1,812 research outputs found

    Regularization dependence of the Higgs mass triviality bound

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    We calculate the triviality bound on the Higgs mass in scalar field theory models whose global symmetry group SU(2)L×SU(2)custodialO(4)SU(2)_L \times SU(2)_{\rm custodial} \approx O(4) has been replaced by O(N)O(N) and NN has been taken to infinity. Limits on observable cutoff effects at four percent in several regularized models with tunable couplings in the bare action yield triviality bounds displaying a large degree of universality. Extrapolating from N=N=\infty to N=4N=4 we conservatively estimate that a Higgs particle with mass up to 0.750 TeV0.750~TeV and width up to 0.290 TeV0.290~TeV is realizable without large cutoff effects, indicating that strong scalar self interactions in the standard model are not ruled out. We also present preliminary numerical results of the physical N=4N=4 case for the F4F_4 lattice that are in agreement with the large NN expectations. Note: The full ps file is also available via anonymous ftp to ftp.scri.fsu.edu. To get the ps file, ftp to this address and use for username "anonymous" and for password your name. The file is in the directory pub/vranas (to go to that directory type: cd pub/vranas) and is called lat92_proc.ps (to get it type: get lat92_proc.ps)Comment: 5 pages with 5 ps figures included. LaTex file. Contribution to the LAT92 proceedings. Preprint, FSU-SCRI-92-150, RU-92-4

    Knee adduction moment and medial contact force - facts about their correlation during gait

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    The external knee adduction moment is considered a surrogate measure for the medial tibiofemoral contact force and is commonly used to quantify the load reducing effect of orthopedic interventions. However, only limited and controversial data exist about the correlation between adduction moment and medial force. The objective of this study was to examine whether the adduction moment is indeed a strong predictor for the medial force by determining their correlation during gait. Instrumented knee implants with telemetric data transmission were used to measure tibiofemoral contact forces in nine subjects. Gait analyses were performed simultaneously to the joint load measurements. Skeletal kinematics, as well as the ground reaction forces and inertial parameters, were used as inputs in an inverse dynamics approach to calculate the external knee adduction moment. Linear regression analysis was used to analyze the correlation between adduction moment and medial force for the whole stance phase and separately for the early and late stance phase. Whereas only moderate correlations between adduction moment and medial force were observed throughout the whole stance phase (R(2)?=?0.56) and during the late stance phase (R(2)?=?0.51), a high correlation was observed at the early stance phase (R(2)?=?0.76). Furthermore, the adduction moment was highly correlated to the medial force ratio throughout the whole stance phase (R(2)?=?0.75). These results suggest that the adduction moment is a surrogate measure, well-suited to predicting the medial force ratio throughout the whole stance phase or medial force during the early stance phase. However, particularly during the late stance phase, moderate correlations and high inter-individual variations revealed that the predictive value of the adduction moment is limited. Further analyses are necessary to examine whether a combination of other kinematic, kinetic or neuromuscular factors may lead to a more reliable prediction of the force magnitud

    Numerical analysis of the Higgs mass triviality bound

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    Previous large NN calculations are combined with numerical work at N=4N=4 to show that the Minimal Standard Model will describe physics to an accuracy of a few percent up to energies of the order 2 to 4 times the Higgs mass, MHM_H, only if MH710±60 GeVM_H \le 710\pm60 ~ GeV. This bound is the result of a systematic search in the space of dimension six operators and is expected to hold in the {\it continuum}. Given that studying the scalar sector in isolation is already an approximation, we believe that our result is sufficiently accurate and that further refinements would be of progressively diminishing interest to particle physics. Note: The full ps file of this preprint is also available via anonymous ftp to ftp.scri.fsu.edu. To get the ps file, ftp to this address and use for username "anonymous" and for password your name. The file is in the directory pub/vranas (to go to that directory type: cd pub/vranas) and is called num_hig.ps (to get it type: get num_hig.ps)Comment: 22 pages with 10 ps figures included. Tex file. FSU-SCRI-93-29, CU-TP-590, RU-93-0

    Characterizing time-irreversibility in disordered fermionic systems by the effect of local perturbations

