3,287 research outputs found

### Addendum: Neutrino Mass Hierarchy Determination Using Reactor Antineutrinos

We update our study of neutrino mass hierarchy determination using a high
statistics reactor electron anti-neutrino experiment in the light of the recent
evidences of a relatively large non-zero value of \theta_{13} from the Daya Bay
and RENO experiments. We find that there are noticeable modifications in the
results, which allow a relaxation in the detector's characteristics, such as
the energy resolution and exposure, required to obtain a significant
sensitivity to, or to determine, the neutrino mass hierarchy in such a reactor
experiment.Comment: 7 pages, 1 figure, to be published in Journal of High Energy Physics
(JHEP

### Neutrino Mass Hierarchy Determination Using Reactor Antineutrinos

Building on earlier studies, we investigate the possibility to determine the
type of neutrino mass spectrum (i.e., "the neutrino mass hierarchy") in a high
statistics reactor electron antineutrino experiment with a relatively large
KamLAND-like detector and an optimal baseline of 60 Km. We analyze
systematically the Fourier Sine and Cosine Transforms (FST and FCT) of
simulated reactor antineutrino data with reference to their specific mass
hierarchy-dependent features discussed earlier in the literature. We perform
also a binned \chi^2 analysis of the sensitivity of simulated reactor electron
antineutrino event spectrum data to the neutrino mass hierarchy, and determine,
in particular, the characteristics of the detector and the experiment (energy
resolution, visible energy threshold, exposure, systematic errors, binning of
data, etc.), which would allow us to get significant information on, or even
determine, the type of the neutrino mass spectrum. We find that if \sin^2
2\theta_{13} is sufficiently large, \sin^2 2\theta_{13} \gtap 0.02, the
requirements on the set-up of interest are very challenging, but not impossible
to realize.Comment: 32 pages, 27 figures, accepted in Journal of High Energy Physic

### On the relation between p-adic and ordinary strings

The amplitudes for the tree-level scattering of the open string tachyons,
generalised to the field of p-adic numbers, define the p-adic string theory.
There is empirical evidence of its relation to the ordinary string theory in
the p_to_1 limit. We revisit this limit from a worldsheet perspective and argue
that it is naturally thought of as a continuum limit in the sense of the
renormalisation group.Comment: 13 pages harvmac (b), 2 eps figures; v2: revtex, shortened, published
versio

### Resolving the Mass Hierarchy with Atmospheric Neutrinos using a Liquid Argon Detector

We explore the potential offered by large-mass Liquid Argon detectors for
determination of the sign of Delta m_{31}^2, or the neutrino mass hierarchy,
through interactions of atmospheric neutrinos. We give results for a 100 kT
sized magnetized detector which provides separate sensitivity to \nu_\mu,
\bar{\nu}_\mu and, over a limited energy range, to \nu_e, \bar{\nu}_e.We also
discuss the sensitivity for the unmagnetized version of such a detector. After
including the effect of smearing in neutrino energy and direction and
incorporating the relevant statistical,theoretical and systematic errors, we
perform a binned \chi^2 analysis of simulated data. The \chi^2 is marginalized
over the presently allowed ranges of neutrino parameters and determined as a
function of \theta_{13}. We find that such a detector offers superior
capabilities for hierarchy resolution, allowing a > 4\sigma determination for a
100 kT detector over a 10 year running period for values of \sin^2 2\theta_{13}
\ge 0.05. For an unmagnetized detector, a 2.5\sigma hierarchy sensitivity is
possible for \sin^2 2\theta_{13} = 0.04.Comment: 13 pages, 3 figures, typing error in the abstract corrected, no other
chang

### Form-factors computation of Friedel oscillations in Luttinger liquids

We show how to analytically determine for $g\leq 1/2$ the "Friedel
oscillations" of charge density by a single impurity in a 1D Luttinger liquid
of spinless electrons.Comment: Revtex, epsf, 4pgs, 2fig

### On the Boundary Entropy of One-dimensional Quantum Systems at Low Temperature

The boundary beta-function generates the renormalization group acting on the
universality classes of one-dimensional quantum systems with boundary which are
critical in the bulk but not critical at the boundary. We prove a gradient
formula for the boundary beta-function, expressing it as the gradient of the
boundary entropy s at fixed non-zero temperature. The gradient formula implies
that s decreases under renormalization except at critical points (where it
stays constant). At a critical point, the number exp(s) is the ``ground-state
degeneracy,'' g, of Affleck and Ludwig, so we have proved their long-standing
conjecture that g decreases under renormalization, from critical point to
critical point. The gradient formula also implies that s decreases with
temperature except at critical points, where it is independent of temperature.
The boundary thermodynamic energy u then also decreases with temperature. It
remains open whether the boundary entropy of a 1-d quantum system is always
bounded below. If s is bounded below, then u is also bounded below.Comment: 12 pages, Latex, 1 eps-figure; v2: some expository material added, a
slightly more condensed version of the paper is publihed in Phys. Rev. Let

### Kink-boundary collisions in a two dimensional scalar field theory

In a two-dimensional toy model, motivated from five-dimensional heterotic
M-theory, we study the collision of scalar field kinks with boundaries. By
numerical simulation of the full two-dimensional theory, we find that the kink
is always inelastically reflected with a model-independent fraction of its
kinetic energy converted into radiation. We show that the reflection can be
analytically understood as a fluctuation around the scalar field vacuum. This
picture suggests the possibility of spontaneous emission of kinks from the
boundary due to small perturbations in the bulk. We verify this picture
numerically by showing that the radiation emitted from the collision of an
initial single kink eventually leads to a bulk populated by many kinks.
Consequently, processes changing the boundary charges are practically
unavoidable in this system. We speculate that the system has a universal final
state consisting of a stack of kinks, their number being determined by the
initial energy

### Large Matter Effects in ${{\nu_\mu \to \nu_\tau}}$ Oscillations

We show that matter effects change the ${\rm {\nu_\mu \to \nu_\tau}}$
oscillation probability by as much as 70% for certain ranges of energies and
pathlengths. Consequently, the ${\rm {\nu_\mu \to \nu_\mu}}$ survival
probability also undergoes large changes. A proper understanding of $\nu_\mu$
survival rates must consider matter effects in $P_{\mu \tau}$ as well as
$P_{\mu e}$. We comment on a) how these matter effects may be observed and the
sign of $\Delta_{31}$ determined in atmospheric neutrino measurements and at
neutrino factories and b) how they lead to heightened sensitivity for small
$\theta_{13}$.Comment: Version to appear in Phys. Rev. Let

### Boundary states for a free boson defined on finite geometries

Langlands recently constructed a map that factorizes the partition function
of a free boson on a cylinder with boundary condition given by two arbitrary
functions in the form of a scalar product of boundary states. We rewrite these
boundary states in a compact form, getting rid of technical assumptions
necessary in his construction. This simpler form allows us to show explicitly
that the map between boundary conditions and states commutes with conformal
transformations preserving the boundary and the reality condition on the scalar
field.Comment: 16 pages, LaTeX (uses AMS components). Revised version; an analogy
with string theory computations is discussed and references adde

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