One-loop contributions to neutral minima in the inert doublet model

Abstract

Abstract:The vacuum structure of the inert doublet model is analysed at the one-loop level using the effective potential formalism, to verify the validity of tree-level predictions for the properties of the global minimum. An inert minimum (with massive fermions) and an inert-like minimum (with massless fermions) can coexist at tree level. But the one-loop analysis reveals that the allowed parameter space for the coexistence of more than one minimum is larger than the tree-level expected one. It is also shown that for some choices of parameters, the global minimum found at the one-loop level may be inert (or inert-like), contrary to what the tree-level analysis indicates.

Strong first order electroweak phase transition in the CP-conserving 2HDM revisited

“…This means that, if a normal minimum exists, all CP or CB stationary points are proven to be saddle points. Recent studies of the Inert 2HDM at one-loop level [68], which apply the effective potential approach, indicate that these statements may not be true any more once higher order corrections are included. We therefore allow for the possibility of a CP-breaking vacuum.…”

One-loop considerations for coexisting vacua in the CP conserving 2HDM

“…Although many of the possible scenarios with coexisting minima are not favored by current LHC data [45,46], we are interested here in studying if the simple use of this discriminant can be carried over to the one-loop corrected effective potential. Already for the inert doublet model [34] it was found that the potential difference of the coexisting minima can change sign when one-loop corrections are taken into account [48]. Therefore, the present work aims to verify the validity of such conclusions for a general CP conserving 2HDM with softly broken Z 2 .…”

“…(2.5) for m 2 12 = 0 can be easily found: there are two degenerate extrema that spontaneously break Z 2 -ZB + and ZB − -and two extrema that preserve Z 2 -ZP 1 and ZP 2 ; the latter are often denoted as inert or inert-like vacuum (see ref. [48] and references therein). Only one of the pairs ZP 1,2 or ZB ± may coexist as minima.…”

“…The A and B functions are the Passarino-Veltman functions [59] which, in the notation of ref. [48], read…”

“…Simplifications for vanishing s can be found in ref. [48]. The contributions coming from gauge bosons and fermions in the loop are also shown in appendix F and all the necessary cubic and quartic couplings of the theory are explicitly shown in appendix E. For example, the SM higgs self-energy is given by…”