120 research outputs found
Muon g-2 anomaly and 125 GeV Higgs : Extra vector-like quark and LHC prospects
The ATLAS and CMS collaborations recently reported indication of a Higgs
boson around 125 GeV. If we add extra vector-like quarks to the MSSM, such a
relatively heavy Higgs can be naturally realized in the GMSB framework,
simultaneously explaining the muon g-2 anomaly. I will discuss LHC prospects of
this attractive model.Comment: 5 pages, 3 figures; talk given at the International Workshop on Grand
Unified Theories (GUT2012), Japan, 15-17 March 201
CP-safe Gravity Mediation and Muon g-2
We propose a CP-safe gravity mediation model, where the phases of the Higgs B
parameter, scalar trilinear couplings and gaugino mass parameters are all
aligned. Since all dangerous CP violating phases are suppressed, we are now
safe to consider low-energy SUSY scenarios. As an application, we consider a
gravity mediation model explaining the observed muon anomaly. The CP-safe
property originates in two simple assumptions: SUSY breaking in the K\"ahler
potential and a shift symmetry of a SUSY breaking field . As a result of the
shift symmetry, the imaginary part of behaves as a QCD axion, leading to an
intriguing possibility: the strong CP problem in QCD and the SUSY CP problem
are solved simultaneously.Comment: 23 pages, 2 figures; v2 with additional explanation
Tagging new physics with charm
We propose a new variable, the charm fraction, for collider searches for new
physics. We analyze this variable in the context of searches for simplified
supersymmetry models with squarks, the gluino, and the bino, assuming that only
the lightest mass-degenerate squarks can be produced at the high-luminosity
LHC. The charm fraction complements event counting and kinematic information,
increasing the sensitivity of the searches for models with heavy gluinos, for
which squark production is flavor-blind. If squarks are discovered at the LHC,
this variable can help discriminate between different underlying models. In
particular, with improved charm tagging, the charm fraction can provide
information on the gluino mass, and in some scenarios, on whether this mass is
within the reach of a future 100 TeV hadron collider.Comment: 16 pages, 9 figures; double-tagging analysis added; discussion of
results expanded; version to appear in JHE
Higgs mass, muon g-2, and LHC prospects in gauge mediation models with vector-like matters
Recently the ATLAS and CMS collaborations presented preliminary results of
Standard Model Higgs searches and reported excesses of events for a Higgs boson
at 124-126 GeV. Such a Higgs mass can be naturally realized, simultaneously
explaining the muon g-2 anomaly, in gauge-mediated SUSY breaking models with
extra vector-like matters. Upper bounds are obtained on the gluino mass,
m_{\tilde g}\lesssim 1.2 (1.8) TeV, and on the extra vector-like quark mass,
M_{Q'} \lesssim 1.0 (1.8) GeV, in the parameter region where the Higgs boson
mass is 124-126 GeV and the muon g-2 is consistent with the experimental value
at the 1 sigma (2 sigma) level. The LHC prospects are explored in the parameter
region. It is found that some of the regions are already excluded by the LHC,
and most of the parameter space is expected to be covered at \sqrt{s} = 14 TeV.
A study on the extra vector-like quarks, especially current bounds on their
masses and prospects for future searches, is also included.Comment: 28 pages, 10 figure
Probing minimal SUSY scenarios in the light of muon and dark matter
We study supersymmetric (SUSY) models in which the muon discrepancy and
the dark matter relic abundance are simultaneously explained. The muon
discrepancy, or a 3 deviation between the experimental and theoretical
results of the muon anomalous magnetic moment, can be resolved by SUSY models,
which implies at least three SUSY multiplets have masses of
. In particular, models with the
bino, higgsino and slepton having
masses are not only capable to explain the muon discrepancy but naturally
contains the neutralino dark matter with the observed relic abundance. We study
constraints and future prospects of such models; in particular, we find that
the LHC search for events with two hadronic taus and missing transverse
momentum can probe this scenario through chargino/neutralino production. It is
shown that almost all the parameter space of the scenario can be probed at the
high-luminosity LHC, and a large part can also be tested at the XENON1T
experiment as well as at the ILC.Comment: 16 pages, 5 figures; the published versio
Type-I Seesaw as the Common Origin of Neutrino Mass, Baryon Asymmetry, and the Electroweak Scale
The type-I seesaw represents one of the most popular extensions of the
Standard Model. Previous studies of this model have mostly focused on its
ability to explain neutrino oscillations as well as on the generation of the
baryon asymmetry via leptogenesis. Recently, it has been pointed out that the
type-I seesaw can also account for the origin of the electroweak scale due to
heavy-neutrino threshold corrections to the Higgs potential. In this paper, we
show for the first time that all of these features of the type-I seesaw are
compatible with each other. Integrating out a set of heavy Majorana neutrinos
results in small masses for the Standard Model neutrinos; baryogenesis is
accomplished by resonant leptogenesis; and the Higgs mass is entirely induced
by heavy-neutrino one-loop diagrams, provided that the tree-level Higgs
potential satisfies scale-invariant boundary conditions in the ultraviolet. The
viable parameter space is characterized by a heavy-neutrino mass scale roughly
in the range GeV and a mass splitting among the nearly
degenerate heavy-neutrino states up to a few TeV. Our findings have interesting
implications for high-energy flavor models and low-energy neutrino observables.
We conclude that the type-I seesaw sector might be the root cause behind the
masses and cosmological abundances of all known particles. This statement might
even extend to dark matter in the presence of a keV-scale sterile neutrino.Comment: 41 pages, 5 figures, matches version published in PR
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