Invariance under the charge, parity, time-reversal (CPT) transformation is one of the fundamental symmetries of the standard model of particle physics. This CPT invariance implies that the ...fundamental properties of antiparticles and their matter-conjugates are identical, apart from signs. There is a deep link between CPT invariance and Lorentz symmetry--that is, the laws of nature seem to be invariant under the symmetry transformation of spacetime--although it is model dependent. A number of high-precision CPT and Lorentz invariance tests--using a co-magnetometer, a torsion pendulum and a maser, among others--have been performed, but only a few direct high-precision CPT tests that compare the fundamental properties of matter and antimatter are available. Here we report high-precision cyclotron frequency comparisons of a single antiproton and a negatively charged hydrogen ion (H(-)) carried out in a Penning trap system. From 13,000 frequency measurements we compare the charge-to-mass ratio for the antiproton (q/m)p- to that for the proton (q/m)p and obtain (q/m)p-/(q/m)p − 1 =1(69) × 10(-12). The measurements were performed at cyclotron frequencies of 29.6 megahertz, so our result shows that the CPT theorem holds at the atto-electronvolt scale. Our precision of 69 parts per trillion exceeds the energy resolution of previous antiproton-to-proton mass comparisons as well as the respective figure of merit of the standard model extension by a factor of four. In addition, we give a limit on sidereal variations in the measured ratio of <720 parts per trillion. By following the arguments of ref. 11, our result can be interpreted as a stringent test of the weak equivalence principle of general relativity using baryonic antimatter, and it sets a new limit on the gravitational anomaly parameter of |α − 1| < 8.7 × 10(-7).
The experimental results on the ratios of branching fractions R(D)=B(Bover ¯→Dτ^{-}νover ¯_{τ})/B(Bover ¯→Dℓ^{-}νover ¯_{ℓ}) and R(D^{*})=B(Bover ¯→D^{*}τ^{-}νover ¯_{τ})/B(Bover ¯→D^{*}ℓ^{-}νover ...¯_{ℓ}), where ℓ denotes an electron or a muon, show a long-standing discrepancy with the standard model predictions, and might hint at a violation of lepton flavor universality. We report a new simultaneous measurement of R(D) and R(D^{*}), based on a data sample containing 772×10^{6} BBover ¯ events recorded at the ϒ(4S) resonance with the Belle detector at the KEKB e^{+}e^{-} collider. In this analysis the tag-side B meson is reconstructed in a semileptonic decay mode and the signal-side τ is reconstructed in a purely leptonic decay. The measured values are R(D)=0.307±0.037±0.016 and R(D^{*})=0.283±0.018±0.014, where the first uncertainties are statistical and the second are systematic. These results are in agreement with the standard model predictions within 0.2, 1.1, and 0.8 standard deviations for R(D), R(D^{*}), and their combination, respectively. This work constitutes the most precise measurements of R(D) and R(D^{*}) performed to date as well as the first result for R(D) based on a semileptonic tagging method.
We present a measurement of R_{K^{*}}, the branching fraction ratio B(B→K^{*}μ^{+}μ^{-})/B(B→K^{*}e^{+}e^{-}), for both charged and neutral B mesons. The ratio for the charged case R_{K^{*+}} is the ...first measurement ever performed. In addition, we report absolute branching fractions for the individual modes in bins of the squared dilepton invariant mass q^{2}. The analysis is based on a data sample of 711 fb^{-1}, containing 772×10^{6} BBover ¯ events, recorded at the ϒ(4S) resonance with the Belle detector at the KEKB asymmetric-energy e^{+}e^{-} collider. The obtained results are consistent with standard model expectations.
