Left-Right Symmetry at FCC-hh

We study the production of right-handed $W_R$ bosons and heavy neutrinos $N$ at a future 100 TeV high energy hadron collider in the context of Left-Right symmetry, including the effects of $W_L-W_R$ gauge-boson mixing. We estimate the collider reach for up to 3/ab integrated luminosity using a multi-binned sensitivity measure. In the Keung-Senjanovi\'c and missing energy channels, the 3$\sigma$ sensitivity extends up to $M_{W_R}=35$ and 37 TeV, respectively. We further clarify the interplay between the missing energy channel and the (expected) limits from neutrinoless double beta decay searches, Big Bang nucleosynthesis and dark matter.Comment: 19 pages, version to appear in PR

Analytic thin wall false vacuum decay rate

We derive a closed-form false vacuum decay rate at one loop in the thin wall limit, where the true and false vacua are nearly degenerate. We obtain the bounce configuration in $D$ dimensions, together with the Euclidean action with a higher order correction, counter-terms and renormalization group running. We extract the functional determinant via the Gel'fand-Yaglom theorem for low and generic orbital multipoles. The negative and zero eigenvalues appear for low multipoles and the translational zeroes are removed. We compute the fluctuations for generic multipoles, multiply and regulate the orbital modes. We find an explicit finite renormalized decay rate in $D = 3, 4$ and give a closed-form expression for the finite functional determinant in any dimension.Comment: 22 pages plus 5 appendices, published in JHEP. In v4 we updated the final result in D=4, after the addition of a term missed in the previous versions. The result in D=3 is unchange

Probing seesaw at LHC

We have recently proposed a simple SU(5) theory with an adjoint fermionic multiplet on top of the usual minimal spectrum. This leads to the hybrid scenario of both type I and type III seesaw and it predicts the existence of the fermionic SU(2) triplet between 100 GeV and 1 TeV for a conventional GUT scale of about 10^{16} GeV, with main decays into W (Z) and leptons, correlated through Dirac Yukawa couplings, and lifetimes shorter than about 10^{-12} sec. These decays are lepton number violating and they offer an exciting signature of Delta L=2 dilepton events together with 4 jets at future pp (p\bar p) colliders. Increasing the triplet mass endangers the proton stability and so the seesaw mechanism could be directly testable at LHC.Comment: 19 pages, discussion on leptogenesis added, new references, main conclusions unchange