461 research outputs found
A Two-Player Game of Life
We present a new extension of Conway's game of life for two players, which we
call p2life. P2life allows one of two types of token, black or white, to
inhabit a cell, and adds competitive elements into the birth and survival rules
of the original game. We solve the mean-field equation for p2life and determine
by simulation that the asymptotic density of p2life approaches 0.0362.Comment: 7 pages, 3 figure
Study of Non-Standard Neutrino Interactions with Atmospheric Neutrino Data in Super-Kamiokande I and II
In this paper we study non-standard neutrino interactions as an example of
physics beyond the standard model using atmospheric neutrino data collected
during the Super-Kamiokande I(1996-2001) and II(2003-2005) periods. We focus on
flavor-changing-neutral-currents (FCNC), which allow neutrino flavor
transitions via neutral current interactions, and effects which violate lepton
non-universality (NU) and give rise to different neutral-current
interaction-amplitudes for different neutrino flavors. We obtain a limit on the
FCNC coupling parameter, varepsilon_{mu tau}, |varepsilon_{mu tau}|<1.1 x
10^{-2} at 90%C.L. and various constraints on other FCNC parameters as a
function of the NU coupling, varepsilon_{e e}. We find no evidence of
non-standard neutrino interactions in the Super-Kamiokande atmospheric data.Comment: 12 Pages, 14 figures. To be submitted to Phys. Rev.
Atmospheric neutrino oscillation analysis with sub-leading effects in Super-Kamiokande I, II, and III
We present a search for non-zero theta_{13} and deviations of sin^2
theta_{23} from 0.5 in the oscillations of atmospheric neutrino data from
Super-Kamiokande -I, -II, and -III. No distortions of the neutrino flux
consistent with non-zero theta_{13} are found and both neutrino mass hierarchy
hypotheses are in agreement with the data. The data are best fit at Delta m^2 =
2.1 x 10^-3 eV^2, sin^2 theta_{13} = 0.0, and sin^2 theta_{23} =0.5. In the
normal (inverted) hierarchy theta_{13} and Delta m^2 are constrained at the
one-dimensional 90% C.L. to sin^2 theta_{13} < 0.04 (0.09) and 1.9 (1.7) x
10^-3 < Delta m^2 < 2.6 (2.7) x 10^-3 eV^2. The atmospheric mixing angle is
within 0.407 <= sin^2 theta_{23} <= 0.583 at 90% C.L.Comment: 17 Pages, 14 figures. To be submitted to Phys. Rev. D Minor update to
text after referee comments. Figures modified for better grayscale printing
Search for Nucleon Decay into Charged Anti-lepton plus Meson in Super-Kamiokande I and II
Searches for a nucleon decay into a charged anti-lepton (e^+ or {\mu}^+) plus
a light meson ({\pi}^0, {\pi}^-, {\eta}, {\rho}^0, {\rho}^-, {\omega}) were
performed using the Super-Kamiokande I and II data. Twelve nucleon decay modes
were searched for. The total exposure is 140.9 kiloton \cdot years, which
includes a 91.7 kiloton \cdot year exposure (1489.2 live days) of
Super-Kamiokande-I and a 49.2 kiloton \cdot year exposure (798.6 live days) of
Super-Kamiokande-II. The number of candidate events in the data was consistent
with the atmospheric neutrino background expectation. No significant evidence
for a nucleon decay was observed in the data. Thus, lower limits on the nucleon
partial lifetime at 90% confidence level were obtained. The limits range from
3.6 \times 10^31 to 8.2 \times 10^33 years, depending on the decay modes.Comment: 25 pages, 18 figure
An Indirect Search for WIMPs in the Sun using 3109.6 days of upward-going muons in Super-Kamiokande
We present the result of an indirect search for high energy neutrinos from
WIMP annihilation in the Sun using upward-going muon (upmu) events at
Super-Kamiokande. Datasets from SKI-SKIII (3109.6 days) were used for the
analysis. We looked for an excess of neutrino signal from the Sun as compared
with the expected atmospheric neutrino background in three upmu categories:
stopping, non-showering, and showering. No significant excess was observed. The
90% C.L. upper limits of upward-going muon flux induced by WIMPs of 100
GeV/c were 6.4 cm sec and 4.0
cm sec for the soft and hard annihilation channels, respectively.
