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1. chinaXiv:201609.01033 [pdf]

Detecting electron neutrinos from solar dark matter annihilation by JUNO

Wan-Lei Guo
Subjects: Physics >> Nuclear Physics

We explore the electron neutrino signals from light dark matter (DM) annihilation in the Sun for the large liquid scintillator detector JUNO. In terms of the spectrum features of three typical DM annihilation channels?χχ→νν?,τ+τ?,bb?, we take two sets of selection conditions to calculate the expected signals and atmospheric neutrino backgrounds based on the Monte Carlo simulation data. Then the JUNO sensitivities to the spin independent DM-nucleon and spin dependent DM-proton cross sections are presented. It is found that the JUNO projected sensitivities are much better than the current spin dependent direct detection experimental limits for the?νν??and?τ+τ??channels. In the spin independent case, the JUNO will give the better sensitivity to the DM-nucleon cross section than the LUX and CDMSlite limits for the?νν??channel with the DM mass lighter than 6.5 GeV. If the?νν??or?τ+τ??channel is dominant, the future JUNO results are very helpful for us to understand the tension between the DAMA annual modulation signal and other direct detection exclusions.

submitted time 2016-09-14 Hits781Downloads406 Comment 0

2. chinaXiv:201609.00978 [pdf]

Neutrino Oscillation Probabilities in Matter with Direct and Indirect Unitarity Violation in the Lepton Mixing Matrix

Yu-Feng Li; Shu Luo
Subjects: Physics >> Nuclear Physics

In the presence of both direct and indirect unitarity violation in the lepton mixing matrix, we derive a complete set of series expansion formulas for neutrino oscillation probabilities in matter of constant density. Expansions in the mass hierarchy parameter?α≡Δm221/Δm231?and those unitarity violation parameters?s2ij?(for i = 1, 2, 3 and j = 4, 5, 6) up to the first order are studied in this paper. We analyse the accuracy of the analytical series expansion formulas in different regions of L / E. A detailed numerical analysis is also performed, of which the different effects of the direct and the indirect unitarity violation are particularly emphasized. We also study in this paper the summed?να→νe,ν,τprobabilities, whose deviation from the unity provides a definite signal of the unitarity violation.

submitted time 2016-09-14 Hits879Downloads495 Comment 0

3. chinaXiv:201609.00917 [pdf]

Neutrino Masses and Flavor Oscillations

Yifang Wang; Zhi-zhong Xing
Subjects: Physics >> Nuclear Physics

This essay is intended to provide a brief description of the peculiar properties of neutrinos within and beyond the standard theory of weak interactions. The focus is on the flavor oscillations of massive neutrinos, from which one has achieved some striking knowledge about their mass spectrum and flavor mixing pattern. The experimental prospects towards probing the absolute neutrino mass scale, possible Majorana nature and CP-violating effects will also be addressed.

submitted time 2016-09-13 Hits943Downloads561 Comment 0

4. chinaXiv:201609.00911 [pdf]

Detection Prospects of the Cosmic Neutrino Background

Yu-Feng Li
Subjects: Physics >> Nuclear Physics

The existence of the cosmic neutrino background (CnuB) is a fundamental prediction of the standard Big Bang cosmology. Although current cosmological probes provide indirect observational evidence, the direct detection of the CnuB in a laboratory experiment is a great challenge to the present experimental techniques. We discuss the future prospects for the direct detection of the CnuB, with the emphasis on the method of captures on beta-decaying nuclei and the PTOLEMY project. Other possibilities using the electron-capture (EC) decaying nuclei, the annihilation of extremely high-energy cosmic neutrinos (EHEC\nus) at the Z-resonance, and the atomic de-excitation method are also discussed in this review.

submitted time 2016-09-13 Hits857Downloads496 Comment 0

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