Context. Transient neutrino sources such as gamma-ray bursts (GRBs) and supernovae (SNe) are hypothesized to emit bursts of high-energy neutrinos on a time-scale of ≲100 s. While GRB neutrinos would ...be produced in high relativistic jets, core-collapse SNe might host soft-relativistic jets, which become stalled in the outer layers of the progenitor star leading to an efficient production of high-energy neutrinos. Aims. To increase the sensitivity to these neutrinos and identify their sources, a low-threshold optical follow-up program for neutrino multiplets detected with the IceCube observatory has been implemented. Methods. If a neutrino multiplet, i.e. two or more neutrinos from the same direction within 100 s, is found by IceCube a trigger is sent to the Robotic Optical Transient Search Experiment, ROTSE. The 4 ROTSE telescopes immediately start an observation program of the corresponding region of the sky in order to detect an optical counterpart to the neutrino events. Results. No statistically significant excess in the rate of neutrino multiplets has been observed and furthermore no coincidence with an optical counterpart was found. Conclusions. The search allows, for the first time, to set stringent limits on current models predicting a high-energy neutrino flux from soft relativistic hadronic jets in core-collapse SNe. We conclude that a sub-population of SNe with typical Lorentz boost factor and jet energy of 10 and 3 × 1051 erg, respectively, does not exceed 4.2% at 90% confidence.
VAMOS1VAMOS is an acronym for: Verification and Assessment Measuring of Observatory Subsystem.1 was a prototype detector built in 2011 at an altitude of 4100m a.s.l. in the state of Puebla, Mexico. ...The aim of VAMOS was to finalize the design, construction techniques and data acquisition system of the HAWC observatory. HAWC is an air-shower array currently under construction at the same site of VAMOS with the purpose to study the TeV sky. The VAMOS setup included six water Cherenkov detectors and two different data acquisition systems. It was in operation between October 2011 and May 2012 with an average live time of 30%. Besides the scientific verification purposes, the eight months of data were used to obtain the results presented in this paper: the detector response to the Forbush decrease of March 2012, and the analysis of possible emission, at energies above 30GeV, for long gamma-ray bursts GRB111016B and GRB120328B.
Inelasticity, the fraction of a neutrino's energy transferred to hadrons, is a quantity of interest in the study of astrophysical and atmospheric neutrino interactions at multi-TeV energies with ...IceCube. In this work, a sample of contained neutrino interactions in IceCube is obtained from five years of data and classified as 2650 tracks and 965 cascades. Tracks arise predominantly from charged-current νμ interactions, and we demonstrate that we can reconstruct their energy and inelasticity. The inelasticity distribution is found to be consistent with the calculation of Cooper-Sarkar et al. across the energy range from ~1 to ~100 TeV. Along with cascades from neutrinos of all flavors, we also perform a fit over the energy, zenith angle, and inelasticity distribution to characterize the flux of astrophysical and atmospheric neutrinos. The energy spectrum of diffuse astrophysical neutrinos is described well by a power law in both track and cascade samples, and a best-fit index γ = 2.62 ± 0.07 is found in the energy range from 3.5 TeV to 2.6 PeV. Limits are set on the astrophysical flavor composition and are compatible with a ratio of ($\frac{1}{3}$ : $\frac{1}{3}$ : $\frac{1}{3}$)⊕. Exploiting the distinct inelasticity distribution of νμ and $\bar{ν}_μ$ interactions, the atmospheric νμ to $\bar{ν}_μ$ flux ratio in the energy range from 770 GeV to 21 TeV is found to be 0.77$_{-0.25}^{+0.44}$ times the calculation by Honda et al. Lastly, the inelasticity distribution is also sensitive to neutrino charged-current charm production. The data are consistent with a leading-order calculation, with zero charm production excluded at 91% confidence level. Future analyses of inelasticity distributions may probe new physics that affects neutrino interactions both in and beyond the Standard Model.
