Recently, via calculation of spatial correlators of J=0,1 isovector operators using a chirally symmetric Dirac operator within NF=2 QCD, it has been found that QCD at temperatures Tc−3Tc is ...approximately SU(2)CS and SU(4) symmetric. The latter symmetry suggests that the physical degrees of freedom are chirally symmetric quarks bound by the chromoelectric field into color singlet objects without chromomagnetic effects. This regime of QCD has been referred to as a Stringy Fluid. Here we calculate correlators for propagation in time direction at a temperature slightly above Tc and find the same approximate symmetries. This means that the meson spectral function is chiral-spin and SU(4) symmetric in the same temperature range.
FLAG Review 2021 Aoki, Y.; Blum, T.; Colangelo, G. ...
The European physical journal. C, Particles and fields,
10/2022, Letnik:
82, Številka:
10
Journal Article
Recenzirano
Odprti dostop
We review lattice results related to pion, kaon,
D
-meson,
B
-meson, and nucleon physics with the aim of making them easily accessible to the nuclear and particle physics communities. More ...specifically, we report on the determination of the light-quark masses, the form factor
f
+
(
0
)
arising in the semileptonic
K
→
π
transition at zero momentum transfer, as well as the decay constant ratio
f
K
/
f
π
and its consequences for the CKM matrix elements
V
us
and
V
ud
. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of
S
U
(
2
)
L
×
S
U
(
2
)
R
and
S
U
(
3
)
L
×
S
U
(
3
)
R
Chiral Perturbation Theory. We review the determination of the
B
K
parameter of neutral kaon mixing as well as the additional four
B
parameters that arise in theories of physics beyond the Standard Model. For the heavy-quark sector, we provide results for
m
c
and
m
b
as well as those for the decay constants, form factors, and mixing parameters of charmed and bottom mesons and baryons. These are the heavy-quark quantities most relevant for the determination of CKM matrix elements and the global CKM unitarity-triangle fit. We review the status of lattice determinations of the strong coupling constant
α
s
. We consider nucleon matrix elements, and review the determinations of the axial, scalar and tensor bilinears, both isovector and flavor diagonal. Finally, in this review we have added a new section reviewing determinations of scale-setting quantities.
We review lattice results related to pion, kaon,
D
- and
B
-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
f
+
(
0
)
, arising in semileptonic
K
→
π
transition at zero momentum transfer, as well as the decay-constant ratio
f
K
/
f
π
of decay constants and its consequences for the CKM matrix elements
V
u
s
and
V
u
d
. Furthermore, we describe the results obtained on the lattice for some of the low-energy constants of
SU
(
2
)
L
×
SU
(
2
)
R
and
SU
(
3
)
L
×
SU
(
3
)
R
Chiral Perturbation Theory and review the determination of the
B
K
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
D
- and
B
-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
α
s
.
Intergroup bias, which is the tendency to behave more positively toward an in‐group member than toward an out‐group member, is pervasive in real life. In particular, intergroup bias in trust ...decisions substantially influences multiple areas of life and thus better understanding of this tendency can provide significant insights into human social behavior. Although previous functional magnetic resonance imaging studies showed the involvement of the right temporoparietal junction (TPJ) in intergroup trust bias, a causal relationship between the two has rarely been explored. By combining repetitive transcranial magnetic stimulation and a newly developed trust game task, we investigated the causal role of the right TPJ in intergroup bias in trust decisions. In the trust game task, the counterpart's group membership (in‐group or out‐group) and reciprocity were manipulated. We applied either neuronavigated inhibitory continuous theta burst stimulation (cTBS) or sham stimulation over the right TPJ before performing the trust game task in healthy volunteers. After the sham stimulation, the participants' degrees of investments with in‐group members were significantly higher than those with out‐group members. However, after cTBS to the right TPJ, this difference was not observed. The current results extend previous findings by showing that the causal roles of the right TPJ can be observed in intergroup bias in trust decisions. Our findings add to our understanding of the mechanisms of human social behavior.