These limits correspond to upper limits of 4.5 cm and
2.7 cm for spin-dependent WIMP-nucleon scattering cross
sections in the soft and hard annihilation channels, respectively.Comment: Add journal reference. Also fixed typo and cosmetic things in the old
draf
Solar neutrino results in Super-Kamiokande-III
The results of the third phase of the Super-Kamiokande solar neutrino
measurement are presented and compared to the first and second phase results.
With improved detector calibrations, a full detector simulation, and improved
analysis methods, the systematic uncertainty on the total neutrino flux is
estimated to be ?2.1%, which is about two thirds of the systematic uncertainty
for the first phase of Super-Kamiokande. The observed 8B solar flux in the 5.0
to 20 MeV total electron energy region is 2.32+/-0.04 (stat.)+/-0.05 (sys.)
*10^6 cm^-2sec^-1, in agreement with previous measurements. A combined
oscillation analysis is carried out using SK-I, II, and III data, and the
results are also combined with the results of other solar neutrino experiments.
The best-fit oscillation parameters are obtained to be sin^2 {\theta}12 =
0.30+0.02-0.01(tan^2 {\theta}12 = 0.42+0.04 -0.02) and {\Delta}m2_21 =
6.2+1.1-1.9 *10^-5eV^2. Combined with KamLAND results, the best-fit oscillation
parameters are found to be sin^2 {\theta}12 = 0.31+/-0.01(tan^2 {\theta}12 =
0.44+/-0.03) and {\Delta}m2_21 = 7.6?0.2*10^-5eV^2 . The 8B neutrino flux
obtained from global solar neutrino experiments is
5.3+/-0.2(stat.+sys.)*10^6cm^-2s^-1, while the 8B flux becomes
5.1+/-0.1(stat.+sys.)*10^6cm^-2s^-1 by adding KamLAND result. In a three-flavor
analysis combining all solar neutrino experiments, the upper limit of sin^2
{\theta}13 is 0.060 at 95% C.L.. After combination with KamLAND results, the
upper limit of sin^2 {\theta}13 is found to be 0.059 at 95% C.L..Comment: 19 pages, 33 figures in the main text. The appendix section on errata
is added in v
Evidence for the Appearance of Atmospheric Tau Neutrinos in Super-Kamiokande
Super-Kamiokande atmospheric neutrino data were fit with an unbinned maximum
likelihood method to search for the appearance of tau leptons resulting from
the interactions of oscillation-generated tau neutrinos in the detector.
Relative to the expectation of unity, the tau normalization is found to be
1.42 \pm 0.35 \ (stat) {\}^{+0.14}_{-0.12}\ (syst) excluding the
no-tau-appearance hypothesis, for which the normalization would be zero, at the
3.8 level. We estimate that 180.1 \pm 44.3\ (stat)
{\}^{+17.8}_{-15.2}\ (syst) tau leptons were produced in the 22.5 kton
fiducial volume of the detector by tau neutrinos during the 2806 day running
period. In future analyses, this large sample of selected tau events will allow
the study of charged current tau neutrino interaction physics with oscillation
produced tau neutrinos.Comment: 7 pages, 4 figures. This is the version as published in Physical
Review Letters including the supplemental figure. A typographical error in
the description of figure 3 is also correcte
Search for Differences in Oscillation Parameters for Atmospheric Neutrinos and Antineutrinos at Super-Kamiokande
We present a search for differences in the oscillations of antineutrinos and
neutrinos in the Super-Kamiokande -I, -II, and -III atmospheric neutrino
sample. Under a two-flavor disappearance model with separate mixing parameters
between neutrinos and antineutrinos, we find no evidence for a difference in
oscillation parameters. Best fit antineutrino mixing is found to be at (dm2bar,
sin2 2 thetabar) = (2.0x10^-3 eV^2, 1.0) and is consistent with the overall
Super-K measurement.Comment: 6 pages, 4 figures. Figure update
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