14,289 research outputs found

    Review of Linac-Ring Type Collider Proposals

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    There are three possibly types of particle colliders schemes: familiar (well known) ring-ring colliders, less familiar however sufficiently advanced linear colliders and less familiar and less advanced linac-ring type colliders. The aim of this paper is two-fold: to present possibly complete list of papers on linac-ring type collider proposals and to emphasize the role of linac-ring type machines for future HEP research.Comment: quality of figures is improved, some misprints are correcte

    The Heliosphere---Blowing in the Interstellar Wind

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    Measurements of the velocity of interstellar HeI inside of the heliosphere have been conducted over the past forty years. These historical data suggest that the ecliptic longitude of the direction of the interstellar flow has increased at an average rate of about 0.19 degrees per year over time. Possible astronomical explanations for these short-term variations in the interstellar gas entering the heliosphere are presented.Comment: Accepted for the proceedings of Solar Wind 1

    Fatigue resistance of new and used nickel-titanium rotary instruments: a comparative study

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    Aim of the present study was twofold. First, to evaluate in vitro, the performance of two different NiTi rotary instruments in one molar case; then, to evaluate their resistance to cyclic fatigue, compared to new ones

    Probe of anomalous quartic WWZγWWZ\gamma couplings in the photon-photon collisions

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    In this paper, we examine the potentials of the processes γγW+WZ\gamma \gamma\rightarrow W^{+} W^{-}Z and e+ee+γγee+W+WZee^{+}e^{-} \rightarrow e^{+}\gamma^{*} \gamma^{*} e^{-} \rightarrow e^{+} W^{+} W^{-} Z e^{-} at the CLIC with s=0.5,1.5\sqrt{s}=0.5,1.5 and 33 TeV to investigate anomalous quartic WWZγWWZ\gamma couplings by two different CP-violating and CP-conserving effective Lagrangians. We find 95%95\% confidence level limits on the anomalous coupling parameters at the three CLIC energies and various integrated luminosities. The best limits obtained from the process γγW+WZ\gamma \gamma\rightarrow W^{+} W^{-}Z on the anomalous k0WΛ2\frac{k_{0}^{W}}{\Lambda^{2}}, kcWΛ2\frac{k_{c}^{W}}{\Lambda^{2}} and k2mΛ2\frac{k_{2}^{m}}{\Lambda^{2}} couplings defined by CP-conserving effective Lagrangians are [1.73;1.73]×107[-1.73;\, 1.73]\times 10^{-7} GeV2^{-2}, [2.44;2.44]×107[-2.44;\, 2.44]\times 10^{-7} and [1.89;1.89]×107[-1.89; \, 1.89]\times 10^{-7} GeV2^{-2}, while anΛ2\frac{a_{n}}{\Lambda^{2}} coupling determined by CP-violating effective Lagrangians is obtained as [1.74;1.74]×107[-1.74;\, 1.74]\times 10^{-7} GeV2^{-2}. In addition, the best limits derived on k0WΛ2\frac{k_{0}^{W}}{\Lambda^{2}}, kcWΛ2\frac{k_{c}^{W}}{\Lambda^{2}} and k2mΛ2\frac{k_{2}^{m}}{\Lambda^{2}} and anΛ2\frac{a_{n}}{\Lambda^{2}} from the process e+ee+γγee+W+WZee^{+}e^{-} \rightarrow e^{+}\gamma^{*} \gamma^{*} e^{-} \rightarrow e^{+} W^{+} W^{-} Z e^{-} are obtained as [1.09;1.09]×106[-1.09;\, 1.09]\times 10^{-6} GeV2^{-2}, [1.54;1.54]×106[-1.54;\, 1.54]\times 10^{-6} GeV2^{-2}, [1.18;1.18]×106[-1.18;\, 1.18]\times 10^{-6} and [1.04;1.04]×106[-1.04;\, 1.04]\times 10^{-6} GeV2^{-2}, respectively.Comment: 33 pages, 27 figures, 4 tables, version to appear in JHE

    Physics at LHC

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    The prospects for physics at the LHC are discussed, starting with the foretaste, preparation (and perhaps scoop) provided by the Tevatron, in particular, and then continuing through the successive phases of LHC operation. These include the start-up phase, the early physics runs, the possible search for new physics in double diffraction, the continuation to nominal LHC running, and the possible upgrade of the LHC luminosity. Emphasis is placed on the prospects for Higgs physics and the search for supersymmetry. The progress and discoveries of the LHC will set the time-scale and agenda for the major future accelerator projects that will follow it.Comment: 21 pages, 12 figures, Concluding talk at the Physics at LHC conference, Krakow, July 200

    Signs of heavy Higgs bosons at CLIC: An e+ee^+ e^- road to the Electroweak Phase Transition

