Review of lattice results concerning low-energy particle physics

We review lattice results related to pion, kaon, [Formula: see text]- and [Formula: see text]-meson physics with the aim of making them easily accessible to the particle-physics community. More specifically, we report on the determination of the light-quark masses, the form factor [Formula: see text], arising in semileptonic [Formula: see text] transition at zero momentum transfer, as well as the decay-constant ratio [Formula: see text] of decay constants and its consequences for the CKM matrix elements [Formula: see text] and [Formula: see text]. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of [Formula: see text] and [Formula: see text] Chiral Perturbation Theory and review the determination of the [Formula: see text] parameter of neutral kaon mixing. The inclusion of heavy-quark quantities significantly expands the FLAG scope with respect to the previous review. Therefore, we focus here on [Formula: see text]- and [Formula: see text]-meson decay constants, form factors, and mixing parameters, since these are most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. In addition we review the status of lattice determinations of the strong coupling constant [Formula: see text].

Precise measurement of the neutrino mixing parameter θ23 from muon neutrino disappearance in an off-axis beam

New data from the T2K neutrino oscillation experiment produce the most precise measurement of the neutrino mixing parameter θ23. Using an off-axis neutrino beam with a peak energy of 0.6 GeV and a data set corresponding to 6.57×10(20) protons on target, T2K has fit the energy-dependent νμ oscillation probability to determine oscillation parameters. The 68% confidence limit on sin(2)(θ23) is 0.514(-0.056)(+0.055) (0.511±0.055), assuming normal (inverted) mass hierarchy. The best-fit mass-squared splitting for normal hierarchy is Δm32(2)=(2.51±0.10)×10(-3)  eV(2)/c(4) (inverted hierarchy: Δm13(2)=(2.48±0.10)×10(-3)  eV(2)/c(4)). Adding a model of multinucleon interactions that affect neutrino energy reconstruction is found to produce only small biases in neutrino oscillation parameter extraction at current levels of statistical uncertainty.

Observation of electron neutrino appearance in a muon neutrino beam

The T2K experiment has observed electron neutrino appearance in a muon neutrino beam produced 295 km from the Super-Kamiokande detector with a peak energy of 0.6 GeV. A total of 28 electron neutrino events were detected with an energy distribution consistent with an appearance signal, corresponding to a significance of 7.3σ when compared to 4.92±0.55 expected background events. In the Pontecorvo-Maki-Nakagawa-Sakata mixing model, the electron neutrino appearance signal depends on several parameters including three mixing angles θ12, θ23, θ13, a mass difference Δm(32)(2) and a CP violating phase δ(CP). In this neutrino oscillation scenario, assuming |Δm(32)(2)|=2.4×10(-3)  eV(2), sin(2)θ(23)=0.5, and Δm322>0 (Δm(32)(2)<0), a best-fit value of sin(2)2θ(13)=0.140(-0.032)(+0.038) (0.170(-0.037)(+0.045)) is obtained at δ(CP)=0. When combining the result with the current best knowledge of oscillation parameters including the world average value of θ(13) from reactor experiments, some values of δ(CP) are disfavored at the 90% C.L.

Measurement of neutrino oscillation parameters from muon neutrino disappearance with an off-axis beam

The T2K Collaboration reports a precision measurement of muon neutrino disappearance with an off-axis neutrino beam with a peak energy of 0.6 GeV. Near detector measurements are used to constrain the neutrino flux and cross section parameters. The Super-Kamiokande far detector, which is 295 km downstream of the neutrino production target, collected data corresponding to 3.01×10(20) protons on target. In the absence of neutrino oscillations, 205±17 (syst) events are expected to be detected while only 58 muon neutrino event candidates are observed. A fit to the neutrino rate and energy spectrum, assuming three neutrino flavors and normal mass hierarchy yields a best-fit mixing angle sin2(θ23)=0.514±0.082 and mass splitting |Δm(32)(2)|=2.44(-0.15)(+0.17)×10(-3) eV2/c4. Our result corresponds to the maximal oscillation disappearance probability.

An isocenter detection and verification device for use in proton therapy

We developed a new device for isocenter detection and verification for use in proton therapy. This device can be used to confirm the isocenters of a room laser, a digital radiography system, and a rotational gantry. Agreement between the isocenters of a room laser and a digital radiography system was examined visually. We used the star-shots method for detecting and verifying the rotational gantry isocenter. The gafchromic film could be irradiated with this method using a 2 mm slitted 200 MeV proton beam. The isocenters of a room laser and digital radiography system were in good agreement. The size distribution of the isocenter by the star-shots method was <2 mm, which is the value recommended by the American Association of Physicists in Medicine Task Group 142. This new device can be used to evaluate comprehensive isocenter detection and verification for related equipment. Subsequent checking using this new device will decrease the uncertainty in measuring an isocenter. When using this device, the working time was significantly reduced to about 30 min, including preparation. These measurements should be useful for high accuracy daily treatments.

