856 research outputs found

    SUSY radiative corrections on mu-tau neutrino refraction including possible R-parity breaking interactions

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    In this paper we investigate the one-loop radiative corrections to the neutrino indices of refraction from supersymmetric models. We consider the Next-to Minimal Supersymmetric extension of the Standard Model (NMSSM) which happens to be a better supersymmetric candidate than the MSSM for both theoretical and experimental reasons. We scan the relevant SUSY parameters and identify regions in the parameter space which yield interesting values for V_{mu tau}. If R-parity is broken there are significant differences between MSSM and NMSSM contributions contrary to the R-parity conserved case. Finally, for a non-zero CP-violating phase, we show analytically that the presence of V_{mu tau} will explicitly imply CP-violation effects on the supernova electron (anti-) neutrino fluxes.Comment: 23 pages, 15 figures; v2: typos and 5 figures correcte

    Possible CP-Violation effects in core-collapse Supernovae

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    We study CP-violation effects when neutrinos are present in dense matter, such as outside the proto-neutron star formed in a core-collapse supernova. Using general arguments based on the Standard Model, we confirm that there are no CP-violating effects at the tree level on the electron neutrino and anti-neutrino fluxes in a core-collapse supernova. On the other hand significant effects can be obtained for muon and tau neutrinos even at the tree level. We show that CP violating effects can be present in the supernova electron (anti)neutrino fluxes as well, if muon and tau neutrinos have different fluxes at the neutrinosphere. Such differences could arise due to physics beyond the Standard Model, such as the presence of flavor-changing interactions.Comment: 11 pages, 18 figure

    Another blast from the past or why the left should embrace strict legalism: a reply to Frank Carrigan

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    This article argues that Carrigan's criticism of Sir Owen Dixon's strict legalism provides a clear example of the preconceptions and misconceptions that blind most opponents of Dixon's method. It argues that Carrigan's examination of a series of labour law cases does not support his contention that Dixon was a covert judicial activist; that, in contrast to the close relationship between strict legalism and popular democracy, opponents of strict legalism seem far more comfortable with the politics of the reactionary past: and that strict legalism is a necessary preconditon if the common law is to act as an institutional counterweight to an unbridled market. Rather than viewing strict legalism as a misleading and misconceived way of understanding the judicial role, it should be understood as an essential precondition for the operation of the rule of law and the continued independence of the common law in an era of impoverished institutional life

    The K-process on a tree as a scaling limit of the GREM-like trap model

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    We introduce trap models on a finite volume kk-level tree as a class of Markov jump processes with state space the leaves of that tree. They serve to describe the GREM-like trap model of Sasaki and Nemoto. Under suitable conditions on the parameters of the trap model, we establish its infinite volume limit, given by what we call a KK-process in an infinite kk-level tree. From this we deduce that the KK-process also is the scaling limit of the GREM-like trap model on extreme time scales under a fine tuning assumption on the volumes.Comment: Published in at http://dx.doi.org/10.1214/13-AAP937 the Annals of Applied Probability (http://www.imstat.org/aap/) by the Institute of Mathematical Statistics (http://www.imstat.org

    On the perturbative corrections around D-string instantons

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    We study F4{\cal F}^4-threshold corrections in an eight dimensional S-dual pair of string theories, as a prototype of dual string vacua with sixteen supercharges. We show that the orbifold CFT description of D-string instantons gives rise to a perturbative expansion similar to the one appearing on the fundamental string side. By an explicit calculation, using the Nambu-Goto action in the static gauge, we show that the first subleading term agrees precisely on the two sides. We then give a general argument to show that the agreement extends to all orders.Comment: 12 page

    Do we need a hybrid law of contract? Why Hugh Collins is wrong and why it matters

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    In Regulating Contracts Hugh Collins takes up the challenge presented by 40 years of empirical studies which show that business people make little use of contract law in settling disputes, preferring instead to rely on trust and various non-legal sanctions to organise their transactions. Indeed, business parties often actively avoid the use of law because of its expense, inconvenience and tendency to harm business relationships. These findings pose a challenge to traditional doctrinal scholars. If business parties do not make much use of contract law, one has to ask what role it does play and whether the attention that is paid to it by orthodox legal scholars is misplaced. Regulating Contracts takes on this challenge directly and is the most substantial attempt made so far to explain the role of contract law in light of the questions raised as to its usefulness.John Gava and Janey Green

    AdS/CFT correspondence and D1/D5 systems in theories with 16 supercharges

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    We discuss spectra of AdS3AdS_3 supergravities, arising in the near horizon geometry of D1/D5 systems in orbifolds/orientifolds of type IIB theory with 16 supercharges. These include models studied in a recent paper (hep-th/0012118), where the group action involves also a shift along a transversal circle, as well as IIB/ΩI4\Omega I_4, which is dual to IIB on K3K3. After appropriate assignements of the orbifold group eigenvalues and degrees to the supergravity single particle spectrum, we compute the supergravity elliptic genus and find agreement, in the expected regime of validity, with the elliptic genus obtained using U-duality map from (4,4) CFTs of U-dual backgrounds. Since this U-duality involves the exchange of KK momentum PP and D1 charge NN, it allows us to test the (4,4) CFTs in the P<N/4P < N/4 and N<P/4N < P/4 regimes by two different supergravity duals.Comment: 28 pages, no figure

    Do we need a hybrid law of contract? Why Hugh Collins is wrong and why it matters

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    In Regulating Contracts Hugh Collins takes up the challenge presented by 40 years of empirical studies which show that business people make little use of contract law in settling disputes, preferring instead to rely on trust and various non-legal sanctions to organise their transactions. Indeed, business parties often actively avoid the use of law because of its expense, inconvenience and tendency to harm business relationships. These findings pose a challenge to traditional doctrinal scholars. If business parties do not make much use of contract law, one has to ask what role it does play and whether the attention that is paid to it by orthodox legal scholars is misplaced. Regulating Contracts takes on this challenge directly and is the most substantial attempt made so far to explain the role of contract law in light of the questions raised as to its usefulness.John Gava and Janey Green

    Core-collapse supernova neutrinos and neutrino properties

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    Core-collapse supernovae are powerful neutrino sources. The observation of a future (extra-)galactic supernova explosion or of the relic supernova neutrinos might provide important information on the supernova dynamics, on the supernova formation rate and on neutrino properties. One might learn more about unknown neutrino properties either from indirect effects in the supernova (e.g. on the explosion or on in the r-process) or from modifications of the neutrino time or energy distributions in a detector on Earth. Here we will discuss in particular possible effects of CP violation in the lepton sector. We will also mention the interest of future neutrino-nucleus interaction measurements for the precise knowledge of supernova neutrino detector response to electron neutrinos.Comment: 9 pages, 5 figures, Proceedings to "Three days of Strong Interactions & Astrophysics HLPW08", 6-8 March 2008, SP
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