681 research outputs found
No-scale supergravity confronts LEP diphoton events
We examine the possibility that some anomalous acoplanar diphoton events
observed at LEP may be consistent with the predictions of our previously
proposed one-parameter no-scale supergravity model with a light gravitino, via
the process e^+e^- -> chi chi -> gamma gamma+E_miss. We find that one such
event may indeed be consistent with the model predictions for m_chi \approx
(60-70) GeV. This region of parameter space is also consistent with the
selectron and chargino interpretations of the CDF ee gamma gamma + E_T,miss
event.Comment: 9 pages, LaTeX, 4 figures (included). Updated to include full LEP161
dat
The SuperWorlds of SU(5) and SU(5)xU(1): A Critical Assessment and Overview
We present an overview of the simplest supergravity models which enforce
radiative breaking of the electroweak symmetry, namely the minimal
supergravity model and the class of string-inspired/derived supergravity models
based on the flipped structure supplemented by a minimal set
of additional matter representations such that unification occurs at the string
scale (\sim10^{18}\GeV). These models can be fully parametrized in terms of
the top-quark mass, the ratio , and three supersymmetry
breaking parameters (). The latter are chosen in the minimal
model such that the stringent constraints from proton decay and
cosmology are satisfied. In the flipped case we consider two
string-inspired supersymmetry breaking scenaria: no-scale
supergravity and a dilaton-induced supersymmetry breaking scenario. Both imply
universal soft supersymmetry breaking parameters: and
m_0=\coeff{1}{\sqrt{3}}m_{1/2}, A=-m_{1/2} respectively. We present a
comparative study of the sparticle and Higgs spectra of both flipped
models and the minimal model and conclude that all can be partially
probed at the Tevatron and LEPII (and the flipped models at HERA too). In both
flipped cases there is a more constrained version which allows to
determine in terms of and which leads to much
sharper and readily accessible experimental predictions. We also discuss the
prospects for indirect experimental detection: a non-trivial fraction of the
parameter space of the flipped models is in conflict with the present
experimental allowed range for the rare decay mode, and the
one-loop electroweak radiative corrections imply the 90\% CL upper boundComment: CERN-TH.6934/93, CTP-TAMU-34/93, LaTeX, 58 pages, 20 embedded
figures. Complete ps file (~12000 blocks, 5.24MB) available via anonymous ftp
from site tamsun.tamu.edu in directory incoming, filename: CTP-TAMU-34-93.p
SU(5)xU(1): a string paradigm of a TOE and its experimental consequences
We present a string-inspired/derived supergravity model based on the flipped
structure supplemented by a minimal set of additional matter
representations such that unification occurs at the string scale
(\sim10^{18}\GeV). This model is complemented by two string supersymmetry
breaking scenaria: the no-scale supergravity model and a
dilaton-induced supersymmetry breaking scenario. Both imply universal soft
supersymmetry breaking parameters: and
m_0=\coeff{1}{\sqrt{3}}m_{1/2}, A=-m_{1/2} respectively. In either case the
models depend on only three parameters: , , and .
We present a comparative study of the sparticle and Higgs spectra of both
models and conclude that even though both can be partially probed at the
Tevatron, LEPII, and HERA, a larger fraction of the parameter space of the
no-scale model is actually accessible. In both cases there is a more
constrained version which allows to determine in terms of
. In the strict no-scale case we find that the value of
determines the sign of (\mu>0:\,m_t\lsim135\GeV,
\mu<0:\,m_t\gsim140\GeV) and whether the lightest Higgs boson mass is above
or below 100\GeV. In the more constrained version of the dilaton scenario,
and m_t\lsim155\GeV, 61\GeV\lsim m_h\lsim91\GeV
follow. Thus, continuing Tevatron top-quark searches and LEPI,II Higgs searches
could probe this restricted scenario completely.Comment: CERN-TH.6926/93, CTP-TAMU-33/93, LaTeX, 33 pages, 11 embedded
figures. Significant numerical correction to the dilaton scenario. Complete
ps file (7943 blocks,3.33MB) available via anonymous ftp from site
tamsun.tamu.edu in directory incoming, filename: CTP-TAMU-33-93.p
A No-Scale Framework for Sub-Planckian Physics
We propose a minimal model framework for physics below the Planck scale with
the following features: (i) it is based on no-scale supergravity, as favoured
in many string compactifications, (ii) it incorporates Starobinsky-like
inflation, and hence is compatible with constraints from the Planck satellite,
(iii) the inflaton may be identified with a singlet field in a see-saw model
for neutrino masses, providing an efficient scenario for reheating and
leptogenesis, (iv) supersymmetry breaking occurs with an arbitrary scale and a
cosmological constant that vanishes before radiative corrections, (v) regions
of the model parameter space are compatible with all LHC, Higgs and dark matter
constraints.Comment: 6 pages, 2 figures, some minor corrections and additions. Final
versio
Starobinsky-like Inflationary Models as Avatars of No-Scale Supergravity
Models of cosmological inflation resembling the Starobinsky R + R^2 model
emerge naturally among the effective potentials derived from no-scale
SU(N,1)/SU(N) x U(1) supergravity when N > 1. We display several examples in
the SU(2,1)/SU(2) x U(1) case, in which the inflaton may be identified with
either a modulus field or a matter field. We discuss how the modulus field may
be stabilized in models in which a matter field plays the role of the inflaton.
