Nuclear Theory·nucl-th

Monday·September 23, 2019

7 papers—4 primary·3 cross-listed

05
[Submitted on 20 Sept 2019] (cross-list from hep-ph)
Reevaluating Reactor Antineutrino Anomalies with Updated Flux Predictions
Jeffrey Berryman🇺🇸 · Patrick Huber🇺🇸
Hints for the existence of a sterile neutrino at nuclear reactors are reexamined using two updated predictions for the fluxes of antineutrinos produced in fissions. These new predictions diverge in their preference for the rate deficit anomaly, relative to previous analyses, but the anomaly in the ratios of measured antineutrino spectra persists. We comment on upcoming experiments and their ability to probe the preferred region of the sterile-neutrino parameter space in the electron neutrino disappearance channel.
Comments:
7 pages, 2 figures
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Experiment (nucl-ex); Nuclear Theory (nucl-th)
arXiv:
1909.09267 [pdf]
PRD(2020)·39 citations
06
[Submitted on 20 Sept 2019] (cross-list from hep-ph)
The decay $J / ψ \to γ ϕϕ$ : spin dependence of amplitude and angular distributions of photons with linear polarizations
A.A. Kozhevnikov🇷🇺
Based on the effective invariant amplitudes of the transitions $J / ψ \to γ X (J^{P})$ and $X (J^{P}) \to ϕϕ$ , the spin dependence of the $J / ψ \to γ X (J^{P}) \to γ ϕϕ$ decay amplitude is obtained in the case of the intermediate resonances $X$ with $J^{P} = 0^{\pm}, 1^{\pm}, 2^{\pm}$ . Angular distributions of photons with the definite linear polarizations relative to the plane spanned by the momentum of initial electron and the total momentum of the $ϕϕ$ pair in the reaction $e^{+} e^{-} \to J / ψ \to γ X (J^{P}) \to γ ϕϕ$ are calculated. It is shown that the sign of the asymmetry of the distributions of the photons polarized in the above plane and orthogonal to it correlates with the signature $P_{X} (- 1)^{J_{X}}$ of the $X$ resonance with given spin-parity $J_{X}^{P_{X}}$ so it may help to establish this quantum number in a way which does not depend on the specific model of the $X (J^{P}) \to ϕϕ$ amplitude.
Comments:
11 pages, 1 figure
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Experiment (hep-ex); Nuclear Theory (nucl-th)
arXiv:
1909.09311 [pdf]
EPJA(2019)·3 citations
07
[Submitted on 20 Sept 2019] (cross-list from hep-ph)
Flavor structures of charged fermions and massive neutrinos
Zhi-zhong Xing🇨🇳
Most of the free parameters in the Standard Model (SM) -- a quantum field theory which has successfully elucidated the behaviors of strong, weak and electromagnetic interactions of all the known fundamental particles, come from the lepton and quark flavors. The discovery of neutrino oscillations has proved that the SM is incomplete, at least in its lepton sector; and thus the door of opportunity is opened to exploring new physics beyond the SM and solving a number of flavor puzzles. In this review article we give an overview of important progress made in understanding the mass spectra, flavor mixing patterns, CP-violating effects and underlying flavor structures of charged leptons, neutrinos and quarks in the past twenty years. After introducing the standard pictures of fermion mass generation, flavor mixing and CP violation in the SM extended with the presence of massive Dirac or Majorana neutrinos, we briefly summarize current experimental knowledge about the flavor parameters of quarks and leptons. Various ways of describing flavor mixing and CP violation are discussed, the renormalization-group evolution of flavor parameters is illuminated, and the matter effects on neutrino oscillations are interpreted. Taking account of possible extra neutrino species, we propose a standard parametrization of the $6 \times 6$ flavor mixing matrix and comment on the phenomenological aspects of heavy, keV-scale and light sterile neutrinos. We pay particular attention to those novel and essentially model-independent ideas or approaches regarding how to determine the Yukawa textures of Dirac fermions and the effective mass matrix of Majorana neutrinos, including simple discrete and continuous flavor symmetries. An outlook to the future development in unravelling the mysteries of flavor structures is also given.
Comments:
227 pages, 36 figures, final version matching the published version in Physics Reports
Subjects:
High Energy Physics — Phenomenology (hep-ph); High Energy Physics — Theory (hep-th); Nuclear Theory (nucl-th)
arXiv:
1909.09610 [pdf]
Phys.Rept.(2020)·338 citations

Affiliations

first authorsco-authorsvia INSPIRE

Reevaluating Reactor Antineutrino Anomalies with Updated Flux Predictions

The decay J/ψ→γϕϕ: spin dependence of amplitude and angular distributions of photons with linear polarizations

Flavor structures of charged fermions and massive neutrinos

Affiliations

The decay $J / ψ \to γ ϕϕ$ : spin dependence of amplitude and angular distributions of photons with linear polarizations