Neutrinos interact only very weakly, so they are extremely penetrating. The theoretical neutrino–nucleon interaction cross-section, however, increases with increasing neutrino energy, and neutrinos ...with energies above 40 teraelectronvolts (TeV) are expected to be absorbed as they pass through the Earth. Experimentally, the cross-section has been determined only at the relatively low energies (below 0.4 TeV) that are available at neutrino beams from accelerators1,2. Here we report a measurement of neutrino absorption by the Earth using a sample of 10,784 energetic upward-going neutrino-induced muons. The flux of high-energy neutrinos transiting long paths through the Earth is attenuated compared to a reference sample that follows shorter trajectories. Using a fit to the two-dimensional distribution of muon energy and zenith angle, we determine the neutrino–nucleon interaction cross-section for neutrino energies 6.3–980 TeV, more than an order of magnitude higher than previous measurements. The measured cross-section is about 1.3 times the prediction of the standard model3, consistent with the expectations for charged- and neutral-current interactions. We do not observe a large increase in the cross-section with neutrino energy, in contrast with the predictions of some theoretical models, including those invoking more compact spatial dimensions4 or the production of leptoquarks5. This cross-section measurement can be used to set limits on the existence of some hypothesized beyond-standard-model particles, including leptoquarks.
A search for diffuse neutrinos with energies in excess of 10 super(5) GeV is conducted with AMANDA-II data recorded between 2000 and 2002. Above 10 super(7) GeV, the Earth is essentially opaque to ...neutrinos. This fact, combined with the limited overburden of the AMANDA-II detector (roughly 1.5 km), concentrates these ultra-high-energy neutrinos at the horizon. The primary background for this analysis is bundles of downgoing, high-energy muons from the interaction of cosmic rays in the atmosphere. No statistically significant excess above the expected background is seen in the data, and an upper limit is set on the diffuse all-flavor neutrino flux of image GeV cm super(-2) s super(-1) sr super(-1) valid over the energy range of image to 10 super(9) GeV. A number of models that predict neutrino fluxes from active galactic nuclei are excluded at the 90% confidence level.
ABSTRACT
This paper presents four searches for flaring sources of neutrinos using the IceCube neutrino telescope. For the first time, a search is performed over the entire parameter space of energy, ...direction, and time with sensitivity to neutrino flares lasting between 20 μs and a year duration from astrophysical sources. Searches that integrate over time are less sensitive to flares because they are affected by a larger background of atmospheric neutrinos and muons that can be reduced by the use of additional timing information. Flaring sources considered here, such as active galactic nuclei, soft gamma-ray repeaters, and gamma-ray bursts, are promising candidate neutrino emitters. Two searches are “untriggered” in the sense that they look for any possible flare in the entire sky and from a predefined catalog of sources from which photon flares have been recorded. The other two searches are triggered by multi-wavelength information on flares from blazars and from a soft gamma-ray repeater. One triggered search uses lightcurves from
Fermi
-LAT which provides continuous monitoring. A second triggered search uses information where the flux states have been measured only for short periods of time near the flares. The untriggered searches use data taken by 40 strings of IceCube between 2008 April 5 and 2009 May 20. The triggered searches also use data taken by the 22-string configuration of IceCube operating between 2007 May 31 and 2008 April 5. The results from all four searches are compatible with a fluctuation of the background.
Using the complete KTeV data set of 5,241 candidate K(L)--> pi(+) pi(-) e(+) e(-) decays (including an estimated background of 204 +/- 14 events), we have measured the coupling g(CR)= 0.163 +/- ...0.0149(stat) +/- 0.023(syst) of the CP conserving charge radius process and from it determined a K(0) charge radius of <r(2)(K(0))> = -0.077 +/- 0.007(stat) +/- 0.011(syst)fm(2). We have determined a first experimental upper limit of 0.04 (90% C.L.) /g(e1)/ / /g(M1)/ of the couplings for the E1 and M1 direct photon emission processes. We also report the measurement of /g(M1)/ including a vector form factor /g(M1)/(1 + (a(1)/a(2))/((M(2)(p)-(M(2)(k))= 2M(K)E(gamma*)), where vector /g(M1)/= 1.11+/- 0.12(stat) +/- 0.08(syst) and a(1)/a(2) = -0.744 +/- 0.027(stat) +/- 0.032(syst) GeV(2)/c(2). Finally, a CP-violating asymmetry of 13.6 +/- 1.4(stat) +/- 1.5(syst)% in the CP and T odd angle phi between the decay planes of the e(+) e(-) and pi(+) pi(-) pairs in the K(L) center of mass is reported.
