| 1. |
- Bhattacharya, Atri, et al.
(författare)
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Charm decay in slow-jet supernovae as the origin of the IceCube ultra-high energy neutrino events
- 2015
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Ingår i: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- We investigate whether the recent ultra-high energy (UHE) neutrino events detected at the IceCube neutrino observatory could come from the decay of charmed mesons produced within the mildly relativistic jets of supernova-like astrophysical sources. We demonstrate that the 5.7σ excess of neutrinos observed by IceCube in the energy range 30 TeV--2 PeV can be explained by a diffuse flux of neutrinos produced in such slow-jet supernovae, using the values of astrophysical and QCD parameters within the theoretical uncertainties associated with neutrino production from charmed meson decay in astrophysical sources. We discuss the theoretical uncertainties inherent in the evaluation of charm production in high energy hadronic collisions, as well as the astrophysical uncertainties associated with slow-jet supernova sources. The proton flux within the source, and therefore also the produced neutrino flux, is cut off at around a few PeV, when proton cooling processes become dominant over proton acceleration. This directly explains the sudden drop in event rates at energies above a few PeV. We incorporate the effect of energy dependence in the spectrum-weighted charm production cross-section and show that this has a very significant effect on the shape, magnitude and cut-off energies for the neutrino flux.
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| 2. |
- Bhattacharya, Atri, et al.
(författare)
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Perturbative charm production and the prompt atmospheric neutrino flux in light of RHIC and LHC
- 2015
-
Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; 6
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Tidskriftsartikel (refereegranskat)abstract
- We re-evaluate the prompt atmospheric neutrino flux, using the measured charm cross sections at RHIC and the Large Hadron Collider to constrain perturbative QCD parameters such as the factorization and renormalization scales, as well as modern parton distribution functions and recent estimates of the cosmic-ray spectra. We find that our result for the prompt neutrino flux is lower than previous perturbative QCD estimates and, consequently, alters the signal-to-background statistics of the recent IceCube measurements at high energies.
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| 3. |
- Bhattacharya, Atri, et al.
(författare)
-
Prompt atmospheric neutrino fluxes: perturbative QCD models and nuclear effects
- 2016
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Ingår i: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; 11
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Tidskriftsartikel (refereegranskat)abstract
- We evaluate the prompt atmospheric neutrino flux at high energies using three different frameworks for calculating the heavy quark production cross section in QCD: NLO perturbative QCD, kT factorization including low-x resummation, and the dipole model including parton saturation. We use QCD parameters, the value for the charm quark mass and the range for the factorization and renormalization scales that provide the best description of the total charm cross section measured at fixed target experiments, at RHIC and at LHC. Using these parameters we calculate differential cross sections for charm and bottom production and compare with the latest data on forward charm meson production from LHCb at 7 TeV and at 13 TeV, finding good agreement with the data. In addition, we investigate the role of nuclear shadowing by including nuclear parton distribution functions (PDF) for the target air nucleus using two different nuclear PDF schemes. Depending on the scheme used, we find the reduction of the flux due to nuclear effects varies from 10% to 35% at the highest energies. Finally, we compare our results with the IceCube limit on the prompt neutrino flux, which is already providing valuable information about some of the QCD models.
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| 4. |
- Jeong, Yu Seon, et al.
(författare)
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Prompt atmospheric neutrino flux
- 2016
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Konferensbidrag (övrigt vetenskapligt/konstnärligt)abstract
- We evaluate the prompt atmospheric neutrino flux including nuclear correction and B hadron contribution in the different frameworks: NLO perturbative QCD and dipole models. The nuclear effect is larger in the prompt neutrino flux than in the total charm production cross section, and it reduces the fluxes by 10%−30% depending on the model. We also investigate the uncertainty using the QCD scales allowed by the charm cross section data from RHIC and LHC experiments.
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| 5. |
- Jeong, Yu Seon, et al.
(författare)
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Prompt atmospheric neutrino flux from the various QCD models
- 2017
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Ingår i: XLVI International Symposium On Multiparticle Dynamics (ISMD 2016). - : EDP Sciences.
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Konferensbidrag (refereegranskat)abstract
- We evaluate the prompt atmospheric neutrino flux using the different QCD models for heavy quark production including the b quark contribution. We include the nuclear correction and find it reduces the fluxes by 10% - 50% according to the models. Our heavy quark results are compared with experimental data from RHIC, LHC and LHCb.
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| 6. |
- Jeong, Yu Seon, et al.
(författare)
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Prompt atmospheric neutrino flux in perturbative QCD and its theoretical uncertainties
- 2017
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Ingår i: XXVII International Conference on Neutrino Physics and Astrophysics (Neutrino2016). - : Institute of Physics Publishing (IOPP).
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Konferensbidrag (refereegranskat)abstract
- Using the most recent PDFs and the cosmic ray spectrum, we evaluate the charm/bottom induced prompt atmospheric muon neutrino fluxes including nuclear corrections. We investigate their impact in perturbative QCD and estimate the comprehensive uncertainties from other various factors. The prompt atmospheric tau neutrino fluxes are also presented.
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