861 research outputs found

    The Effect of the Short-Range Correlations on the Generalized Momentum Distribution in Finite Nuclei

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    The effect of dynamical short-range correlations on the generalized momentum distribution n(p⃗,Q⃗)n(\vec{p},\vec{Q}) in the case of Z=NZ=N, ℓ\ell-closed shell nuclei is investigated by introducing Jastrow-type correlations in the harmonic-oscillator model. First, a low order approximation is considered and applied to the nucleus 4^4He. Compact analytical expressions are derived and numerical results are presented and the effect of center-of-mass corrections is estimated. Next, an approximation is proposed for n(p⃗,Q⃗)n(\vec{p}, \vec{Q}) of heavier nuclei, that uses the above correlated n(p⃗,Q⃗)n(\vec{p},\vec{Q}) of 4^4He. Results are presented for the nucleus 16^{16}O. It is found that the effect of short-range correlations is significant for rather large values of the momenta pp and/or QQ and should be included, along with center of mass corrections for light nuclei, in a reliable evaluation of n(p⃗,Q⃗)n(\vec{p},\vec{Q}) in the whole domain of pp and QQ.Comment: 29 pages, 8 figures. Further results, figures and discussion for the CM corrections are added. Accepted by Journal of Physics

    The association of parental genetic, lifestyle, and social determinants of health with offspring overweight

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    In the UK, the number of comorbidities seen in children has increased along with the worsening obesity rate. These comorbidities worsen into adulthood. Genomewide association studies have highlighted single nucleotide polymorphisms associated with the weight status of adults and offspring individually. To date, in the UK, parental genetic, lifestyle, and social determinants of health have not been investigated alongside one another as influencers of offspring weight status. A comprehensive obesity prevention scheme would commence prior to conception and involve parental intervention including all known risk factors. This current study aims to identify the proportion of overweight that can be explained by known parental risk factors, including genetic, lifestyle, and social determinants of health with offspring weight status in the UK. Methods: A crosssectional study was carried out on 123 parents. Parental and offspring anthropometric data and parental lifestyle and social determinants of health data were self-reported. Parental genetic data were collected by use of GeneFiX saliva collection vials and genotype were assessed for brain-derived neurotrophic factor (BDNF) gene rs6265, melanocortin 4 receptor (MC4R) gene rs17782313, transmembrane protein 18 (TMEM18) gene rs2867125, and serine/threonine-protein kinase (TNN13K) gene rs1514175. Associations were assessed between parental data and the weight status of offspring. Results: Maternal body mass index modestly predicted child weight status (p < 0.015; R2 = 0.15). More mothers of overweight children carried the MC4R rs17782313 risk allele (77.8%; p = 0.007) compared to mothers of normal-weight children. Additionally, fathers who were not Caucasian and parents who slept for < 7 h/night had a larger percentage of overweight children when compared to their counterparts (p = 0.039; p = 0.014, respectively). Conclusion: Associations exist between the weight status of offspring based solely on parental genetic, lifestyle, and social determinants of health data. Further research is required to appropriately address future interventions based on genetic and lifestyle risk groups on a pre-parent cohort

    Final-state interactions in the response of nuclear matter

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    Final-state interactions in the response of a many-body system to an external probe delivering large momentum are normally described using the eikonal approximation, for the trajectory of the struck particle, and the frozen approximation, for the positions of the spectators. We propose a generalization of this scheme, in which the initial momentum of the struck particle is explicitly taken into account. Numerical calculations of the nuclear matter response at 1 <∣q∣<< |{\bf q}| < 2 GeV/c show that the inclusion of this momentum dependence leads to a sizable effect in the low energy tail. Possible implications for the analysis of existing electron-nucleus scattering data are discussed.Comment: 21 pages, 4 figure

    Radiation hardness qualification of PbWO4 scintillation crystals for the CMS Electromagnetic Calorimeter

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    This is the Pre-print version of the Article. The official published version can be accessed from the link below - Copyright @ 2010 IOPEnsuring the radiation hardness of PbWO4 crystals was one of the main priorities during the construction of the electromagnetic calorimeter of the CMS experiment at CERN. The production on an industrial scale of radiation hard crystals and their certification over a period of several years represented a difficult challenge both for CMS and for the crystal suppliers. The present article reviews the related scientific and technological problems encountered

    Intercalibration of the barrel electromagnetic calorimeter of the CMS experiment at start-up

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    Calibration of the relative response of the individual channels of the barrel electromagnetic calorimeter of the CMS detector was accomplished, before installation, with cosmic ray muons and test beams. One fourth of the calorimeter was exposed to a beam of high energy electrons and the relative calibration of the channels, the intercalibration, was found to be reproducible to a precision of about 0.3%. Additionally, data were collected with cosmic rays for the entire ECAL barrel during the commissioning phase. By comparing the intercalibration constants obtained with the electron beam data with those from the cosmic ray data, it is demonstrated that the latter provide an intercalibration precision of 1.5% over most of the barrel ECAL. The best intercalibration precision is expected to come from the analysis of events collected in situ during the LHC operation. Using data collected with both electrons and pion beams, several aspects of the intercalibration procedures based on electrons or neutral pions were investigated
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