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Wei-Shu Hou

Publications and source records attributed to Wei-Shu Hou.

At least 127 records · Page 7Linked to original sources
arXiv2000

Possibility of Large Final State Interaction Phases in Light of B \to Kπand ππData

The newly observed $\bar B^0 \to \bar K^0π^0$ mode is quite sizable while $π^-π^+$ is rather small. Data also hint at $π^-π^0 \gtrsim π^-π^+$. Though consistent with zero, central values of CP violating asymmetries in $K^-π^{+,0}$ and $\bar K^0π^-$ show an interesting pattern. Taking cue from these, we suggest that, besides $γ\equiv {\rm arg} (V_{ub}^*)$ being large, the rescattering phase $δ$ in $Kπ$ and $ππ$ modes may be greater than $90^\circ$. If this is true, not only the above trends can be accounted for, one would also find $π^0π^0 \sim π^-π^{+,0}$, and the CP asymmetry in $\bar B^0$ vs. $B^0 \to π^-π^+$ could be as large as -60%. These results can be tested in a couple of years.

hep-ph↗
arXiv1999

On the Mixing Amplitude of J/psi and Vector Glueball O

We study the mixing angle θ_{Oψ} and mixing amplitude f_{Oψ} of J/psi and vector glueball O, in the framework of potential models of heavy quarks and constituent gluons. While the state vectors of J/psi and O are constructed from the wave functions of few-body Schroedinger equations, the mixing dynamics is governed by perturbative QCD. We obtain a value of the mixing angle of |\tan θ_{Oψ}| \approx 0.015 and the mixing amplitude of |f_{Oψ}(m_{Oψ}^2)| \approx 0.008 GeV^2, which is compatible with phenomenological analysis.

hep-ph↗
arXiv1999

Determination of the Phase of Vub from Charmless Hadronic B Decay Rates

We perform a model dependent fit to recent data on charmless hadronic B decays and determine $γ$, the phase of $V^*_{ub}$. We find $γ= 114^{+25}_{-21}$ degrees, which disfavors the often quoted $γ\sim 60^\circ$ at the two standard deviation level. We also fit for the form factors $F_0^{Bπ}$ and $A_0^{Bρ}$, and the strange-quark mass. They are consistent with theoretical expectations, although $m_s$ is somewhat low. Such agreement and the good $χ^2$ for the fit may be interpreted as a confirmation of the adequacy of our model assumptions.

hep-ex↗
arXiv1999

Tree-Penguin Interference and Tests for $\cosγ< 0$ in Rare $B\to PP$, $PV$ and $VV$ Decays

Recent rare $B \to PP$, $PV$ decay data suggest that factorization holds well if, contrary to current fits, one has $\cosγ< 0$ where $γ\equiv {\rm arg}(V_{ub}^*)$. We update previous results with light cone sum rule form factors, which seem to work better. We then discuss various $B\to VV$ modes as well as the $K^{*} η$ modes. Finding the pattern of $ρ^+ω^0 < ρ^+ρ^0$, $K^{*+}ρ^{-,0} > K^{*0}ρ^+$, $K^{*+}ω^0 > K^{*0}ω^0$ and $K^{*+}η> K^{*0}η$ would strengthen the support for $\cosγ< 0$. The electroweak penguin enhances (suppresses) the $K^{*+}ρ^{0}$ ($K^{*0}ρ^{0}$) rate by a factor of 2, and finding $K^{*+}ρ^{0} \simeq K^{*+}ρ^{-}$ would be strong evidence for the electroweak penguin.

hep-ph↗
arXiv1999

Indications for Factorization and $Re V_{ub} < 0$ from Rare B Decay Data

Surveying known hadronic rare B decays, we find that the factorization approximation can give a coherent account of $Kπ$, $ππ$ and $ρ^0π^+$ data and give predictions for $ω^0π^+$, $ρπ$ and $K^*π$ modes, {\it if ${Re}V_{ub}$ is taken as negative} (in standard phase convention) rather than positive. As further confirmation, we expect a lower $\sin2β$ value at B Factories as compared to current fits, and $B_s$ mixing close to LEP bounds at SLD and CDF.

