Phys.Rev.D74:055001,2006 We consider a class of little Higgs theories with T-parity where ALL new
particles responsible for canceling the standard model contributions to the
one-loop quadratic ...divergences in the Higgs potential are odd under T-parity,
including the heavy top partner which was previously taken to be T-even. The
new construction significantly simplifies the spectrum in the top sector and
completely changes the phenomenology of the top partner. At hadron colliders
the signals of this class of T-invariant models appear to be even more similar
to supersymmetry. We initiate a study on the collider phenomenology and discuss
the challenge of distinguishing this class of models from supersymmetry at the
Large Hadron Collider.
We study the possibility of discovering and measuring the properties of the lightest Kaluza-Klein excitation of the gluon in a Randall-Sundrum scenario where the Standard Model matter and gauge ...fields propagate in the bulk. The KK-gluon decays primarily into top quarks. We discuss how to use the \(t \bar{t}\) final states to discover and probe the properties of the KK-gluon. Identification of highly energetic tops is crucial for this analysis. We show that conventional identification methods relying on well separated decay products will not work for heavy resonances but suggest alternative methods for top identification for energetic tops. We find, conservatively, that resonances with masses less than 5 TeV can be discovered if the algorithm to identify high \(p_T\) tops can reject the QCD background by a factor of 10. We also find that for similar or lighter masses the spin can be determined and for lighter masses the chirality of the coupling to \(t\bar t\) can be measured. Since the energetic top pair final state is a generic signature for a large class of new physics as the top quark presumably couples most strongly to the electroweak symmetry breaking sector, the methods we have outlined to study the properties of the KK-gluon should also be important in other scenarios.
Various methods of searching for supersymmetric dark matter are sensitive to WIMPs with different properties. One consequence of this is that the phenomenology of dark matter detection can vary ...dramatically in different supersymmetric breaking scenarios. In this paper, we consider the sensitivities to supersymmetric dark matter of different detection methods and techniques in a wide variety of supersymmetric breaking scenarios. We discuss the ability of various astrophysical experiments, such as direct experiments, gamma-rays satellites, neutrino telescopes and positron and anti-proton cosmic ray experiments, to test various supersymmetry breaking scenarios. We also discuss what information can be revealed about supersymmetry breaking by combining results from complementary experiments. We place an emphasis on the differences between various experimental techniques.
B → φ K S and supersymmetry Kane, G. L.; Ko, P.; Wang, Haibin ...
Physical review. D, Particles, fields, gravitation, and cosmology,
8/2004, Letnik:
70, Številka:
3
Journal Article
For lifetime non-smokers, lung cancer risk is mainly associated with inhalation exposure to air pollution. For the Chinese population, indoor air pollution due to solid fuel combustion has been the ...primary source of inhalation exposure for decades. Polycyclic aromatic hydrocarbons （PAHs） are the by-products of incomplete combustion.
The catechol-O-methyltransferase（COMT） gene is a schizophrenia susceptibility gene. A common functional polymorphism of this gene,Val158/158 Met,has been proposed to influence gray matter ...volume（GMV）. However,the effects of this polymorphism on cortical thickness/surface area in schizophrenic patients are less clear. In this study,we explored the relationship between the Val158 Met polymorphism of the COMT gene and the GMV/ cortical thickness/cortical surface area in 150 firstepisode treatment-nave patients with schizophrenia and 100 healthy controls. Main effects of diagnosis were found for GMV in the cerebellum and the visual,medial temporal,parietal,and middle frontal cortex. Patients with schizophrenia showed reduced GMVs in these regions. And main effects of genotype were detected for GMV in the left superior frontal gyrus. Moreover,a diagnosis × genotype interaction was found for the GMV of the left precuneus,and the effect of the COMT gene on GMV was due mainly to cortical thickness rather than cortical surface area. In addition,a pattern ofincreased GMV in the precuneus with increasing Met dose found in healthy controls was lost in patients with schizophrenia. These findings suggest that the COMTMet variant is associated with the disruption of dopaminergic influence on gray matter in schizophrenia,and the effect of the COMT gene on GMV in schizophrenia is mainly due to changes in cortical thickness rather than in cortical surface area.
