We present an overview of the phenomenological implications of the theory of resummed quantum gravity. We discuss its prediction for the cosmological constant in the context of the Planck scale cosmology of Bonanno and Reuter, its relationship to Wei
nbergs asymptotic safety idea, and its relationship to Weinbergs soft graviton resummation theorem. We also discuss constraints and consistency checks of the theory.
To exploit properly the precision physics program at the FCC-ee, the theoretical precision tag on the respective luminosity will need to be improved from the 0.054$%$ (0.061$%$) results at LEP to 0.01$%$, where the former (latter) LEP result has (doe
s not have) the pairs correction. We present an overview of the roads one may take to reach the required 0.01$%$ precision tag at the FCC-ee and we discuss possible synergistic effects of the walk along these roads for other FCC precision theory requirements.
One may use amplitude-based resummation in QED $otimes$ QCD to achieve IR-improvement of unintegrable singularities in the infrared regime to arbitrary precision in principle. We illustrate such improvement in specific examples in precision LHC/FCC physics.
Continuing with our investigations of the expected sizes of multiple photon radiative effects in heavy gauge boson production with decay to charged lepton pairs in the context of the precision physics of the LHC, using KK{MC}-hh 4.22 we consider IFI
and ISR effects for specific Z/$gamma^*$ Drell-Yan observables measured by the ATLAS and CMS Collaborations. With this version of KK{MC}-hh, we have coherent exclusive exponentiation (CEEX) electroweak (EW) exact ${cal O}(alpha^2 L)$ corrections in a hadronic MC and control over the corresponding EW initial-final interference (IFI) effects as well. Specifically, we illustrate the interplay between cuts of the type used in the measurement of $A_{FB}$ and $A_4$ at the LHC and the sizes of the expected responses of the attendant higher order corrections. We find that there are per cent to per mille level effects in the initial-state radiation, fractional per mille level effects in the IFI and per mille level effects in the over-all ${cal O}(alpha^2 L)$ corrections that any treatment of EW corrections at the per mille level should consider. Our results are applicable to current LHC experimental data analyses.
IR-improvement based on amplitude-level resummation allows one to control unintegrable results in quantum field theory with arbitrary precision in principle. We illustrate such resummation in specific examples in precision LHC and FCC physics and in quantum gravity.
We present pathways to the required theoretical precision for the luminosity targeted by the FCC-ee precision studies. We put the discussion in context by reviewing briefly the situation at the time of LEP. We then present the current status and rout
es to the desired 0.01% targeted by the FCC-ee (as well as by the ILC).
${cal KK}$MC-hh is a precision event-generator for Z production and decay in hadronic collisions, which applies amplitude-level resummation to both initial and final state photon radiation, including perturbative residuals exact through ${cal O}(alph
a^2L)$, together with exact ${cal O}(alpha)$ EW matrix element corrections. We present some comparisons to other programs and results showing the effect of multi-photon radiation for cuts motivated by a recent ATLAS W mass analysis. We also show preliminary untuned comparisons of the electroweak corrections of ${cal KK}$MC-hh to those of HORACE, which includes exact ${cal O}(alpha)$ corrections with resummed final-state photon radiation.
We give a status report on the theory of resummed quantum gravity. We recapitulate the use of our resummed quantum gravity approach to Einsteins general theory of relativity to estimate the value of the cosmological constant as $rho_Lambda=(0.0024{ma
thrm{eV}})^4$. The estimate is made in the context of the Planck scale cosmology formulation of Bonanno and Reuter. We discuss the constraints on susy GUT models that follow from the closeness of the estimate to experiment. Various consistency checks on the calculation are addressed and we use the Heisenberg uncertainty principle to remove a large part of the remaining uncertainty in our estimate of $rho_Lambda$.
Working in the context of the Planck scale cosmology formulation of Bonanno and Reuter, we use our resummed quantum gravity approach to Einsteins general theory of relativity to estimate the value of the cosmological constant as $rho_Lambda =(0.0024
eV)^4$. We show that susy GUT models are constrained by the closeness of this estimate to experiment. We also address various consistency checks on the calculation. In particular, we use the Heisenberg uncertainty principle to remove a large part of the remaining uncertainty in our estimate of $rho_Lambda$
We present recent developments in the theory and application of IR-improved QED$otimes$QCD resummation methods, realized by MC event generator methods, for LHC and FCC physics scenarios.