Purpose We determined if ileal/colonic bladder augmentation performed in patients with congenital bladder abnormalities is an independent risk factor for bladder malignancy. Materials and Methods We ...reviewed a registry of patients with bladder dysfunction due to neurological abnormalities, exstrophy and posterior urethral valves. Individuals treated with augmentation cystoplasty were matched (1:1) to a control group treated with intermittent catheterization based on etiology of bladder dysfunction, gender and age (± 2 years). Results We evaluated 153 patients with an ileal/colonic cystoplasty and a matched control population. There was no difference (p = 0.54) in the incidence of bladder cancer in patients with augmentation cystoplasty (7 patients 4.6%) vs controls (4 2.6%). In addition, there was no difference between the 2 groups regarding age at diagnosis (51 vs 49.5 years, p >0.7), stage (3.4 vs 3.8, p >0.5), mortality rate (5 of 7 71% vs 4 of 4 100%, p >0.4) or median survival (18 vs 17 months, p >0.8). Irrespective of augmentation status patients with a history of renal transplant on chronic immunosuppression had a significantly higher incidence of bladder cancer (3 of 20 15%), compared to patients who were not immunosuppressed (8 of 286 2.8%, p = 0.03). Conclusions In patients with congenital bladder dysfunction ileal/colonic bladder augmentation does not appear to increase the risk of bladder malignancy over the inherent cancer risk associated with the underlying congenital abnormality. In addition, immunosuppression irrespective of bladder treatment is an independent risk factor for malignancy in this patient population.
The ability to avoid obstacles efficiently and safely is important for older adults to prevent injuries from tripping and falling. It is important to find an optimal spatial margin between the body ...and an obstacle considering both safety and efficiency. One side of finding the optimal margin is to decrease the margin in terms of motor efficiency. In this study, we tested whether fingertip-contact intervention to obtain haptic feedback information to perceive the relationship between body and the environment could immediately improve spatial perception and collision avoidance behavior (an instantaneous effect).
Twenty-seven older adults (12 males and 15 females) participated in the experiment. In the intervention of the fingertip-contact group, they lightly touched the edge of a door with both fingertips while walking. The test task before and after the intervention involved grasping a horizontal bar and passing through a narrow opening. As dependent variables, we measured the spatial margin and the collision rate.
The fingertip-contact group showed a significant decrease in the spatial margin after the intervention. On the other hand, there was no significant improvement in the collision rate after the intervention but rather a decrease only in the control group.
The results obtained in this study indicate that touching obstacles with the fingertips had an instantaneous effect, leading to efficient movement learning, although a possible side effect of an increased collision rated was also found. The proposed intervention might promote an efficiency-based strategy due to learning the spatial relationship between the body and the environment, and it may suppress the excessive avoidance of older adults.
Environmental radioactive contamination caused by the Fukushima Dai-ichi Nuclear Power Plant accident has aroused great concern regarding a possible increase in the incidence of childhood thyroid ...cancer. The ultrasound examinations were conducted immediately after the accident as part of the Fukushima Health Management Survey (FHMS), which is divided into the preliminary baseline survey (PBLS) and the full-scale survey (FSS). Some of their outcomes are reported regularly and made available to the public. We have detailed measurements of the air-dose rates and radioactive elements in soil in many places all over the Fukushima prefecture. To study the dose-response relationship, we begin with the assumption that the external and internal doses are correlated with the air-dose rate and the amount of
I in soil, respectively. We then investigate the relationship between these estimated doses and the PBLS and FSS thyroid cancer cases. Our analysis shows that the dose-response curve with the FSS data clearly differs from that with the PBLS data. Finally, we consider the potential mitigating effects of evacuation from highly contaminated areas in both external and internal exposure scenarios.
Our current understanding of the Universe comes, among others, from particle physics and cosmology. In particle physics an almost perfect symmetry between matter and antimatter exists. On ...cosmological scales, however, a striking matter/antimatter imbalance is observed. This contradiction inspires comparisons of the fundamental properties of particles and antiparticles with high precision. Here we report on a measurement of the g-factor of the antiproton with a fractional precision of 0.8 parts per million at 95% confidence level. Our value /2=2.7928465(23) outperforms the previous best measurement by a factor of 6. The result is consistent with our proton g-factor measurement g
/2=2.792847350(9), and therefore agrees with the fundamental charge, parity, time (CPT) invariance of the Standard Model of particle physics. Additionally, our result improves coefficients of the standard model extension which discusses the sensitivity of experiments with respect to CPT violation by up to a factor of 20.
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