hep-ph↗
arXiv1999

CP Violating B ---> s Gamma Decay in Supersymmetric Models

Supersymmetric models with nonuniversal down type squark masses can enrich the chiral structure and CP violating phenomena in $b\to sγ$ decays. Direct CP violation in $b\to s γ$, mixing induced CP violation in radiative $B_{d,s}$ decays (such as $B_s\to ϕγ$ and $B_d \to K^*_{1,2}γ$), and $Λ$ polarization in $Λ_b \to Λγ$ can be substantially different from the Standard Model. Future experiements at $e^+ e^-$ and hadronic B factories will give important information on the underlying theory for radiative $b$ decays.

hep-ph↗
arXiv1999

Electroweak Penguins, Final State Interaction Phases and CP Violatioin in $B\to K π$ Decays

The recently observed $B^-\to K^- π^0$, $\bar K^0 π^-$ and $\bar B^0 \to K^- π^+$ decay modes appear to have nearly equal branching ratios. This suggests that tree and electroweak penguins play an important role, and inclusion of the latter improves agreement between factorization calculation and experimental data. The value $γ$ in the range $90^\circle - 130^\circle$ and $220^\circle - 260^\circle$ is favored, while the $\bar B^0 \to \bar K^0 π^0$ rate is suppressed. Direct CP violation for $B\to K π$ modes can be large if final state interaction phases are large.

hep-ph↗
arXiv1998

Prospects for Direct CP Violaton in Exclusive and Inclusive Charmless B decays

Within the Standard Model, CP rate asymmetries for $B\to K^-π^{+,0}$ could reach 10%. With strong final state phases, they could go up to 20--30%, even for $\bar K^0π^-$ mode which would have opposite sign. We can account for $K^-π^{+}$, $\bar K^0π^-$ and $ϕK$ rate data with new physics enhanced color dipole coupling and destructive interference. Asymmetries could reach 40--60% for $Kπ$ and $ϕK$ modes and are all of the same sign. We are unable to account for $K^-π^0$ rate. Our inclusive study supports our exclusive results.

hep-ph↗
arXiv1998

CP Violating Phase Difference between $B\to J/ψK_S$ and $J/ψK_S π^0$ from New Physics

The small P wave compoment of $B\to J/ψK^*$ measured by CLEO makes it practical to measure $\sin2β$ using $B^0\to J/ψK^{*0}\to J/ψK_S π^0$, independent from $B^0\to J/ψK_S$. Because these modes are color suppressed, new physics enhanced color dipole $bsg$ coupling, as hinted from the persistent ${\cal B}_{s.l.}$ and $n_C$ problems as well as the newly observed large semi-inclusive $B\to η^\prime + X_s$ decay, may have significant impact. We show that it may lead to a difference in the $\sin 2β$ measurements between $B^0\to J/ψK_S$ and $J/ψK_S π^0$ measureable at the B Factories in the near future.

hep-ph↗
arXiv1997

Implications for $B \to ηK$ and $B \to Glueball + K$ Modes from Observed Large $B\to η' K+X$

The unexpectedly large branching ratios for $B\to η' K (η' X_s)$ decays could be of gluonic origin. We study the implications for $B\to ηK (ηX_s)$ and $P K (PX_s)$, where $P$ is the pseudoscalar glueball. In the mechanism proposed by Fritzsch, large branching ratios are predicted for these modes. The $B\to ηK$ rate is barely within the experimental limit, and $B\to P K$, $PX_s$ could be at the 0.1% and 1% level, respectively. Smaller but less definite results are found for the mechanism of $g^* \to η' g$ via the gluon anomaly.

hep-ph↗
arXiv1997

Enhanced $b\to sg$ Decay, Inclusive $η^\prime$ Production, and the Gluon Anomaly

The experimental hint of large $B\to η^\prime + X_s$ is linked to the $b\to s$ penguins via the gluon anomaly. Using running $α_s$ in the $η^\prime$-$g$-$g$ coupling, the standard $b\to sg^*$ penguin alone seems insufficient, calling for the need of dipole $b\to sg$ at 10% level from new physics, which could also resolve the ${\cal B}_{s.l.}$ and charm counting problems. The intereference of standard and new physics contributions may result in direct CP asymmetries at 10% level, which could be observed soon at B Factories.

