1,169 research outputs found
Phenomenology of Neutrino Oscillations
We review the status of several phenomenological topics of current interest
in neutrino oscillations: (i) Solar neutrino oscillations after the first
Sudbury Neutrino Observatory measurements, including both model-independent and
model-dependent results; (ii) Dominant nu_mu-->nu_tau oscillations of
atmospheric and K2K neutrinos, and possible subdominant oscillations induced by
either extra states or extra interactions; and (iii) Four-neutrino scenarios
embedding the controversial LSND evidence for oscillations.Comment: 9 pages, including 12 figures. Presented at TAUP 2001: Topics in
Astroparticle and Underground Physics, Assergi, Italy, 8-12 Sep. 200
Analysis of oscillations of atmospheric neutrinos
We briefly review the current status of standard oscillations of atmospheric
neutrinos in schemes with two, three, and four flavor mixing. It is shown that,
although the pure \nu_\mu-->\nu_\tau channel provides an excellent 2\nu fit to
the data, one cannot exclude, at present, the occurrence of additional
subleading \nu_\mu-->\nu_e oscillations (3\nu schemes) or of sizable
\nu_\mu-->\nu_s oscillations (4\nu schemes). It is also shown that the wide
dynamical range of energy and pathlength probed by the Super-Kamiokande
experiment puts severe constraints on nonstandard explanations of the
atmospheric neutrino data, with a few notable exceptions.Comment: Talk at the 19th International Conference on Neutrino Physics and
Astrophysics - Neutrino 2000 (Sudbury, Ontario, Canada, 16-21 June 2000
Addendum to: Model-dependent and -independent implications of the first Sudbury Neutrino Observatory results
In the light of recent experimental and theoretical improvements, we review
our previous model-independent comparison [hep-ph/0106247] of the
Super-Kamiokande (SK) and Sudbury Neutrino Observatory (SNO) solar neutrino
event rates, including updated values for the ``equalized'' SK datum and for
the reference Standard Solar Model (SSM) B neutrino flux. We find that the
joint SK+SNO evidence for active neutrino flavor transitions is confirmed at
the level of 3.3 standard deviations, independently of possible transitions to
sterile states. Barring sterile neutrinos, we estimate the 3-sigma range for
the B neutrino flux (normalized to SSM) as f_B=0.96 +0.54-0.55.
Accordingly, the 3-sigma range for the energy-averaged nu_e survival
probability is found to be = 0.31 +0.55-0.16, independently of the
functional form of P_ee. An increase of the reference nu_e + d --> p + p + e
cross section by ~3%, as suggested by recent theoretical calculations, would
slightly shift the central values of f_B and of to ~1.00 and ~0.29,
respectively, and would strengthen the model-independent evidence for nu_e
transitions into active states at the level of ~3.6 sigma.Comment: 6 pages + 2 figures. Addendum to hep-ph/010624
Analysis of energy- and time-dependence of supernova shock effects on neutrino crossing probabilities
It has recently been realized that supernova neutrino signals may be affected
by shock propagation over a time interval of a few seconds after bounce. In the
standard three-neutrino oscillation scenario, such effects crucially depend on
the neutrino level crossing probability P_H in the 1-3 sector. By using a
simplified parametrization of the time-dependent supernova radial density
profile, we explicitly show that simple analytical expressions for P_H
accurately reproduce the phase-averaged results of numerical calculations in
the relevant parameter space. Such expressions are then used to study the
structure of P_H as a function of energy and time, with particular attention to
cases involving multiple crossing along the shock profile. Illustrative
applications are given in terms of positron spectra generated by supernova
electron antineutrinos through inverse beta decay.Comment: Major changes both in the text and in the figures in order to include
the effect of a step-like shock front density profile; final version to
appear in Physical Review
Probing supernova shock waves and neutrino flavor transitions in next-generation water-Cherenkov detectors
Several current projects aim at building a large water-Cherenkov detector,
with a fiducial volume about 20 times larger than in the current
Super-Kamiokande experiment. These projects include the Underground nucleon
decay and Neutrino Observatory (UNO) in the Henderson Mine (Colorado), the
Hyper-Kamiokande (HK) detector in the Tochibora Mine (Japan), and the MEgaton
class PHYSics (MEMPHYS) detector in the Frejus site (Europe). We study the
physics potential of a reference next-generation detector (0.4 Mton of fiducial
mass) in providing information on supernova neutrino flavor transitions with
unprecedented statistics. After discussing the ingredients of our calculations,
we compute neutrino event rates from inverse beta decay (), elastic scattering on electrons, and scattering on oxygen, with emphasis on
their time spectra, which may encode combined information on neutrino
oscillation parameters and on supernova forward (and possibly reverse) shock
waves. In particular, we show that an appropriate ratio of low-to-high energy
events can faithfully monitor the time evolution of the neutrino crossing
probability along the shock-wave profile. We also discuss some background
issues related to the detection of supernova relic neutrinos, with and without
the addition of gadolinium.Comment: Revised version (27 pages, 13 eps figures), to appear in JCAP.
