Abstract
We discuss how to calculate cross sections as well as rapidity, transverse momentum and energy distributions of ντ and {overline{nu}}_{tau } produced from the direct {D}_s^{pm}to {nu}_{tau }/{overline{nu}}_{tau } and chain {D}_s^{pm}to {tau}^{+}/{tau}^{-}to {nu}_{tau }/{overline{nu}}_{tau } decays in p+96 Mo scattering with proton beam Elab = 400 GeV i.e. at {sqrt{s}}_{NN} = 27.4 GeV. The τ decays are simulated with the help of the Tauola code and include multiple decay channels of τ in amounts proportional to their branching ratios. In our calculations we include {D}_s^{pm } from charm fragmentation c → {D}_s^{+} and overline{c}to {D}_s^{-} as well as those from subleading fragmentation of strange quarks/antiquarks s → {D}_s^{-} and overline{s}to {D}_s^{+} . The sne overline{s} asymmetry of the strange quark content of proton is included. The different contributions to {D}_s^{+} and {nu}_{tau }/{overline{nu}}_{tau } are shown explicitly. We discuss and quantify a not discussed so far effect of asymmetries for production of ντ and {overline{nu}}_{tau } caused by subleading fragmentation mechanism and discuss related uncertainties. A potential measurement of the asymmetry is discussed. Estimates of a number of observed {nu}_{tau }/{overline{nu}}_{tau } in the {nu}_{tau }/{overline{nu}}_{tau } +208Pb reaction, with 2m long target are given with the help of the NuWro program. We refer also to the production of the high-energy (anti)neutrinos in the atmosphere.
Highlights
We discuss how to calculate cross sections as well as rapidity, transverse momentum and energy distributions of ντ and ντ produced from the direct Ds± → ντ /ντ and chain
The c and ccross sections are calculated in the collinear NLO approximation using the Fonll framework [17, 18] or in the kt-factorization approach [19–24]
Production of Ds meson might be driven by fragmentation of both charm and strange quark. The latter mechanism leads to the production asymmetry due to the asymmetric strange sea quark content of the proton encoded in the parton distribution functions (PDFs)
Summary
In the present paper we discuss two mechanisms of Ds meson production:. c → Ds+, c → Ds−, called leading fragmentation,. We follow the assumptions relevant for the case of low c.m.s. collision energies and/or small transverse momenta of hadrons, as discussed in our recent analysis [32], and we assume that the hadron H is emitted in the direction of parent quark/antiquark q, i.e. ηH = ηq (the same pseudorapidities or polar angles) Within this approach we set the light-cone z-scaling, i.e. we define p+H = zp+q , where p+ = E + p. Production of Ds meson might be driven by fragmentation of both charm and strange quark The latter mechanism leads to the production asymmetry due to the asymmetric strange sea quark content of the proton encoded in the PDFs. The three lines correspond to the calculations with different fragmentation functions shown above. The discrepancy between KMR-CT14lo and KMR-MMHT2014lo results comes from a significant differences of up and down quark distributions at very small-Q2 and large-x incorporated in the MMHT2014lo and CT14lo collinear PDFs. The major part of the cross section for q∗q∗
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