Observation of the strange sea in the proton via inclusive Phi-meson production in neutral current deep inelastic scattering at HERA

Abstract

Inclusive phi-meson production in neutral current deep inelastic e+p scattering has been measured with the ZEUS detector at HERA using an integrated luminosity of 45 pb^{-1}. The phi mesons were studied in the range 10<Q2<100 GeV2, where Q2 is the virtuality of the exchanged photon, and in restricted kinematic regions in the transverse momentum, p_T, pseudorapidity, eta, and the scaled momentum in the Breit frame, x_p. Monte Carlo models with the strangeness-suppression factor as determined by analyses of e+e- annihilation events overestimate the cross sections. A smaller value of the strangeness-suppression factor reduces the predicted cross sections, but fails to reproduce the shapes of the measured differential cross sections. High-momentum phi mesons in the current region of the Breit frame give the first direct evidence for the strange sea in the proton at low x.

20 pages including 5 figures and 2 tables

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Cited by in corpus (5)

• Infrared safe definition of jet flavour
• Measurement of the inclusive phi cross-section in pp collisions at sqrt(s) = 7 TeV
• Review of High Energy Diffraction in Real and Virtual Photon Proton scattering at HERA
• Measurement of K0S, Lambda, Antilambda production at HERA
• Hyperfine splitting effects in string hadronization