54 research outputs found

    Light Pseudoscalar Higgs boson in Neutralino Decays in the Next-to-Minimal Supersymmetric Standard Model

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    We point out another important production channel of a light pseudoscalar Higgs boson a1a_1 via the decays of neutralinos, including χ~2,30χ~10a1\widetilde{\chi}_{2,3}^0 \to \widetilde{\chi}_{1}^0 a_1, in the framework of the NMSSM. We scan the whole parameter space using the most up-to-date version of NMHDECAY and search for regions where B(χ~2,30χ~10a1)>0.5B(\widetilde{\chi}_{2,3}^0 \to \widetilde{\chi}_{1}^0 a_1) > 0.5. If the gluino and squarks are light enough for copious production of SUSY events at the LHC, there would be numerous number of χ~2,30\widetilde{\chi}_{2,3}^0 in subsequent decays of gluinos and squarks. Therefore, the production rates of a1a_1 via neutralino decays would be more important than ha1a1h \to a_1 a_1 and others. Potentially, the final state is filled with many τ\tau leptons, which can be reconstructed at the mass of a1a_1. This is a clean, observable, and distinguishable signature for NMSSM.Comment: RevTex, 11 pages, 3 figures; references adde

    The light pseudoscalar Higgs boson in NMSSM

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    We study the associated production of a very light pseudoscalar Higgs boson with a pair of charginos. The novel signature involves a pair of charged leptons from chargino decays and a pair of photons from the pseudoscalar Higgs boson decay, plus large missing energy at the LHC and ILC. The signal may help us to distinguish the NMSSM from MSSM, provided that the experiment can resolve the two photons from the decay of the pseudoscalar Higgs boson.Comment: pages, 2 figures; to appear in Proceedings of SUSY06, the 14th International Conference on Supersymmetry and the Unification of Fundamental Interactions, UC Irvine, California, 12-17 June 200

    A CT18 global PDF fit at the leading order in QCD

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    In this paper, we present a CT18 PDFs fitted with Leading-Order QCD perturbation theory. The CT18 LO PDFs is obtained within the general CT18 framework, along with two additional treatments being imposed to improve the quality of the fit. We take the WW-boson charge asymmetry and inclusive single-top production at LHC as examples to illustrate the implication of the CT18 LO PDFs

    Impact of Lattice Strangeness Asymmetry Data in the CTEQ-TEA Global Analysis

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    We study the impact of lattice data on the determination of the strangeness asymmetry distribution s(x)s(x)sˉ(x)s_-(x) \equiv s(x) - {\bar s}(x) in the general CTEQ-TEA global analysis of parton distribution functions (PDFs) of the proton. Firstly, we find that allowing a nonvanishing s(x)s_-(x), at the initial Q0=1.3Q_0=1.3~GeV scale, in a global PDF analysis leads to a CT18As fit with similar quality to CT18A. Secondly, including the lattice data in the CT18As\_Lat fit greatly reduces the ss_--PDF error band size in the large-xx region. To further reduce its error would require more precise lattice data, extended to smaller xx values. We take ATLAS 7 TeV WW and ZZ production data, SIDIS di-muon production data, F3F_3 structure function data, E866 NuSea data, and E906 SeaQuest data as examples to illustrate the implication of CT18As and CT18As\_Lat fits. The parametrization dependence for PDF ratio (s+sˉ)/(uˉ+dˉ)(x)(s+\bar{s})/(\bar{u}+\bar{d})(x) is analyzed with CT18As2 and CT18As2\_Lat fits as results.Comment: 37 pages, 19 figures. arXiv admin note: text overlap with arXiv:2204.0794

    On the Momentum Dependence of the Flavor Structure of the Nucleon Sea

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    Difference between the uˉ\bar u and dˉ\bar d sea quark distributions in the proton was first observed in the violation of the Gottfried sum rule in deep-inelastic scattering (DIS) experiments. The parton momentum fraction xx dependence of this difference has been measured over the region 0.02<x<0.350.02 < x < 0.35 from Drell-Yan and semi-inclusive DIS experiments. The Drell-Yan data suggested a possible sign-change for dˉ(x)uˉ(x)\bar d(x)-\bar u(x) near x0.3x \sim 0.3, which has not yet been explained by existing theoretical models. We present an independent evidence for the dˉ(x)uˉ(x)\bar d(x)-\bar u(x) sign-change at x0.3x \sim 0.3 from an analysis of the DIS data. We further discuss the xx-dependence of dˉ(x)uˉ(x)\bar d(x)-\bar u(x) in the context of meson cloud model and the lattice QCD formulation.Comment: 5 pages, 5 figures, final versio
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