Light neutrinos without heavy mass scales: A higher-dimensional seesaw mechanism

Keith R Dienes, Emilian Dudas, Tony Gherghetta

Research output: Contribution to journalArticle

368 Citations (Scopus)

Abstract

Recent theoretical developments have shown that extra space-time dimensions can lower the fundamental GUT, Planck, and string scales. However, recent evidence for neutrino oscillations suggests the existence of light non-zero neutrino masses, which in turn suggests the need for a heavy mass scale via the seesaw mechanism. In this paper, we make several observations in this regard. First, we point out that allowing the right-handed neutrino to experience extra space-time dimensions naturally permits the left-handed neutrino mass to be power-law suppressed relative to the masses of the other fermions. This occurs due to the power-law running of the neutrino Yukawa couplings, and therefore does not require a heavy scale for the right-handed neutrino. Second, we show that a higher-dimensional analogue of the seesaw mechanism may also be capable of generating naturally light neutrino masses without the introduction of a heavy mass scale. Third, we show that such a higher-dimensional seesaw mechanism may even be able to explain neutrino oscillations without neutrino masses, with oscillations induced indirectly via the masses of the Kaluza-Klein states. Fourth, we point out that even when higher-dimensional right-handed neutrinos are given a bare Majorana mass, the higher-dimensional seesaw mechanism surprisingly replaces this mass scale with the radius scale of the extra dimensions. Finally, we also discuss a possible new mechanism for inducing lepton-number violation by shifting the positions of D-branes in Type I string theory.

Original languageEnglish (US)
Pages (from-to)25-59
Number of pages35
JournalNuclear Physics B
Volume557
Issue number1-2
StatePublished - Sep 20 1999
Externally publishedYes

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neutrinos
oscillations
grand unified theory
string theory
leptons
strings
fermions
analogs
radii

ASJC Scopus subject areas

  • Nuclear and High Energy Physics

Cite this

Light neutrinos without heavy mass scales : A higher-dimensional seesaw mechanism. / Dienes, Keith R; Dudas, Emilian; Gherghetta, Tony.

In: Nuclear Physics B, Vol. 557, No. 1-2, 20.09.1999, p. 25-59.

Research output: Contribution to journalArticle

Dienes, Keith R ; Dudas, Emilian ; Gherghetta, Tony. / Light neutrinos without heavy mass scales : A higher-dimensional seesaw mechanism. In: Nuclear Physics B. 1999 ; Vol. 557, No. 1-2. pp. 25-59.
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