D meson production asymmetry, unfavoured fragmentation and consequences for prompt atmospheric neutrino production · arXivDesk
1711.08616Nov 23, 201720 pages, 12 figures, The initial calculations were improved by modifying fragmentation algorithm and using two different fragmenatation functions
D meson production asymmetry, unfavoured fragmentation and consequences for prompt atmospheric neutrino production
We consider unfavoured light quark/antiquark to D meson fragmentation. We discuss nonperturbative effects for small transverse momenta. The asymmetry for D+ and D− production measured by the LHCb collaboration provides natural constraints on the parton (quark/antiquark) fragmentation functions. We find that already a fraction of q/qˉ→D
Nearby in the stack
fragmentation probability is sufficient to account for the measured asymmetry. We make predictions for similar asymmetry for neutral
D
mesons. Large
D
-meson production asymmetries are found for large
xF
which is related to dominance of light quark/antiquark
q/qˉ→D
fragmentation over the standard
c→D
fragmentation. As a consequence, prompt atmospheric neutrino flux at high neutrino energies can be much larger than for the conventional
c→D
fragmentation. The latter can constitute a sizeable background for the cosmic neutrinos claimed to be observed recently by the IceCube Observatory. Large rapidity-dependent
D+/D−
and
D0/Dˉ0
asymmetries are predicted for low (
s=
20 - 100 GeV) energies. The
q/qˉ→D
fragmentation leads to enhanced production of
D
mesons at low energies. At
s
= 20 GeV the enhancement factor with respect to the conventional contribution is larger than a factor of five. In the considered picture the large-
xF
D
mesons are produced dominantly via fragmentation of light quarks/antiquarks. Predictions for fixed target
p+4He
collisions relevant for a fixed target LHCb experiment are presented.