Right-handed Neutrinos as Superheavy Dark Matter

We propose that right-handed neutrinos are very long-lived dark matter. The long lifetime is realized by the separation of the wavefunction of right-handed neutrinos and that of other fermions in an extra dimension. Such long-lived and superheavy dark matter can naturally explain observed ultra high energy cosmic rays above the GZK cutoff (5 * 10^{19} eV) and huge amounts of cold dark matter simultaneously. Furthermore, the exponentially suppressed Yukawa couplings of right-handed neutrinos leads to the high predictablilty on the mass parameter of the neutrinoless double beta decay, as all the models which predict very small neutrino mass of one generation.Comment: 11 pages, 5 figures, to appear in JHE

Neutrinoless Double Beta Decay with R-parity Violation

We consider recently observed neutrinoless double beta decay in the context of the minimal supersymmetric standard model with R-parity violating couplings lambda^{'}. We observe that most of the current experimental bounds on the R-parity violating couplings do not exclude the possibility that the neutrinoless double beta decay is caused by R-parity violation. But if we consider K-bar{K} oscillation, we observe that we have to make the R-parity violating couplings generation-dependent to accomodate with the observed neutrinoless double beta decay. And furthermore, we need some mechanism to cancel the contribution to K-bar{K} mixing from a large R-parity violating coupling. We realized this cancellation by assuming that the first- and the second- generation of quark sector do not couple with the first-generation lepton sector by R-parity violating couplings except the term W=lambda_{111}^{'} L_{1} Q_{1} D_{1}^{c}, which is responsible for the observed neutrinoless double beta decay.Comment: 9 pages, 2 figures. Version 3, reference error was correcte

Preoperative Use of Alpha-1 Receptor Blockers in Male Patients Undergoing Extracorporeal Shock Wave Lithotripsy for a Ureteral Calculus

In this retrospective single-center cohort study, we investigated the impact of preoperative use of an alpha-1 adrenergic receptor (AR) blocker on the outcome of single-session extracorporeal shock wave lithotripsy (SWL) in 193 male patients who underwent SWL for a single ureteral calculus between 2006 and 2016. We reviewed their medical records to obtain the data on the preoperative use of alpha-1 AR blockers. The primary outcome was treatment success after single-session SWL. We performed a multivariable logistic regression analysis adjusting for clinically important confounders to examine the association between preoperative use of alpha-1 AR blockers and the treatment success of SWL. Among the 193 patients, 15 (7.8%) were taking an alpha-1 AR blocker preoperatively. A multivariable analysis showed that preoperative use of an alpha-1 AR blocker was a significant negative predictor for treatment success of SWL (adjusted odds ratio 0.17; 95% confidence intervals, 0.04-0.74). Our findings suggest that the preoperative use of an alpha-1 AR blocker was a negative predictor of treatment success of SWL in male patients with a single ureteral calculus. Clinicians should pay more attention to the preoperative drug use in determining an appropriate stone therapy modality

Ultra High Energy Cosmic Ray, Superheavy Dark Matter and Extra Dimension

We propose a new mechanism for explaining the very long lifetime of superheavy dark matter X, which is proposed as a source of the ultra high-energy cosmic rays above the GZK cutoff (5 \times 10^{19} eV). The singlet X particle couples to the MSSM particles only through a bulk singlet field which develops the v.e.v. in the ``hidden'' brane. The distance between this hidden brane and the ``visible'' brane naturally leads to the exponential suppression of the coupling. The X particle decays predominantly into the higgsino and higgs boson of the MSSM, and its decay spectrum is completely determined once their properties are known.Comment: 7 pages, no figures. To appear in Phys.Lett.