63 research outputs found
Possible Supersymmetric Effects on Angular Distributions in Decays
We investigate the angular distributions of the rare B decay, , in general supersymmetric extensions of the standard
model. We consider the new physics contributions from the operators
in small invariant mass region of lepton pair. We show that the
azimuthal angle distribution of the decay can tell us the new physics effects
clearly from the behavior of the distribution, even if new physics does not
change the decay rate substantially from the standard model prediction
Lepton polarization correlations in
In this work we will study the polarizations of both leptons () in the
decay channel . In the case of the dileptonic inclusive
decay , where apart from the polarization asymmetries
of single lepton , one can also observe the polarization asymmetries of
both leptons simultaneously. If this sort of measurement is possible then we
can have, apart from decay rate, FB asymmetry and the six single lepton
polarization asymmetries (three each for and ), nine more
double polarization asymmetries. This will give us a very useful tool in more
strict testing of SM and the physics beyond. We discuss the double polarization
asymmetries of leptons in the decay mode within
the SM and the Minimal Supersymmetric extensions of it.Comment: 21 pages, 21 figures; version to match paper to appear in PR
Model Independent Analysis of the Forward-Backward Asymmetry for the Decay
The sensitivity of the zero position of the forward backward asymmetry
for the exclusive
decay is examined by using most general non-standard 4-fermion interactions.
Our analysis shows that the zero position of the forward backward asymmetry is
very sensitive to the sign and size of the Wilson coefficients corresponding to
the new vector type interactions, which are the counter partners of the usual
Standard Model operators but have opposite chirality. In addition to these, the
other significant effect comes from the interference of Scalar-Pseudoscalar and
Tensor type operators. These results will not only enhance our theoretical
understanding about the axial vector mesons but will also serve as a good tool
to look for physics beyond the SM.Comment: 14 pages, 8 figures, Published version that appears in EPJ
The Forward-Backward Asymmetry of B to (pi,K) l^+ l^-: Supersymmetry at Work
We analyze the forward-backward asymmetry of the decays B to (pi,K) l^+ l^-
with l = mu or tau in the framework of the constrained minimal supersymmetric
standard model. We find that, the asymmetry is enhanced at large tan beta and
depends strongly on the sign of the mu parameter. For mu > 0, the asymmetry is
typically large and observable whereas for mu < 0, it changes the sign and is
suppressed by an order of magnitude. Including cosmological constraints we find
that the asymmetry has a maximal value of about 30 %, produced when Higgs- and
gauge- induced flavor violations are of comparable size, at a value of tan beta
simeq 35. The present constraints from the B-factories are too weak to
constrain parameter space, and the regions excluded by them are already
disfavoured by at least one of B to X_s gamma, g-2, and/or cosmology. The size
of the asymmetry is mainly determined by the flavor of the final state lepton
rather than the flavor of the pseudoscalar.Comment: 18 pages; 11 eps figures; minor changes in text; journal versio
Supersymmetric effects on Forward Backward asymmetries of
Leptonic and semi-leptonic rare decays of B-mesons are very clean (both
theoretically and experimentally) signatures of any new physics beyond the
Standard Model (SM). More specifically the decay \btokll has been theoretically
observed to be very sensitive to new physics as the Forward Backward (FB)
asymmetry in this decay mode vanishes in the SM. Supersymmetry, however,
predicts a non-vanishing value of this asymmetry. In this work we will study
the polarized lepton pair FB asymmetry, i.e. the FB asymmetry of the lepton
when one (or both) final state lepton(s) are polarized. We will study these
asymmetries both within the SM and for Supersymmetric corrections to the SM.Comment: 18 pages, RevTeX file including 21 eps figures; version accepted for
publication in Phys. Rev. D. Some references adde
A century of trends in adult human height
Being taller is associated with enhanced longevity, and higher education and earnings. We reanalysed 1472 population-based studies, with measurement of height on more than 18.6 million participants to estimate mean height for people born between 1896 and 1996 in 200 countries. The largest gain in adult height over the past century has occurred in South Korean women and Iranian men, who became 20.2 cm (95% credible interval 17.5-22.7) and 16.5 cm (13.3-19.7) taller, respectively. In contrast, there was little change in adult height in some sub-Saharan African countries and in South Asia over the century of analysis. The tallest people over these 100 years are men born in the Netherlands in the last quarter of 20th century, whose average heights surpassed 182.5 cm, and the shortest were women born in Guatemala in 1896 (140.3 cm; 135.8-144.8). The height differential between the tallest and shortest populations was 19-20 cm a century ago, and has remained the same for women and increased for men a century later despite substantial changes in the ranking of countries
Rising rural body-mass index is the main driver of the global obesity epidemic in adults
Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities 1,2 . This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity 3�6 . Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55 of the global rise in mean BMI from 1985 to 2017�and more than 80 in some low- and middle-income regions�was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing�and in some countries reversal�of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories. © 2019, The Author(s)
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The Mechanical Behavior of AISI H13 Hot-Work Tool Steel Processed by Selective Laser Melting under Tensile Stress
AISI H13 tool steel is commonly used in hot-working applications include die casting dies,
inserts, forging dies, extrusion dies, etc. Molds fabricated by selective laser melting (SLM) with
conforming cooling channels can maintain a steady and uniform cooling performance to the
molding parts, which ensures high quality of the products and general reduction of the cycle time.
Therefore, SLM process has gained increasing attention in the hot-work tool field. The present
study concerns the properties of H13 materials that with and without preheating during the SLM
process. X-ray diffraction (XRD), field emission scanning electron microscope (SEM), and high-temperature tensile tests were applied to investigate the phases, microstructures and resultant
mechanical properties of SLM processed H13. Results show that the application of preheating
during SLM process results in a more homogeneous microstructure of the material with better
mechanical properties compared to those without preheating. High-temperature tensile strength
increased from 1066 MPa to 1183 MPa, the total elongation increased from 5.7% to 8.1%. The
high-temperature tensile strength of those parts with preheating was higher than those of the
treated commercial H13 tool steel, while the total elongation was much lower than those
commercial materials.Mechanical Engineerin
A simplified dynamic model based on response factor method for thermal performance analysis of capillary radiant floors
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