Cosmological Sign of Neutrino CP Violation
It is shown how, in a class of models, the sign of the baryon number of the universe can be related to CP violation in neutrino oscillation experiments.
hep-ph↗
arXiv subjects
S. L. Glashow
Publications and source records attributed to S. L. Glashow.
No-go for detecting CP violation via neutrinoless double beta decay
We present a necessary condition on the solar oscillation amplitude for CP violation to be detectable through neutrinoless double beta (0νββ) decay. It depends only on the fractional uncertainty in the ν_e-ν_e element of the neutrino mass matrix. We demonstrate that even under very optimistic assumptions about the sensitivity of future experiments to the absolute neutrino mass scale, and on the precision with which nuclear matrix elements that contribute to 0νββdecay are calculable, it will be impossible to detect neutrino CP violation arising from Majorana phases.
hep-ph↗
Neutrinoless double beta decay can constrain neutrino dark matter
We examine how constraints can be placed on the neutrino component of dark matter by an accurate measurement of neutrinoless double beta ($0νββ$) decay and the solar oscillation amplitude. We comment on the alleged evidence for $0νββ$ decay.
hep-ph↗
Neutrinos on Earth and in the Heavens
Recent data lead us to a simple and intriguing form of the neutrino mass matrix. In particular, we find solar neutrino oscillations to be nearly maximal (and rule out the small-angle MSW explanation of solar neutrino observations) if relic neutrinos comprise at least one~percent of the critical mass density of the universe.
hep-ph↗
A Matter-Antimatter Universe?
We ask whether the universe can be a patchwork consisting of distinct regions of matter and antimatter. We demonstrate that, after recombination, it is impossible to avoid annihilation near regional boundaries. We study the dynamics of this process to estimate two of its signatures: a contribution to the cosmic diffuse gamma-ray background and a distortion of the cosmic microwave background. The former signal exceeds observational limits unless the matter domain we inhabit is virtually the entire visible universe. On general grounds, we conclude that a matter-antimatter symmetric universe is empirically excluded.
astro-ph↗
Comments on Neutrino Tests of Special Relativity
We point out that the assumption of Lorentz noninvariance examined recently by Coleman and Glashow leads to neutrino flavor oscillations which are phenomenologically equivalent to those obtained by assuming the neutrinos violate the principle of equivalence. We then comment on the limits on Lorentz noninvariance which can be derived from solar, atmospheric, and accelerator neutrino experiments.
hep-ph↗
Cabibbo Mixing and the Search for CP Violation
We examine certain extensions of the standard model in which $CP$ violation is spontaneous and the strong $CP$ problem is resolved. In these models, the $3 \times 3$ quark mixing matrix is neither real nor unitary. However, to a precision of 0.1%, it is real and orthogonal. There are no readily observable $CP$-violating effects besides those in the neutral kaon system.
hep-ph↗
Neutrino Helioseismology
The observed deficit of $\rm ^8B$ solar neutrinos may call for an improved standard model of the sun or an expanded standard model of particle physics ({\it e.g.,} with neutrino masses and mixing). In the former case, contemporary fluid motions and thermal fluctuations in the sun's core may modify nuclear reaction rates and restore agreement. To test this notion, we propose a search for short--term variations of the solar neutrino flux.
hep-ph↗
Physics Focus and Fiscal Forces
Two items are reproduced herein: my `Outlook' talk, an amended version of which was presented at the 1991 joint Lepton--Photon and EPS Conference in Geneva, and an Open Letter addressed to HEPAP. One is addressed primarily to the European high--energy physics community, the other to the American. A common theme of these presentations is a plea for the rational allocation of the limited funds society provides for high--energy physics research. If my `loose cannon' remarks may seem irresponsible to some of my colleagues, my silence would be more so.
hep-th↗