43,483 research outputs found
3D structure of hadrons by generalized distribution amplitudes and gravitational form factors
Generalized distribution amplitudes (GDAs) are one type of three-dimensional
structure functions, and they are related to the generalized distribution
functions (GPDs) by the - crossing of the Mandelstam variables. The GDA
studies provide information on three-dimensional tomography of hadrons. The
GDAs can be investigated by the two-photon process , and the GPDs are studied by the deeply virtual Compton scattering . The GDA studies had been pure theoretical topics, although the
GPDs have been experimentally investigated, because there was no available
experimental measurement. Recently, the Belle collaboration reported their
measurements on the differential cross
section, so that it became possible to find the GDAs from their measurements.
Here, we report our analysis of the Belle data for determining the pion GDAs.
From the GDAs, the timelike gravitational form factors and
can be calculated, which are mechanical (pressure, shear force)
and mass (energy) form factors, respectively. They are converted to the
spacelike form factors by using the dispersion relation, and then gravitational
radii are evaluated for the pion. The mass and mechanical radii are obtained
from and as fm and fm, whereas the experimental charge radius is fm for the charged pion. Future
developments are expected in this new field to explore gravitational physics in
the quark and gluon level.Comment: 6 pages, LaTeX, 1 style file, 8 figure files, Proceedings of the XXV
International Workshop on Deep-Inelastic Scattering and Related Subjects,
April 3-7, 2017, University of Birmingham, U
Bunching Transitions on Vicinal Surfaces and Quantum N-mers
We study vicinal crystal surfaces with the terrace-step-kink model on a
discrete lattice. Including both a short-ranged attractive interaction and a
long-ranged repulsive interaction arising from elastic forces, we discover a
series of phases in which steps coalesce into bunches of n steps each. The
value of n varies with temperature and the ratio of short to long range
interaction strengths. We propose that the bunch phases have been observed in
very recent experiments on Si surfaces. Within the context of a mapping of the
model to a system of bosons on a 1D lattice, the bunch phases appear as quantum
n-mers.Comment: 5 pages, RevTex; to appear in Phys. Rev. Let
The influence of relatives on the efficiency and error rate of familial searching
We investigate the consequences of adopting the criteria used by the state of
California, as described by Myers et al. (2011), for conducting familial
searches. We carried out a simulation study of randomly generated profiles of
related and unrelated individuals with 13-locus CODIS genotypes and YFiler
Y-chromosome haplotypes, on which the Myers protocol for relative
identification was carried out. For Y-chromosome sharing first degree
relatives, the Myers protocol has a high probability (80 - 99%) of identifying
their relationship. For unrelated individuals, there is a low probability that
an unrelated person in the database will be identified as a first-degree
relative. For more distant Y-haplotype sharing relatives (half-siblings, first
cousins, half-first cousins or second cousins) there is a substantial
probability that the more distant relative will be incorrectly identified as a
first-degree relative. For example, there is a 3 - 18% probability that a first
cousin will be identified as a full sibling, with the probability depending on
the population background. Although the California familial search policy is
likely to identify a first degree relative if his profile is in the database,
and it poses little risk of falsely identifying an unrelated individual in a
database as a first-degree relative, there is a substantial risk of falsely
identifying a more distant Y-haplotype sharing relative in the database as a
first-degree relative, with the consequence that their immediate family may
become the target for further investigation. This risk falls disproportionately
on those ethnic groups that are currently overrepresented in state and federal
databases.Comment: main text: 19 pages, 4 tables, 2 figures supplemental text: 2 pages,
5 tables all together as single fil
Evidence for a chemical-thermal structure at base of mantle from sharp lateral P-wave variations beneath Central America
Compressional waves that sample the lowermost mantle west of Central America show a rapid change in travel times of up to 4 s over a sampling distance of 300 km and a change in waveforms. The differential travel times of the PKP waves (which traverse Earth's core) correlate remarkably well with predictions for S-wave tomography. Our modeling suggests a sharp transition in the lowermost mantle from a broad slow region to a broad fast region with a narrow zone of slowest anomaly next to the boundary beneath the Cocos Plate and the Caribbean Plate. The structure may be the result of ponding of ancient subducted Farallon slabs situated near the edge of a thermal and chemical upwelling
Sacrificing Accuracy for Reduced Computation: Cascaded Inference Based on Softmax Confidence
We study the tradeoff between computational effort and accuracy in a cascade
of deep neural networks. During inference, early termination in the cascade is
controlled by confidence levels derived directly from the softmax outputs of
intermediate classifiers. The advantage of early termination is that
classification is performed using less computation, thus adjusting the
computational effort to the complexity of the input. Moreover, dynamic
modification of confidence thresholds allow one to trade accuracy for
computational effort without requiring retraining. Basing of early termination
on softmax classifier outputs is justified by experimentation that demonstrates
an almost linear relation between confidence levels in intermediate classifiers
and accuracy. Our experimentation with architectures based on ResNet obtained
the following results. (i) A speedup of 1.5 that sacrifices 1.4% accuracy with
respect to the CIFAR-10 test set. (ii) A speedup of 1.19 that sacrifices 0.7%
accuracy with respect to the CIFAR-100 test set. (iii) A speedup of 2.16 that
sacrifices 1.4% accuracy with respect to the SVHN test set
Geometric Phase, Hannay's Angle, and an Exact Action Variable
Canonical structure of a generalized time-periodic harmonic oscillator is
studied by finding the exact action variable (invariant). Hannay's angle is
defined if closed curves of constant action variables return to the same curves
in phase space after a time evolution. The condition for the existence of
Hannay's angle turns out to be identical to that for the existence of a
complete set of (quasi)periodic wave functions. Hannay's angle is calculated,
and it is shown that Berry's relation of semiclassical origin on geometric
phase and Hannay's angle is exact for the cases considered.Comment: Submitted to Phys. Rev. Lett. (revised version
In-medium modification of P-wave charmonia from QCD sum rules
We investigate the changes of the masses and widths of and
in hot gluonic matter near and in nuclear medium using QCD
sum rules. As in the previous works for the and , in-medium
effects are incorporated through the changes of gluon condensates. Twist-2
terms for the and are also included
for the first time. The results show that larger mass shifts and width
broadenings take place as compared to the -wave states. As the critical
change take place near , related measurements can reveal critical
phenomenon in QCD.Comment: 7 pages, 6 figures, to be published in Phys.Rev.
Predicting Solid-State Heats of Formation of Newly Synthesized Polynitrogen Materials by Using Quantum Mechanical Calculations
We present density functional theory level predictions and analysis of the basic properties of newly synthesized high-nitrogen compounds together with 3,6-bis(2H-tetrazol-5-yl)-1,2,4,5-tetrazine (BTT) and 3,3′-azobis(6-amino-1,2,4,5-tetrazine) (DAAT), for which experimental data are available. The newly synthesized high-nitrogen compounds are based on tricycle fused 1,2,4-triazine and 1,2,4,5-tetrazine heterocycles. In this work, the molecules BTT and DAAT have been studied in order to validate the theoretical approach and to facilitate further progress developments for the molecules of interest. Molecular structural properties are clarified, and IR spectra predictions are provided to help detection of those compounds in the experiment. The energy content of the molecules in the gas phase is evaluated by calculating standard enthalpies of formation, by using a special selection of isodesmic reaction paths. We also include estimates of the condensed-phase heats of formation and heats of sublimation in the framework of the Politzer approach. The obtained properties are consistent with those new high-nitrogen compounds being a promising set of advanced energetic materials
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