Modified Dark Matter: Relating Dark Energy, Dark Matter and Baryonic Matter

Modified dark matter (MDM) is a phenomenological model of dark matter, inspired by gravitational thermodynamics. For an accelerating Universe with positive cosmological constant ($\Lambda$), such phenomenological considerations lead to the emergence of a critical acceleration parameter related to $\Lambda$. Such a critical acceleration is an effective phenomenological manifestation of MDM, and it is found in correlations between dark matter and baryonic matter in galaxy rotation curves. The resulting MDM mass profiles, which are sensitive to $\Lambda$, are consistent with observational data at both the galactic and cluster scales. In particular, the same critical acceleration appears both in the galactic and cluster data fits based on MDM. Furthermore, using some robust qualitative arguments, MDM appears to work well on cosmological scales, even though quantitative studies are still lacking. Finally, we comment on certain non-local aspects of the quanta of modified dark matter, which may lead to novel non-particle phenomenology and which may explain why, so far, dark matter detection experiments have failed to detect dark matter particles

Testing Modified Dark Matter with Galaxy Clusters: Does Dark Matter know about the Cosmological Constant?

We discuss the possibility that the cold dark matter mass profiles contain information on the cosmological constant, and that such information constrains the nature of cold dark matter (CDM). We call this approach Modified Dark Matter (MDM). In particular, we examine the ability of MDM to explain the observed mass profiles of 13 galaxy clusters. Using general arguments from gravitational thermodynamics, we provide a theoretical justification for our MDM mass profile and successfully compare it to the NFW mass profiles both on cluster and galactic scales. Our results suggest that indeed the CDM mass profiles contain information about the cosmological constant in a non-trivial way

Testing MONDian Dark Matter with Galactic Rotation Curves

MONDian dark matter (MDM) is a new form of dark matter quantum that naturally accounts for Milgrom's scaling, usually associated with modified Newtonian dynamics (MOND), and theoretically behaves like cold dark matter (CDM) at cluster and cosmic scales. In this paper, we provide the first observational test of MDM by fitting rotation curves to a sample of 30 local spiral galaxies (z approximately 0.003). For comparison, we also fit the galactic rotation curves using MOND, and CDM. We find that all three models fit the data well. The rotation curves predicted by MDM and MOND are virtually indistinguishable over the range of observed radii (~1 to 30 kpc). The best-fit MDM and CDM density profiles are compared. We also compare with MDM the dark matter density profiles arising from MOND if Milgrom's formula is interpreted as Newtonian gravity with an extra source term instead of as a modification of inertia. We find that discrepancies between MDM and MOND will occur near the center of a typical spiral galaxy. In these regions, instead of continuing to rise sharply, the MDM mass density turns over and drops as we approach the center of the galaxy. Our results show that MDM, which restricts the nature of the dark matter quantum by accounting for Milgrom's scaling, accurately reproduces observed rotation curves.Comment: Preprint number IPMU13-0147. Accepted for publication in Ap

International trade agreements and international migration

Despite large potential economic gains to the countries concerned, bilateral and multilateral negotiations regarding liberalization of migration have not had the high profile of trade negotiations and agreements. Migration and trade have been traditionally the prerogative of different ministries, yet there are many interdependencies between international trade, foreign investment and migration. The relevance of these interdependencies for trade negotiations has been remarkably ignored in the literature. In this paper we therefore focus on the two-way interaction between international migration and agreements designed to enhance cross-border trade or investment. Liberalization of international trade in services and the movement of people are likely to offer much more significant economic gains than liberalization of remaining barriers to goods trade. However, progress within multilateral frameworks is fraught with difficulty. Mode IV of GATS is restricted to temporary movement of service employees and has yielded little progress so far. Negotiations within more flexible unilateral and bilateral frameworks are likely to be more successful in liberalizing the movement of labour. We discuss several specific examples and conclude that trade negotiations are increasingly accommodating migration policies that favour temporary migration over permanent migration and that the migration regulatory framework is likely to be further linked to trade and investment over time

