2,127 research outputs found
Revisiting Critical Vortices in Three-Dimensional SQED
We consider renormalization of the central charge and the mass of the supersymmetric Abelian vortices in 2+1 dimensions. We obtain
supersymmetric theory in 2+1 dimensions by dimensionally reducing the SQED in 3+1 dimensions with two chiral fields carrying opposite charges.
Then we introduce a mass for one of the matter multiplets without breaking N=2
supersymmetry. This massive multiplet is viewed as a regulator in the large
mass limit. We show that the mass and the central charge of the vortex get the
same nonvanishing quantum corrections, which preserves BPS saturation at the
quantum level. Comparison with the operator form of the central extension
exhibits fractionalization of a global U(1) charge; it becomes 1/2 for the
minimal vortex. The very fact of the mass and charge renormalization is due to
a "reflection" of an unbalanced number of the fermion and boson zero modes on
the vortex in the regulator sector.Comment: 24 pages, 2 figures Minor modifications, reference adde
Shift in the LHC Higgs diphoton mass peak from interference with background
The Higgs diphoton amplitude from gluon fusion at the LHC interferes with the
continuum background induced by quark loops. I investigate the effect of this
interference on the position of the diphoton invariant mass peak used to help
determine the Higgs mass. At leading order, the interference shifts the peak
towards lower mass by an amount of order 150 MeV or more, with the precise
value dependent on the methods used to analyze and fit the data.Comment: 10 pages. v2: comments on scale variation added, reference adde
Indirect Detection of Little Higgs Dark Matter
Little Higgs models with T parity contain an attractive dark matter
candidate, the heavy photon. We compute the cross section of the heavy photon
annihilation into Z-photon pairs, which turns out to be substantially higher
than the previously computed cross section for the two photon final state.
Unfortunately, even with this enhancement, the monochromatic photon flux from
galactic heavy photon annihilation is unlikely to be detectable by GLAST or the
currently operating atmospheric Cerenkov telescopes. We also compute the flux
of high-energy neutrinos from the annihilation of the heavy photons captured by
the Sun and the Earth. The maximum flux of upward-going muons due to such
neutrinos is about 1 yr^{-1}km^{-2}.Comment: 13 pages, 3 figure
Large-N Solution of the Heterotic CP(N-1) Model with Twisted Masses
We address a number of unanswered questions in the N=(0,2)-deformed CP(N-1)
model with twisted masses. In particular, we complete the program of solving
CP(N-1) model with twisted masses in the large-N limit. In hep-th/0512153
nonsupersymmetric version of the model with the Z_N symmetric twisted masses
was analyzed in the framework of Witten's method. In arXiv:0803.0698 this
analysis was extended: the large-N solution of the heterotic N=(0,2) CP(N-1)
model with no twisted masses was found. Here we solve this model with the
twisted masses switched on. Dynamical scenarios at large and small m are
studied (m is the twisted mass scale). We found three distinct phases and two
phase transitions on the m plane. Two phases with the spontaneously broken
Z_N-symmetry are separated by a phase with unbroken Z_N. This latter phase is
characterized by a unique vacuum and confinement of all U(1) charged fields
("quarks"). In the broken phases (one of them is at strong coupling) there are
N degenerate vacua and no confinement, similarly to the situation in the
N=(2,2) model. Supersymmetry is spontaneously broken everywhere except a circle
|m|=\Lambda in the Z_N-unbroken phase. Related issues are considered. In
particular, we discuss the mirror representation for the heterotic model in a
certain limiting case.Comment: 69 pages, 14 figures; typos corrected, final version to appear in
PRD; v Jan. 2014 Erratum added on p. 50, two references added and two
references update
Dynamical GUT breaking and mu-term driven supersymmetry breaking
Models for dynamical breaking of supersymmetric grand unified theories are
presented. The doublet-triplet splitting problem is absent since the Higgs
doublet superfields can be identified with the massless mesons of the strong
gauge group whereas there are no massless states corresponding to the colored
Higgs fields. Various strong gauge groups SU(Nc), Sp(Nc) and SO(Nc) are
examined. In a model with SO(9) strong gauge group, adding the mu-term for the
Higgs fields triggers to break supersymmetry in a meta-stable vacuum. The
pattern of the supersymmetry breaking parameters is predicted to be the
gauge-mediation type with modifications in the Higgs sector.Comment: 23 pages, 1 figure; version to appear in PR
Are There Hints of Light Stops in Recent Higgs Search Results?
The recent discovery at the LHC by the CMS and ATLAS collaborations of the
Higgs boson presents, at long last, direct probes of the mechanism for
electroweak symmetry breaking. While it is clear from the observations that the
new particle plays some role in this process, it is not yet apparent whether
the couplings and widths of the observed particle match those predicted by the
Standard Model. In this paper, we perform a global fit of the Higgs results
from the LHC and Tevatron. While these results could be subject to
as-yet-unknown systematics, we find that the data are significantly better fit
by a Higgs with a suppressed width to gluon-gluon and an enhanced width to
gamma gamma, relative to the predictions of the Standard Model. After
considering a variety of new physics scenarios which could potenially modify
these widths, we find that the most promising possibility is the addition of a
new colored, charged particle, with a large coupling to the Higgs. Of
particular interest is a light, and highly mixed, stop, which we show can
provide the required alterations to the combination of gg and gamma gamma
widths.Comment: 6 pages, 5 figure
Direct Mediation of Meta-Stable Supersymmetry Breaking
The supersymmetric SU(Nc) Yang-Mills theory coupled to Nf matter fields in
the fundamental representation has meta-stable vacua with broken supersymmetry
when Nc < Nf < 3/2 Nc. By gauging the flavor symmetry, this model can be
coupled directly to the standard model. We show that it is possible to make a
slight deformation to the model so that gaugino masses are generated and the
Landau pole problem can be avoided. The deformed model has simple realizations
on intersecting branes in string theory, where various features of the
meta-stable vacua are encoded geometrically as brane configurations.Comment: 22 pages, 4 figures, a reference added, version to appear in PR
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