Different patterns of fornix damage in idiopathic normal pressure hydrocephalus and Alzheimer disease

BACKGROUND AND PURPOSE

The fornix contains efferent fibers of the hippocampus and is in close contact with the corpus callosum. Part of the fornix is directly attached to the corpus callosum, and another part is suspended from the corpus callosum via the septum pellucidum. DTI can be used to evaluate the morphology and microstructural integrity of the fornix. We examined the pattern of fornix damage in patients with iNPH or AD.

MATERIALS AND METHODS

We enrolled 22 patients with iNPH, 20 with AD, and 20 healthy controls. DTI data were obtained. The morphology (volume, length, and mean cross-sectional area) and FA values of the fornix were evaluated by using tract-specific analysis and compared among groups.

RESULTS

The volume, cross-sectional area, and FA value of the fornix were significantly smaller in patients with iNPH than in controls, whereas the length was significantly greater. In patients with AD, the volume, mean cross-sectional area, and FA value of the fornix were significantly smaller than those in controls, whereas the length was not altered. The fornix was significantly longer in patients with iNPH than in patients with AD, whereas the volume and cross-sectional areas were significantly smaller.

CONCLUSIONS

Our results suggest that the different pathogeneses of these diseases lead to fornix damage through different mechanisms: through mechanical stretching due to lateral ventricular enlargement and corpus callosum deformation in patients with iNPH, and through degeneration secondary to hippocampal atrophy in patients with AD.

Retroperitoneal approach for laparoscopic nephroureterectomy with stripping technique: extracorporeal ligation of ureter and ureteral catheter

INTRODUCTION

The pluck and stripping techniques are used for lower ureter management in renal pelvic cancer patients. Herein, we report our experience of extracorporeal ligation of the ureter and the ureteral catheter through the trocar port, which differs from conventional laparoscopic ligation in the retroperitoneal space. This technique was selected to reduce the time needed for ureter management using the stripping technique and to provide secure ligation.

MATERIALS AND SURGICAL TECHNIQUE

We performed this stripping technique in patients with T1 and T2 stage renal pelvic cancer without imaging-evident lymph node metastasis. After transurethrally placing a ureteral catheter, we resected the circumference of the ureteral orifice. After laparoscopic nephrectomy via a retroperitoneal approach, the ureteral catheter and distal ureter were ligated extracorporeally. The catheter was pulled to invaginate the ureter so it could then be pulled through the external urethral orifice.

DISCUSSION

This technique of extracorporeal ligation ensures more a secure ligation of the ureter and ureteral catheter. This modified stripping technique does not require lower ureter management with laparotomy, and it is also useful in shortening the operative time. This method is effective for relatively early stage renal pelvic cancer.

White matter alteration of the cingulum in Parkinson disease with and without dementia: evaluation by diffusion tensor tract-specific analysis

BACKGROUND AND PURPOSE

In PD, the neurodegenerative process begins in the brain stem and extends to the limbic system and finally into the cerebral cortex. We used diffusion tensor tractography to investigate the FA of the cingulate fiber tracts in patients with PD with and without dementia.

MATERIALS AND METHODS

Fifteen patients with PD, 15 patients with PDD, and 15 age-matched healthy controls underwent diffusion tensor imaging with a 3T MR imager. Diffusion tensor tractography images of the anterior and posterior cingulate fiber tracts were generated. Mean diffusivity and FA were measured along the tractography of the anterior and posterior cingulate fiber tracts. One-way ANOVA with the Scheffé post hoc test was used to compare results among the groups.

RESULTS

FA was significantly lower in patients with PDD than in healthy controls in both the anterior and the posterior cingulate fiber tracts (P = .003, P = .015) and significantly lower in patients with PD than in healthy controls (P = .003) in the anterior cingulate fiber tract. There were no significant mean diffusivity differences among the groups. MMSE and FA values of the anterior cingulate fiber tracts in patients with PDD were significantly correlated (r = 0.633, P < .05).

CONCLUSIONS

The reduced FA in patients with PD and PDD might reflect neuropathologic changes such as Lewy body pathology in the cingulate fibers. This abnormality might contribute to the dementing process in PD.

White matter alteration in idiopathic normal pressure hydrocephalus: tract-based spatial statistics study

BACKGROUND AND PURPOSE

White matter alteration in iNPH has not been well-investigated. TBSS is a voxelwise statistical analysis developed for DTI data. We aimed to elucidate the cerebral white matter alteration in patients with iNPH by using DTI and to test the accuracy of TBSS analysis.

MATERIALS AND METHODS

DTI data were obtained from 20 patients with iNPH and 20 age- and sex-matched controls. The FA values were evaluated by using TBSS, region-of-interest and tract-specific analysis of the CST. The accuracy of TBSS analysis was tested by using "back-projection" of TBSS results and by comparing the TBSS analysis results with those of region-of-interest and tract-specific analysis.

RESULTS

Back-projection of the TBSS results showed accurate registration of the whole brain, with the exception of parts of the thalamus, fornix, and white matter around the posterior body of the lateral ventricle. The TBSS analysis results were consistent with those of the region-of-interest analysis and tract-specific analysis. In patients with iNPH compared with control subjects, the FA values were significantly decreased in parts of the corpus callosum, periventricular white matter, and juxtacortical white matter in the frontal and parietal lobes. In contrast, FA values were significantly increased in the internal capsule, extending to the white matter in the centrum semiovale.

