arXiv subjects

Guo-Hong Wu

Publications and source records attributed to Guo-Hong Wu.

27 records · Page 2Linked to original sources

arXiv1997

On the Interactions of Light Gravitinos

In models of spontaneously broken supersymmetry, certain light gravitino processes are governed by the coupling of its Goldstino components. The rules for constructing SUSY and gauge invariant actions involving the Goldstino couplings to matter and gauge fields are presented. The explicit operator construction is found to be at variance with some previously reported claims. A phenomenological consequence arising from light gravitino interactions in supernova is reexamined and scrutinized.

hep-ph↗

arXiv1997

Polarization Measurements and T-Violation in Exclusive Semileptonic B Decays

We provide a general analysis of time reversal invariance violation in the exclusive semileptonic B decays B to D l nu and B to D* l nu. Measurements of the lepton and D* polarizations can be used to search for and identify non-standard model sources of T violation. Upper limits are placed on the T-odd polarization observables in both the supersymmetric R-parity conserving and R-parity breaking theories, as well as in some non-supersymmetric extensions of the standard model, including multi-Higgs-doublet models, leptoquark models, and left-right symmetric models. It is noted that many of these models allow for large T-violating polarization effects which could be within the reach of the planned B factories.

hep-ph↗

arXiv1997

Disentangling Non-Standard Model T-Violating Sources in Exclusive Semileptonic B Decays

Measurements of the polarization of the lepton and D* in the exclusive semileptonic B decays, B to D l nu and B to D* l nu, can be used to separate and identify the non-standard model sources of T violation. These T-odd effects, estimated in both supersymmetric and non-supersymmetric models, could be within the reach of the planned B factories.

hep-ph↗

arXiv1997

Testing Time Reversal Invariance in Exclusive Semileptonic B Meson Decays

We demonstrate that polarization measurements in exclusive semileptonic B decays are powerful tools for unraveling non-standard model sources of T-violation. Measurements of the transverse polarization of the tau lepton in the B to D tau nu and B to D* tau nu decays probe separately effective scalar and pseudoscalar CP-violating four-Fermi interactions, whereas the D* polarization in the B to D* l nu (l=e,mu) decay is sensitive to an effective right-handed quark current interaction. Two T-odd polarization structures exist involving the D* polarization and they can be isolated and studied separately. An estimate of these T-odd effects is also given in the context of supersymmetric theories.

hep-ph↗

arXiv1996

Supersymmetric Time Reversal Violation in Semileptonic Decays of Charged Mesons

We provide a general analysis of time reversal violation arising from misalignment between quark and squark mass eigenstates. In particular, we focus on the possibility of large enhancement effects due to the top quark mass. For semileptonic decays of the charged mesons, $K^+ \rightarrow π^0 μ^+ ν_μ$, $D^+ \rightarrow \overline{K}^0 μ^+ ν_μ$, and $B^+ \rightarrow \overline{D}^0 τ^+ ν_τ$, the transverse polarization of the lepton $P^{\bot}_l$ is a $T$-odd observable that is of great experimental interest. It is noted that under favorable choice of parameters, $P^{\bot}_μ$ in $K^+_{\mu3}$ decay can be detectable at the ongoing KEK experiment and it holds a promising prospect for discovery at the proposed BNL experiment. Furthermore, $P^{\bot}_τ$ in $B^{\pm}$ decay could well be within the reach of $B$ factories, but $P^{\bot}_μ$ in $D^{\pm}$ decay is not large enough for detection at the proposed $τ$-charm factory.

hep-ph↗

arXiv1996

T-Violation in $K^+ \to μ^+ νγ$ Decay And Supersymmetry

Measurement of the transverse muon polarization $P^{\bot}_μ$ in the $K^+ \rightarrow μ^+νγ$ decay will be attempted for the first time at the ongoing KEK E246 experiment and also at a proposed BNL experiment. We provide a general analysis of how $P^{\bot}_μ$ is sensitive to the physical $CP$-violating phases in new physics induced four-Fermi interactions, and then we calculate the dominant contributions to $P^{\bot}_μ$ from squark family mixings in generic supersymmetric models. Estimates of the upper bounds on $P^{\bot}_μ$ are also given. It is found that a supersymmetry-induced right-handed quark current from $W$ boson exchange gives an upper limit on $P^{\bot}_μ$ as large as a few per cent, whereas with charged-Higgs-exchange induced pseudoscalar interaction, $P^{\bot}_μ$ is no larger than a few tenths of a per cent. Possible correlations between the muon polarization measurements in $K^+ \rightarrow μ^+νγ$ and $K^+ \rightarrow π^0μ^+ν$ decays are discussed, and distinctive patterns of this correlation from squark family-mixings and from the three-Higgs-doublet model are noted.

hep-ph↗

arXiv1995

Nonoblique Effects and Weak-Isospin Breaking from Extended Technicolor

Several aspects of the flavor-diagonal extended technicolor (ETC) gauge boson are reviewed. Among them are an increase of $R_b$ that could explain the LEP $R_b$ excess, a sizable, positive correction to the $τ$ asymmetry parameter $A_τ$, and a contribution to the weak-isospin breaking $ρ$ parameter that is just barely acceptable by present data.

hep-ph↗

arXiv1995

Nonoblique Corrections in Technicolor Theories Revisited

In extended technicolor (ETC) theories, while the sideways ETC boson exchange decreases the width $Γ_b \equiv Γ(Z\rightarrow b \bar{b})$, the flavor-diagonal ETC boson exchange tends to increase it, and the ETC-corrected $R_b \equiv Γ_b / Γ_{\mbox{\footnotesize had}}$ value could agree with recent measurements. The $τ$ asymmetry parameter may also increase in a way consistent with experiment. The weak-interaction $ρ$ parameter receives a correction from diagonal ETC exchange which is just barely acceptable by experiments.

hep-ph↗

arXiv1994

The Electroweak Chiral Lagrangian and CP-Violating Effects in Technicolor Theories

We estimate the CP-violating $WWγ$ and $WWZ$ anomalous form factors, arising from CP-violating interactions in extended technicolor theories, and discuss their future experimental detectability. The electric dipole moment of the $W$ boson is found to be as large as ${\cal O}(10^{-21}) \; \mbox{$e$ cm}$. We connect the CP-odd $WWγ$ and $WWZ$ couplings to the corresponding CP-violating electroweak chiral lagrangian operators. The electric dipole moments of the neutron and the electron in technicolor theories are estimated to be as large as ${\cal O}(10^{-26}) \; \mbox{$e$ cm}$ and ${\cal O}(10^{-29}) \; \mbox{$e$ cm}$ respectively. We also suggest the potential to observe large CP-violating technicolor effects in the decay $t \rightarrow b + W^+$.

hep-ph↗