https://digital.csic.es/bitstream/10261/108964/1/experiment%20at%20the%20LHC.pdf

Observation of a new boson at a mass of 125 GeV with the CMS experiment at the LHC

http://risa.stanford.edu/teaching/362/particledarkmatter.pdf

Particle dark matter: Evidence, candidates and constraints

QCD and resonance physics. theoretical foundations

http://cds.cern.ch/record/147992/files/198312192.pdf

Chiral perturbation theory to one loop

Supersymmetry, Supergravity and Particle Physics

The present cosmic mass density of possible stable neutral heavy leptons is calculated in a standard cosmological model. In order for this density not to exceed the upper limit of 2\ifmmode\times\else\texttimes\fi{}${10}^{\ensuremath{-}29}$ g/${\mathrm{cm}}^{3}$, the lepton mass would have to be greater than a lower bound of the order of 2 GeV.

Cosmological lower bound on heavy-neutrino masses

We give an $S$-matrix-theoretic demonstration that if the Higgs-boson mass exceeds ${M}_{c}={(8\ensuremath{\pi}\frac{\sqrt{2}}{3}{G}_{F})}^{\frac{1}{2}}$, parital-wave unitarity is not respected by the tree diagrams for two-body scattering of gauge bosons, and the weak interactions must become strong at high energies. We exhibit the relation of this bound to the structure of the Higgs-Goldstone Lagrangian, and speculate on the consequences of strongly coupled Higgs-Goldstone systems. Prospects for the observation of massive Higgs scalars are noted.

Weak interactions at very high energies: The role of the Higgs-boson mass

The effective nonleptonic weak interaction is examined assuming the Weinberg-Salam theory of weak interactions and an exactly-conserved-color gauge symmetry for strong interactions. It is shown that the octet part of the nonleptonic weak interaction is more singular at short distances than the 27 part. The resulting enhancement of the octet term in the effective local weak Lagrangian, together with suggested mechanisms for the suppression of matrix elements of the 27 operator, may be sufficient to account for the observed $|\ensuremath{\Delta}I|=\frac{1}{2}$ rule.

Δ I = 1 2 Rule for Nonleptonic Decays in Asymptotically Free Field Theories

It is shown that if the Higgs boson mass exceeds Mc=(8π23GF)12 partial-wave unitarity is not respected by the tree diagrams for two-body reactions of gauge bosons, and the weak interactions must become strong.

Strength of weak interactions at very high energies and the Higgs boson mass

We analyze the circumstances under which the violations of an approximate symmetry in a unified gauge theory of weak interactions are naturally suppressed; in particular, we investigate approximate muon- and electron-type lepton-number conservation as an example of such a symmetry. Extending earlier work, we propose a unified treatment of this symmetry together with strangeness conservation by the weak neutral current and $\mathrm{CP}$ invariance. The rate for the decay $\ensuremath{\mu}\ensuremath{\rightarrow}e\ensuremath{\gamma}$ is calculated for a general SU(2) \ifmmode\times\else\texttimes\fi{} U(1) gauge model. From this and a similar study of the decay $\ensuremath{\mu}\ensuremath{\rightarrow}\mathrm{ee}\overline{e}$ we derive a set of conditions which guarantees that the violation of muon- and electron-type lepton-number conservation is naturally strongly suppressed. As part of this, we compute the nondiagonal electromagnetic vertex to one-loop order for an arbitrary SU(2) \ifmmode\times\else\texttimes\fi{} U(1) gauge theory. We then focus on the phenomenological predictions of a particular gauge model with three left-handed doublets of leptons and quarks. These include the existence of charged and neutral heavy leptons and of small violations of $\ensuremath{\mu}$-$e$ universality and the relation ${G}_{F}^{\ensuremath{\beta}}sec{\ensuremath{\theta}}_{C}={G}_{F}^{\ensuremath{\mu}}$. Other muon- and electron-number-violating effects include nonvanishing rates for the decays ${K}^{\ifmmode\pm\else\textpm\fi{}}\ensuremath{\rightarrow}{\ensuremath{\pi}}^{\ifmmode\pm\else\textpm\fi{}}e\overline{\ensuremath{\mu}}$ and ${K}_{L}\ensuremath{\rightarrow}e\overline{\ensuremath{\mu}}$ and for the reactions $\ensuremath{\mu}+N\ensuremath{\rightarrow}e+N$ and ${\ensuremath{\nu}}_{\ensuremath{\mu}}+N\ensuremath{\rightarrow}{e}^{\ensuremath{-}}+X$.

Benjamin W. Lee

Papers

Cosmological lower bound on heavy-neutrino masses

Weak interactions at very high energies: The role of the Higgs-boson mass

Δ I = 1 2 Rule for Nonleptonic Decays in Asymptotically Free Field Theories

Strength of weak interactions at very high energies and the Higgs boson mass

Natural suppression of symmetry violation in gauge theories: Muon- and electron-lepton-number nonconservation