1,011 research outputs found
A study of atmospheric neutrinos with the IMB detector
A sample of 401 contained neutrino interactions collected in the 3300 metric ton fiducial mass IMB detector was used to study neutrino oscillations, geomagnetic modulation of the flux and to search for point sources. The majority of these events are attributed to neutrino interactions. For the most part, these neutrinos are believed to originate as tertiary products of cosmic ray interactions in the atmosphere. The neutrinos are a mixture of v sub e and v sub micron
Gravitational Radiation from Triple Star Systems
We have studied the main features of the gravitational radiation generated by
an astrophysical system constituted of three compact objects attracting one
another (only via gravitational interaction) in such a manner that stable
orbits do exist. We have limited our analysis to systems that can be treated
with perturbative methods. We show the profile of the gravitational waves
emitted by such systems. These results can be useful within the framework of
the new gravitational astronomy which will be made feasible by means of the new
generation of gravitational detectors such as LISA in a no longer far future.Comment: 10 pages plus 9 postscript figures; revtex; accepted for publication
in Int. J. Mod. Phys.
Dirac neutrino magnetic moment and a possible time evolution of the neutrino signal from a supernova
We analyze the influence of neutrino helicity conversion, ,
on the neutrino flux from a supernova caused by the interaction of the Dirac
neutrino magnetic moment with a magnetic field. We show that if the neutrino
has a magnetic moment in the interval and provided that a magnetic field of G exists in the supernova envelope, a peculiar kind of time evolution
of the neutrino signal from the supernova caused by the resonance transition
in the magnetic field of the envelope can appear. If a
magnetar with a poloidal magnetic field is formed in a supernova explosion,
then the neutrino signal could have a pulsating behavior, i.e., a kind of a
neutrino pulsar could be observed, when it rotates around an axis that does not
coincide with its magnetic moment and when the orientation of its rotation axis
is favourable for our observation.Comment: 9 pages, LaTeX, 2 EPS figures, based on the talk presented by A.V.
Kuznetsov at the XVI International Seminar Quarks'2010, Kolomna, Moscow
Region, June 6-12, 2010, to appear in the Proceeding
SoundCloud and Bandcamp as alternative music platforms
We examine two ‘producer-oriented’ audio distribution platforms, SoundCloud and Bandcamp, that have been important repositories for the hopes of musicians, commentators and audiences that digital technologies and cultural platforms might promote democratisation of the cultural industries, and we compare their achievements and limitations in this respect. We show that the emancipatory elements enshrined in SoundCloud’s ‘bottom-up’ abundance are compromised by two elements that underpin the platform: the problematic ‘culture of connectivity’ of the social media systems to which it must remain integrally linked, and the systems of intellectual property that the firm has been increasingly compelled to enforce. By contrast, it seems that Bandcamp has been relatively stable in financial terms while being at odds with some key aspects of ‘platformization’, and we explore the possibility that some of the platform’s apparent success may derive from how its key features makes it attractive to indie musicians and fans drawn to an independent ethos. Nevertheless, we argue, even while in some respects Bandcamp acts more effectively as an ‘alternative’ than does SoundCloud, the former is also congruent economically and discursively with how platforms capitalise on the activity of self-managing, self-auditing, specialist, worker-users
Screening of Long-Range Leptonic Forces by Cosmic Background Neutrinos
The absence of dispersion effects of the SN~1987A neutrino pulse has been
used to constrain novel long-range forces between neutrinos and galactic
baryonic or non-baryonic matter. If these forces are mediated by vector bosons,
screening effects by the cosmic neutrino background invalidate the SN~1987A
limits and other related arguments.Comment: REVTeX 3.0 document, 6 pages, no figures
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The cultural grammar of governance: The UK Code of Corporate Governance, reflexivity, and the limits of 'soft' regulation
We identify limits of ‘reflexive governance’ by examining the UK Code of Corporate Governance that is celebrated for its ‘reflexivity’. By placing the historical genesis of the Code within its politico-economic context, it is shown how its scope and penetration is impeded by a shallow, ‘single loop’ of reflexivity. Legitimized by agency theory, the Code is infused by a ‘cultural grammar’ that perpetuates relations of shareholder primacy as it restricts accountability to narrow forms of information disclosure directed exclusively at shareholders. Engagement of a deeper, ‘double loop’ reflexivity allows account to be taken of the historical conditions and theoretical conceptions that shape practices and outcomes of corporate governance. Only then is it possible to disclose, challenge and reform narrow conceptions, boundaries and workings of ‘reflexive governance’
Potential for Supernova Neutrino Detection in MiniBooNE
The MiniBooNE detector at Fermilab is designed to search for oscillation appearance at and to make a
decisive test of the LSND signal. The main detector (inside a veto shield) is a
spherical volume containing 0.680 ktons of mineral oil. This inner volume,
viewed by 1280 phototubes, is primarily a \v{C}erenkov medium, as the
scintillation yield is low. The entire detector is under a 3 m earth
overburden. Though the detector is not optimized for low-energy (tens of MeV)
events, and the cosmic-ray muon rate is high (10 kHz), we show that MiniBooNE
can function as a useful supernova neutrino detector. Simple trigger-level cuts
can greatly reduce the backgrounds due to cosmic-ray muons. For a canonical
Galactic supernova at 10 kpc, about 190 supernova
events would be detected. By adding MiniBooNE to the international network of
supernova detectors, the possibility of a supernova being missed would be
reduced. Additionally, the paths of the supernova neutrinos through Earth will
be different for MiniBooNE and other detectors, thus allowing tests of
matter-affected mixing effects on the neutrino signal.Comment: Added references, version to appear in PR
Resonant Spin-Flavor Conversion of Supernova Neutrinos and Deformation of the Electron Antineutrino Spectrum
The neutrino spin-flavor conversion of \bar\nu_e and \nu_\mu which is induced
by the interaction of the Majorana neutrino magnetic moment and magnetic fields
in the collapse-driven supernova is investigated in detail. We calculate the
conversion probability by using the latest precollapse models of Woosley and
Weaver (1995), and also those of Nomono and Hashimoto (1988), changing the
stellar mass and metallicity in order to estimate the effect of the
astrophysical uncertainties. Contour maps of the conversion probability are
given for all the models as a function of neutrino mass squared difference and
the neutrino magnetic moment times magnetic fields. It is shown that in the
solar metallicity models some observational effects are expected with \Delta
m^2 = 10^{-5}--10^{-1} [eV^2] and \mu_\nu >~ 10^{-12} (10^9 G / B_0) [\mu_B],
where B_0 is the strength of the magnetic fields at the surface of the iron
core. We also find that although the dependence on the stellar models or
stellar mass is not so large, the metallicity of precollapse stars has
considerable effects on this conversion. Such effects may be seen in a
supernova in the Large or Small Magellanic Clouds, and should be taken into
account when one considers an upper bound on \mu_\nu from the SN1987A data.Comment: 19 pages, LaTeX, using revtex. To appear in Phys. Rev. D. 16 figures
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