1,537 research outputs found
Kaluza-Klein Mediated Supersymmetry Breaking
We discuss a framework for communicating supersymmetry breaking to the
visible sector where the radius modulus, which determines the size of extra
dimensions, has an auxiliary vacuum expectation value. The modulus couplings
generate mass splitting in Kaluza-Klein supermultiplets and they act as
messengers of supersymmetry breaking. The soft masses are expressed in terms of
renormalization-group functions and the sparticle spectrum is determined by
what kind of field propagates in the bulk. This framework also provides new
possibilities for solving the supersymmetric flavor problem.Comment: 10 page
New RG-invariants of Soft Supersymmetry Breaking Parameters
We study new renormalization-group invariant quantities of soft supersymmetry
breaking parameters other than the ratio of gaugino mass to gauge coupling
squared by using the spurion method. The obtained invariants are useful to
probe supersymmetry breaking and mu-term generation mechanisms at high-energy
scale. We also discuss the convergence behavior of fixed points of
supersymmetry breaking parameters.Comment: 9 page
4D construction of bulk supersymmetry breaking
In this letter, we discuss a four-dimensional model with modulus fields which
are responsible for supersymmetry breaking. Given non-trivial moduli dependence
of the action, the model is found to give a proper description of
higher-dimensional supersymmetry breaking. We explicitly calculate gaugino and
scalar mass spectrum and show that several classes of scenarios proposed in the
literature are described in certain regions of the parameter space of the
moduli vacuum expectation values. The model in other generic regions of the
moduli space gives unexplored scenarios (mass spectra) of supersymmetry
breaking in four dimensions.Comment: 16 page
Yukawa hierarchy from extra dimensions and infrared fixed points
We discuss the existence of hierarchy of Yukawa couplings in the models with
extra spatial dimensions. The hierarchical structure is induced by the power
behavior of the cutoff dependence of the evolution equations which yield large
suppressions of couplings at the compactification scale. The values of coupling
constants at this scale can be made stable almost independently of the initial
input parameters by utilizing the infrared fixed point. We find that the Yukawa
couplings converge to the fixed points very quickly because of the enhanced
energy dependence of the suppression factor from extra dimensions as well as in
the case of large gauge couplings at high-energy scale.Comment: 13 pages, 3 eps figure
Focus Issue on Male Infertility
Male infertility problems can occur when sperms are limited in number or function. In this paper, we describe the clinical evaluation of male infertility. A detailed history, physical examination, and basic semen analysis are required. In addition, ultrasound, karyotyping, and hormonal studies are needed to determine specific causes of infertility. In addition, the World Health Organization (WHO, 2009) has developed a manual to provide guidance in performing a comprehensive semen analysis. Among the possible reasons for male infertility, nonobstructive azoospermia is the least treatable, because few or no mature sperm may be produced. In many cases, men with nonobstructive azoospermia typically have small-volume testes and elevated FSH. Although treatment may not completely restore the quality of semen from men with subnormal fertility, in some cases a successful pregnancy can still be achieved through assisted reproductive technology
Edge state on hydrogen-terminated graphite edges investigated by scanning tunneling microscopy
The edge states that emerge at hydrogen-terminated zigzag edges embedded in
dominant armchair edges of graphite are carefully investigated by
ultrahigh-vacuum scanning tunneling microscopy (STM) measurements. The edge
states at the zigzag edges have different spatial distributions dependent on
the - or -site edge carbon atoms. In the case that the defects
consist of a short zigzag (or a short Klein) edge, the edge state is present
also near the defects. The amplitude of the edge state distributing around the
defects in an armchair edge often has a prominent hump in a direction
determined by detailed local atomic structure of the edge. The tight binding
calculation based on the atomic arrangements observed by STM reproduces the
observed spatial distributions of the local density of states.Comment: 9 pages, 11 figures, accepted for Physical Review
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