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    We study the effects of local perturbations on the dynamics of disordered fermionic systems in order to characterize time-irreversibility. We focus on three different systems, the non-interacting Anderson and Aubry-Andr\'e-Harper (AAH-) models, and the interacting spinless disordered t-V chain. First, we consider the effect on the full many-body wave-functions by measuring the Loschmidt echo (LE). We show that in the extended/ergodic phase the LE decays exponentially fast with time, while in the localized phase the decay is algebraic. We demonstrate that the exponent of the decay of the LE in the localized phase diverges proportionally to the single-particle localization length as we approach the metal-insulator transition in the AAH model. Second, we probe different phases of disordered systems by studying the time expectation value of local observables evolved with two Hamiltonians that differ by a spatially local perturbation. Remarkably, we find that many-body localized systems could lose memory of the initial state in the long-time limit, in contrast to the non-interacting localized phase where some memory is always preserved

    Energy of sections of the Deligne–Hitchin twistor space

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    We study a natural functional on the space of holomorphic sections of the Deligne–Hitchin moduli space of a compact Riemann surface, generalizing the energy of equivariant harmonic maps corresponding to twistor lines. We show that the energy is the residue of the pull-back along the section of a natural meromorphic connection on the hyperholomorphic line bundle recently constructed by Hitchin. As a byproduct, we show the existence of a hyper-Kähler potentials for new components of real holomorphic sections of twistor spaces of hyper-Kähler manifolds with rotating S1-action. Additionally, we prove that for a certain class of real holomorphic sections of the Deligne–Hitchin moduli space, the energy functional is basically given by the Willmore energy of corresponding equivariant conformal map to the 3-sphere. As an application we use the functional to distinguish new components of real holomorphic sections of the Deligne–Hitchin moduli space from the space of twistor lines. © 2020, The Author(s)

    Semi-Analytical Solution of the ϕ4\phi^4 Theory on an F4F_4 Lattice

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    Investigating the cutoff dependence of the Higgs mass triviality bound, the ϕ4\phi^4 theory is formulated on an F4F_4 lattice which preserves Lorentz invariance to a higher degree than the commonly used hypercubic lattice. I solve this model non-perturbatively by evaluating the high temperature expansion through 13th order following the approach of L\"uscher and Weisz. The results are continued across the transition line into the broken phase by integrating the perturbative RG equations. In the broken phase, the renormalized coupling never exceeds 2/3 of the tree level unitarity bound when Λ/mR2\Lambda/m_R \geq 2. The results confirm recent Monte Carlo data and I obtain as an upper bound for the Higgs mass mR/fπ2.46±0.02HTE±0.08PTm_R/f_\pi \leq 2.46 \pm 0.02_{\rm HTE} \pm 0.08_{\rm PT} at Λ/mR=2\Lambda/m_R=2.Comment: 36 pages, CU-TP-603, Latex, 3 PS figures included, uuencoded compressed shar fil

    Fachspezifische Indexierung von historischen Dokumenten II. Ein Framework zur approximativen Indexierung semistrukturierter Dokumente

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    Bei Projekten zur Digitalisierung in Geisteswissenschaften ist heute die Realisierung größerer, überregionaler und über das World Wide Web abfragbarer Lösungen erforderlich. Die Beiträge dieses Bandes wurden auf der Tagung des Staatsarchivs Hamburg und des Zentrums "Geisteswissenschaften in der digitalen Welt" an der Universität Hamburg am 10. und 11. April 2006 gehalten. Sie leisten einen interdisziplinären Beitrag zur erforderlichen Standardisierung dieser Angebote, die erst den dringend notwendigen Austausch erleichtern und die gemeinsame Nutzung strukturierter Daten ermöglichen kann.Today, digitization projects in the Humanities require the implementation of larger, supraregional solutions. The contributions in this volume were presented at the conference of the Hamburg State Archives and the Center for the Humanities in the Digital World at the University of Hamburg on April 10 and 11, 2006. They make an interdisciplinary contribution to the required standardisation of corresponding services which can only facilitate the urgently needed exchange of information and make it possible to share structured data

    Approximative Indexierungstechnik für historische deutsche Textvarianten

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    Historical documents have specific properties which make life hard for traditional information retrieval techniques. The missing notion of orthography and a general high degree of variation in the phonetic-graphemic representation, as well as in derivational morphology obstruct the possibility to find documents upon the entry of a modern word as the search term. The following paper gives an overview of existing string approximation technologies as used in bioinformatics, but also of phonetic approximation algorithms. It proposes an architecture of combining both notions, while using Jörg Michael’ phonet program to deduct from graphemes to a phonetic representation and a levenshtein automaton to allow for fast approximative matching. The final part of the paper evaluates the suitability of the approach, while using the levenshtein algorithm in its non-automaton-based implementation
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