29,878 research outputs found
Window on Higgs Boson: Fourth Generation Decays Revisited
Direct and indirect searches of the Higgs boson suggest that 113 GeV
170 GeV is likely. With the LEP era over and the
Tevatron Run II search via arduous, we revisit a case where
or jets could arise via strong pair
production. In contrast to 10 years ago, the tight electroweak constraint on
-- (hence --) splitting reduces FCNC
, rates, making naturally competitive.
Such a "cocktail solution" is precisely the mix that could evade the CDF search
for , and the 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.
Singlet Charge Quark hiding the Top: Tevatron and LEP Implications
If and quarks are strongly mixed with a weak singlet charge
quark, could be suppressed via the mode,
thereby the top quark could still hide below , whereas the heavy quark
signal observed at the Tevatron is due to the dominantly singlet quark .
This may occur without affecting the small value. Demanding GeV and m_t \ltap M_W, we find that cannot be too
suppressed. The heavy quark decays via , and bosons. The latter
can lead to -tagged jet events, while the strong -- mixing is
reflected in sizable fraction. decay occurs at tree
level and may be at the order, leading to the signature of , all isolated and with large , at order.Comment: 10 pages + 3 Figures (not included), ReVTeX, NTUTH-94-1
Grazing activity increases decomposition of yak dung and litter in an alpine meadow on the Qinghai-Tibet plateau
Publishe
Entanglement detection beyond the CCNR criterion for infinite-dimensions
In this paper, in terms of the relation between the state and the reduced
states of it, we obtain two inequalities which are valid for all separable
states in infinite-dimensional bipartite quantum systems. One of them provides
an entanglement criterion which is strictly stronger than the computable
cross-norm or realignment (CCNR) criterion.Comment: 11 page
Evolution of the single-hole spectral function across a quantum phase transition in the anisotropic-triangular-lattice antiferromagnet
We study the evolution of the single-hole spectral function when the ground
state of the anisotropic-triangular-lattice antiferromagnet changes from the
incommensurate magnetically-ordered phase to the spin-liquid state. In order to
describe both of the ground states on equal footing, we use the large-N
approach where the transition between these two phases can be obtained by
controlling the quantum fluctuations via an 'effective' spin magnitude. Adding
a hole into these ground states is described by a t-J type model in the
slave-fermion representation. Implications of our results to possible future
ARPES experiments on insulating frustrated magnets, especially CsCuCl,
are discussed.Comment: 8 pages, 7 figure
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 , 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&
Eigenvalues of Ruijsenaars-Schneider models associated with root system in Bethe ansatz formalism
Ruijsenaars-Schneider models associated with 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
Tevatron Mass Limits for Heavy Quarks Decaying via Flavor Changing Neutral Current
The dimuon and dielectron data from the Tevatron collider are used
to probe for heavy quarks, which decay dominantly via flavour changing neutral
current. Depending on whether the decay occurs at the tree or loop
level, one gets a lower mass limit of 85 or 75 GeV. The former applies to
singlet, vector doublet and mirror type quarks while the latter applies to a
lefthanded quark doublet of the fourth generation.Comment: 13 pages, TIFR/TH/92-58, Two figures to be supplied on reques
Masses of a Fourth Generation with Two Higgs Doublets
We use sampling techniques to find robust constraints on the masses of a
possible fourth sequential fermion generation from electroweak oblique
variables. We find that in the case of a light (115 GeV) Higgs from a single
electroweak symmetry breaking doublet, inverted mass hierarchies are possible
for both quarks and leptons, but a mass splitting more than M(W) in the quark
sector is unlikely. We also find constraints in the case of a heavy (600 GeV)
Higgs in a single doublet model. As recent data from the Large Hadron Collider
hints at the existence of a resonance at 124.5 GeV and a single Higgs doublet
at that mass is inconsistent with a fourth fermion generation, we examine a
type II two Higgs doublet model. In this model, there are ranges of parameter
space where the Higgs sector can potentially counteract the effects of the
fourth generation. Even so, we find that such scenarios produce qualitatively
similar fermion mass distributions.Comment: v2: 9 pages, 7 figures, improved analysis of Higgs decay constraints,
typos corrected and reference adde
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