Includes revised numerical estimates and figures. In particular: calculations
of inverse beta decay event rates improved by using the differential cross
section by Vissani and Strumia (astro-ph/0302055); supernova relic neutrino
flux calculations updated by using recent GALEX Mission data
(astro-ph/0411424) on the star formation rate (SFR). References added.
Conclusions unchange
Zenith distribution of atmospheric neutrino events and electron neutrino mixing
Assuming atmospheric neutrino oscillations with dominant nu_munu_tau
transitions, we discuss how subdominant nu_e mixing (within the Chooz reactor
bounds) can alter the zenith distributions of neutrino-induced electrons and
muons. We isolate two peculiar distortion effects, one mainly related to nu_e
mixing in vacuum and the other to matter oscillations, that may be sufficiently
large to be detected by the SuperKamiokande atmospheric nu experiment. These
effects (absent for pure two-flavor nu_munu_tau transitions) do not vanish
in the limit of energy-averaged oscillations.Comment: 6 pages, RevTeX, no figure
The solar neutrino problem after three hundred days of data at SuperKamiokande
We present an updated analysis of the solar neutrino problem in terms of both
Mikheyev-Smirnov-Wolfenstein (MSW) and vacuum neutrino oscillations, with the
inclusion of the preliminary data collected by the SuperKamiokande experiment
during 306.3 days of operation. In particular, the observed energy spectrum of
the recoil electrons from 8B neutrino scattering is discussed in detail and is
used to constrain the mass-mixing parameter space. It is shown that: 1) the
small mixing MSW solution is preferred over the large mixing one; 2) the vacuum
oscillation solutions are strongly constrained by the energy spectrum
measurement; and 3) the detection of a possible semiannual modulation of the 8B
\nu flux due to vacuum oscillations should require at least one more year of
operation of SuperKamiokande.Comment: 15 pages (RevTeX) + 8 figures (postscript). Requires epsfig.st
Atmospheric, Solar, and CHOOZ neutrinos: a global three generation analysis
We perform a global three generation analysis of the current solar and
atmospheric evidence in favor of neutrino oscillations. We also include the
negative results coming from CHOOZ to constrain the nu_e mixing. We study the
zones of mass-mixing oscillations parameters compatible with all the data. It
is shown that almost pure nu_mu nu_tau oscillations are required to
explain the atmospheric neutrino anomaly and almost pure nu_1 nu_2
oscillations to account for the solar neutrino deficit.Comment: 4 pages, talk given at 36th Rencontres de Moriond: Electroweak
Interactions and Unified Theories, Les Arcs, France, 10-17 Mar 200
Integrating ChatGPT with Blockly for End-User Development of Robot Tasks
This paper presents an End-User Development environment for collaborative robot programming, which integrates Open AI ChatGPT with Google Blockly. Within this environment, a user, who is neither expert in robotics nor in computer programming, can define the items characterizing the application domain (e.g., objects, actions, and locations) and define pick-and-place tasks involving these items. Task definition can be achieved with a combination of natural language and block-based interaction, which exploits the computational capabilities of ChatGPT and the graphical interaction features offered by Blockly, to check the correctness of generated robot programs and modify them through direct manipulation
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