Abstract
Background
Patients with gastrointestinal cancer (GICA) are at high risk for venous thromboembolism (VTE). Data from randomized clinical trials in cancer-associated VTE suggest that direct ...oral anticoagulants (DOACs) conferred similar or superior efficacy but a heterogeneous safety profile in patients with GICA. We compared the safety and effectiveness of DOACs in patients with GICA and VTE at MD Anderson Cancer Center.
Materials and Methods
This was a retrospective chart review of patients with GICA and VTE receiving treatment with DOACs for a minimum of 6 months. Primary outcomes were the proportion of patients experiencing major bleeding (MB), clinically relevant non-major bleeding (CRNMB), and recurrent VTE. Secondary outcomes were time to bleeding and recurrent VTE.
Results
A cohort of 433 patients with GICA who were prescribed apixaban (n = 300), or rivaroxaban (n = 133) were included. MB occurred in 3.7% (95% confidence interval CI 2.1-5.9), CRNMB in 5.3% (95% CI 3.4-7.9), and recurrent VTE in 7.4% (95% CI 5.1-10.3). The cumulative incidence rates of CRNMB and recurrent VTE were not significantly different when comparing apixaban to rivaroxaban.
Conclusion
Apixaban and rivaroxaban had a similar risk of recurrent VTE and bleeding and could be considered as anticoagulant options in selected patients with GICA and VTE.
Patients with cancer are at increased risk for venous thromboembolism. This article evaluates the safety and effectiveness of direct oral anticoagulants in patients with gastrointestinal cancer and cancer-associated venous thromboembolism.
Here, we introduce a search for a light sterile neutrino using three years of atmospheric neutrino data from the DeepCore detector in the energy range of approximately 10–60 GeV. DeepCore is the ...low-energy subarray of the IceCube Neutrino Observatory. The standard three-neutrino paradigm can be probed by adding an additional light (Δ$m^{2}_{41}$~1 eV2) sterile neutrino. Sterile neutrinos do not interact through the standard weak interaction and, therefore, cannot be directly detected. Yet, their mixing with the three active neutrino states leaves an imprint on the standard atmospheric neutrino oscillations for energies below 100 GeV. A search for such mixing via muon neutrino disappearance is presented here. The data are found to be consistent with the standard three-neutrino hypothesis. Thus, we derive limits on the mixing matrix elements at the level of |Uμ4|2<0.11 and |Uτ4|2<0.15 (90% C.L.) for the sterile neutrino mass splitting Δ$m^{2}_{41}$=1.0 eV2.
We present new results of searches for neutrino point sources in the northern sky, using data recorded in 2007-2008 with 22 strings of the IceCube detector (approximately one-fourth of the planned ...total) and 275.7 days of live time. The final sample of 5114 neutrino candidate events agrees well with the expected background of atmospheric muon neutrinos and a small component of atmospheric muons. No evidence of a point source is found, with the most significant excess of events in the sky at 2.2 sigma after accounting for all trials. The average upper limit over the northern sky for point sources of muon-neutrinos with E -2 spectrum is , in the energy range from 3 TeV to 3 PeV, improving the previous best average upper limit by the AMANDA-II detector by a factor of 2.
We report on the search for electromagnetic and hadronic showers (“cascades”) produced by a diffuse flux of extraterrestrial neutrinos in the AMANDA neutrino telescope. Data for this analysis were ...recorded during 1001
days of detector livetime in the years 2000–2004. The observed event rates are consistent with the background expectation from atmospheric neutrinos and muons. An upper limit is derived for the diffuse flux of neutrinos of all flavors assuming a flavor ratio of
ν
e
:
ν
μ
:
ν
τ
=
1:1:1 at the detection site. The all-flavor flux of neutrinos with an energy spectrum
Φ
∝
E
−2 is less than 5.0
×
10
−7
GeV
s
−1
sr
−1
cm
−2 at a 90% C.L. Here, 90% of the simulated signal would fall within the energy range 40
TeV to 9
PeV. We discuss flux limits in the context of several specific models of extraterrestrial and prompt atmospheric neutrino production.
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