In the context of the minimal supersymmetric extension of the Standard Model with the right-handed Majorana neutrinos, we study lepton flavor violating processes including full renormalization group ...running effects. We systematically compare our results with the commonly used leading logarithmic approximation, resorting to a “best fit” approach to fix all the high energy Yukawa matrices. We find significant deviations in large regions of the SUSY parameter space, which we outline in detail. We also give, within this setting, some results on the cosmo-phenomenologically preferred stau coannihilation region. Finally, we propose a parametrization, in terms of the SUSY input parameters, of the common SUSY mass appearing in the leading log and mass insertion approximation formula for the charged lepton flavor violating decay rates, which fits our full renormalization group results with high precision.
The Large Hadron–Electron Collider at the HL-LHC Aksakal, H; Alekhin, S; Allport, P P ...
Journal of physics. G, Nuclear and particle physics,
11/2021, Letnik:
48, Številka:
11
Journal Article
In a large class of SUSY GUT models with see-saw mechanism of neutrino mass generation, lepton flavor violating (LFV) decays μ→e+γ, τ→μ+γ, etc., are predicted with rates that are within the reach of ...present and planned experiments. A crucial element in these predictions is the matrix of neutrino Yukawa couplings Yν which can be expressed in terms of the light and RH heavy neutrino masses, the neutrino mixing PMNS matrix U, and an orthogonal matrix R. Leptogenesis can take place only if R is complex. Considering the case of quasi-degenerate neutrinos and assuming that R is complex, we derive simple analytical expressions for the μ→e+γ, τ→μ+γ and τ→e+γ decay rates. Taking into account the leptogenesis constraints on the relevant parameters we show that the predicted rates of the LFV decays μ→e+γ, and τ→e+γ are generically enhanced by a factor of ∼103 to ∼106 with respect to the rates calculated for real R, while the τ→μ+γ decay rate is enhanced approximately by two orders of magnitude.
We study charged lepton flavor violating processes in the context of supersymmetric models with non-universal gaugino masses. We consider the generic case of free gaugino masses, as well as specific ...models based on gaugino mediation and
SU(5) GUTs. Under the assumption that the main source of lepton flavor violation resides in the off-diagonal elements of the left-handed slepton mass matrix, we show that BR(
μ→
eγ) strongly depends on gaugino non-universality. When
M
1 and
M
2 have opposite signs, cancellations occurring between the neutralino and the chargino contributions can suppress, even completely, the branching ratio of charged lepton flavor violating decays. Moreover, we find that for
M
3>
M
2,
M
1, BR(
μ→
eγ) is an increasing function of
M
3.
Phys.Rev. D69 (2004) 115009 We consider supersymmetric scenarios, compatible with all cosmological and
phenomenological requirements, where the lightest SUSY particles (LSPs) are the
neutralino and a ...quasi degenerate gluino. We study the neutralino relic
abundance, focusing on gluino (co-)annihilation effects. In case the neutralino
is bino-like, in a wide mass window the relic abundance is naturally driven in
the correct range for the LSP to be the main cold dark matter constituent. We
show that the gluino is the strongest possible coannihilating partner of a
bino-like neutralino in the general MSSM. Moreover, contrary to other
coannihilation scenarios, gluino pair annihilations always dominate over
coannihilation processes, even at relatively large gluino-neutralino mass
splittings. Finally, we present prospects for neutralino dark matter detection
in the outlined framework.
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