Right-handed sneutrino as thermal dark matter

We study an extension of the MSSM with a singlet S with coupling SH1H2 in order to solve the mu problem as in the NMSSM, and right-handed neutrinos N with couplings SNN in order to generate dynamically electroweak-scale Majorana masses. We show how in this model a purely right-handed sneutrino can be a viable candidate for cold dark matter in the Universe. Through the direct coupling to the singlet, the sneutrino can not only be thermal relic dark matter but also have a large enough scattering cross section with nuclei to detect it directly in near future, in contrast with most of other right-handed sneutrino dark matter models.Comment: 5 pages, 2 figures. References added and minor changes. Final version to appear in Phys. Rev.

Hiding cosmic strings in supergravity D-term inflation

The influence of higher-order terms in the K\"{a}hler potential of the supergravity D-term inflation model on the density perturbation is studied. We show that these terms can make the inflaton potential flatter, which lowers the energy scale of inflation under the COBE/WMAP normalization. As a result, the mass per unit length of cosmic strings, which are produced at the end of inflation, can be reduced to a harmless but detectable level without introducing a tiny Yukawa coupling. Our scenario can naturally be implemented in models with a low cut-off as in Type I or Type IIB orientifold models.Comment: 15 pages, 4 figure

Reheating and gravitino production in braneworld inflation

We consider the constraints that can be imposed on a wide class of Inflation models in modified gravity scenarios in which the Friedmann equation is modified by the inclusion of $\rho^2$ terms, where $\rho$ is the total energy density. In particular we obtain the reheating temperature and gravitino abundance associated with the end of inflation. Whereas models of chaotic inflation and natural inflation can easily avoid the conventional gravitino overproduction problem, we show that supersymmetric hybrid inflation models (driven by both F and D-terms) do not work in the $\rho^2$ dominated era. We also study inflation driven by exponetial potentials in this modified background, and show that the gravitino production is suppressed enough to avoid there being a problem, although other conditions severely constrain these models.Comment: 24page

Relativistic Resonant Relations between Massive Black Hole Binary and Extreme Mass Ratio Inspiral

One component of a massive black hole binary (MBHB) might capture a small third body, and then a hierarchical, inclined triple system would be formed. With the post-Newtonian approximation including radiation reaction, we analyzed the evolution of the triple initially with small eccentricities. We found that an essentially new resonant relation could arise in the triple system. Here relativistic effects are crucial. Relativistic resonances, including the new one, stably work even for an outer MBHB of comparable masses, and significantly change the orbit of the inner small body.Comment: 9 pages, 5 figures, to appear in PR

Light wino dark matter in brane world cosmology

The thermal relic density of the wino-like neutralino dark matter in the brane world cosmology is studied. The expansion law at a high energy regime in the brane world cosmology is modified from the one in the standard cosmology, and the resultant relic density can be enhanced if the five dimensional Planck mass $M_5$ is low enough. We calculate the wino-like neutralino relic density in the anomaly mediated supersymmetry breaking scenario and show that the allowed region is dramatically modified from the one in the standard cosmology and the wino-like neutralino with mass of order 100 GeV can be a good candidate for the dark matter. Since the allowed region disappears eventually as $M_5$ is decreasing, we can find a lower bound on $M_5 \gtrsim 100$ TeV according to the neutralino dark matter hypothesis, namely the lower bound in order for the allowed region of the neutralino dark matter to exist.Comment: 16 pages, 9 figures, final versio

Neutralino dark matter in brane world cosmology

The thermal relic density of the neutralino dark matter in the brane world cosmology is studied. Since the expansion law at a high energy regime in the brane world cosmology is modified from the one in the standard cosmology, the resultant relic density can be altered. It has been found that, if the five dimensional Planck mass $M_5$ is lower than $10^4$ TeV, the brane world cosmological effect is significant at the decoupling time and the resultant relic density is enhanced. We calculate the neutralino relic density in the Constrained Minimal Supersymmetric Standard Model (CMSSM) and show that the allowed region is dramatically modified from the one in the standard cosmology and eventually disappears as $M_5$ is decreasing. We also find a new lower bound on $M_5 \gtrsim 600$ TeV based on the neutralino dark matter hypothesis, namely the lower bound in order for the allowed region of the neutralino dark matter to exist.Comment: 12 pages, 8 figure

