73 research outputs found
The complete spectrum of the area from recoupling theory in loop quantum gravity
We compute the complete spectrum of the area operator in the loop
representation of quantum gravity, using recoupling theory. This result extends
previous derivations, which did not include the ``degenerate'' sector, and
agrees with the recently computed spectrum of the connection-representation
area operator.Comment: typos corrected in eqn.(21). Latex with IOP and epsf styles, 1 figure
(eps postscript file), 12 pages. To appear in Class. Quantum Gra
Axion gauge symmetries and generalized Chern-Simons terms in N=1 supersymmetric theories
We compute the form of the Lagrangian of N=1 supersymmetric theories with
gauged axion symmetries. It turns out that there appear generalized
Chern-Simons terms that were not considered in previous superspace formulations
of general N=1 theories. Such gaugings appear in supergravities arising from
flux compactifications of superstrings, as well as from Scherk-Schwarz
generalized dimensional reduction in M-theory. We also present the dual
superspace formulation where axion chiral multiplets are dualized into linear
multiplets.Comment: References added and few misprints correcte
Absence of charge backscattering in the nonequilibrium current of normal-superconductor structures
We study the nonequilibrium transport properties of a
normal-superconductor-normal structure, focussing on the effect of adding an
impurity in the superconducting region. Current conservation requires the
superfluid velocity to be nonzero, causing a distortion of the quasiparticle
dispersion relation within the superconductor. For weakly reflecting interfaces
we find a regime of intermediate voltages in which Andreev transmission is the
only permitted mechanism for quasiparticles to enter the superconductor.
Impurities in the superconductor can only cause Andreev reflection of these
quasiparticles and thus cannot degrade the current. At higher voltages, a state
of gapless superconductivity develops which is sensitive to the presence of
impurities.Comment: Latex file, 11 pages, 2 figures available upon request
[email protected], to be published in Journal of Physics: Condensed Matte
Model Independent Approach to Focus Point Supersymmetry: from Dark Matter to Collider Searches
The focus point region of supersymmetric models is compelling in that it
simultaneously features low fine-tuning, provides a decoupling solution to the
SUSY flavor and CP problems, suppresses proton decay rates and can accommodate
the WMAP measured cold dark matter (DM) relic density through a mixed
bino-higgsino dark matter particle. We present the focus point region in terms
of a weak scale parameterization, which allows for a relatively model
independent compilation of phenomenological constraints and prospects. We
present direct and indirect neutralino dark matter detection rates for two
different halo density profiles, and show that prospects for direct DM
detection and indirect detection via neutrino telescopes such as IceCube and
anti-deuteron searches by GAPS are especially promising. We also present LHC
reach prospects via gluino and squark cascade decay searches, and also via
clean trilepton signatures arising from chargino-neutralino production. Both
methods provide a reach out to m_{\tg}\sim 1.7 TeV. At a TeV-scale linear
e^+e^- collider (LC), the maximal reach is attained in the \tz_1\tz_2 or
\tz_1\tz_3 channels. In the DM allowed region of parameter space, a
\sqrt{s}=0.5 TeV LC has a reach which is comparable to that of the LHC.
However, the reach of a 1 TeV LC extends out to m_{\tg}\sim 3.5 TeV.Comment: 34 pages plus 36 eps figure
Shifts in the Properties of the Higgs Boson from Radion Mixing
We examine how mixing between the Standard Model Higgs boson, , and the
radion present in the Randall-Sundrum model of localized gravity modifies the
expected properties of the Higgs boson. In particular, we demonstrate that the
total and partial decay widths of the Higgs, as well as the branching
fraction, can be substantially altered from their Standard Model expectations.
The remaining branching fractions are modified less than \lsim 5% for most of
the parameter space volume.Comment: 17 pages, 7 figs., LaTex; revised versio
Supersymmetry Without Prejudice
We begin an exploration of the physics associated with the general
CP-conserving MSSM with Minimal Flavor Violation, the pMSSM. The 19 soft SUSY
breaking parameters in this scenario are chosen so as to satisfy all existing
experimental and theoretical constraints assuming that the WIMP is a
conventional thermal relic, ie, the lightest neutralino. We scan this parameter
space twice using both flat and log priors for the soft SUSY breaking mass
parameters and compare the results which yield similar conclusions. Detailed
constraints from both LEP and the Tevatron searches play a particularly
important role in obtaining our final model samples. We find that the pMSSM
leads to a much broader set of predictions for the properties of the SUSY
partners as well as for a number of experimental observables than those found
in any of the conventional SUSY breaking scenarios such as mSUGRA. This set of
models can easily lead to atypical expectations for SUSY signals at the LHC.Comment: 61 pages, 24 figs. Refs., figs, and text added, typos fixed; This
version has reduced/bitmapped figs. For a version with better figs please go
to http://www.slac.stanford.edu/~rizz
Particle-Antiparticle Mixing, epsilon_K, Delta Gamma_q, A_SL^q, A_CP(B_d -> psi K_S), A_CP(B_s -> psi phi) and B -> X_{s,d} gamma in the Littlest Higgs Model with T-Parity
We calculate a number of observables related to particle-antiparticle mixing
in the Littlest Higgs model with T-parity (LHT). The resulting effective
Hamiltonian for Delta F=2 transitions agrees with the one of Hubisz et al., but
our phenomenological analysis goes far beyond the one of these authors. In
particular, we point out that the presence of mirror fermions with new flavour
and CP-violating interactions allows to remove the possible Standard Model (SM)
discrepancy between the CP asymmetry S_{psi K_S} and large values of |V_ub| and
to obtain for the mass difference Delta M_s < (Delta M_s)_SM as suggested by
the recent result by the CDF collaboration. We also identify a scenario in
which simultaneously significant enhancements of the CP asymmetries S_{phi psi}
and A_SL^q relative to the SM are possible, while satisfying all existing
constraints, in particular from the B -> X_s gamma decay and A_CP(B -> X_s
gamma) that are presented in the LHT model here for the first time. In another
scenario the second, non-SM, value for the angle gamma=-(109+-6) from tree
level decays, although unlikely, can be made consistent with all existing data
with the help of mirror fermions. We present a number of correlations between
the observables in question and study the implications of our results for the
mass spectrum and the weak mixing matrix of mirror fermions. In the most
interesting scenarios, the latter one turns out to have a hierarchical
structure that differs significantly from the CKM one.Comment: 51 pages, 20 figures, 1 table. Extended discussion of the phases in
the new mixing matrix V_Hd, some references added or updated, conclusions
unchanged. Final version published in JHE
Supersymmetry and the relationship between a class of singular potentials in arbitrary dimensions
The eigenvalues of the potentials
and
, and of the special cases of these potentials such as the Kratzer and
Goldman-Krivchenkov potentials, are obtained in N-dimensional space. The
explicit dependence of these potentials in higher-dimensional space is
discussed, which have not been previously covered.Comment: 13 pages article in LaTEX (uses standard article.sty). Please check
"http://www1.gantep.edu.tr/~ozer" for other studies of Nuclear Physics Group
at University of Gaziante
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