8,302 research outputs found
Incoherent Mollow triplet
A counterpart of the Mollow triplet (luminescence lineshape of a two-level
system under coherent excitation) is obtained for the case of incoherent
excitation in a cavity. Its analytical expression, in excellent agreement with
numerical results, pinpoints analogies and differences between the conventional
resonance fluorescence spectrum and its cavity QED analogue under incoherent
excitation.Comment: 4 pages, 3 figure
Finding the Higgs Boson through Supersymmetry
The study of displaced vertices containing two b--jets may provide a double
discovery at the Large Hadron Collider (LHC): we show how it may not only
reveal evidence for supersymmetry, but also provide a way to uncover the Higgs
boson necessary in the formulation of the electroweak theory in a large region
of the parameter space. We quantify this explicitly using the simplest minimal
supergravity model with bilinear breaking of R-parity, which accounts for the
observed pattern of neutrino masses and mixings seen in neutrino oscillation
experiments.Comment: 7 pages, 7 figures. Final version to appear at PRD. Discussion and
results were enlarge
Heavy Neutrinos and Lepton Flavour Violation in Left-Right Symmetric Models at the LHC
We discuss lepton flavour violating processes induced in the production and
decay of heavy right-handed neutrinos at the LHC. Such particles appear in
left-right symmetrical extensions of the Standard Model as the messengers of
neutrino mass generation, and can have masses at the TeV scale. We determine
the expected sensitivity on the right-handed neutrino mixing matrix, as well as
on the right-handed gauge boson and heavy neutrino masses. By comparing the
sensitivity of the LHC with that of searches for low energy LFV processes, we
identify favourable areas of the parameter space to explore the complementarity
between LFV at low and high energies.Comment: 34 pages, 16 figures, PRD versio
Constraining nonstandard neutrino-quark interactions with solar, reactor and accelerator data
We present a reanalysis of nonstandard neutrino-down-quark interactions of
electron and tau neutrinos using solar, reactor and accelerator data. In
addition updating the analysis by including new solar data from SNO phase III
and Borexino, as well as new KamLAND data and solar fluxes, a key role is
played in our analysis by the combination of these results with the CHARM data.
The latter allows us to better constrain the axial and axial-vector electron
and tau-neutrino nonstandard interaction parameters characterizing the
deviations from the Standard Model predictions.Comment: 11 pages, 6 figures, 2 tables, typo corrected in Figure 2, version
published in Phys. Rev.
Probing Neutrino Oscillations in Supersymmetric Models at the Large Hadron Collider
The lightest supersymmetric particle may decay with branching ratios that
correlate with neutrino oscillation parameters. In this case the CERN Large
Hadron Collider (LHC) has the potential to probe the atmospheric neutrino
mixing angle with sensitivity competitive to its low-energy determination by
underground experiments. Under realistic detection assumptions, we identify the
necessary conditions for the experiments at CERN's LHC to probe the simplest
scenario for neutrino masses induced by minimal supergravity with bilinear R
parity violation.Comment: 11 pages, 6 figures. To appear in Physical Review
Reverse logistics for recycling: the customer service determinants
Customer service is a central concern in the logistics practice and a study topic in the forward logistics research. This article investigates the elements of customer service and their importance in reverse logistics for recycling. Since consumer is the first intervenient in any reverse system that aims to recycle household residues, the provision of an adequate customer service gains an increased importance. Applying multivariate statistical methods (exploratory factor analysis, confirmatory factor analysis and discriminant analysis) to the data from a sample of 267 Portuguese citizens, this study identifies the levels of customer service in this reverse logistics chain and evaluates their relative importance in achieving consumers' participation. The study finds that, as in forward logistics, the customer service in reverse channels for recycling also has a hard and a soft level, being the former more important than the later. The results of this research suggest important guidelines to improve such a complex logistics service
Probing neutrino mass with multilepton production at the Tevatron in the simplest R-parity violation model
We analyze the production of multileptons in the simplest supergravity model
with bilinear violation of R parity at the Fermilab Tevatron. Despite the small
R-parity violating couplings needed to generate the neutrino masses indicated
by current atmospheric neutrino data, the lightest supersymmetric particle is
unstable and can decay inside the detector. This leads to a phenomenology quite
distinct from that of the R-parity conserving scenario. We quantify by how much
the supersymmetric multilepton signals differ from the R-parity conserving
expectations, displaying our results in the plane. We
show that the presence of bilinear R-parity violating interactions enhances the
supersymmetric multilepton signals over most of the parameter space, specially
at moderate and large .Comment: 26 pages, 23 figures. Revised version with some results corrected and
references added. Conclusions remain the sam
Two-parameter neutrino mass matrices with two texture zeros
We reanalyse Majorana-neutrino mass matrices M_nu with two texture zeros, by
searching for viable hybrid textures in which the non-zero matrix elements of
M_nu have simple ratios. Referring to the classification scheme of Frampton,
Glashow and Marfatia, we find that the mass matrix denoted by A1 allows the
ratios (M_nu)_{mu mu} : (Mnu)_{tau tau} = 1:1 and (M_nu)_{e tau} : (Mnu)_{mu
tau} = 1:2. There are analogous ratios for texture A2. With these two hybrid
textures, one obtains, for instance, good agreement with the data if one
computes the three mixing angles in terms of the experimentally determined
mass-squared differences Delta m^2_21 and Delta m^2_31. We could not find
viable hybrid textures based on mass matrices different from those of cases A1
and A2.Comment: 10 pages, no figures, minor changes, some references adde
Luminescence Spectra of Quantum Dots in Microcavities. I. Bosons
We provide a unified theory of luminescence spectra of coupled light-matter
systems realized with semiconductor heterostructures in microcavities,
encompassing: i) the spontaneous emission case, where the system decays from a
prepared (typically pure) initial state, and ii) luminescence in the presence
of a continuous, incoherent pump. While the former case has been amply
discussed in the literature (albeit mainly for the case of resonance), no
consideration has been given to the influence of the incoherent pump. We show
how, by provoking a self-consistent quantum state, the pump considerably alters
the emission spectra, even at vanishing intensities. The main outcome of our
analysis is to unambiguously identify strong-coupling in situations where it
appears in disguise or only seems to appear. Here, we consider bosonic matter
fields, in which case fully analytical solutions can be obtained. This
describes the case of quantum wells or large quantum dots, or the limit of low
excitation where the average populations remain much smaller than one
Search for axion-like particles using a variable baseline photon regeneration technique
We report the first results of the GammeV experiment, a search for milli-eV
mass particles with axion-like couplings to two photons. The search is
performed using a "light shining through a wall" technique where incident
photons oscillate into new weakly interacting particles that are able to pass
through the wall and subsequently regenerate back into detectable photons. The
oscillation baseline of the apparatus is variable, thus allowing probes of
different values of particle mass. We find no excess of events above background
and are able to constrain the two-photon couplings of possible new scalar
(pseudoscalar) particles to be less than 3.1x10^{-7} GeV^{-1} (3.5x10^{-7}
GeV^{-1}) in the limit of massless particles.Comment: 5 pages, 4 figures. This is the version accepted by PRL and includes
updated limit
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