13,342 research outputs found

    Mass Dependence of Higgs Production at Large Transverse Momentum

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    The transverse momentum distribution of the Higgs at large PTP_T is complicated by its dependence on three important energy scales: PTP_T, the top quark mass mtm_t, and the Higgs mass mHm_H. A strategy for simplifying the calculation of the cross section at large PTP_T is to calculate only the leading terms in its expansion in mt2/PT2m_t^2/P_T^2 and/or mH2/PT2m_H^2/P_T^2. The expansion of the cross section in inverse powers of PTP_T is complicated by logarithms of PTP_T and by mass singularities. In this paper, we consider the top-quark loop contribution to the subprocess qqˉ→H+gq\bar{q}\to H+g at leading order in αs\alpha_s. We show that the leading power of 1/PT21/P_T^2 can be expressed in the form of a factorization formula that separates the large scale PTP_T from the scale of the masses. All the dependence on mtm_t and mHm_H can be factorized into a distribution amplitude for ttˉt \bar t in the Higgs, a distribution amplitude for ttˉt \bar t in a real gluon, and an endpoint contribution. The factorization formula can be used to simplify calculations of the PTP_T distribution at large PTP_T to next-to-leading order in αs\alpha_s.Comment: 49 pages, 8 figure

    Large Magnetoresistance over an Extended Temperature Regime in Monophosphides of Tantalum and Niobium

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    We report extremely large magnetoresistance (MR) in an extended temperature regime from 1.5 K to 300 K in non-magnetic binary compounds TaP and NbP. TaP exhibits linear MR around 1.8Γ—1041.8\times 10^4 at 2 K in a magnetic field of 9 Tesla, which further follows its linearity up to 1.4Γ—1051.4\times 10^5 in a magnetic field of 56 Tesla at 1.5 K. At room temperature the MR for TaP and NbP follows a power law of the exponent about 1.51.5 with the values larger than 300%300\% in a magnetic field of 9 Tesla. Such large MR in a wide temperature regime is not likely only due to a resonance of the electron-hole balance, but indicates a complicated mechanism underneath.Comment: 13 pages, 4 figures; submitted in May 20, 2015; accepted for publicatio

    Relationship between single-nucleotide polymorphisms in un-translated region of human leukocyte antigen-G and preeclampsia

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    Purpose: The aim of this study was to unravel the link between human leukocyte antigen-G untranslated region (HLA-G 3-UTR) single-nucleotide polymorphism (SNP) and preeclampsia by examining polymorphisms in HLA-G 3-UTR in preeclampsia patients and their newborns, as well as those of women with normal pregnancy and their newborns.Methods: Single pregnant mothers and their newborns at the Third Affiliated Hospital of Zhengzhou University, China, were divided into preeclampsia group (144 cases), and normal pregnancy group (122 cases). Blood samples from the two groups were collected for DNA extraction, and the DNA samples were analyzed for HLA-G 3'-UTR SNP by polymerase chain reaction (RT-PCR) and direct sequencing method.Results: The frequency of CG genotype in HLA-G 3-UTR 3127 gene in the preeclampsia group was significantly lower, while the frequency of AA genotype in HLA-G 3-UTR 3172 gene in the preeclampsia group was significantly higher (p < 0.05) when compared with the normal pregnancy group. Furthermore, frequencies of the compatible genotype AA/AA (mothers/newborns) in HLA-G 3-UTR 3172 gene in the preeclampsia group were significantly higher relative to the normal pregnancy group (p< 0.05).Conclusion: These results suggest that when CC/GG is the compatible genotype in HLA-G 3-UTR 3127 gene of mothers/newborns, preeclampsia risk may decrease, but it may increase if the compatible genotype is AA/AA. Thus, SNP in HLA-G 3-UTR 3127 gene may be a protective factor against preeclampsia in Chinese Han pregnant women, while SNP in 3172 gene may be associated with susceptibility to preeclampsia.Keywords: Single-nucleotide polymorphisms, Human leukocyte antigen-G, Un-translated Region, Preeclampsi
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