653 research outputs found

    Neutrino oscillations and uncertainty relations

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    We show that coherent flavor neutrino states are produced (and detected) due to the momentum-coordinate Heisenberg uncertainty relation. The Mandelstam-Tamm time-energy uncertainty relation requires non-stationary neutrino states for oscillations to happen and determines the time interval (propagation length) which is necessary for that. We compare different approaches to neutrino oscillations which are based on different physical assumptions but lead to the same expression for the neutrino transition probability in standard neutrino oscillation experiments. We show that a Moessbauer neutrino experiment could allow to distinguish different approaches and we present arguments in favor of the 163Ho-163Dy system for such an experiment.Comment: Some small changes in section 2, results unchanged. Added referenc

    Recoilless resonant neutrino capture and basics of neutrino oscillations

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    It is shown that the experiment on recoilless resonant emission and absorption of νˉe\bar \nu_{e}, proposed recently by Raghavan, could have an important impact on our understanding of the physics of neutrino oscillations.Comment: Additional information in the last chapte

    Improved description of charged Higgs boson production at hadron colliders

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    We present a new method for matching the two twin-processes gb->H+/-t and gg->H+/-tb in Monte Carlo event generators. The matching is done by defining a double-counting term, which is used to generate events that are subtracted from the sum of these two twin-processes. In this way we get a smooth transition between the collinear region of phase space, which is best described by gb->H+/-t, and the hard region, which requires the use of the gg->H+/-tb process. The resulting differential distributions show large differences compared to both the gb-> H+/-t and gg->H+/-tb processes illustrating the necessity to use matching when tagging the accompanying b-jet.Comment: 21 pages, 9 figures. Revised with updated discussion and reference

    Experimental Status of Neutrino Physics

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    After a fascinating phase of discoveries, neutrino physics still has a few mysteries such as the absolute mass scale, the mass hierarchy, the existence of CP violation in the lepton sector and the existence of right-handed neutrinos. It is also entering a phase of precision measurements. This is what motivates the NUFACT 11 conference which prepares the future of long baseline neutrino experiments. In this paper, we report the status of experimental neutrino physics. We focus mainly on absolute mass measurements, oscillation parameters and future plans for oscillation experiments

    Inversion of Randomly Corrugated Surfaces Structure from Atom Scattering Data

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    The Sudden Approximation is applied to invert structural data on randomly corrugated surfaces from inert atom scattering intensities. Several expressions relating experimental observables to surface statistical features are derived. The results suggest that atom (and in particular He) scattering can be used profitably to study hitherto unexplored forms of complex surface disorder.Comment: 10 pages, no figures. Related papers available at http://neon.cchem.berkeley.edu/~dan

    The relationship between tissue levels of flavone acetic acid (NSC 347512) and site dependent anti-tumour activity in murine colon tumours.

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    Flavone acetic acid (FAA) is extremely active against subcutaneous transplantable tumours in mice, but disappointingly there has been no demonstrable clinical activity. Previous studies have shown that lung tumour deposits are less responsive than the same cells implanted subcutaneously. The aim of this study is to examine the tissue disposition of FAA in an attempt to explain this site-dependent activity. The data show clearly that FAA clearance curves are influenced by the presence of MAC 15A tumours growing either subcutaneously or systemically. The decreased clearance of FAA from MAC 15A tumour bearing animals does not however explain the resistance of lung deposits. Neither can this be explained by differences in metabolism in these different sites. Cytotoxic metabolites have not been detected either in vitro or in vivo and their role in the mechanism of action of FAA is questionable

    Psychopolitics: Peter Sedgwick’s legacy for mental health movements

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    This paper re-considers the relevance of Peter Sedgwick's Psychopolitics (1982) for a politics of mental health. Psychopolitics offered an indictment of ‘anti-psychiatry’ the failure of which, Sedgwick argued, lay in its deconstruction of the category of ‘mental illness’, a gesture that resulted in a politics of nihilism. ‘The radical who is only a radical nihilist’, Sedgwick observed, ‘is for all practical purposes the most adamant of conservatives’. Sedgwick argued, rather, that the concept of ‘mental illness’ could be a truly critical concept if it was deployed ‘to make demands upon the health service facilities of the society in which we live’. The paper contextualizes Psychopolitics within the ‘crisis tendencies’ of its time, surveying the shifting welfare landscape of the subsequent 25 years alongside Sedgwick's continuing relevance. It considers the dilemma that the discourse of ‘mental illness’ – Sedgwick's critical concept – has fallen out of favour with radical mental health movements yet remains paradigmatic within psychiatry itself. Finally, the paper endorses a contemporary perspective that, while necessarily updating Psychopolitics, remains nonetheless ‘Sedgwickian’
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