抄録
We have measured the cross sections d2σ/d P Tdη) for production of isolated direct photons in pp̄ collisions at two different center-of-mass energies, 1.8 TeV and 0.63 TeV, using the Collider Detector at Fermilab. The normalization of both data sets agrees with the predictions of quantum chromodynamics for a photon transverse momentum (PT) of 25 GeV/c, but the shapes versus photon PT do not. These shape differences lead to a significant disagreement in the ratio of cross sections in the scaling variable xT(≡ 2PT/√s). This disagreement in the xT ratio is difficult to explain with conventional theoretical uncertainties such as scale dependence and parton distribution parametrizations.
本文言語 | English |
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論文番号 | 112003 |
ジャーナル | Physical Review D |
巻 | 65 |
号 | 11 |
DOI | |
出版ステータス | Published - 2002 |
ASJC Scopus subject areas
- 核物理学および高エネルギー物理学