The neuropeptide oxytocin may be an effective therapeutic strategy for the currently untreatable social and communication deficits associated with autism. Our recent paper reported that oxytocin ...mitigated autistic behavioral deficits through the restoration of activity in the ventromedial prefrontal cortex (vmPFC), as demonstrated with functional magnetic resonance imaging (fMRI) during a socio-communication task. However, it is unknown whether oxytocin exhibited effects at the neuronal level, which was outside of the specific task examined. In the same randomized, double-blind, placebo-controlled, within-subject cross-over clinical trial in which a single dose of intranasal oxytocin (24 IU) was administered to 40 men with high-functioning autism spectrum disorder (UMIN000002241/000004393), we measured N-acetylaspartate (NAA) levels, a marker for neuronal energy demand, in the vmPFC using (1)H-magnetic resonance spectroscopy ((1)H-MRS). The differences in the NAA levels between the oxytocin and placebo sessions were associated with oxytocin-induced fMRI signal changes in the vmPFC. The oxytocin-induced increases in the fMRI signal could be predicted by the NAA differences between the oxytocin and placebo sessions (P=0.002), an effect that remained after controlling for variability in the time between the fMRI and (1)H-MRS scans (P=0.006) and the order of administration of oxytocin and placebo (P=0.001). Furthermore, path analysis showed that the NAA differences in the vmPFC triggered increases in the task-dependent fMRI signals in the vmPFC, which consequently led to improvements in the socio-communication difficulties associated with autism. The present study suggests that the beneficial effects of oxytocin are not limited to the autistic behavior elicited by our psychological task, but may generalize to other autistic behavioral problems associated with the vmPFC.
The transition temperature (Tc) of QCD is determined by Symanzik improved gauge and stout-link improved staggered fermionic lattice simulations. We use physical masses both for the light quarks (mud) ...and for the strange quark (ms). Four sets of lattice spacings (Nt=4, 6, 8 and 10) were used to carry out a continuum extrapolation. It turned out that only Nt=6, 8 and 10 can be used for a controlled extrapolation, Nt=4 is out of the scaling region. Since the QCD transition is a non-singular cross-over there is no unique Tc. Thus, different observables lead to different numerical Tc values even in the continuum and thermodynamic limit. The peak of the renormalized chiral susceptibility predicts Tc=151(3)(3) MeV, wheres Tc-s based on the strange quark number susceptibility and Polyakov loops result in 24(4) MeV and 25(4) MeV larger values, respectively. Another consequence of the cross-over is the non-vanishing width of the peaks even in the thermodynamic limit, which we also determine. These numbers are attempted to be the full result for the T≠0 transition, though other lattice fermion formulations (e.g. Wilson) are needed to cross-check them.
Magma stored beneath volcanoes is sometimes transported out of the magma chambers by means of laterally propagating dikes, which can lead to fissure eruptions if they intersect the Earth's surface. ...The driving force for lateral dike propagation can be a lateral tectonic stress gradient, the stress gradient due to the topographic loads, the overpressure of the magma chamber, or a combination of those forces.
The 2000 dike intrusion at Miyakejima volcano, Izu arc, Japan, propagated laterally for about 30 km and stopped in correspondence of a strike-slip system, sub-perpendicular to the dike plane. Then the dike continued to inflate, without further propagation. Abundant seismicity was produced, including five M>6 earthquakes, one of which occurred on the pre-existing fault system close to the tip of the dike, at approximately the time of arrest. It has been proposed that the main cause for the dike arrest was the fault-induced stress.
Here we use a boundary element numerical approach to study the interplay between a propagating dike and a pre-stressed strike-slip fault and check the relative role played by dike–fault interaction and topographic loading in arresting the Miyakejima dike. We calibrate the model parameters according to previous estimates of dike opening and fault displacement based on crustal deformation observations. By computing the energy released during the propagation, our model indicates whether the dike will stop at a given location. We find that the stress gradient induced by the topography is needed for an opening distribution along the dike consistent with the observed seismicity, but it cannot explain its arrest at the prescribed location. On the other hand, the interaction of dike with the fault explains the arrest but not the opening distribution. The joint effect of the topographic load and the stress interaction with strike-slip fault is consistent with the observations, provided the pre-existing fault system is pre-loaded with a significant stress, released gradually during the dike–fault interplay.
Our results reveal how the mechanical interaction between dikes and faults may affect the propagation of magmatic intrusions in general. This has implications for our understanding of the geometrical arrangement of rift segments and transform faults in Mid Ocean Ridges, and for the interplay between dikes and dike-induced graben systems.
•We simulate the arrest of the 2000 Miyakejima dike by means of a 2D mechanical model.•We consider the mechanical interaction of the intrusion with a strike slip fault.•We account for the lateral pressure gradient induced by topography slopes.•We compute the expected distance traveled by the dike and its shape.•The stress transfer between dike and fault was the main cause for the dike arrest.
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•Cu/CeO2 contains three CuO species, isolated Cu2+, CuO film, and CuO particle.•CuO film shows the highest NO–CO reaction activity than the other species.•Reduction of Cu–O–Ce ...interface is highly important for Cu/CeO2 catalytic activity.
