13,215 research outputs found

    Gauge boson fusion as a probe of inverted hierarchies in supersymmetry

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    Supersymmetric scenarios with inverted mass hierarchy can be hard to observe at a hadron collider, particularly for the non-strongly interacting sector. We show how the production of stau-pairs via gauge boson fusion, along with hard jets in the high rapidity region, can be instrumental in uncovering the signatures of such scenarios. We demonstrate this both in a model-independent way and with reference to some specific, well-motivated models.Comment: RevTeX4, 4 pages, 2 figures. Final version to appear in Phys.Rev.D Changes in context, figures modified. References added. Conclusions unchange

    Does the butterfly diagram indicate asolar flux-transport dynamo?

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    We address the question whether the properties of the observed latitude-time diagram of sunspot occurence (the butterfly diagram) provide evidence for the operation of a flux-transport dynamo, which explains the migration of the sunspot zones and the period of the solar cycle in terms of a deep equatorward meridional flow. We show that the properties of the butterfly diagram are equally well reproduced by a conventional dynamo model with migrating dynamo waves, but without transport of magnetic flux by a flow. These properties seem to be generic for an oscillatory and migratory field of dipole parity and thus do not permit an observational distinction between different dynamo approaches.Comment: 4 pages, 1 figur

    One-loop Effective Potential for a Fixed Charged Self-interacting Bosonic Model at Finite Temperature with its Related Multiplicative Anomaly

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    The one-loop partition function for a charged self-interacting Bose gas at finite temperature in D-dimensional spacetime is evaluated within a path integral approach making use of zeta-function regularization. For D even, a new additional vacuum term ---overlooked in all previous treatments and coming from the multiplicative anomaly related to functional determinants-- is found and its dependence on the mass and chemical potential is obtained. The presence of the new term is shown to be crucial for having the factorization invariance of the regularized partition function. In the non interacting case, the relativistic Bose-Einstein condensation is revisited. By means of a suitable charge renormalization, for D=4 the symmetry breaking phase is shown to be unaffected by the new term, which, however, gives actually rise to a non vanishing new contribution in the unbroken phase.Comment: 25 pages, RevTex, a new Section and several explanations added concering the non-commutative residue and the physical discussio

    Implications of the Partial Width Z->bb for Supersymmetry Searches and Model-Building

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    Assuming that the actual values of the top quark mass at FNAL and of the ratio of partial widths Z->bb/Z->hadrons at LEP are within their current one-sigma reported ranges, we present a No-Lose Theorem for superpartner searches at LEP II and an upgraded Tevatron. We impose only two theoretical assumptions: the Lagrangian is that of the Minimal Supersymmetric Standard Model with arbitrary soft-breaking terms, and all couplings remain perturbative up to scales of order 10^16 GeV; there are no assumptions about the soft SUSY breaking parameters, proton decay, cosmology, etc. In particular, if the LEP and FNAL values hold up and supersymmetry is responsible for the discrepancy with the SM prediction of the partial width of Z->bb, then we must have charginos and/or top squarks observable at the upgraded machines. Furthermore, little deviation from the SM is predicted within "super-unified" SUSY. Finally, it appears to be extremely difficult to find any unified MSSM model, regardless of the form of soft SUSY breaking, that can explain the partial width for large tan(beta); in particular, no model with top-bottom-tau Yukawa coupling unification appears to be consistent with the experiments.Comment: 15 pages, University of Michigan preprint UM-TH-94-23. LaTeX file with 4 uuencoded figures sent separately. Compressed PS file (114Kb) available by anonymous FTP from 141.211.96.66 in /pub/preprints/UM-TH-94-23.ps.

