Search for Direct Single Photon Production at Large p(T) in Proton Proton Collisions at s**(1/2) = 62.4-GeV

The CERN-Columbia-Oxford-Rockefeller & CCOR collaborations Angelis, A.L.S. ; Besch, H.J. ; Blumenfeld, Barry J. ; et al.
Phys.Lett.B 94 (1980) 106-112, 1980.
Inspire Record 153483 DOI 10.17182/hepdata.27178

As part of a study of large p T phenomena in photon-proton collisions at the CERN ISR, a search for direct single photon production has been performed. A statistical division of the data sample into the fraction consistent with single photon and the fraction due to multiphoton decays of neutral hadrons is accomplished by measuring the average conversion probability for the sample in a one radiation length thick converter. The fraction of the sample attributable to direct single photon production is 〈 γ /all〉 = 0.074 ± 0.012 for 6 GeV/ c < p T 10 GeV/ c , and 〈 γ /all〉 = 0.26 ± 0.04 for p T > 10 GeV/ c , with an additional systematic uncertainty of ±0.05 for both values.

1 data table

No description provided.


A Measurement of Inclusive pi0 Production at Large p(T) from p p Collisions at the CERN ISR

The CERN-Columbia-Oxford-Rockefeller & CCOR collaborations Angelis, A.L.S. ; Blumenfeld, Barry J. ; Camilleri, L. ; et al.
Phys.Lett.B 79 (1978) 505-510, 1978.
Inspire Record 132910 DOI 10.17182/hepdata.27381

The inclusive cross section for larger p T π 0 production near 90° in p-p collisions at the CERN ISR is presented for centre-of-mass energies 30.7, 53.1 and 62.4 GeV. The data are inconsistent with scaling of the form p T − n F ( x T ), with constant n or with n allowed to depend on x T = 2p T / s . For s = 53.1 and 62.4 GeV , the value of n found for 3.5 < p T < 7.0 GeV/ c is n = 8.0 ± 0.5, in agreement with previous experiments. However, for 7.5 < p T < 14.0 GeV/ c the value becomes n = 5.1 ± 0.4.

3 data tables

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A Measurement of the Production of Massive $e^+ e^-$ Pairs in Proton Proton Collisions at $\sqrt{s}$=62.4 GeV

The CERN-Columbia-Oxford-Rockefeller & CCOR collaborations Angelis, A.L.S. ; Besch, H.J. ; Blumenfeld, Barry J. ; et al.
Phys.Lett.B 87 (1979) 398-402, 1979.
Inspire Record 142896 DOI 10.17182/hepdata.27278

An apparatus consisting of a superconducting solenoid magnet, cylindrical drift-chambers, and two arrays of lead-glass Čerenkov counters has been used at the CERN ISR to study the production of e + e − pairs of invariant mass above 6.5 GeV/ c 2 . Cross sections for the continuum and the ϒ family of resonances are presented, as well as the mean transverse momentum 〈 p T 〉 of the electron-positron pairs in the continuum and resonance region.

1 data table

No description provided.


Determination of the Angular and Energy Dependence of Hard Constituent Scattering From $\pi^0$ Pair Events at the {CERN} Intersecting Storage Rings

The CERN-Columbia-Oxford-Rockefeller & CCOR collaborations Angelis, A.L.S. ; Besch, H.J. ; Blumenfeld, Barry J. ; et al.
Nucl.Phys.B 209 (1982) 284-300, 1982.
Inspire Record 179519 DOI 10.17182/hepdata.34059

We present data on proton-proton collisions, obtained at the CERN Intersecting Storage Rings, in which two roughly back-to-back π 0 's of high transverse momentum ( p T ) were produced. The angular distribution of the dipion axis relative to the collision axis is found to be independent of both the effective mass m of the dipion system and the centre-of-mass energy √ s of the proton-proton collision. The cross-sections d σ d m at the values of √ s satisfy a scaling law of the form d σ d m = G(x) m n , where x = m(π 0 , π 0 )//trs and n = 6.5 ± 0.5 . We show from our data that the leading π 0 carries most of the momentum of the scattered parton. Given this fact, the axis of the dipion system follows closely the direction of the scattered constituents, and we exploit this to determine the angular dependence of the hard-scattering subprocess. We also compare our data with the lowest order QCD predictions using structure functions as determined in deep-inelastic scattering and fragmentation functions from electron-positron annihilation.

1 data table

No description provided.