Direct Photon Production at the $\psi$

Scharre, D.L. ; Alam, M.S. ; Boyarski, A. ; et al.
Phys.Rev.D 23 (1981) 43, 1981.
Inspire Record 153865 DOI 10.17182/hepdata.24079

We present results of a detailed analysis of inclusive direct photon production at the ψ(3095). The direct-photon momentum distribution for x>0.4 is presented and compared with the leading-order quantum-chromodynamic prediction. The total production rate is found to be consistent with theoretical expectations, but the observed momentum distribution is considerably softer. Results of an analysis of some inclusive properties of the hadronic system recoiling against the direct photon are presented. The mean charged-particle and Ks multiplicities are presented as functions of the invariant mass of the hadronic system. These data agree well with the corresponding mean multiplicities measured in e+e− annihilations at center-of-mass energies comparable to the invariant mass of the hadronic system.

4 data tables

TOTAL INCLUSIVE PHOTON MOMENTUM SPECTRUM. ERRORS ARE STATISTICAL ONLY.

PHOTON SPECTRUM PREDICTED FROM MEASUREMENT OF THE PI0 AND ETA DISTRIBUTIONS. ERRORS INCLUDE BOTH STATISTICAL AND RELATIVE SYSTEMATIC COMPONENTS.

INCLUSIVE PI0 MOMENTUM DISTRIBUTION. QUOTED ERRORS ARE STATISTICAL ONLY. OVERALL AND RELATIVE SYSTEMATIC ERRORS ARE LESS THAN 30 PCT AND MAY VARY SLOWLY WITH X.

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Measurement of High-energy Direct Photons in $\psi$ Decays

Abrams, G.S. ; Alam, M.S. ; Blocker, C.A. ; et al.
Phys.Rev.Lett. 44 (1980) 114, 1980.
Inspire Record 142835 DOI 10.17182/hepdata.20729

The inclusive γ and π0 momentum distributions at the ψ have been measured. Using these data and estimates of η production, it is found that (4.1 ± 0.8)% of ψ decays contain a direct photon with energy greater than 60% of the beam energy. The expected momentum distribution for direct photons calculated to lowest order in quantum chromodynamics is qualitatively different from that observed in the data.

1 data table

INCLUSIVE PHOTON AND PI0 MOMENTUM DISTRIBUTION.


Delta0 rho- Production in the pi- n --> p pi- pi- pi0 Reaction at 9.1-GeV/c

Armenise, N. ; Fogli-Muciaccia, M.T. ; Nuzzo, S. ; et al.
Nuovo Cim.A 34 (1976) 37-47, 1976.
Inspire Record 115803 DOI 10.17182/hepdata.37636

From the reaction π−n→pπ−π−π0 at 9.140 GeV/c the Δ0ϱ− reaction has been selected. The upper limit in the cross-section ofμb

6 data tables

A SMALL CORRECTION FOR THE DEL0 TAIL IS NOT PERFORMED.

No description provided.

No description provided.

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Reaction pi+ p ---> eta0 delta++ - a test of a2 regge pole exchange

Grether, D.F. ; Gidal, G. ;
Phys.Rev.Lett. 26 (1971) 792-795, 1971.
Inspire Record 69010 DOI 10.17182/hepdata.21507

New results are presented on the reaction π+p→η0Δ++ between 1.2 and 2.67 GeVc. The data above 2 GeVc, when combined with some existing data, give evidence for a dip in the t distribution near t=−1.5 (GeVc).2 This dip, and other features of the data, are adequately described by an A2 Regge-pole model. The effective A2 trajectory is calculated and found to disagree with that obtained from the reaction π−p→η0n.

1 data table

No description provided.