    Report of the Higgs Working Group of the Tevatron Run 2 SUSY/Higgs Workshop

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    This report presents the theoretical analysis relevant for Higgs physics at the upgraded Tevatron collider and documents the Higgs Working Group simulations to estimate the discovery reach in Run 2 for the Standard Model and MSSM Higgs bosons. Based on a simple detector simulation, we have determined the integrated luminosity necessary to discover the SM Higgs in the mass range 100-190 GeV. The first phase of the Run 2 Higgs search, with a total integrated luminosity of 2 fb-1 per detector, will provide a 95% CL exclusion sensitivity comparable to that expected at the end of the LEP2 run. With 10 fb-1 per detector, this exclusion will extend up to Higgs masses of 180 GeV, and a tantalizing 3 sigma effect will be visible if the Higgs mass lies below 125 GeV. With 25 fb-1 of integrated luminosity per detector, evidence for SM Higgs production at the 3 sigma level is possible for Higgs masses up to 180 GeV. However, the discovery reach is much less impressive for achieving a 5 sigma Higgs boson signal. Even with 30 fb-1 per detector, only Higgs bosons with masses up to about 130 GeV can be detected with 5 sigma significance. These results can also be re-interpreted in the MSSM framework and yield the required luminosities to discover at least one Higgs boson of the MSSM Higgs sector. With 5-10 fb-1 of data per detector, it will be possible to exclude at 95% CL nearly the entire MSSM Higgs parameter space, whereas 20-30 fb-1 is required to obtain a 5 sigma Higgs discovery over a significant portion of the parameter space. Moreover, in one interesting region of the MSSM parameter space (at large tan(beta)), the associated production of a Higgs boson and a b b-bar pair is significantly enhanced and provides potential for discovering a non-SM-like Higgs boson in Run 2.Comment: 185 pages, 124 figures, 55 table

    PDFS: Practical Data Feed Service for Smart Contracts

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    Smart contracts are a new paradigm that emerged with the rise of the blockchain technology. They allow untrusting parties to arrange agreements. These agreements are encoded as a programming language code and deployed on a blockchain platform, where all participants execute them and maintain their state. Smart contracts are promising since they are automated and decentralized, thus limiting the involvement of third trusted parties, and can contain monetary transfers. Due to these features, many people believe that smart contracts will revolutionize the way we think of distributed applications, information sharing, financial services, and infrastructures. To release the potential of smart contracts, it is necessary to connect the contracts with the outside world, such that they can understand and use information from other infrastructures. For instance, smart contracts would greatly benefit when they have access to web content. However, there are many challenges associated with realizing such a system, and despite the existence of many proposals, no solution is secure, provides easily-parsable data, introduces small overheads, and is easy to deploy. In this paper we propose PDFS, a practical system for data feeds that combines the advantages of the previous schemes and introduces new functionalities. PDFS extends content providers by including new features for data transparency and consistency validations. This combination provides multiple benefits like content which is easy to parse and efficient authenticity verification without breaking natural trust chains. PDFS keeps content providers auditable, mitigates their malicious activities (like data modification or censorship), and allows them to create a new business model. We show how PDFS is integrated with existing web services, report on a PDFS implementation and present results from conducted case studies and experiments.Comment: Blockchain; Smart Contracts; Data Authentication; Ethereu

    Radiative Corrections to the ZbbˉZ b \bar{b} Vertex and Constraints on Extended Higgs Sectors

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    We explore the radiative corrections to the process ZbbˉZ \to b \bar b in models with extended Higgs sectors. The observables Rb=Γ(Zbbˉ)/Γ(Zhadrons)R_b = \Gamma(Z \to b \bar b)/\Gamma(Z \to \rm{hadrons}) and the ZbbˉZ b \bar b coupling asymmetry, Ab=(gL2gR2)/(gL2+gR2)A_b = (g_L^2 - g_R^2)/(g_L^2 + g_R^2), are sensitive to these corrections. We present general formulae for the one-loop corrections to RbR_b and AbA_b in an arbitrary extended Higgs sector, and derive explicit results for a number of specific models. We find that in models containing only doublets, singlets, or larger multiplets constrained by a custodial SU(2)cSU(2)_{c} symmetry so that MW=MZcosθWM_W = M_Z \cos\theta_W at tree level, the one-loop corrections due to virtual charged Higgs bosons always worsen agreement with experiment. The RbR_{b} measurement can be used to set lower bounds on the charged Higgs masses. Constraints on models due to the one-loop contributions of neutral Higgs bosons are also examined.Comment: 54 pages, 11 figure
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