2,070 research outputs found

    Mechanical structures inside proton with configurational entropy language

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    The structure of the proton remains a significant challenge within the field of Quantum Chromodynamics, with the origin of its spin and mass still lacking a satisfactory explanation. In this study, we utilize the gravitational form factor of the proton as the foundation for constructing the configurational entropy of the proton energy system. Employing this approach, we are able to determine key mechanical quantities such as the proton's mass radius and pressure distribution. Our analysis yields the root-mean-square mass radius of rM2=0.720\sqrt{\langle r_M^2\rangle}=0.720 fm and scalar radius of rS2=1.024\sqrt{\langle r_S^2\rangle}=1.024 fm for proton, which are found to be in excellent agreement with recent measurements from the Hall-C collaboration group at Jefferson Lab. Additionally, we examine the radial distribution of pressure and shear force within the proton.Comment: 6 pages, 3 figures and 1 tabl

    Unraveling Proton Strangeness: Robust Determination of the Strangeness Sigma Term with High Statistical Significance

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    This study delves into the contribution of the strange quark within the proton, which influences several fundamental proton properties. By establishing a robust relationship between the proton's quantum anomalous energy and the sigma term, we successfully extract the strangeness sigma term (σsN\sigma_{sN}) with a precise value of 420.1±59.3420.1\pm59.3 MeV. Additionally, we present novel results for the proton trace anomalous energy, observing a value of 0.12±0.020.12\pm0.02. Our analysis integrates the most recent data from the Hall C and GlueX collaborations, warranting a strong endorsement for the existence of a non-zero strangeness component inside the proton, with a remarkable statistical significance of 7.1σ7.1\sigma. Furthermore, we investigate the possibility of scheme-independence in the extraction results and examine the uniformity of sigma terms obtained from the datasets provided by the two collaborations. Our analysis reveals compatibility between the extraction results of the respective experiments.Comment: 5 pages, 3 figures, 2 table

    Trace Anomaly of Proton Mass with Vector Meson Near-Thresholds Photoproduction Data

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    Trace anomalous contribution to proton mass is particularly important in understanding the QCD mass structure. The value and the scale-dependent of the trace anomalous energy of the strong interaction are still not clear in combination of theories and experiments. In this paper, we explore the near-threshold photoproduction data of ϕ\phi and J/ψ\psi to study the quantum anomalous energy in QCD and its scale-dependence. The vector-meson-dominance model and the van der Waals interaction between the vector meson and the proton are used. We find that the quantum anomalous energy to the proton mass is scale-dependent and it can be described as Ma=0.25exp(A/μ2)MNM_a=0.25\exp(-A/\mu^2)M_N with A=0.101±0.029A=0.101\pm0.029 GeV2^2. The empirical result is consistent with the LQCD calculation at μ2=4\mu^2=4 GeV2^2. Finally, the corresponding evolution equation for trace anomaly part is given by our calculation.Comment: 6 pages, 4 figures, Corrected spelling mistake

    4,8-Dimeth­oxy­furo[2,3-b]quinoline (γ-fagarine)

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    The title mol­ecule, C13H11NO3, a natural compound extracted from Phellodendron chinense, exhibits a near planar framework: the mean deviations from the furo[2,3-b]quinoline ring system and from the whole mol­ecule (not including the H atoms) are 0.006 and 0.062 Å, respectively

    Central catecholamine depletion inhibits peripheral lymphocyte proliferation and splenocyte cytokine production

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    Evidence demonstrating that immune response is under the control of central nervous system has been accumulated during the past two decades. Central catecholamines have been proved to play a pivotal role in modulation of humoral and cellular immunity both in vitro and in vivo. However, the modulation of central catecholamine depletion on peripheral cellular immune response remains somewhat unclear. Therefore, we designed a set of experiments to analyse the influence of central catecholamine depletion by i.c.v. 6-OHDA injection on peripheral cellular immune functions. Two, four and seven days after the injection in rats, they were sacrificed and spleen and blood samples were collected to measure the lymphocyte proliferation, cytokine production and IL-2 mRNA expression. Brain and spleen samples were obtained for catecholamine determination as well. Our data demonstrate that two, four and seven days after i.c.v. 6-OHDA treatment, dopamine, norepinephrine and epinephrine levels in the hypothalamus and in the cortex are significantly reduced. Additionally, norepinephrine and epinephrine concentrations in the spleen are significantly decreased four days after the injection. In contrast, the serotonin levels in the brain and in the spleen are not changed seven days after the central 6-OHDA treatment. More importantly, Con A-induced lymphocyte proliferation and splenocyte cytokine production at both protein (IL-2 and IFN-?) and mRNA (IL-2) levels are significantly reduced seven days after i.c.v. 6-OHDA injection. These results confirm the important role of central catecholamines in modulating peripheral cellular immune response. Although the precise mechanism of how central catecholamine depletion alters peripheral cellular immunity is still not clear, the fact that a significant reduction in splenic catecholamine contents is observed four days after i.c.v. 6-OHDA treatment suggests that peripheral sympathetic nervous system plays a role in these effects