Phys.Rev.D75:095010,2007 One way to ameliorate the SUSY flavor and CP problems is to postulate that
scalar masses lie in the TeV or beyond regime. For example, the focus point
(FP) region of the ...minimal supergravity (mSUGRA) model is especially compelling
in that heavy scalar masses can co-exist with low fine-tuning while yielding
the required relic abundance of cold dark matter (via a mixed higgsino-bino
neutralino). We examine many of the characteristics of collider events expected
to arise at the CERN LHC in models with multi-TeV scalars, taking the mSUGRA FP
region as a case study. The collider events are characterized by a hard
component arising from gluino pair production, plus a soft component arising
from direct chargino and neutralino production. Gluino decays in the FP region
are characterized by lengthy cascades yielding very large jet and lepton
multiplicities, and a large b-jet multiplicity. Thus, as one steps to higher
jet, b-jet or lepton multiplicity, signal-over-background rates should steadily
improve. The lengthy cascade decays make mass reconstruction via kinematic
edges difficult; however, since the hard component is nearly pure gluino pair
production, the gluino mass can be extracted to +- 8% via total rate for \eslt
+\ge 7-jet +\ge 2 b-jet events, assuming 100 fb^{-1} of integrated luminosity.
The distribution of invariant mass of opposite-sign/same-flavor dileptons in
the hard component exhibits two dilepton mass edges: m_{\tz_2}-m_{\tz_1} and
m_{\tz_3}-m_{\tz_1}. As a consistency check, the same mass edges should be seen
in isolated opposite-sign dileptons occurring in the soft component trilepton
signal which originates mainly from chargino-neutralino production.
We describe a coherent strategy and set of tools for reconstructing the
fundamental theory of the TeV scale from LHC data. We show that On-Shell
Effective Theories (OSETs) effectively characterize ...hadron collider data in
terms of masses, production cross sections, and decay modes of candidate new
particles. An OSET description of the data strongly constrains the underlying
new physics, and sharply motivates the construction of its Lagrangian.
Simulating OSETs allows efficient analysis of new-physics signals, especially
when they arise from complicated production and decay topologies. To this end,
we present MARMOSET, a Monte Carlo tool for simulating the OSET version of
essentially any new-physics model. MARMOSET enables rapid testing of
theoretical hypotheses suggested by both data and model-building intuition,
which together chart a path to the underlying theory. We illustrate this
process by working through a number of data challenges, where the most
important features of TeV-scale physics are reconstructed with as little as 5
inverse femtobarns of simulated LHC signals.
Phys.Lett. B563 (2003) 191-202; Erratum-ibid. B603 (2004) 257-259 We analyze the loop induced decays of the Higgs boson into pairs of gluons
and photons in the Littlest Higgs model. We find that the ...deviation of the
partial widths for these decays relative to their Standard Model values scales
with 1/f^2, where f ~ TeV is the mass scale of the new heavy particles in the
model. For f = 1 TeV, Gamma(H -> gg) is reduced by 6-10% and Gamma(H -> gamma
gamma) is reduced by 5-7% compared to their Standard Model values. While the
LHC and a linear e+e- collider would be sensitive to these deviations only for
relatively low values of f <~ 650 GeV, a photon collider could probe the
deviation in Gamma(H -> gamma gamma) up to f <~ 1.1 (0.7) TeV at the 2 (5)
sigma level.
Phys.Rev. D67 (2003) 095004 We study the low energy phenomenology of the little Higgs model. We first
discuss the linearized effective theory of the "littlest Higgs model" and study
the low energy ...constraints on the model parameters. We identify sources of the
corrections to low energy observables, discuss model-dependent arbitrariness,
and outline some possible directions of extensions of the model in order to
evade the precision electroweak constraints. We then explore the characteristic
signatures to test the model in the current and future collider experiments. We
find that the LHC has great potential to discover the new SU(2) gauge bosons
and the possible new U(1) gauge boson to the multi-TeV mass scale. Other states
such as the colored vector-like quark T and doubly-charged Higgs boson Phi^{++}
may also provide interesting signals. At a linear collider, precision
measurements on the triple gauge boson couplings could be sensitive to the new
physics scale of a few TeV. We provide a comprehensive list of the linearized
interactions and vertices for the littlest Higgs model in the appendices.
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