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    We analyse the sensitivity of the proposed Compact Linear Collider (CLIC) to the existence of beyond the Standard Model (SM) Higgs bosons through their decays into pairs of massive gauge bosons HVVH \to VV and SM-like Higgses HhhH \to hh, considering CLIC centre of mass energies s=1.4\sqrt{s} = 1.4 TeV and 33 TeV. We find that resonant di-Higgs searches at CLIC would allow for up to two orders of magnitude improvement w.r.t. the sensitivity achievable by HL-LHC in the mass range mH[250GeV,1TeV]m_H \in [250\,\mathrm{GeV},\, 1 \,\mathrm{TeV}]. Focusing then on a real singlet extension of the SM, we explore the prospects of heavy Higgs searches at CLIC for probing the regions of parameter space yielding a strongly first order electroweak phase transition that could generate the observed matter-antimatter asymmetry of the Universe. Our study illustrates the complementarity between CLIC and other possible future colliders like FCC-ee in probing singlet extensions of the SM, and shows that high-energy e+ee^+ e^- colliders provide a powerful means to unravel the nature of electroweak symmetry breaking in the early Universe.Comment: 27 pages, 15 figure

    Constraining the Higgs self couplings at e+ee^+e^- colliders

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    We study the sensitivity to the shape of the Higgs potential of single, double, and triple Higgs production at future e+ee^+e^- colliders. Physics beyond the Standard Model is parameterised through the inclusion of higher-dimensional operators (ΦΦv2/2)n/Λ(2n4)(\Phi^\dagger \Phi- v^2/2)^n/\Lambda^{(2n-4)} with n=3,4n=3,4, which allows a consistent treatment of independent deviations of the cubic and quartic self couplings beyond the tree level. We calculate the effects induced by a modified potential up to one loop in single and double Higgs production and at the tree level in triple Higgs production, for both ZZ boson associated and WW boson fusion production mechanisms. We consider two different scenarios. First, the dimension six operator provides the dominant contribution (as expected, for instance, in a linear effective-field-theory(EFT)); we find in this case that the corresponding Wilson coefficient can be determined at O(10%)\mathcal{O}(10\%) accuracy by just combining accurate measurements of single Higgs cross sections at s^=\sqrt{\hat s}=240-250 GeV and double Higgs production in WW boson fusion at higher energies. Second, both operators of dimension six and eight can give effects of similar order, i.e., independent quartic self coupling deviations are present. Constraints on Wilson coefficients can be best tested by combining measurements from single, double and triple Higgs production. Given that the sensitivity of single Higgs production to the dimension eight operator is presently unknown, we consider double and triple Higgs production and show that combining their information colliders at higher energies will provide first coarse constraints on the corresponding Wilson coefficient.Comment: minor changes, version accepted for publication in JHE

    Capacitated facility location: Valid inequalities and facets

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    Location Theory;Optimization;Capacity;econometrics

    Establishing the Isolated Standard Model

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    The goal of this article is to initiate a discussion on what it takes to claim "there is no new physics at the weak scale," namely that the Standard Model (SM) is "isolated." The lack of discovery of beyond the SM (BSM) physics suggests that this may be the case. But to truly establish this statement requires proving all "connected" BSM theories are false, which presents a significant challenge. We propose a general approach to quantitatively assess the current status and future prospects of establishing the isolated SM (ISM), which we give a reasonable definition of. We consider broad elements of BSM theories, and show many examples where current experimental results are not sufficient to verify the ISM. In some cases, there is a clear roadmap for the future experimental program, which we outline, while in other cases, further efforts -- both theoretical and experimental -- are needed in order to robustly claim the establishment of the ISM in the absence of new physics discoveries.Comment: 10 pages, 2 figures, 1 tabl

    Summary of ICHEP 2004

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    Aspects of ICHEP 2004 are summarized from a theoretical point of view. QCD works, new NNLO calculations are becoming available and new string calculational tools are emerging, but no conclusions can yet be drawn about the discovery of the quark-gluon plasma or pentaquarks. The small upward shift in the experimental value of m_t raises somewhat the central value of the Higgs mass extracted from a global electroweak fit, and the CKM model describes well the data from the B factories. The Super-Kamiokande, KamLAND and K2K experiments have evidence for oscillation dips in their neutrino data. Little Higgs models are interesting alternatives to low-energy supersymmetry for stabilizing the electroweak scale. Convincing experimental evidence for dark matter particles is still lacking. The LHC is on its way, the technology choice clarifies the roadmap for the ILC, and a multi-TeV CLIC would also have rich physics agenda.Comment: 19 pages LaTeX, 12 eps figures, Summary of the International Conference on High-Energy Physics, Beijing, China, August 200
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