL CROSS SECTION CALCULATED FROM LEGENDRE POLYNOMIAL COEFFICIENTS AND ERROR MATRICES.

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INCLUSIVE PRODUCTION OF NEUTRAL STRANGE PARTICLES BY 147-GeV/c PI+ K+ p INTERACTIONS IN HYDROGEN

Brick, D. ; Shapiro, A.M. ; Widgoff, M. ; et al.
Nucl.Phys.B 164 (1980) 1, 1980.
Inspire Record 156268 DOI 10.17182/hepdata.8251

Results are presented from a study of inclusive neutral strange particle production by a 147 GeV/ c tagged π + /K + /p beam in the Fermilab 30-inch hydrogen bubble chamber. The experiment made use of the proportional hybrid spectrometer system. Results are based on 995 K S 0 , 485 Λ, and 83 Λ found in a sample of 132 000 pictures. Cross sections are given for inclusive production of these particles by each of the three beam particles, and comparisons are made with measurements at other energies. Topological cross sections are also calculated, and KNO multiplicity scaling is investigated. Distributions are presented of invariant cross sections as functions of the Feynman scaling variable x and c.m. rapidity y . The transverse momentum-squared distributions with their fitted slopes are also given. Comparisons are made of the production characteristics for the three beam types.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


EVIDENCE AGAINST THE NARROW S (1936) IN A MEASUREMENT OF ANTI-P P TOTAL CROSS-SECTION

Kamae, T. ; Aihara, H. ; Chiba, J. ; et al.
Phys.Rev.Lett. 44 (1980) 1439-1442, 1980.
Inspire Record 157934 DOI 10.17182/hepdata.20724

The total p¯p cross section has been measured in the S region by the transmission method with use of a beam-monitoring spectrometer. The result is inconsistent with the existence of the narrow resonance S(1936) with cross sections reported by previous experiments.

1 data table
Table 1

No description provided.


ANALYZING POWER IN LARGE ANGLE PROTON NEUTRON ELASTIC SCATTERING

Makdisi, Y. ; Marshak, M.L. ; Mossberg, B. ; et al.
Phys.Rev.Lett. 45 (1980) 1529-1533, 1980.
Inspire Record 159455 DOI 10.17182/hepdata.20701

The large-angle analyzing power A in proton-neutron elastic scattering at 2, 3, and 6 GeV/c with use of the polarized proton beam at the Argonne zero-gradient synchrotron and a liquid deuterium target have been measured. The measurements, the first at high energy, show that A is large (20-40%) and negative over much of the angular range and shows no decrease with incident energy, unlike the earlier data at smaller angles.

6 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

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DEPOLARIZATION PARAMETER IN P P INCLUSIVE SCATTERING AT 6-GEV/C

Courant, H. ; Kagan, H. ; Makdisi, Y. ; et al.
Phys.Rev.Lett. 44 (1980) 1373-1376, 1980.
Inspire Record 158285 DOI 10.17182/hepdata.20737

The depolarization parameter for pp inclusive scattering at an incident momentum of 6 GeV/c was measured. The D parameter for inclusive scattering indicates the dominance of natural-parity exchange at small t, except in the case of N*(1232) production, where π exchange is more important. D for elastic scattering has also been measured. This parameter shows a small decrease from unity with increasing momentum transfer.

3 data tables
Table 1

No description provided.

Table 2

No description provided.

Table 3

No description provided.


Diffraction Dissociation, Resonances and Deck Mechanism in the $K \omega$ Systems of the Reactions $K^+^- p \to$ ($K^+^- \omega$) $p$

The Aachen-Berlin-CERN-London-Vienna & Birmingham-Brussels-CERN-Mons-Serpukhov collaborations Otter, G. ; Rudolph, G. ; Wieczorek, H. ; et al.
Nucl.Phys.B 181 (1981) 1-21, 1981.
Inspire Record 153195 DOI 10.17182/hepdata.34348

A study is presented of the reactions K + p→(K + ω )p at 8.25 and 16 GeV/ c and K − p→(K − ω )p at 10 and 16 GeV/ c and comparison is made with K + results at 10 GeV/ c and K − at 7.3 GeV/ c . The (K + ω) and (K − ω) mass spectra both present a strong enhancement very near threshold, while a second peak at ∼1.7 GeV is evident only with incident K − at the lower energies. The threshold peak has very weak energy dependence and is mostly due to the 1 + S state which is produced conserving s -channel helicity. It is suggested that this is another decay mode of the resonance Q 1 (1290) known to decay mainly into Kϱ. The ratio of the Q 1 coupling constants to the Kω and Kϱ decay channels, R ω = g K ω 2 / g K ϱ 2 is determined to be 0.21±0.04. The enhancement at 1.7 GeV is predominantly, but not exclusively, due to the 2 − state. While the K + and K − induced reactions give basically similar results, small differences are observed that can be qualitatively explained in the framework of the Deck model.

2 data tables
Table 1

No description provided.

Table 2

No description provided.