41,376 research outputs found

    Collins Fragmentation and the Single Transverse Spin Asymmetry

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    We study the Collins mechanism for the single transverse spin asymmetry in the collinear factorization approach. The correspondent twist-three fragmentation function is identified. We show that the Collins function calculated in this approach is universal. We further examine its contribution to the single transverse spin asymmetry of semi-inclusive hadron production in deep inelastic scattering and demonstrate that the transverse momentum dependent and twist-three collinear approaches are consistent in the intermediate transverse momentum region where both apply.Comment: 10 pages, 2 figure

    On the Structure of the Bose-Einstein Condensate Ground State

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    We construct a macroscopic wave function that describes the Bose-Einstein condensate and weakly excited states, using the su(1,1) structure of the mean-field hamiltonian, and compare this state with the experimental values of second and third order correlation functions.Comment: 10 pages, 2 figure

    Folding of Cu, Zn superoxide dismutase and Familial Amyotrophic Lateral Sclerosis

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    Cu,Zn superoxide dismutase (SOD1) has been implicated in the familial form of the neurodegenerative disease Amyotrophic Lateral Sclerosis (ALS). It has been suggested that mutant mediated SOD1 misfolding/aggregation is an integral part of the pathology of ALS. We study the folding thermodynamics and kinetics of SOD1 using a hybrid molecular dynamics approach. We reproduce the experimentally observed SOD1 folding thermodynamics and find that the residues which contribute the most to SOD1 thermal stability are also crucial for apparent two-state folding kinetics. Surprisingly, we find that these residues are located on the surface of the protein and not in the hydrophobic core. Mutations in some of the identified residues are found in patients with the disease. We argue that the identified residues may play an important role in aggregation. To further characterize the folding of SOD1, we study the role of cysteine residues in folding and find that non-native disulfide bond formation may significantly alter SOD1 folding dynamics and aggregation propensity.Comment: 16 pages, 5 figure

    Levels and long-term trends in earnings inequality: Overcoming Current Population Survey censoring problems using the GB2 distribution

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    Over its history, the March Current Population Survey (CPS) has increasingly captured the upper tail of the distribution of all sources of income. This, together with time-consistency problems in top coding, means that users of both the public-use and restricted-access CPS will understate the level of wage earnings and income inequality in earlier years and overstate their growth over time. We address this problem by modeling the personal earnings of full-time, full-year workers using the generalized beta distribution of the second kind, calculating Gini coefficients from the estimated parameters, and comparing them with past findings

    Hadronic Dijet Imbalance and Transverse-Momentum Dependent Parton Distributions

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    We compare several recent theoretical studies of the single transverse spin asymmetry in dijet-correlations at hadron colliders. We show that the results of these studies are all consistent. To establish this, we investigate in particular the two-gluon exchange contributions to the relevant initial and final state interactions in the context of a simplifying model. Overall, the results confirm that the dijet imbalance obeys at best a non-standard or "generalized" transverse-momentum-dependent factorization.Comment: 13 pages, 3 figure

    Sense Beyond Expressions: Cuteness

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    With the development of Internet culture, cuteness has become a popular concept. Many people are curious about what factors making a person look cute. However, there is rare research to answer this interesting question. In this work, we construct a dataset of personal images with comprehensively annotated cuteness scores and facial attributes to investigate this high-level concept in depth. Based on this dataset, through an automatic attributes mining process, we find several critical attributes determining the cuteness of a person. We also develop a novel Continuous Latent Support Vector Machine (C-LSVM) method to predict the cuteness score of one person given only his image. Extensive evaluations validate the effectiveness of the proposed method for cuteness prediction.Comment: 4 page

    Direct X(3872) production in e+e- collisions

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    Direct production of the charmonium-like state X(3872)X(3872) in e+e−e^+e^- collisions is considered in the framework of the vector meson dominance model. An order-of-magnitude estimate for the width Γ(X→e+e−)\Gamma(X\to e^+e^-) is found to be ≳\gtrsim0.03 eV. The same approach applied to the χc1\chi_{c1} charmonium decay predicts the corresponding width of the order 0.1 eV in agreement with earlier estimates. Experimental perspectives for the direct production of the 1++1^{++} charmonia in e+e−e^+e^- collisions are briefly discussed.Comment: LaTeX2e, 11 pages, 1 figure, version published in Phys.Lett.
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