hep-ph↗
arXiv1997

Massiveness of Glueballs as Origin of the OZI Rule

The heaviness of the glueball mass scale is suggested as the source of the OZI rule at low energy. The $J/ψ\to ρπ$ decay "anomaly" implies the vector glueball $O$ has mass $m_O \approx m_{J/ψ}$. Such a heavy mass is supported by other glueball studies. Glueball-meson matrix elements turn out to be not suppressed at all at the 1 GeV scale, and a simple and intuitive picture emerges which is consistent with the Gell-Mann-Okubo mass formula as well as the measured sign of $ϕ$-$ω$ mixing. The suppression of glueball mediated $\bar q_iq_i \longleftrightarrow \bar q_jq_j$ transitions and the cancellation mechanism in two-step meson rescatterings are viewed as related by duality. Extensions to the $2^{++}$, $3^{--}$ meson sectors, and failure for $0^{\pm +}$ mesons are also discussed.

hep-ph↗
arXiv1997

Probing Flavor Changing Neutral Higgs Couplings at LHC

Uniquely heavy with mass at the weak scale, the top quark may have large flavor changing couplings to Higgs bosons that are as yet unexplored. We show that such couplings can be directly probed at the LHC through the parton subprocess $c(\bar c)g \to t (\bar t)A^0$, where the pseudoscalar $A^0$ subsequently decays into $t \bar c$ or ${\bar t} c$, giving rise to the intriguing final state of like sign top quark pairs. After demanding $\ell^\pm\ell^\pm$, missing energy and two $b$-jets, the major background turns out to be $q\bar q' \to Wt \bar t$, which can be partially suppressed by jet counting. The signal can then manifest itself in the asymmetry of numbers of $\ell^+\ell^+$ and $\ell^-\ell^-$ events. To further improve the signal over background, efficient $t$ vs. $\bar t$ tagging methods should be developed.

hep-ph↗
arXiv1996

Glueballs: Charmonium Decay and $\bar p p$ Annihilation

The vector glueball $O$, made of 3 valence gluons, is expected to be ``clean": it mixes less with quarkonia, but mediates OZI violations. The recent $0^{++} $ glueball candidate and the persistence of the $J/ψ, ψ' \to ρπ$ puzzle suggest $m_O\simeq m_{J/ψ}$, with mixing angle $\sim 2^\circ - 4^\circ$, hence $Γ(O\to ρπ$, $K^+K^-$, $e^+e^-) \sim$ MeV, few keV, few eV. Lower and upper bounds on $Γ_O$ can be argued from $e^+e^- \to ρπ$ energy scan data and the condition $B(O\to ρπ) > B(J/ψ\to ρπ)$. $O$ dominance may explain the ``large" OZI violation in $^1S_0(\bar pp)\to ϕγ$ vs. $ωγ$.

hep-ph↗
arXiv1996

$Zb\bar{b}$ Loop Correction with Charge 2/3 Singlet Quarks

We calculate the non-universal correction to the $Zb\bar{b}$ vertex in a simple extension of the Standard Model, where a charge $+2/3$ isosinglet quark is added to the standard spectrum. Comparison is made with other solutions to $R_b$ (and $R_c$) that demand particles lighter than $M_W$.

hep-ph↗
arXiv1995

$R_b$ -- $R_c$ Crisis and New Physics

The experimental values of $R_b$ and $R_c$ are the only data which do not seem to agree with Standard Model predictions. Although it is still premature to draw any definite conclusions, it is timely to look for new physics which could explain the excess in $R_b$ and deficit in $R_c$. We investigate this problem in a simple extension of the Standard Model, where a charge $+2/3$ isosinglet quark is added to the standard spectrum. Upon the further introduction of an extra scalar doublet, one finds a solution with interesting consequences.

hep-ph↗
arXiv1995

Like Sign Top Quark Pair Production at Linear Colliders

In the general two Higgs doublet model with flavor changing neutral Higgs couplings, neutral Higgs bosons may decay dominantly via $t\bar c$ or $\bar tc$ final states. At the linear collider, $e^+e^- \to h^0A^0$ or $H^0A^0$ production processes may result in $b\bar bt\bar c$, $W^+W^-t\bar c$ or $tt\bar c\bar c$ (or $\bar t\bar tcc$) final states. The process $γγ\to h^0,\ A^0 \to t\bar c$ is also promising, but $e^+e^- \to (h^0,\ H^0) Z^0 \to t\bar c Z^0$ is relatively suppressed. The possibility of observing like sign lepton pairs, usually the hallmark for neutral meson mixing, is quite interesting since $T^0$ mesons do not even form.

hep-ph↗