Michael S. Chanowitz

The TeV Physics of Strongly Interacting W's and Z's

Abstract There are two possibilities for electroweak symmetry breaking: either there is a scalar particle much lighter than 1 TeV or the longitudinal components of W and Z bosons interact strongly at center of mass energies of order 1 TeV or more. We study the general signatures of a strongly interacting W, Z system and conclude that these two possibilities can be unambiguously distinguished by a hadron collider facility capable of observing the enhanced production of WW, WZ and ZZ pairs that will occur if Ws and Zs have strong interactions. Detection of the enhanced signal over background requires hadron collisions at a center of mass energy of order √ s = 40 TeV and an integrated luminosity of order 10 40 cm −2 . With these parameters we predict 3800 to 6000 gauge boson pairs satisfying cuts for which only 2600 pairs would be produced in the absence of strong interactions. As our results draw on the global chiral SU(2) symmetry of the scalar sector of the standard SU(2) × U(1) model, we give an extended proof, to all orders in the generalized renormalizable gauge, that high-energy amplitudes of longitudinal Ws and Zs are well approximated by amplitudes of the corresponding unphysical scalars. The results are applicable to the broad class of strong interaction models that admit a global chiral SU(2) symmetry.

Weak interactions of ultra heavy fermions

Abstract We study the weak interactions of ultra heavy fermions, their scattering at high energies and the renormalization corrections they induce at low energies.

Weak interactions of ultra heavy fermions (II)

Abstract We discuss the weak interactions of ultra heavy fermions at low and high energy in the SU(2)L × U(1) gauge theory. Using partial-wave unitarity at high energy we establish critical fermion mass values beyond which strong couplings occur in the theory and the perturbation expansion fails. The critical masses are ( 500 √N ) GeV for quarks and ( 1.0 √N ) TeV for leptons, where N is the number of nearly degenerate SU(2)L doublets of quarks and leptons respectively. At low energies, far below their production threshold, we show that ultra heavy fermions would induce large, observable one-loop radiative corrections. One of these corrections (obtained also by Veltman) implies, using present experimental data, an upper limit of ∼700 GeV for a heavy lepton in an SU(2)L doublet with a massless neutrino.

Hybrids: Mixed states of quarks and gluons☆

We calculate the spectrum of the four ground state hybrid (qqg) nonets, JPC = (0, 1, 2)−+, 1−−, using the MIT bag model to first order in cavity perturbation theory. Quark and gluon self-energies are included by a fit to the s-wave mesons and baryons and to the glueball candidate i(1440). We find a large gluon self-energy which substantially increases our predictions of the glueball and hybrid masses. We discuss the phenomenology of hybrids, including a suggestion that the A3 (1670) and a second peak at 1850 MeV in the fπ channel may be mixtures of the isovector qq d-wave state with the qqg s-wave.

The axial current in dimensional regularization

Abstract We show that a fully anticommuting γ 5 is a correct and natural prescription for the dimensional regularization of one fermion loop graphs in spontaneously broken gauge theories. Other prescriptions introduce spurious anomalies into Ward identities which are actually anomly free. Our prescription is correct even though no such γ 5 exists: it cannot exist precisely because of the familiar chiral anomaly.

Multiple Production of W and Z as a Signal of New Strong Interactions

Anomalously large cross sections for multi W and Z final states will occur at SSC energies if electroweak symmetry breaking is due to new strong interactions.

Higgs boson triplets with Mw=Mzcos θw

Abstract We construct a potential for Higgs doublets and triplets that preserves ϱ=M2w/M2wcos2θw=1, allowing the triplets to make the dominant contribution to W and Z boson masses.

Higgs particle production by Z→Hγ ☆

Abstract The rate for the decay of a Z-boson into a Higgs boson and monochromatic photon is computed to leading order in the standard SU(2) × U(1) gauge theory. The coupling has contributions from fermion and W-boson loops. The W-boson loop dominates unless the number of heavy fermion generations exceeds six. The branching ratio computed from the W-boson loop contribution, B(Z→Hγ), is approximately 2 × 10−6 (1−( M H 2 M Z 2 )) 3 .

Perturbative solution of the chiral Schwinger model

Abstract The anomalous chiral Schwinger model is solved by summing the perturbation series. A gauge invariant spectrum is obtained if a Wess-Zumino term is appended to the original action. The resulting spectrum depends on ambiguities in the specification of the anomaly and is singular at the value corresponding to the minimal anomaly.

Glueballs and meiktons which decay to multi-kaon final states

Abstract We observe in the usual spherical cavity approximation to the bag model that TM gluon modes couple predominantly in the s-channel to s s quarks. We compute the spectrum of glueballs and meiktons containing TM gluons, which have unique decays to states of two, three, or four kaons.