Masses Of New Bosons Research Articles

Large mass hierarchies from strongly-coupled dynamics

Besides the Higgs particle discovered in 2012, with mass 125 GeV, recent LHC data show tentative signals for new resonances in diboson as well as diphoton searches at high center-of-mass energies (2 TeV and 750 GeV, respectively). If these signals are confirmed (or other new resonances are discovered at the TeV scale), the large hierarchies between masses of new bosons require a dynamical explanation. Motivated by these tentative signals of new physics, we investigate the theoretical possibility that large hierarchies in the masses of glueballs could arise dynamically in new strongly-coupled gauge theories extending the standard model of particle physics. We study lattice data on non-Abelian gauge theories in the (near-)conformal regime as well as a simple toy model in the context of gauge/gravity dualities. We focus our attention on the ratio $R$ between the mass of the lightest spin-2 and spin-0 resonances, that for technical reasons is a particularly convenient and clean observable to study. For models in which (non-perturbative) large anomalous dimensions arise dynamically, we show indications that this mass ratio can be large, with $R>5$. Moreover, our results suggest that $R$ might be related to universal properties of the IR fixed point. Our findings provide an interesting step towards understanding large mass ratios in the non-perturbative regime of quantum field theories with (near) IR conformal behaviour.

Study of electron-neutrino-electron elastic scattering at LAMPF.

Neutrino-electron elastic scattering was observed with a 15-ton fine-grained tracking calorimeter exposed to electron neutrinos from muon decay at rest. The measured ${\ensuremath{\nu}}_{e}{e}^{\ensuremath{-}}\ensuremath{\rightarrow}{\ensuremath{\nu}}_{e}{e}^{\ensuremath{-}}$ elastic scattering rate of 236\ifmmode\pm\else\textpm\fi{}35 events yields the total elastic scattering cross section $10.0\ifmmode\pm\else\textpm\fi{}1.5(\mathrm{stat})\ifmmode\pm\else\textpm\fi{}0.9(\mathrm{syst})\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}45} \mathrm{c}{\mathrm{m}}^{2}\ifmmode\times\else\texttimes\fi{}[{E}_{\ensuremath{\nu}} (\mathrm{MeV})]$, and a model-independent measurement of the strength of the destructive interference between the charged and neutral currents, $I=\ensuremath{-}1.07\ifmmode\pm\else\textpm\fi{}0.21$, that agrees well with the standard model (SM) prediction $I=\ensuremath{-}1.08$. The agreement between the measured electroweak parameters and SM expectations is used to place limits on neutrino properties, such as neutrino flavor-changing neutral currents and neutrino electromagnetic moments. Limits are placed on the masses of new bosons that interact with leptons: for a neutral tensor boson, ${M}_{T}g105$ GeV; for a neutral (pseudo)scalar boson, ${M}_{P,S}g47$ GeV; for a charged Higgs boson, ${M}_{{\ensuremath{\chi}}^{+}}g87$ GeV; and for a purely left-handed charged (neutral) vector boson, ${M}_{x}g239 (119)$ GeV.