In the framework of model with Lorentz violation (LV) we discuss a physical observables for \(q\bar{q}\) pair production at lepton-lepton colliders and describe the experimental signal to be ...detected. We obtain a conservative limits on Lorentz-violating dimensionless coupling for quark sector from LEP data. We also make a phenomenological prediction for LV model at the future lepton collider.
Borexino collaboration reported about first measurement of solar CNO-\(\nu\) interaction rate in Borexino detector. This result is consistent with Hydridic Earth model prediction about the ...contribution of \(^{40}\)K geo-antineutrino interactions in single Borexino events. The potassium abundance in the Earth in the range \(1 \div 1.5\)\% of the Earth mass could give the observed enhancement of counting rate above expected CNO-\(\nu\) counting rate. The Earth intrinsic heat flux must be in the range \(200 \div 300\) TW for this potassium abundance. This value of the heat flux can explain the ocean heating observed by the project ARGO. We consider that Hydridic Earth model actually corresponds better to CNO-\(\nu\) Borexino results than Silicate Earth model.
We propose to include in the analysis of Borexino single event energy spectrum the scattering of \(^{40}\)K geo-antineutrinos by scintillator electrons. The Hydridic Earth model predicts the ...concentration of potassium in modern Earth from 1\% to 4\% of the Earth mass. We calculated contribution of \(^{40}\)K geo-antineutrino interactions in single Borexino events for these concentrations. This contribution is comparable to the contribution from the interaction of CNO neutrinos. We discuss the reasons for using the Hydridic Earth model.
The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle
$\theta _{13}$
have led to a re-evaluation of the physics ...potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal
$\sin ^22\theta _{23}$
, the octant of
$\theta _{23}$
, and the mass hierarchy, in addition to the measurements of
$\delta _{{\rm CP}}$
,
$\sin ^2\theta _{23}$
, and
$\Delta m^2_{32}$
, for various combinations of
$\nu$
-mode and
$\bar {\nu }$
-mode data-taking.
With an exposure of
$7.8\times 10^{21}$
protons-on-target, T2K can achieve 1
$\sigma$
resolution of 0.050 (0.054) on
$\sin ^2\theta _{23}$
and
$0.040\ (0.045)\times 10^{-3}\,\rm {eV}^2$
on
$\Delta m^2_{32}$
for 100% (50%) neutrino beam mode running assuming
$\sin ^2\theta _{23}=0.5$
and
$\Delta m^2_{32} = 2.4\times 10^{-3}\,\hbox {eV}^2$
. T2K will have sensitivity to the CP-violating phase
$\delta _{\rm {CP}}$
at 90% C.L. or better over a significant range. For example, if
$\sin ^22\theta _{23}$
is maximal (i.e.
$\theta _{23}=45^\circ$
) the range is
$-115^\circ \lt \delta _{\rm {CP}}\lt -60^\circ$
for normal hierarchy and
$+50^\circ \lt \delta _{\rm {CP}}\lt +130^\circ$
for inverted hierarchy. When T2K data is combined with data from the NO
$\nu$
A experiment, the region of oscillation parameter space where there is sensitivity to observe a non-zero
$\delta _{{\rm CP}}$
is substantially increased compared to if each experiment is analyzed alone.
Galactic sites of acceleration of cosmic rays to energies of order 10^15 eV and higher, dubbed PeVatrons, reveal themselves by recently discovered gamma radiation of energies above 100 TeV. However, ...joint gamma-ray and neutrino production, which marks unambiguously cosmic-ray interactions with ambient matter and radiation, was not observed until now. In November 2020, the IceCube neutrino observatory reported an ~150 TeV neutrino event from the direction of one of the most promising Galactic PeVatrons, the Cygnus Cocoon. Here we report on the observation of a 3.1-sigma (post trial) excess of atmospheric air showers from the same direction, observed by the Carpet-2 experiment and consistent with a few-months flare in photons above 300 TeV, in temporal coincidence with the neutrino event. The fluence of the gamma-ray flare is of the same order as that expected from the neutrino observation, assuming the standard mechanism of neutrino production. This is the first evidence for the joint production of high-energy neutrinos and gamma rays in a Galactic source.
We report on the search of astrophysical gamma rays with energies in the 100 TeV to several PeV range arriving in directional and temporal coincidence with public alerts from HAWC (TeV gamma rays) ...and IceCube (neutrinos above ~100 TeV). The observations have been performed with the Carpet-2 air-shower detector at the Baksan Neutrino Observatory, working in the "photon-friendly" mode since 2018. Photon candidate showers are selected by their low muon content. No significant excess of the photon candidates have been observed, and upper limits on gamma-ray fluences associated with the alerts are obtained. For events with good viewing conditions, the Carpet-2 effective area for photons is of the order of the IceCube effective area for neutrinos of the same energy, so the constraints start to probe the production of neutrinos in fast flares of Galactic sources.
We report a measurement of the nu sub(mu)-nucleus inclusive charged-current cross section (=sigma super(cc)) on iron using data from the INGRID detector exposed to the J-PARC neutrino beam. The ...detector consists of 14 modules in total, which are spread over a range of off-axis angles from 0degrees to 1.1degrees. The variation in the neutrino energy spectrum as a function of the off-axis angle, combined with event topology information, is used to calculate this cross section as a function of neutrino energy. The cross section is measured to be sigma super(cc)(1.1GeV)=1.10+ or -0.15 (10 super(-38)cm super(2)/nucleon), sigma super(cc)(2.0GeV)=2.07+ or -0.27 (10 super(-38)cm super(2)/nucleon), and sigma super(cc)(3.3GeV)=2.29+ or -0.45 (10 super(-38)cm super(2)/nucleon), at energies of 1.1, 2.0, and 3.3 GeV, respectively. These results are consistent with the cross section calculated by the neutrino interaction generators currently used by T2K. More importantly, the method described here opens up a new way to determine the energy dependence of neutrino-nucleus cross sections.
The Sydney University Giant Air-shower Recorder (SUGAR) measured the energy spectrum of ultra-high-energy cosmic rays reconstructed from muon-detector readings, while the Pierre Auger Observatory, ...looking at the same Southern sky, uses the calorimetric fluorescence method for the same purpose. Comparison of their two spectra allows us to reconstruct the empirical dependence of the number of muons in the shower on the primary energy for energies between \(10^{17}\) and \(10^{18.5}\) eV. We compare this dependence with the predictions of hadronic interaction models \mbox{QGSJET-II-04} and \mbox{EPOS-LHC}. The empirically determined number of muons with energies above 0.75 GeV exceeds the simulated one by the factors \(\sim\)1.67 and \(\sim\)1.28 for \(10^{17}\) eV proton and iron primaries, respectively. The muon excess grows moderately with the primary energy, increasing by an additional factor of \(\sim 1.2\) for \(10^{18.5}\) eV primaries.
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