Neutrino Majorana masses from string theory instanton effects

By Luis E Ibáñez, A. Uranga. 2006

328 citations recorded by the source corpus.

Finding a plausible origin for right-handed neutrino Majorana masses in semirealistic compactifications of string theory remains one of the most difficult problems in string phenomenology. We argue that right-handed neutrino Majorana masses are induced by non-perturbative instanton effects in certain classes of string compactifications in which the U(1)B−L gauge boson has a Stuckelberg mass. The induced operators are of the form e−UνRνR where U is a closed string modulus whose imaginary part transforms appropriately under B−L. This mass term may be quite large since this is not a gauge instanton and Re U is not directly related to SM gauge couplings. Thus the size of the induced right-handed neutrino masses could be a few orders of magnitude below the string scale, as phenomenologically required. It is also argued that this origin for neutrino masses would predict the existence of R-parity in SUSY versions of the SM. Finally we comment on other phenomenological applications of similar instanton effects, like the generation of a μ-term, or of Yukawa couplings forbidden in perturbation theory.

Subfields: Nuclear and High Energy Physics, Political Science and International Relations, Statistical and Nonlinear Physics

View Paper: https://www.semanticscholar.org/paper/39492915ac20988a0347c55208d481ecd7c82200

How researchers see this paper

The researchers whose trusted networks rank it highest, strongest advocate first. Every researcher gets a different order.

In Nuclear and High Energy Physics

In Political Science and International Relations

In Statistical and Nonlinear Physics

Citations in the corpus

Global F-theory GUTs (2009, background): “In fact the generation of Majorana masses for ν R by Euclidean D3-branes in Type IIB [68, 69] has an analogue also in F-theory.”
MODELS OF PARTICLE PHYSICS FROM TYPE IIB STRING THEORY AND F-THEORY: A REVIEW (2012, background): “A possible solution to this problem was given in [160–163] where it was shown that the coupling could be generated non-perturbatively with an O(1) E3-instanton.”
Gaugino Condensates and D-terms from D7-branes (2006, background): “For a recent discussion of Euclidean D3-branes, see [13, 14].”
GUTs and exceptional branes in F-theory — II. Experimental predictions (2008, background): “In type II D-brane constructions, contributions to the superpotential from wrapped Euclidean branes can produce an appropriately large Majorana mass term for right-handed neutrinos [54, 83].”
Instanton Induced Neutrino Majorana Masses in CFT Orientifolds with MSSM-like spectra (2007, methodology): “In this context, it is satisfactory to verify that the instanton couplings are unrelated to the gauge couplings, as expected since they do not correspond to gauge instantons [3], and are in fact less suppressed than the latter.”
The Weak Gravity Conjecture in three dimensions (2016, background): “In theories with Chern-Simons terms and monopoles, gauge invariance requires [44–47] that any such monopole spits out N units of electric charge.”
Stringy instantons and quiver gauge theories (2006, background): “Very recently [20], such effects were applied to neutrino masses in a similar context.”
Explicit de Sitter flux vacua for global string models with chiral matter (2013, background): “The number of E3 zero-modes in the fundamental representation of the hidden U(4) gauge group is [46, 54–56]:”
d-Brane Instantons in Type II Orientifolds (2009, methodology): “Finally, there will generically be zero modes which arise at the intersection of the instanton E with the D-branes Da [20, 21, 22].”
Moduli Stabilisation versus Chirality for MSSM like Type IIB Orientifolds (2007, methodology): “It is therefore much more convenient to perform the zero mode analysis directly in the Type IIB orientifold model, where we can rely on recent work on space-time instanton effects in Dbrane models [44, 45, 46, 47, 48, 49, 50].”
GUTs in Type IIB Orientifold Compactifications (2008, background): “On the other hand, investigations of non-perturbative corrections for Type II orientifold models [25, 26, 27] have revealed that the 10 10 5H Yukawa coupling can be generated by Euclidean D-brane instantons wrapping suitable cycles Γ in the internal manifold with the right zero mode structure [28].”