Singlet Charge 2/32/3 Quark hiding the Top: Tevatron and LEP Implications

If $c$ and $t$ quarks are strongly mixed with a weak singlet charge $2/3$ quark, $BR(t\to \ell\nu + X)$ could be suppressed via the $t\to cH^0$ mode, thereby the top quark could still hide below $M_W$, whereas the heavy quark signal observed at the Tevatron is due to the dominantly singlet quark $Q$. This may occur without affecting the small $m_c$ value. Demanding $m_Q \simeq 175$ GeV and m_t \ltap M_W, we find that $BR(t\to \ell\nu + X)$ cannot be too suppressed. The heavy quark $Q$ decays via $W,\ H$, and $Z$ bosons. The latter can lead to $b$-tagged $Z + 4$ jet events, while the strong $c$--$Q$ mixing is reflected in sizable $Q\to sW$ fraction. $Z\to t\bar c$ decay occurs at tree level and may be at the $10^{-3}$ order, leading to the signature of $Z\to \ell\nu b\bar c$, all isolated and with large $p_T$, at $10^{-5}$ order.Comment: 10 pages + 3 Figures (not included), ReVTeX, NTUTH-94-1

Eigenvalues of Ruijsenaars-Schneider models associated with An−1A_{n-1} root system in Bethe ansatz formalism

Ruijsenaars-Schneider models associated with $A_{n-1}$ root system with a discrete coupling constant are studied. The eigenvalues of the Hamiltonian are givein in terms of the Bethe ansatz formulas. Taking the "non-relativistic" limit, we obtain the spectrum of the corresponding Calogero-Moser systems in the third formulas of Felder et al [20].Comment: Latex file, 25 page

Bosonic Super Liouville System: Lax Pair and Solution

We study the bosonic super Liouville system which is a statistical transmutation of super Liouville system. Lax pair for the bosonic super Liouville system is constructed using prolongation method, ensuring the Lax integrability, and the solution to the equations of motion is also considered via Leznov-Saveliev analysis.Comment: LaTeX, no figures, 11 page

Fermi resonance-algebraic model for molecular vibrational spectra

A Fermi resonance-algebraic model is proposed for molecular vibrations, where a U(2) algebra is used for describing the vibrations of each bond, and Fermi resonances between stretching and bending modes are taken into account. The model for a bent molecule XY_2 and a molecule XY_3 is successfully applied to fit the recently observed vibrational spectrum of the water molecule and arsine (AsH_3), respectively, and results are compared with those of other models. Calculations show that algebraic approaches can be used as an effective method for describing molecular vibrations with small standard deviations

The spectral energy distribution of galaxies at z > 2.5: Implications from the Herschel/SPIRE color-color diagram

We use the Herschel SPIRE color-color diagram to study the spectral energy distribution (SED) and the redshift estimation of high-z galaxies. We compiled a sample of 57 galaxies with spectroscopically confirmed redshifts and SPIRE detections in all three bands at $z=2.5-6.4$, and compared their average SPIRE colors with SED templates from local and high-z libraries. We find that local SEDs are inconsistent with high-z observations. The local calibrations of the parameters need to be adjusted to describe the average colors of high-z galaxies. For high-z libraries, the templates with an evolution from z=0 to 3 can well describe the average colors of the observations at high redshift. Using these templates, we defined color cuts to divide the SPIRE color-color diagram into different regions with different mean redshifts. We tested this method and two other color cut methods using a large sample of 783 Herschel-selected galaxies, and find that although these methods can separate the sample into populations with different mean redshifts, the dispersion of redshifts in each population is considerably large. Additional information is needed for better sampling.Comment: 17 pages, 14 figures, accepted for publication in A&

Is the Top Quark Really Heavier than the WW Boson?

Scalar induced top decays may drastically suppress $B(t\to \ell\nu + jet)$ and still hide the top below $M_W$. The $p\bar p$ collider experiments should enlarge the scope and study the $m_t - B(t\to\ell\nu j)$ plane. Specific model signatures such as $t\to ch^0\to cb\bar b$ (multiple high $p_T$ $b$-jets) and $t\to bH^+\to bc\bar s$, $b\tau^+\nu$ (with $B(t\to b\tau\nu) \ \raisebox{-.5ex}{\rlap{$\sim$}} \raisebox{.4ex}{$<$}\ 1/3$) should be explored. Without ruling out these possibilities, isolated lepton signals in the future might actually be due to the 4th generation$t^\prime$or$b^\prime$ quark, while top quark and toponium physics could still turn up at LEP-II.Comment: 11 pages (RevTex), 3 figures (not included), NTUTH-93-0

Window on Higgs Boson: Fourth Generation b′b^\prime Decays Revisited

Direct and indirect searches of the Higgs boson suggest that 113 GeV $\lesssim m_H \lesssim$ 170 GeV is likely. With the LEP era over and the Tevatron Run II search via $p\bar p \to WH+X$ arduous, we revisit a case where $WH$ or $ZH +$ jets could arise via strong $b^\prime\bar b^\prime$ pair production. In contrast to 10 years ago, the tight electroweak constraint on $t^\prime$--$b^\prime$ (hence $t^\prime$--$t$) splitting reduces FCNC $b^\prime\to bZ$, $bH$ rates, making $b^\prime\to cW$ naturally competitive. Such a "cocktail solution" is precisely the mix that could evade the CDF search for $b^\prime\to bZ$, and the $b^\prime$ may well be lurking below the top. In light of the Higgs program, this two-in-one strategy should be pursued.Comment: 4 pages, RevTex, 4 eps figures, One more figure, version to be published in Phys. Rev.

Distinguishing left- and right-handed molecules by two-step coherent pulses

Chiral molecules with broken parity symmetries can be modeled as quantum systems with cyclic-transition structures. By using these novel properties, we design two-step laser pulses to distinguish left- and right-handed molecules from the enantiomers. After the applied pulse drivings, one kind chiral molecules are trapped in coherent population trapping state, while the other ones are pumped to the highest states for ionizations. Then, different chiral molecules can be separated.Comment: 11 pages, 3 figures