| 1. |
- Bhattacharya, Atri, et al.
(author)
-
Charm decay in slow-jet supernovae as the origin of the IceCube ultra-high energy neutrino events
- 2015
-
In: Journal of Cosmology and Astroparticle Physics. - : IOP Publishing. - 1475-7516. ; 6
-
Journal article (peer-reviewed)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.
|
|
| 2. |
- Bhattacharya, Atri, et al.
(author)
-
Energy-dependent flavour ratios in neutrino telescopes from charm
- 2024
-
In: Journal of Cosmology and Astroparticle Physics. - : Institute of Physics Publishing (IOPP). - 1475-7516. ; 2024:3
-
Journal article (peer-reviewed)abstract
- The origin of the observed diffuse neutrino flux is not yet known. Studies of the relative flavour content of the neutrino flux detected at Earth can give information on the production mechanisms at the sources and on flavour mixing, complementary to measurements of the spectral index and normalisation. Here we demonstrate the effects of neutrino fluxes with different spectral shapes and different initial flavour compositions dominating at different energies, and we study the sensitivity of future measurements with the IceCube Neutrino Observatory. Where one kind of flux gives way to another, this shows up as a non-trivial energy dependence in the flavour compositions. We explore this in the context of slow-jet supernovae and magnetar-driven supernovae – two examples of astrophysical sources where charm production may be effective. Using current best-fit neutrino mixing parameters and their projected 2040 uncertainties, we use event ratios of different event morphologies at IceCube to illustrate the possibilities of distinguishing the energy dependence of neutrino flavour ratios.
|
|
| 3. |
- Bhattacharya, Atri, et al.
(author)
-
Perturbative charm production and the prompt atmospheric neutrino flux in light of RHIC and LHC
- 2015
-
In: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; 6
-
Journal article (peer-reviewed)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.
|
|
| 4. |
- Bhattacharya, Atri, et al.
(author)
-
Prompt atmospheric neutrino fluxes: perturbative QCD models and nuclear effects
- 2016
-
In: Journal of High Energy Physics (JHEP). - 1126-6708 .- 1029-8479. ; 11
-
Journal article (peer-reviewed)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.
|
|
| 5. |
- Enberg, Rikard, et al.
(author)
-
Perturbative Charm Production and the Prompt Atmospheric Neutrino Flux in light of RHIC and LHC
- 2020
-
Conference paper (other academic/artistic)abstract
- Prompt neutrinos due to the decay of charmed mesons produced in the atmosphere from cosmic-ray and atmospheric nuclei interactions may be a significant source of background to ultra-high energy neutrino searches above 10 TeV. We re-evaluate this flux using updated charm production cross-sections based on QCD parameters, the charm quark mass, and the range for the factorization and renormalization scales that provide the best description of this data at fixed target experiments, at RHIC, and at LHC. We find that the prompt neutrino flux is reduced from previous results in the literature by a factor between two and eight, depending on the energy. We discuss the implications of our results for current IceCube data.
|
|
| 6. |
- Jeong, Yu Seon, et al.
(author)
-
Prompt atmospheric neutrino flux
- 2016
-
Conference paper (other academic/artistic)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.
|
|
| 7. |
- Jeong, Yu Seon, et al.
(author)
-
Prompt atmospheric neutrino flux from the various QCD models
- 2017
-
In: XLVI International Symposium On Multiparticle Dynamics (ISMD 2016). - : EDP Sciences.
-
Conference paper (peer-reviewed)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.
|
|
| 8. |
- Jeong, Yu Seon, et al.
(author)
-
Prompt atmospheric neutrino flux in perturbative QCD and its theoretical uncertainties
- 2017
-
In: XXVII International Conference on Neutrino Physics and Astrophysics (Neutrino2016). - : Institute of Physics Publishing (IOPP).
-
Conference paper (peer-reviewed)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.
|
|