The stoichiometric NO–CO reaction was studied over Cu/CeO2 catalysts prepared with different Cu loadings and specific surface areas of CeO2 to investigate the relationship between catalytic activity and the copper–ceria interaction. XRD, ESR and H2-TPR results revealed that CuO species interacted with CeO2 in three structurally different forms: isolated Cu2+, a highly dispersed CuO film, and large CuO particles. The CuO film showed a higher NO–CO reaction activity than the other species. An Operando XAFS study revealed that the reduction of the CuO film during the NO–CO reaction occurred at the Cu–O–Ce interface. Thus, we concluded that the most suitable CuO structure to effectively exploit Cu–O–Ce interface sites in the NO–CO reaction is a two-dimensionally dispersed CuO film.
Based on a complete set of J = 0 and J = 1 spatial isovector correlation functions calculated with NF = 2 domain wall fermions we identify an intermediate temperature regime of T~220–500 MeV ...(1.2Tc–2.8Tc), where chiral symmetry is restored but the correlators are not yet compatible with a simple free quark behavior. More specifically, in the temperature range T~220–500 MeV we identify a multiplet structure of spatial correlators that suggests emergent SU(2)CS and SU(4) symmetries, which are not symmetries of the free Dirac action. The symmetry breaking effects in this temperature range are less than 5%. Our results indicate that at these temperatures the chromomagnetic interaction is suppressed and the elementary degrees of freedom are chirally symmetric quarks bound into color-singlet objects by the chromoelectric component of the gluon field. At temperatures between 500 and 660 MeV the emergent SU(2)CS and SU(4) symmetries disappear and one observes a smooth transition to the regime above T~1 GeV where only chiral symmetries survive, which are finally compatible with quasifree quarks.
Seismic anisotropy, the directional dependence of wave speeds, may be caused by stress-oriented cracks or by strain-oriented minerals, yet few studies have quantitatively compared anisotropy to ...stress and strain over large regions. Here we compare crustal stress and strain rates on the Island of Kyushu, Japan, as measured from inversions of focal mechanisms, GPS and shear wave splitting. Over 85,000 shear wave splitting measurements from local and regional earthquakes are obtained from the NIED network between 2004 and 2012, and on Aso, Sakurajima, Kirishima and Unzen volcano networks. Strain rate measurements are made from the Japanese Geonet stations. JMA-determined S arrival times processed with the MFAST shear wave splitting code measure fast polarisations (Φ), related to the orientation of the anisotropic medium and time delays (dt), related to the path length and the percent anisotropy. We apply the TESSA 2-D delay time tomography and spatial averaging code to the highest quality events, which have nearly vertical incidence angles, separating the 3455 shallow (depth < 40 km) from the 4957 deep (>=40 km) earthquakes. Using square grids with 30 km sides for all the inversions, the best correlations are observed between splitting from shallow earthquakes and stress. Axes of maximum horizontal stress (SHmax) and Φ correlate with a coefficient c of 0.56, significant at the 99% confidence level. Their mean difference is 31.9°. Axes of maximum compressional strain rate and SHmax are also well aligned, with an average difference of 28°, but they do not correlate with each other, meaning that where they differ, the difference is not systematic. Anisotropy strength is negatively correlated with the stress ratio parameter determined from focal mechanism inversion (c=−0.64; significant at the 99% confidence level). The anisotropy and stress results are consistent with stress-aligned microcracks in the crust in a dominantly strike-slip regime. Eigenvalues of maximum horizontal strain rate correlate positively with stress ratio (c=0.43, significant at 99% confidence). All three orientations are E–W in central Kyushu, where the compressional strain rate is highest. Both splitting and stress suggest plate-boundary-parallel maximum principal stress just off the coast of Kyushu, where strain rate measurements are sparse. South western Kyushu has the largest difference between directions of strain rate and stress. Φ from shallow and deep earthquakes are not well aligned, suggesting that the deep earthquake waveforms are not simply split in the crust. Causes for the anisotropy may be olivine crystals aligned by drag of the subducting Philippine Sea plate in the mantle and stress-aligned microcracks in the crust.
•Shallow earthquake fast directions (ϕ) correlate well with maximum horizontal stress.•Delay times correlate with stress ratio R.•Stress-controlled cracks in strike-slip strain regime explain these observations.•Structure-controlled ϕ along shearing Median Tectonic Line.•ϕ from deep earthquakes may record mantle flow patterns.
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