16,466 research outputs found
Strange Quark Contribution to the Proton Spin, from Elastic and Scattering
The strangeness contribution to the vector and axial form factors of the
proton is presented for momentum transfers in the range 0.45 < < 1.0
GeV. The results are obtained via a combined analysis of forward-scattering
parity-violating elastic asymmetry data from the G0 and HAPPEx
experiments at Jefferson Lab, and elastic and scattering
data from Experiment 734 at Brookhaven National Laboratory. The combination of
the two data sets allows for the simultaneous extraction of , ,
and over a significant range of for the very first time.
Determination of the strange axial form factor is vital to an
understanding of the strange quark contribution to the proton spin.Comment: 4 pages, 1 figure; proceedings for SPIN 2006; will be published in
AIP Conference Proceeding
PHENIX Measurement of Parity-Violating Single Spin Asymmetry in W Production in p+p Collisions at 500 GeV
The flavor-separated polarized parton distribution functions for light quarks
and anti-quarks in the proton can be studied in the production of bosons in
+ collisions. The s are produced in processes like
and and we observe the
lepton (an electron or muon) from the decay channel . The electron energy spectrum from decays measured with an
integrated luminosity of approximately 10 pb will be shown, with a
measurement of the electron single spin asymmetry in central rapidity.Comment: Proceedings of the DIFFRACTION 2010 Conference; 4 pages, 2 figure
A Short Proof of Gamas's Theorem
If \chi^\lambda is the irreducible character of the symmetric group S_n
corresponding to the partition \lambda of n then we may symmetrize a tensor v_1
\otimes ... \otimes v_n by \chi^\lambda. Gamas's theorem states that the result
is not zero if and only if we can partition the set {v_i} into linearly
independent sets whose sizes are the parts of the transpose of \lambda. We give
a short and self-contained proof of this fact
Progress On Neutrino-Proton Neutral-Current Scattering In MicroBooNE
The MicroBooNE Experiment at the Fermi National Accelerator Laboratory, an
89-ton active mass liquid argon time projection chamber, affords a unique
opportunity to observe low- neutral-current neutrino-proton scattering
events. Neutral-current neutrino-proton scattering at GeV is
dominated by the proton's axial form factor, which can be written as a
combination of contributions from the up, down, and strange quarks: . The contribution from up and
down quarks has been established in past charged-current measurements. The
contribution from strange quarks at low remains unmeasured; this is of
great interest since the strange quark contribution to the proton spin can be
determined from the low- behavior: . MicroBooNE
began operating in the Booster Neutrino Beam in October 2015. I will present
the status in observing isolated proton tracks in the MicroBooNE detector as a
signature for neutral-current neutrino-proton events. The sensitivity of the
MicroBooNE experiment for measuring the strange quark contribution to the
proton spin will be discussed.Comment: Proceedings for the 26th International Nuclear Physics Conference,
11-16 September, 2016, Adelaide, Australi
Predictability effects in adult-directed and infant-directed speech: Does the listener matter?
A well-known effect in speech production is that more predictable words tend to be phonetically reduced. Recent work has suggested that predictability effects result from hardwired properties of the language production system, rather than active modulation by the talker to accommodate the listener. However, these studies investigated only minor manipulations of listener characteristics. Here, we examine predictability effects with two very different listener populations: adults and preverbal infants. Using mixed effects regressions on spontaneous speech corpora, we compare the effect of word frequency, probability in context, and previous mention on word duration in adult-directed and infant-directed speech. We find that the effects of preceding context and word frequency differ according to listener. Contrary to previous work, these results suggest that talkers do modulate the phonetic effects of predictability based on listener characteristics. To our knowledge, this study is also the first published analysis of predictability effects in infant-directed speech
Unsupervised syntactic chunking with acoustic cues: Computational models for prosodic bootstrapping
Learning to group words into phrases without supervision is a hard task for NLP systems, but infants routinely accomplish it. We hypothesize that infants use acoustic cues to prosody, which NLP systems typically ignore. To evaluate the utility of prosodic information for phrase discovery, we present an HMM-based unsupervised chunker that learns from only transcribed words and raw acoustic correlates to prosody. Unlike previous work on unsupervised parsing and chunking, we use neither gold standard part-of-speech tags nor punctuation in the input. Evaluated on the Switchboard corpus, our model outperforms several baselines that exploit either lexical or prosodic information alone, and, despite producing a flat structure, performs competitively with a state-of-the-art unsupervised lexicalized parser, with a substantial advantage in precision. Our results support the hypothesis that acoustic-prosodic cues provide useful evidence about syntactic phrases for language-learning infants.10 page(s
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Hydrologic Data for Urban Studies in The Austin Metropolitan Area, Texas, 1986
The report references Waller Creek and includes data from surrounding watersheds.Waller Creek Working Grou
Soft Factorization in QED from 2D Kac-Moody Symmetry
The soft factorization theorem for 4D abelian gauge theory states that the
-matrix factorizes into soft and hard parts, with the universal
soft part containing all soft and collinear poles. Similarly, correlation
functions on the sphere in a 2D CFT with a Kac-Moody current algebra
factorize into current algebra and non-current algebra factors, with the
current algebra factor fully determined by its pole structure. In this paper,
we show that these 4D and 2D factorizations are mathematically the same
phenomena. The soft `tHooft-Wilson lines and soft photons are realized as a
complexified 2D current algebra on the celestial sphere at null infinity. The
current algebra level is determined by the cusp anomalous dimension. The
associated complex boson lives on a torus whose modular parameter is
. The correlators of this 2D
current algebra fully reproduce the known soft part of the 4D
-matrix, as well as a conjectured generalization involving
magnetic charges.Comment: 20 page
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