1,977 research outputs found

    Possible new resonance from WLWLW_L W_L-hhhh interchannel coupling

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    We propose and theoretically study a possible new resonance caused by strong coupling between the Higgs-Higgs and the W_L W_L (Z_L Z_L) scattering channels, without regard to the intensity of the elastic interaction in either channel at low energy (that could be weak as in the Standard Model). We expose this channel-coupling resonance from unitarity and dispersion relations encoded in the Inverse Amplitude Method, applied to the Electroweak Chiral Lagrangian with a scalar Higgs.Comment: 4 pages, 7 figure

    Unitarity, analyticity, dispersion relations and resonances in strongly interacting WLWLW_L W_L, ZLZLZ_L Z_L and hhhh scattering

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    If the Electroweak Symmetry Breaking Sector turns out to be strongly interacting, the actively investigated effective theory for longitudinal gauge bosons plus Higgs can be efficiently extended to cover the regime of saturation of unitarity (where the perturbative expansion breaks down). This is achieved by dispersion relations, whose subtraction constants and left cut contribution can be approximately obtained in different ways giving rise to different unitarization procedures. We illustrate the ideas with the Inverse Amplitude Method, one version of the N/D method and another improved version of the K-matrix. In the three cases we get partial waves which are unitary, analytical with the proper left and right cuts and in some cases poles in the second Riemann sheet that can be understood as dynamically generated resonances. In addition they reproduce at Next to Leading Order (NLO) the perturbative expansion for the five partial waves not vanishing (up to J=2) and they are renormalization scale (μ\mu) independent. Also the unitarization formalisms are extended to the coupled channel case. Then we apply the results to the elastic scattering amplitude for the longitudinal components of the gauge bosons V=W,ZV=W, Z at high energy. We also compute hh→hhh h \rightarrow h h and the inelastic process VV→hhVV\rightarrow h h which are coupled to the elastic VVVV channel for custodial isospin I=0I=0. We numerically compare the three methods for various values of the low-energy couplings and explain the reasons for the differences found in the I=J=1I=J=1 partial wave. Then we study the resonances appearing in the different elastic and coupled channels in terms of the effective Lagrangian parameters.Comment: 45 pages, 28 figure

    One-loop WLWLW_L W_L and ZLZLZ_L Z_L scattering from the Electroweak Chiral Lagrangian with a light Higgs-like scalar

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    By including the recently discovered Higgs-like scalar φ\varphi in the Electroweak Chiral Lagrangian, and using the Equivalence Theorem, we carry out the complete one-loop computation of the elastic scattering amplitude for the longitudinal components of the gauge bosons V=W,ZV=W, Z at high energy. We also compute φφ→φφ\varphi\varphi \rightarrow \varphi\varphi and the inelastic process VV→φφVV\rightarrow \varphi\varphi, and identify the counterterms needed to cancel the divergences, namely the well known a4a_4 and a5a_5 chiral parameters plus three additional ones only superficially treated in the literature because of their dimension 8. Finally we compute all the partial waves and discuss the limitations of the one-loop computation due to only approximate unitarity.Comment: 28 pages, 19 plots, 9 Feynman-diagram sets This version revised and accepted in JHE

    Coupling WW, ZZ unitarized amplitudes to γγ\gamma\gamma in the TeV region

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    We define and calculate helicity partial-wave amplitudes for processes linking the Electroweak Symmetry Breaking Sector (EWSBS) to γγ\gamma\gamma, employing (to NLO) the Higgs-EFT (HEFT) extension of the Standard Model and the Equivalence Theorem, while neglecting all particle masses. The resulting amplitudes can be useful in the energy regime (500 GeV−3 TeV500\,{\rm GeV}-3\,{\rm TeV}). We also deal with their unitarization so that resonances of the EWSBS can simultaneously be described in the γγ\gamma\gamma initial or final states. Our resulting amplitudes satisfy unitarity, perturbatively in α\alpha, but for all ss values. In this way we improve on the HEFT that fails as interactions become stronger with growing ss and provide a natural framework for the decay of dynamically generated resonances into WWWW, ZZZZ and γγ\gamma\gamma pairs.Comment: 23 pages, 9 figure

    Collider production of Electroweak resonances from photon-photon states

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    We estimate production cross sections for 2-body resonances of the Electroweak Symmetry Breaking sector (in WLWLW_LW_L and ZLZLZ_LZ_L rescattering) from γγ\gamma\gamma scattering. We employ unitarized Higgs Effective Field Theory amplitudes previously computed coupling the two photon channel to the EWSBS. We work in the Effective Photon Approximation and examine both e−e+e^-e^+ collisions at energies of order 1-2 TeV (as relevant for future lepton machines) and pppp collisions at LHC energies. Dynamically generating a spin-0 resonance around 1.5 TeV (by appropriately choosing the parameters of the effective theory) we find that the differential cross section per unit ss, pt2p_t^2 is of order 0.01 fbarn/TeV4^4 at the LHC. Injecting a spin-2 resonance around 2 TeV we find an additional factor 100 suppression for ptp_t up to 200 GeV. The very small cross sections put these γγ\gamma\gamma processes, though very clean, out of reach of immediate future searches.Comment: 36 pages, 20 plot

    Does the level of social cultural beliefs affect the level of agreement of the respondents on the motivational dimensions of microinsurance?

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    Insurance products and services in general are intended to transfer the risks brought about by both man-made and natural hazards from an individual or an entity to another. But since there is a misconception that insurance offered by commercial insurers are expensive and only for the moneyed consumers, or people need a lot of money to insure, insurance is only good for those who have big businesses or valuable properties. The poor and the vulnerable have relied on informal risk-mitigating measures like community-based insurance system or worst do not have any other means to help them cope and become risk-averse. This misconception has led to the conceptualization of microinsurance as an offshoot to microfinance primarily to offer insurance products and services that are affordable, the contractual obligations of both the insured and the insurer are nonlegalistic and lesser technical to make it more understandable to the intended market.  This study aims to assess if social-cultural beliefs affect the level of agreement of the respondents on the motivational dimensions of microinsurance.  A descriptive-correlational method was used in this research.  A 40-item self-made questionnaire was subjected to validity and reliability tests before the same was distributed to six hundred respondents all over the Philippines. There were 422 retrieved questionnaires which 70% of the total number of questionnaires deployed. Conclusively, the results indicate that the level of agreement of the respondents on the motivational dimensions of microinsurance vary from one factor to anothe
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