Probing minimal supergravity in the type-I seesaw mechanism with lepton flavour violation at the CERN LHC

Abstract

The most general supersymmetric seesaw mechanism has too many parameters to be predictive and thus can not be excluded by any measurements of lepton flavour violating (LFV) processes. We focus on the simplest version of the type-I seesaw mechanism assuming minimal supergravity boundary conditions. We compute branching ratios for the LFV scalar tau decays, ${\tilde{\tau }}_2\to (e,\mu )+{\chi }_1^0$, as well as loop-induced LFV decays at low energy, such as $l_i\to l_j+\gamma$ and $l_i\to 3l_j$, exploring their sensitivity to the unknown seesaw parameters. We find some simple, extreme scenarios for the unknown right-handed parameters, where ratios of LFV branching ratios correlate with neutrino oscillation parameters. If the overall mass scale of the left neutrinos and the value of the reactor angle were known, the study of LFV allows, in principle, to extract information about the so far unknown right-handed neutrino parameters.

29 pages, 27 figures; added explanatory comments, corrected typos, final version for publication

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Cited by in corpus (5)

• Supersymmetric seesaw type II: CERN LHC and lepton flavour violating phenomenology
• Measuring Lepton Flavour Violation at LHC with Long-Lived Slepton in the Coannihilation Region
• Flavour violation at the LHC: type-I versus type-II seesaw in minimal supergravity
• Neutrinos as cosmic messengers
• Lepton flavour violating stau decays versus seesaw parameters: correlations and expected number of events for both seesaw type-I and II