arXiv subjects

Dan-di Wu

Publications and source records attributed to Dan-di Wu.

6 recordsLinked to original sources

arXiv1996

CP symmetry and fermion masses in O(10) grand unification models

O(10) grand unification models which do not necessarily have an extra global symmetry are discussed, taking the model with one 10-plet in the Yukawa sector as an example. A strong correlation between mass ratios and CP is found. The mass relation $m_t/m_b=v_u/v_d$ is recovered when $G_W=0$; and another special relation $m_t/m_b=G_E/G_W$ appears when $v_d=0$, where $G_{E,W}$ are Yukawa coupling constants and $v_{u,d}$ are VEVs. To facilitate this discussion, a set of $O(10)$ $γ$- matrices is offered based on a physical representation of the spinors and that of the vector of the $SO(10)$ group. Flavor changing neutral currents in such models are also discussed.

hep-ph↗

arXiv1996

Small Elements in Fermion Mass Matrices and Anomalous Dipole Moments

Assuming the small entries in the mass matrices are produced by fermion-scalar loops, we calculate the anomalous dipole moments of the leptons and quarks. The top quark appears in all the loops as the mass seed. When comparing the results with experimental data, including electric and magnetic dipole moments, and radiative transition rates, we obtain the mass limits which are typically larger than .1 TeV for the relevant neutral scalars, and 70 TeV for the relevant lepto-quarks. We then discuss the $P-\bar P$ mixing with a toy model. Rates of the known mixings require the masses of some neutral scalars to be large.

hep-ph↗

arXiv1995

Cascade Global Symmetry and Quark Mass Hierarchy

Cascade global symmetry and multi-vacuum expectation values are combined to produce an {\bf initial} texture of the quark mass matrices. Required corrections to the initial texture zeros ({\bf ITZ)} are all at the order of $10^{-3}m_t$ or less. The possibility of {\bf radiative corrections} as the source of the complete mass matrices is briefly discussed.

hep-ph↗

arXiv1995

Mass hierarchy and the spectrum of scalars

We use the natural $SU(3)\times U(1)$ global symmetry of the gauge-fermion interaction sector of the standard model to discuss the fermion mass hierarchy problem. The $SU(3)$ sixtet and triplet Higgs are introduced. The Yukawa sector is partially symmetric. The smaller the symmetry of a Yukawa term, the smaller its coupling constant. The mass hierarchy is a combined effect of smaller coupling constants and smaller VEVs. There is a bunch of pseudo-goldstone bosons which obtains their masses mainly from the small explicit breaking terms in the Higgs potential.

hep-ph↗

arXiv1993

Higgs particle detection using jets

We study the possibility of detecting the Higgs boson in the intermediate mass range via its two jet channel. We consider only Higgs bosons produced in association with a $t \bar{t}$ pair. Both $t$ and $\bar{t}$ are required to decay semileptonically to reduce the QCD background. The signal is compared with the main background, $t \bar{t} + 2$ jets, after appropriate cuts. A sizable signal above background is seen in our simulation at the parton level. Use of the $t\bar{t}Z$ channel with $ Z$ decaying to $l^+ l^-$ is suggested for eliminating theoretical uncertainties in determining the $t \bar{t}H$ signal.

hep-ph↗

arXiv1992

A Z' Model Which May Be Relevant to the New LEP Events

A multi-Higgs model with an extra neutral gauge boson ($Z'$) is introduced. One scalar Higgs boson ($H_2$) in this model decays dominantly into a photon pair. The $Z'$ decay to $μ^+μ^-$ gets a much larger branching ratio than the $Z$ decay to this channel. The $Z Z' H_2$ vertex provides a final state from $Z$ decay resembling the new $l^+l^-γγ$ events at the LEP. Other promising phenomenology, such as $Z \rightarrow l\bar l Z'$ is also discussed.

hep-ph↗