Lee-Wick standard model at finite temperature

Abstract

The Lee-Wick Standard Model at temperatures near the electroweak scale is considered, with the aim of studying the electroweak phase transition. While Lee-Wick theories possess states of negative norm, they are not pathological but instead are treated by imposing particular boundary conditions and using particular integration contours in the calculation of S-matrix elements. It is not immediately clear how to extend this prescription to formulate the theory at finite temperature; we explore two different pictures of finite-temperature LW theories, and calculate the thermodynamic variables and the (one-loop) thermal effective potential. We apply these results to study the LeeWick Standard Model and find that the electroweak phase transition is a continuous crossover, much like in the Standard Model. However, the high-temperature behavior is modified due to cancellations between thermal corrections arising from the negative-and positive-norm states.

Can X(5568) be a tetraquark state?

“…Tetraquark states in the large N c limit of QCD has been explored in Refs. [19][20][21], which indicates that a compact tetraquark meson may have narrow decay widths which scale as 1/N c . This gives reasonable candidates for the additional spectroscopic hadron series apart from the quark model.…”

Lee-Wick extension of the two-Higgs doublet model

“…Grinstein, et al [6] also demonstrated that the scattering of longitudinally polarized massive vector bosons satisfied perturbative unitarity. Explicitly, they later showed that unitarity and Lorentz-invariance are preserved in the S-matrix to all orders and that causality arises as an emergent macroscopic phenomenon [7].Since the Grinstein et al papers, there have been numerous phenomenological studies of the LWSM, including, but not limited to the study the possibility of observing the microcausality violation at colliders [8][9][10][11][12][13], the effects of the LWSM on precision electroweak measurements [14][15][16][17][18][19], and finite temperature effects [20][21][22]. The LW partners of the light quarks and gluons must be relatively heavy, O(10) TeV, in order to avoid detection.…”