We also discuss models that generalize the Starobinsky model but display
different relations between the tilt in the spectrum of scalar density
perturbations, n_s, the tensor-to-scalar ratio, r, and the number of e-folds,
N_*. Finally, we discuss how such models can be probed by present and future
CMB experiments.Comment: 23 pages, 3 figure
From Gravity to No-Scale Supergravity
We show that gravity coupled conformally to scalar fields is equivalent
to the real bosonic sector of SU(N,1)/SU(N)U(1) no-scale supergravity,
where the conformal factor can be identified with the K\"ahler potential, and
we review the construction of Starobinsky-like models of inflation within this
framework.Comment: 15 pages, version accepted for publicatio
Probing the No-Scale - One-Parameter Model via Gluino Searches at the LHC2
In our recent paper entitled "The return of the King: No-Scale -", we showed that the model space supporting the most favorable
phenomenology should have been probed in 2016 at the LHC2, with an even further
reach into this region of the model in 2017-18. This ideal realm of the
one-parameter version of No-Scale - yields a 1.9-2.3 TeV
gluino mass at the very same point where the light Higgs boson mass enters its
rather narrow experimentally determined range of GeV.
Given the recent results reported at Moriond 2017 for 36 of
luminosity collected in 2016 at the 13 TeV LHC2, we now update the status of
the No-Scale - model space in light of the gluino mass
exclusion limits presented by the ATLAS and CMS Collaborations. We illustrate
that a resolution could be reached soon as to whether supersymmetry lives in
this most critical region of the model space.Comment: 4 pages, 2 figures, Physics Letters B versio
The strongest experimental constraints on SU(5)xU(1) supergravity models
We consider a class of well motivated string-inspired flipped
supergravity models which include four supersymmetry breaking scenarios:
no-scale, strict no-scale, dilaton, and special dilaton, such that only three
parameters are needed to describe all new phenomena . We show that the LEP precise measurements of the electroweak parameters
in the form of the variable, and the CLEOII allowed range for
\bsg are at present the most important experimental constraints on this class
of models. For m_t\gsim155\,(165)\GeV, the constraint (at
90(95)\%CL) requires the presence of light charginos
(m_{\chi^\pm_1}\lsim50-100\GeV depending on ). Since all sparticle
masses are proportional to , m_{\chi^\pm_1}\lsim100\GeV
implies: m_{\chi^0_1}\lsim55\GeV, m_{\chi^0_2}\lsim100\GeV, m_{\tilde
g}\lsim360\GeV, m_{\tilde q}\lsim350\,(365)\GeV, m_{\tilde
e_R}\lsim80\,(125)\GeV, m_{\tilde e_L}\lsim120\,(155)\GeV, and
m_{\tilde\nu}\lsim100\,(140)\GeV in the no-scale (dilaton) flipped
supergravity model. The \bsg constraint excludes a significant fraction of
the otherwise allowed region in the plane
(irrespective of the magnitude of the chargino mass), while future experimental
improvements will result in decisive tests of these models. In light of the
constraint, we conclude that the outlook for chargino and
selectron detection at LEPII and at HERA is quite favorable in this class of
models.Comment: CTP-TAMU-40/93, Latex, 13 pages, 10 figures (available as uuencoded
0.963MB file from [email protected]
QED-Cavity model of microtubules implies dissipationless energy transfer and biological quantum teleportation
We refine a QED-cavity model of microtubules (MTs), proposed earlier by two
of the authors (N.E.M. and D.V.N.), and suggest mechanisms for the formation of
biomolecular mesoscopic coherent and/or entangled quantum states, which may
avoid decoherence for times comparable to biological characteristic times. This
refined model predicts dissipationless energy transfer along such "shielded"
macromolecules at near room temperatures as well as quantum teleportation of
states across MTs and perhaps neurons.Comment: 20 pages LATEX, three ps figures incorporate
New phenomena in the standard no-scale supergravity model
We revisit the no-scale mechanism in the context of the simplest no-scale
supergravity extension of the Standard Model. This model has the usual
five-dimensional parameter space plus an additional parameter . We show how predictions of the model may be extracted over
the whole parameter space. A necessary condition for the potential to be stable
is , which is satisfied if \bf m_{3/2}\lsim2 m_{\tilde
q}. Order of magnitude calculations reveal a no-lose theorem guaranteeing
interesting and potentially observable new phenomena in the neutral scalar
sector of the theory which would constitute a ``smoking gun'' of the no-scale
mechanism. This new phenomenology is model-independent and divides into three
scenarios, depending on the ratio of the weak scale to the vev at the minimum
of the no-scale direction. We also calculate the residual vacuum energy at the
unification scale (), and find that in typical models one must
require . Such constraints should be important in the search for the
correct string no-scale supergravity model. We also show how specific classes
of string models fit within this framework.Comment: 11pages, LaTeX, 1 figure (included), CERN-TH.7433/9
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