We present the development and application of a generic analysis scheme for the measurement of neutrino spectra with the IceCube detector. This scheme is based on regularized unfolding, preceded by ...an event selection which uses a Minimum Redundancy Maximum Relevance algorithm to select the relevant variables and a random forest for the classification of events. The analysis has been developed using IceCube data from the 59-string configuration of the detector. 27,771 neutrino candidates were detected in 346 days of livetime. A rejection of 99.9999 % of the atmospheric muon background is achieved. The energy spectrum of the atmospheric neutrino flux is obtained using the TRUEE unfolding program. The unfolded spectrum of atmospheric muon neutrinos covers an energy range from 100 GeV to 1 PeV. Compared to the previous measurement using the detector in the 40-string configuration, the analysis presented here, extends the upper end of the atmospheric neutrino spectrum by more than a factor of two, reaching an energy region that has not been previously accessed by spectral measurements.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
The purpose of this study was to perform a systematic review and meta-analysis of the current evidence in the literature to determine how arthroscopic Bankart repair (ABR) and remplissage compare ...with ABR alone and the open Latarjet procedure for anterior shoulder instability in patients with concomitant Hill-Sachs lesions.
A literature search was performed based on the PRISMA (Preferred Reporting Items for Systematic Reviews and Meta-analyses) guidelines. Studies comparing ABR and remplissage vs. ABR alone or the Latarjet procedure for anterior shoulder instability in patients with Hill-Sachs lesions were included. Clinical outcomes were compared, with all statistical analysis performed using Review Manager (version 5.3). P < .05 was considered statistically significant.
Twelve clinical trials were included. There was a significant difference between ABR plus remplissage and ABR alone in total recurrence rate (3.2% vs. 16.8%, P < .05) but not the rate of revision due to recurrence (1.7% vs. 8.5%, P = .06). There was no significant difference between the Latarjet procedure and ABR plus remplissage in total recurrence rate (7.0% vs. 9.8%, P = .39), total revision rate (3.7% vs. 5.7%, P = .41), and rate of revision due to recurrence (1.6% vs. 2.1%, P = .79). There was a significantly lower rate of complications with ABR and remplissage compared with the Latarjet procedure (0.5% vs. 8.6%, P = .003).
In patients with Hill-Sachs lesions and subcritical glenoid bone loss, ABR with remplissage resulted in lower rates of recurrent instability compared with ABR alone while resulting in similar recurrence rates, as well as similar patient-reported outcomes, with lower morbidity and fewer complications, compared with the Latarjet procedure.
Level III; Systematic Review
► We have measured the cosmic-ray energy spectrum from 1 to 100PeV. ► Five months of data from the 26-station configuration of IceTop were used. ► Zenith angle dependences put constraints on the mass ...composition. ► In addition to the ‘knee’ feature the spectrum exhibits a hardening above 22PeV.
We report on a measurement of the cosmic ray energy spectrum with the IceTop air shower array, the surface component of the IceCube Neutrino Observatory at the South Pole. The data used in this analysis were taken between June and October, 2007, with 26 surface stations operational at that time, corresponding to about one third of the final array. The fiducial area used in this analysis was 0.122km2. The analysis investigated the energy spectrum from 1 to 100PeV measured for three different zenith angle ranges between 0° and 46°. Because of the isotropy of cosmic rays in this energy range the spectra from all zenith angle intervals have to agree. The cosmic-ray energy spectrum was determined under different assumptions on the primary mass composition. Good agreement of spectra in the three zenith angle ranges was found for the assumption of pure proton and a simple two-component model. For zenith angles θ<30°, where the mass dependence is smallest, the knee in the cosmic ray energy spectrum was observed at about 4PeV, with a spectral index above the knee of about −3.1. Moreover, an indication of a flattening of the spectrum above 22PeV was observed.
We present a fast likelihood method for including event-level neutrino telescope data in parameter explorations of theories for new physics, and announce its public release as part of DarkSUSY 5.0.6. ...Our construction includes both angular and spectral information about neutrino events, as well as their total number. We also present a corresponding measure for simple model exclusion, which can be used for single models without reference to the rest of a parameter space. We perform a number of supersymmetric parameter scans with IceCube data to illustrate the utility of the method: example global fits and a signal recovery in the constrained minimal supersymmetric standard model (CMSSM), and a model exclusion exercise in a 7-parameter phenomenological version of the MSSM. The nal IceCube detector conguration will probe almost the entire focus-point region of the CMSSM, as well as a number of MSSM-7 models that will not otherwise be accessible to e.g. direct detection. Our method accurately recovers the mock signal, and provides tight constraints on model parameters and derived quantities. We show that the inclusion of spectral information signicantly improves the accuracy of the recovery, providing motivation for its use in future IceCube analyses.
In the analyses, published in Ref. 1, the exclusion limits are calculated in dependence of the mean free path of the magnetic monopole - nucleon catalysis interaction.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
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