920 research outputs found
Low Energy Theorem for SUSY Breaking with Gauge Supermultiplets
Low energy theorems of Nambu-Goldstone fermion associated with spontaneously
broken supersymmetry are studied for gauge supermultiplets. Two possible terms
in the effective Lagrangian are needed to deal with massless gaugino and/or
massless gauge boson. As an illustrative example, a concrete model is worked
out which can interpolate massless as well as massive gaugino and/or gauge
boson to examine the low energy effective interaction of NG-fermion.Comment: 14page
Moduli Space of Global Symmetry in N=1 Supersymmetric Theories and the Quasi-Nambu-Goldstone Bosons
We derive the moduli space for the global symmetry in N=1 supersymmetric
theories. We show, at the generic points, it coincides with the space of
quasi-Nambu-Goldstone (QNG) bosons, which appear besides the ordinary
Nambu-Goldstone (NG) bosons when global symmetry G breaks down spontaneously to
its subgroup H with preserving N=1 supersymmetry. At the singular points, most
of the NG bosons change to the QNG bosons and the unbroken global symmetry is
enhanced. The G-orbits parametrized by the NG bosons are the fibre at the
moduli space and the singular points correspond to the point where H-orbit (in
G-orbit) shrinks. We also show the low-energy effective Lagrangian is the
arbitrary function of the orbit map.Comment: LaTex, 42 pages, 8 figures, final version to appear in
Int.J.Mod.Phys.
Strong Conformal Dynamics at the LHC and on the Lattice
Conformal technicolor is a paradigm for new physics at LHC that may solve the
problems of strong electroweak symmetry breaking for quark masses and precision
electroweak data. We give explicit examples of conformal technicolor theories
based on a QCD-like sector. We suggest a practical method to test the conformal
dynamics of these theories on the lattice.Comment: v2: Generalized discussion of lattice measurement of hadron masses,
references added, minor clarifications v3: references added, minor change
Mediation of supersymmetry breaking in extra dimensions
We review the mechanisms of supersymmetry breaking mediation that occur in
sequestered models, where the visible and the hidden sectors are separated by
an extra dimension and communicate only via gravitational interactions. By
locality, soft breaking terms are forbidden at the classical level and reliably
computable within an effective field theory approach at the quantum level. We
present a self-contained discussion of these radiative gravitational effects
and the resulting pattern of soft masses, and give an overview of realistic
model building based on this set-up. We consider both flat and warped extra
dimensions, as well as the possibility that there be localized kinetic terms
for the gravitational fields.Comment: LaTex, 15 pages; brief review prepared for MPLA. v2: minor
correction
Partially composite 2-Higgs-doublet model
In the extra dimensional scenarios with gauge fields in the bulk, the
Kaluza-Klein (KK) gauge bosons can induce Nambu-Jona-Lasinio (NJL) type
attractive four-fermion interactions, which can break electroweak symmetry
dynamically with accompanying composite Higgs fields. We consider a possibility
that electroweak symmetry breaking (EWSB) is triggered by both a fundamental
Higgs and a composite Higgs arising in a dynamical symmetry breaking mechanism
induced by a new strong dynamics. The resulting Higgs sector is a partially
composite two-Higgs doublet model with specific boundary conditions on the
coupling and mass parameters originating at a compositeness scale .
The phenomenology of this model is discussed including the collider
phenomenology at LHC and ILC.Comment: To appear in the proceeding of LCWS06, Bangalore, Indi
Anomaly Matching Conditions in Supersymmetric Gauge Theories
Sufficient conditions are proven for 't Hooft's consistency conditions to
hold at points in the moduli space of supersymmetric gauge theories. Known
results for anomaly matching in supersymmetric QCD are rederived as a sample
application of the results. The results can be used to show that the anomaly
matching conditions hold for s-confining theories.Comment: 14 pages, revte
Orbitally Excited Baryons in Large N_c QCD
We present a model-independent analysis of the mass spectrum of nonstrange
l=1 baryons in large N_c QCD. The 1/N_c expansion is used to select and order a
basis of effective operators that spans the nine observables (seven masses and
two mixing angles). Comparison to the data provides support for the validity of
the 1/N_c expansion, but also reveals that only a few nontrivial operators are
strongly preferred. We show that our results have a consistent interpretation
in a constituent quark model with pseudoscalar meson exchange interactions.Comment: 4 pages LaTeX. Invited parallel session talk presented at the XVth
Particles and Nuclei International Conference (PANIC99), June 10, 1999,
Uppsala, Swede
Phase Transition in a One-Dimensional Extended Peierls-Hubbard Model with a Pulse of Oscillating Electric Field: III. Interference Caused by a Double Pulse
In order to study consequences of the differences between the
ionic-to-neutral and neutral-to-ionic transitions in the one-dimensional
extended Peierls-Hubbard model with alternating potentials for the TTF-CA
complex, we introduce a double pulse of oscillating electric field in the
time-dependent Schr\"odinger equation and vary the interval between the two
pulses as well as their strengths. When the dimerized ionic phase is
photoexcited, the interference effect is clearly observed owing to the
coherence of charge density and lattice displacements. Namely, the two pulses
constructively interfere with each other if the interval is a multiple of the
period of the optical lattice vibration, while they destructively interfere if
the interval is a half-odd integer times the period, in the processes toward
the neutral phase. The interference is strong especially when the pulse is
strong and short because the coherence is also strong. Meanwhile, when the
neutral phase is photoexcited, the interference effect is almost invisible or
weakly observed when the pulse is weak. The photoinduced lattice oscillations
are incoherent due to random phases. The strength of the interference caused by
a double pulse is a key quantity to distinguish the two transitions and to
evaluate the coherence of charge density and lattice displacements.Comment: 16 pages, 8 figure
Anomaly Matching Conditions and the Moduli Space of Supersymmetric Gauge Theories
The structure of the moduli space of N=1 supersymmetric gauge theories is
analyzed from an algebraic geometric viewpoint. The connection between the
fundamental fields of the ultraviolet theory, and the gauge invariant composite
fields of the infrared theory is explained in detail. The results are then used
to prove an anomaly matching theorem. The theorem is used to study anomaly
matching for supersymmetric QCD, and can explain all the known anomaly matching
results for this case.Comment: 28 pages revtex, amssym
Visible Effects of the Hidden Sector
The renormalization of operators responsible for soft supersymmetry breaking
is usually calculated by starting at some high scale and including only visible
sector interactions in the evolution equations, while ignoring hidden sector
interactions. Here we explain why this is correct only for the most trivial
structures in the hidden sector, and discuss possible implications. This
investigation was prompted by the idea of conformal sequestering. In that
framework hidden sector renormalizations by nearly conformal dynamics are
critical. In the original models of conformal sequestering it was necessary to
impose hidden sector flavor symmetries to achieve the sequestered form. We
present models which can evade this requirement and lead to no-scale or anomaly
mediated boundary conditions; but the necessary structures do not seem generic.
More generally, the ratios of scalar masses to gaugino masses, the -term,
the -term, -terms, and the gravitino mass can be significantly
affected.Comment: 23 pages, no figure
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