Prompt Neutrino Fluxes from Charm Production in the Atmosphere

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1 Prompt Neutrino Fluxes from Charm Production in the Atmosphere Yu Seon Jeong Yonsei University Wor in progress with M. H. Reno, and C. S. Kim, and with A. Bhattacharya, I. Sarcevic, and R. nberg YongPyong-High1 015 Joint Winter Conference High1 Resort, Korea, January 5-31, 015

2 Atmospheric Neutrino Cosmic rays interact with air nuclei in the atmosphere and produce hadrons. Hadrons subsequently decay producing neutrinos. Atmospheric neutrino e. g. pp X e Atmospheric neutrinos are the bacground to astrophysical neutrinos. e

3 Conventional Neutrino Flux Neutrino flux from pion and aon decay is called the conventional flux. Κ, π long-lived particles interact before the decay suppress the neutrino production at high IceCube

4 Prompt Neutrino Flux IceCube Neutrino flux from the decay of the charmed hadrons is called the prompt flux. e.g. D-mesons The charmed hadrons are short-lived particles. The resulting neutrino flux less depends on energy.

5 Cascade equations The neutrino flux is obtained by solving the coupled cascade equations for nucleon, meson and lepton fluxes. d N dx N N S NA NY N - nucleon flux d dx M M M S NA MY S MA MY dec M M dl dx S M ly M 0 0 M D, D, D, Ds, c for prompt fluxes from charm The function S is responsible for the generation.

6 d dn d S, ; Cascade equations generation function for decay, 1 for production,, 1, ; A d Y d d Y A d d dn dn/d the energy distribution of the final state particle.

7 Z-moments d dn X X d Z, ;,,, : Assumption X X d dn d Z, ; P. Lipari, Astropart. Phys P. Gondolo, G. Ingelman and M.Thunman, Astropart. Phys TIG

8 Approximate Lepton Fluxes low l Z Ml Z NM 1 Z NN N high l Z Ml Z NM 1 Z NN ln 1 M N / / N M M N i i / 1 Z ii i N, M The lepton flux can be obtained by interpolating these two solutions.

9 The essential input to the neutrino flux evaluation is the charm production cross section. The charm production cross section can be calculated 1 in the perturbative QCD, in the dipole model, 3 with non-perturbative intrinsic charm production.

10 Charm Production Cross Section in QCD The cross section for charm pair production d dx LO F dm x x 1 cc s ggcc sˆ G x 1, G x, x 1, 1 x F 4M s cc x F At high energies, x1xf and x 1. e.g. at p = 1 PeV, x 10-6 for xf 1. x become smaller at higher energy.

11 Gluon distribution at small x The gluon distribution increases rapidly as x becomes small. At the high density region, gluons can be overlapped and recombined. Saturation effect K.Golec-Biernat conf. proceeding arxiv:

12 Color Dipole Model C. werz et al, JHP The virtual photon splits into a quar-antiquar pair color dipole before scattering on the proton. * N x, Q f 1 0 dz d r z, r, Q ˆ qqn r, x z, r, Q - fluctuation ˆ r, x - interaction of qqn a dipole with a target

13 PP collisions in the dipole model The differential cross section for heavy quar production from proton-proton collision Gp, x, d pp QQX x1 G x1, Q dy The partonic cross section in the dipole model Gp Q x,, Q dzd r z, r x, G dg r Q G z, r - splitting of gluon to dipole dg x, r - interaction of qq pair from a gluon with the target nucleon

14 dg x, r a d a PP collisions in the dipole model 9 1 x, r d d d 8 8 x x 0 0 x x r r r brc x, zr x,1 z r x, r for r 0.5 and r 1.8 e b 1 r ce d r for 0.5 r r r 0.17r 0.044r r 0.035r 0.004r 3 r 1.8 r 1.8 r a b c d e r <r r> YSJ, C. S. Kim, M. V. Luu and M. H. Reno, JHP

15 Cosmic Ray Flux for Nucleon T.K. Gaisser, Astropart. Phys

16 Prompt Flux in Dipole Model New dipole cross section from the recent F parameterization increases the flux by ~15%. The effect of CR spectrum above 1 PeV, reduction in flux is by a factor of 3-4.

17 Intrinsic charm Charm can be produced from non-perturbative fluctuation of nucleon and it goes into a charmed baryon-meson pair. e.g. p c D Meson-Baryon Model MBM 0 c In the MBM, is produced through D 0 c and D * 0 c. T.J. Hobbs, J.T. Londergan and W. Melnitchou, PRD HLM

18 Intrinsic charm production cross section d dx F c M D, D f * c M x F Mp tot Dp tot * D tot p 0 10 mb y 1 xf f c M - splitting function T.J. Hobbs, J.T. Londergan and W. Melnitchou, PRD HLM

19 Prompt Flux Intrinsic charm

20 Conclusion The prompt flux with more realistic cosmic ray nucleon spectrum is reduced relative to the prompt spectrum using the broen power law. At 1 PeV, the reduction in flux is about a factor of 3. The dipole cross section from the F parameterization by Bloc et al increase the flux about 15%. Intrinsic charm contribution based on the Hobbs et al MBM results may be important. wor in progress More update with separate lepton flavors with bottom quar contribution with other models for intrinsic charm

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22 Prompt flux : DM vs. NLO QCD