Fighting off field dependence in MSSM Higgs-mass corrections of order $$\alpha _t\,\alpha _s$$ and $$\alpha _t^2$$

The connection between gauge and Higgs sectors makes supersymmetric extensions of the Standard Model predictive frameworks for the derivation of Higgs masses. In this paper, we study the contamination of such predictions by field-renormalization constants, in the MSSM with two-loop gaugeless corrections of $$\mathcal {O}\big (\alpha _{t,b}\,\alpha _s,\,\alpha _{t,b}^2\big )$$ O ( α t , b α s , α t , b 2 ) and full momentum dependence, and demonstrate how strict perturbative expansions allow to systematically neutralize the dependence on such unphysical objects. On the other hand, the popular procedure consisting in an iterative pole search remains explicitly dependent on field counterterms. We then analyze the magnitude of the intrinsic uncertainty that this feature implies for the iterative method, both in non-degenerate and near-degenerate regimes, and conclude that this strategy does not improve on the predictions of the more straightforward expansion. We also discuss several features related to the inclusion of the orders $$\alpha _{t,b}\,\alpha _s$$ α t , b α s and $$\alpha _{t,b}^2$$ α t , b 2 in the so-called ‘fixed-order’ approach, such as the resummation of UV-logarithms for heavy supersymmetric spectra.

Renormalizing spacetime

We propose that the consistent field renormalization of gravity requires a specific Weyl transformation of the metric tensor. As a consequence, proper length and time, as well as energy and momentum, become functions of scale. We estimate the functional form of the field renormalization factor by imposing a minimum resolvable distance scale under an infinitesimal Weyl transformation. The derived transformation is applied to two key problems in quantum gravity: its nonconformal scaling and nonrenormalizability.

Compositeness of hadron resonances in chiral dynamics

Recent experimental observations of many unconventional hadronic states stimulate an interest in the structure of hadrons. While various internal configurations have been proposed, it is a subtle problem to identify the structure of hadron resonances in a model independent manner. Here we discuss the composite/elementary nature of hadrons using the field renormalization constant Z. In particular, we show that the magnitude of the effective range parameter re is related to the structure of s-wave near-threshold resonances.

CONFINEMENT AND QUANTUM ANOMALY IN QUASI-1D SPINLESS FERMION CHAINS

We consider the field renormalization group (RG) of two coupled one-spatial dimension (1D) spinless fermion chains under intraforward, interforward, interbackscattering and interumklapp interactions until two-loops order. Up to this order, we demonstrate the quantum confinement in the RG flow, where the interband chiral Fermi points reduce to single chiral Fermi points and the renormalized interaction couplings have Luttinger liquid fixed points. We show that this quasi-1D system is equivalently described in terms of one- and two-color interactions and address the problem of quantum anomaly, inherent to this system, as a direct consequence of coupling 1+1 free Dirac fields to one- and two-color interactions.