T-Violation in K+→μ+νγK^+ \to \mu^+ \nu \gamma Decay And Supersymmetry

Measurement of the transverse muon polarization $P^{\bot}_{\mu}$ in the $K^+ \rightarrow \mu^+\nu\gamma$ decay will be attempted for the first time at the ongoing KEK E246 experiment and also at a proposed BNL experiment. We provide a general analysis of how $P^{\bot}_{\mu}$ is sensitive to the physical $CP$-violating phases in new physics induced four-Fermi interactions, and then we calculate the dominant contributions to $P^{\bot}_{\mu}$ from squark family mixings in generic supersymmetric models. Estimates of the upper bounds on $P^{\bot}_{\mu}$ are also given. It is found that a supersymmetry-induced right-handed quark current from $W$ boson exchange gives an upper limit on $P^{\bot}_{\mu}$ as large as a few per cent, whereas with charged-Higgs-exchange induced pseudoscalar interaction, $P^{\bot}_{\mu}$ is no larger than a few tenths of a per cent. Possible correlations between the muon polarization measurements in $K^+ \rightarrow \mu^+\nu\gamma$ and $K^+ \rightarrow \pi^0\mu^+\nu$ decays are discussed, and distinctive patterns of this correlation from squark family-mixings and from the three-Higgs-doublet model are noted.Comment: Revtex, 29 pages including 4 epsf figure

Brane World Scenarios and the Cosmological Constant

Brane world scenarios offer a way of ensuring that a Poincare invariant four dimensional world can emerge, without fine tuning, as a solution to the equations of motion of an effective action. We discuss the different ways in which this happens, and point out that the underlying reason is that there is a contribution to the effective cosmological constant which is a constant of integration, that maybe adjusted to ensure a flat space solution. Basically this is an old idea revived in a new context and we speculate that there may be string scenarios that provide a concrete realization of it. Finally we discuss to what extent this is a solution to the cosmological constant problem.Comment: Expanded discussion of the brane world scenario in type IIB. Version to be published in Nuclear Physics

Supersymmetric Time Reversal Violation in Semileptonic Decays of Charged Mesons

We provide a general analysis of time reversal violation arising from misalignment between quark and squark mass eigenstates. In particular, we focus on the possibility of large enhancement effects due to the top quark mass. For semileptonic decays of the charged mesons, $K^+ \rightarrow \pi^0 \mu^+ \nu_{\mu}$, $D^+ \rightarrow \overline{K}^0 \mu^+ \nu_{\mu}$, and $B^+ \rightarrow \overline{D}^0 \tau^+ \nu_{\tau}$, the transverse polarization of the lepton $P^{\bot}_l$ is a $T$-odd observable that is of great experimental interest. It is noted that under favorable choice of parameters, $P^{\bot}_{\mu}$ in $K^+_{\mu3}$ decay can be detectable at the ongoing KEK experiment and it holds a promising prospect for discovery at the proposed BNL experiment. Furthermore, $P^{\bot}_{\tau}$ in $B^{\pm}$ decay could well be within the reach of $B$ factories, but $P^{\bot}_{\mu}$ in $D^{\pm}$ decay is not large enough for detection at the proposed $\tau$-charm factory.Comment: LaTex, 14 pages, 2 figures, minor changes, version to appear in Phys. Lett.

Body mass index and motor coordination: Non-linear relationships in children 6–10 years

Background: Given the concern for health-related consequences of an elevated body mass index (BMI; obesity), the potential consequences of a low BMI in children are often overlooked. The purpose was to evaluate the relationship between the BMI across its entire spectrum and motor coordination (MC) in children 6–10 years. Methods: Height, weight, and MC (Körperkoordinationstest für Kinder, KTK test battery) were measured in 1,912 boys and 1,826 girls of 6–10 years of age. BMI (kg/m2) was calculated. KTK scores for each of the four tests were also converted to a motor quotient (MQ). One-way ANOVA was used to test differences in the BMI, individual test items, and MQ among boys and girls within age groups. Sex-specific quadratic regressions of individual KTK items and the MQ on the BMI were calculated. Girls and boys were also classified into four weight status groups using International Obesity Task Force criteria: thin, normal, overweight, and obese. Differences in specific test items and MQ between weight status groups were evaluated by age group in each sex. Results: Thirty-one percent of the sample was overweight or obese, whereas 5% was thin. On average, normal weight children had the highest MQ in both sexes across the age range with few exceptions. Overweight/obese children had a lower MQ than normal weight and thin children. The quadratic regression lines generally presented an inverted parabolic relationship between the BMI and MC and suggested a decrease in MC with an increase in the BMI. Conclusion: In general, BMI shows a curvilinear, inverted parabolic relationship with MC in children 6–10 years.Portuguese Foundation for Science and Technology, Grant/Award Numbers: DTP/04045/ 2013, POCI‐01‐0145‐FEDER‐006969, UID/DTP/00617/2013 and POCI‐01‐0145‐ FEDER‐006969; NORTE 2020, Grant/Award Number: NORTE‐01‐0145‐FEDER‐000016info:eu-repo/semantics/publishedVersio