Thermal leptogenesis in brane world cosmology

The thermal leptogenesis in brane world cosmology is studied. In brane world cosmology, the expansion law is modified from the four-dimensional standard cosmological one at high temperature regime in the early universe. As a result, the well-known upper bound on the lightest light neutrino mass induced by the condition for the out-of-equilibrium decay of the lightest heavy neutrino, $\tilde{m}_1 \lesssim 10^{-3}$ eV, can be moderated to be $\tilde{m}_1 \lesssim 10^{-3} {eV} \times (M_1/T_t)^2$ in the case of $T_t \leq M_1$ with the lightest heavy neutrino mass ($M_1$) and the ``transition temperature'' ($T_t$), at which the modified expansion law in brane world cosmology is smoothly connecting with the standard one. This implies that the degenerate mass spectrum of the light neutrinos can be consistent with the thermal leptogenesis scenario. Furthermore, as recently pointed out, the gravitino problem in supersymmetric case can be solved if the transition temperature is low enough $T_t \lesssim 10^{6-7}$ GeV. Therefore, even in the supersymmetric case, thermal leptogenesis scenario can be successfully realized in brane world cosmology.Comment: 9 pages, final versio

Signature of the Overhauser field on the coherent spin dynamics of donor-bound electron in a single CdTe quantum well

We have studied the coherent spin dynamics in an oblique magnetic field of electrons localized on donors and placed in the middle of a single CdTe quantum well, by using a time-resolved optical technique: the photo-induced Faraday rotation. We showed that this dynamics is affected by a weak Overhauser field created via the hyperfine interaction of optically spin-polarized donor-bound electrons with the surrounding nuclear isotopes carrying non-zero spins. We have measured this nuclear field, which is on the order of a few mT and can reach a maximum experimental value of 9.4 mT. This value represents 13 % of the maximal nuclear polarization, and corresponds also to 13 % of maximal electronic polarization.Comment: 15 pages, 4 figure

A Survey of the Use of Physical Agents and Therapeutic Modalities in Physical Therapy

Background and Purpose. It is desirable that physical therapy programs update their curricula according to the clinical application patterns of physical agents and therapeutic modalities in physical therapy. The purpose of this study is to 1) determine the frequency of use of physical agents and therapeutic modalities, 2) determine the factors in deciding which physical agent or therapeutic modality to use, 3) determine the educational coverage of each physical agent or therapeutic modality and identify strengths and weaknesses of the respondents training, and 4) compare the frequency of use with the current training in physical agents and therapeutic modalities at the University of North Dakota\u27s physical therapy program (UND-PT). Subjects and Methods. A survey was sent to 690 physical therapists at 230 clinical sites in the United States affiliated with the UNO-PT. It consisted of seven sections: thermomodalities, electromodalities, mechanical agents, hydromodalities, educational coverage, open-ended questions, and demographic information. The data were analyzed and the results are depicted within this study. Results. The three most frequently used physical agents or therapeutic modalities were cold packs (x = 19 ± 23 times/week), ultrasound (x = 17 ± 23 times/week), and hot packs (x = 15 ± 23 times/week). Primary practice setting influenced the choice of the three most used modalities, with a markedly greater use of physical agents and therapeutic modalities in the outpatient orthopedics and sports medicine settings. The three most important factors in deciding which physical agent or therapeutic modality to use were the purpose/availability/ease of application of the physical agent or therapeutic modality (18%), patient signs and symptoms (16%), and effectiveness (15%). The three most frequent strengths of the respondents\u27 educational coverage were the amount of lab time spent practicing to use the modalities (32%), depth of coverage (22%), and variety of coverage (20%). The four most frequently perceived limitations of educational coverage were practice time (25%), depth of coverage for the entire course (13%), equipment concerns (13%), and a limited emphasis on research (13%). We consider the coverage of physical agents and therapeutic modalities at UND-PT to be consistent with the results of our survey. Discussion and Conclusion. A sparse amount of research on this topic exists, limiting comparisons between studies, which could account for many differences. These differences existed in geographical regions, time span between studies, and the narrow scope of clinical settings and modalities studied. Currently, reimbursement issues, evidence-based practice, and clinical effectiveness influence the frequency of use of physical agents and therapeutic modalities. Further research is needed on the use of physical agents and therapeutic modalities across practice settings and clinical experience. Further research can also be studied on a broader population base