25,771 research outputs found

    Measuring the ratio of HWWHWW and HZZHZZ couplings through W+WHW^+W^-H production

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    For a generic Higgs boson, measuring the relative sign and magnitude of its couplings with the WW and ZZ bosons is essential in determining its origin. Such a test is also indispensable for the 125-GeV Higgs boson. We propose that the ratio of the HWWHWW and HZZHZZ couplings λWZ\lambda_{WZ} can be directly determined through the W+WHW^+W^-H production, where HH denotes a generic Higgs boson, owing to the tree-level interference effect. While this is impractical at the LHC due to the limited sensitivity, it can be done at future e+ee^+e^- colliders, such as a 500-GeV ILC with the beam polarization P(e,e+)=(0.8,+0.3)P(e^-,e^+)=(-0.8,+0.3) in the jj±bbjj\ell^{\pm}bb and ±±jj\ell^{\pm}\ell^{\pm}\ell^{\mp}jj channels. The discovery potential of a general ratio and the power to discriminate it from the SM value are studied in detail. Combining the cross section of e+eW+WHe^+e^-\to W^+ W^- H with the measurements of HZZHZZ coupling at the HL-LHC, one can further improve the sensitivity of λWZ\lambda_{WZ}.Comment: 24 pages, 10 figures, 2 table

    Production of Charmed Tetraquarks from BcB_c and BB decays

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    Hadronic states composed of multi-quark flavors may exist in reality since they are not prohibited by QCD. Compact four quark systems of color singlet are classified as tetraquarks. To understand the properties of these states, more theoretical and experimental efforts are needed. In this work, we study charmed tetraquarks with three light flavors using flavor SU(3)SU(3) symmetry. States with three different light quarks must be in a 6ˉ{\bf \bar 6 } or a 15{\bf 15} multiplet. We investigate the production of charmed tetraquarks XcX_c in BXc(Xc)PB\to X_c (\overline {X}_c) P and BcXcPB_c \to X_c P decays. Whether the states with three light quarks belong to 6ˉ{\bf \bar 6} or 15{\bf 15} can be determined by studying various tetraquark BB and BcB_c decays. We demonstrate that the decay amplitudes for these decays can be parametrized by a few irreducible SU(3) invariant amplitudes. We then derive relations for decay widths and CP violating rate difference which can be examined experimentally. Although no experimental measurement is available yet, they might be accessed at the ongoing and forthcoming experiments like the LHCb and Belle-II. Measurements of these observables can not only provide useful information for the study of exotics spectroscopy but are also valuable information towards a better understanding of some non-perturbative aspects of QCD.Comment: 14 page

    Unification of Flavor SU(3) Analyses of Heavy Hadron Weak Decays

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    Analyses of heavy mesons and baryons hadronic charmless decays using the flavor SU(3) symemtry can be formulated in two different forms. One is to construct the SU(3) irreducible representation amplitude (IRA) by decomposing effective Hamiltonian, and the other is to draw the topological diagrams (TDA). In the flavor SU(3) limit, we study various B/DPP,VP,VVB/D\to PP,VP,VV, BcDP/DVB_c\to DP/DV decays, and two-body nonleptonic decays of beauty/charm baryons, and demonstrate that when all terms are included these two ways of analyzing the decay amplitudes are completely equivalent. Furthermore we clarify some confusions in drawing topological diagrams using different ways of describing beauty/charm baryons.Comment: 36 pages, 6 figures, 16 table

    A ZZ^\prime Model for bsˉb\to s \ell\bar \ell Flavour Anomalies

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    We study the implications of flavour-changing neutral currents (FCNC's) in a model with the SU(2)l×SU(2)h×U(1)YSU(2)_l\times SU(2)_h\times U(1)_Y electroweak gauge symmetry for several anomalies appearing in bsˉb\to s \ell\bar \ell induced BB decays in LHCb data. In this model, SU(2)lSU(2)_l and SU(2)hSU(2)_h govern the left-handed fermions in the first two generations and the third generation, respectively. The physical ZZ and ZZ' generate the bsb\to s transition at tree level, leading to additional contributions to the bsb \to s semileptonic operators O9,10{\cal O}_{9,10}. We find that although BsB_s-Bˉs\bar B_s mixing constrains the parameters severely, the model can produce values of C9,10NP{\cal C}^{\rm NP}_{9,10} in the range determined by Descotes-Genon {\it et. al.} in Ref.~\cite{Descotes-Genon:2015uva} for this scenario to improve the global fit of observables in decays induced by the bsμμˉb\to s \mu \bar \mu transition. The ZZ' boson in this model also generates tree-level FCNC's for the leptonic interactions that can accommodate the experimental central value of RK=B(BKμμˉ)/B(BKeeˉ)=0.75R_K = {\cal B}(B\to K \mu \bar \mu)/{\cal B}(B\to K e\bar e)=0.75. In this case, the model predicts sizeable branching ratios for BKeτˉB\to K e \bar \tau, BKτeˉB\to K \tau \bar e, and an enhancement of BKττˉB\to K \tau \bar \tau with respect to its SM value.Comment: ReTex, 13 pages with two figures. A few typos corrected and several references adde

    Efficient Algorithms for Node Disjoint Subgraph Homeomorphism Determination

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    Recently, great efforts have been dedicated to researches on the management of large scale graph based data such as WWW, social networks, biological networks. In the study of graph based data management, node disjoint subgraph homeomorphism relation between graphs is more suitable than (sub)graph isomorphism in many cases, especially in those cases that node skipping and node mismatching are allowed. However, no efficient node disjoint subgraph homeomorphism determination (ndSHD) algorithms have been available. In this paper, we propose two computationally efficient ndSHD algorithms based on state spaces searching with backtracking, which employ many heuristics to prune the search spaces. Experimental results on synthetic data sets show that the proposed algorithms are efficient, require relative little time in most of the testing cases, can scale to large or dense graphs, and can accommodate to more complex fuzzy matching cases.Comment: 15 pages, 11 figures, submitted to DASFAA 200

    Implications for BηKB \to \eta K and BGlueball+KB \to Glueball + K Modes from Observed Large BηK+XB\to \eta' K+X

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    The unexpectedly large branching ratios for BηK(ηXs)B\to \eta' K (\eta' X_s) decays could be of gluonic origin. We study the implications for BηK(ηXs)B\to \eta K (\eta X_s) and PK(PXs)P K (PX_s), where PP is the pseudoscalar glueball. In the mechanism proposed by Fritzsch, large branching ratios are predicted for these modes. The BηKB\to \eta K rate is barely within the experimental limit, and BPKB\to P K, PXsPX_s could be at the 0.1% and 1% level, respectively. Smaller but less definite results are found for the mechanism of gηgg^* \to \eta' g via the gluon anomaly.Comment: 11 pages, revtex, no fig
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