CONCLUSIONS

Our results suggest that patients with iNPH have various patterns of white matter damage and that TBSS analysis is a promising tool for performing accurate voxelwise statistical analysis of the iNPH brain, with the exception of misregistered areas.

Dynamic alteration of regional cerebral blood flow during carotid compression and proof of reversibility

Background

It is difficult to non-invasively visualize changes in regional cerebral blood flow caused by manual compression of the carotid artery.

Purpose

To visualize dynamic changes in regional cerebral blood flow during and after manual compression of the carotid artery.

Material and Methods

Two healthy volunteers were recruited. Anatomic features and flow directions in the circle of Willis were evaluated with time-of-flight magnetic resonance angiography (MRA) and two-dimensional phase-contrast (2DPC) MRA, respectively. Regional cerebral blood flow was visualized with territorial arterial spin-labeling magnetic resonance imaging (TASL-MRI). TASL-MRI and 2DPC-MRA were performed in three states: at rest, during manual compression of the right carotid artery, and after decompression. In one volunteer, time-space labeling inversion pulse (Time-SLIP) MRA was performed to confirm collateral flow.

Results

During manual carotid compression, in one volunteer, the right thalamus changed to be fed only by the vertebrobasilar system, and the right basal ganglia changed to be fed by the left internal carotid artery. In the other volunteer, the right basal ganglia changed to be fed by the vertebrobasilar system. 2DPC-MRA showed that the flow direction changed in the right A1 segment of the anterior cerebral artery and the right posterior communicating artery. Perfusion patterns and flow directions recovered after decompression. Time-SLIP MRA showed pial vessels and dural collateral circulation when the right carotid artery was manually compressed.

Conclusion

Use of TASL-MRI and 2DPC-MRA was successful for non-invasive visualization of the dynamic changes in regional cerebral blood flow during and after manual carotid compression.

Altered microstructure in corticospinal tract in idiopathic normal pressure hydrocephalus: comparison with Alzheimer disease and Parkinson disease with dementia

BACKGROUND AND PURPOSE

Previous neuropathologic studies in chronic hydrocephalus have suggested the presence of white matter damage, presumably from mechanical pressure due to ventricular enlargement and metabolic derangement. This study aimed to investigate the diffusional properties of the CST in patients with iNPH by using DTI and to determine whether this method could be used as a new diagnostic tool to differentiate patients with iNPH from those with AD and PDD and control subjects.

MATERIALS AND METHODS

We enrolled 18 patients with iNPH, 11 patients with AD, 11 patients with PDD, and 19 healthy control subjects. Diffusion tensor metrics of the segmented CST, including FA values, axial eigenvalues, and radial eigenvalues, were evaluated by using tract-specific analysis. The anisotropy color-coding tractography of the CST was visually evaluated. The DTI findings were compared among groups.

RESULTS

Tract-specific analysis of the CST showed that FA values and axial eigenvalues were significantly increased (P < .001), whereas radial eigenvalues were not significantly altered, in patients with iNPH compared with other subjects. The CST tractographic images in patients with iNPH was visually different from those in other subjects (P < .001). In discriminating patients with iNPH from other subjects, the CST FA values had a sensitivity of 94% and specificity of 80% at a cutoff value of 0.59.

CONCLUSIONS

Our results suggest that patients with iNPH have altered microstructures in the CST. Quantitative and visual CST evaluation by using DTI may be useful for differentiating patients with iNPH from patients with AD or PDD or healthy subjects.

Indication of electron neutrino appearance from an accelerator-produced off-axis muon neutrino beam

The T2K experiment observes indications of ν(μ) → ν(e) appearance in data accumulated with 1.43×10(20) protons on target. Six events pass all selection criteria at the far detector. In a three-flavor neutrino oscillation scenario with |Δm(23)(2)| = 2.4×10(-3)  eV(2), sin(2)2θ(23) = 1 and sin(2)2θ(13) = 0, the expected number of such events is 1.5±0.3(syst). Under this hypothesis, the probability to observe six or more candidate events is 7×10(-3), equivalent to 2.5σ significance. At 90% C.L., the data are consistent with 0.03(0.04) < sin(2)2θ(13) < 0.28(0.34) for δ(CP) = 0 and a normal (inverted) hierarchy.

Superconducting yba2cu3o7‐x Thin Film on Metal Substrate by Chemical Vapor Deposition Process

Superconducting YBa2Cu307_x thin films were prepared by chemical vapor deposition using beta‐diketonate chelates on various oxide substrates and metal substrates. According to X‐ray diffraction patterns, the existence of a well‐oriented orthorhombic YBagCUgO^x structure has been confirmed in all specimens. The temperature of complete superconducting transition were observed at 89K on single‐crystalline oxide substrate, and 84K on metal substrate. Reduced critical current density of the film on single‐crystalline substrate in magnetic fields up to 600mT at 77K remained one or two order of magnitude higher than that of the film on metal substrate.