paper

D meson production asymmetry, unfavoured fragmentation and consequences for prompt atmospheric neutrino production

arXiv:1711.08616 · doi:10.1103/PhysRevD.97.074001

Abstract

We consider unfavoured light quark/antiquark to meson fragmentation. We discuss nonperturbative effects for small transverse momenta. The asymmetry for and production measured by the LHCb collaboration provides natural constraints on the parton (quark/antiquark) fragmentation functions. We find that already a fraction of fragmentation probability is sufficient to account for the measured asymmetry. We make predictions for similar asymmetry for neutral mesons. Large -meson production asymmetries are found for large which is related to dominance of light quark/antiquark fragmentation over the standard fragmentation. As a consequence, prompt atmospheric neutrino flux at high neutrino energies can be much larger than for the conventional fragmentation. The latter can constitute a sizeable background for the cosmic neutrinos claimed to be observed recently by the IceCube Observatory. Large rapidity-dependent and asymmetries are predicted for low ( 20 - 100 GeV) energies. The fragmentation leads to enhanced production of mesons at low energies. At = 20 GeV the enhancement factor with respect to the conventional contribution is larger than a factor of five. In the considered picture the large- mesons are produced dominantly via fragmentation of light quarks/antiquarks. Predictions for fixed target collisions relevant for a fixed target LHCb experiment are presented.

20 pages, 12 figures, The initial calculations were improved by modifying fragmentation algorithm and using two different fragmenatation functions

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