Narrow Results

IceCube collaboration has published two papers on ultrahigh energy neutrinos observation, recently. They have used the data collected in two years in their first publication, which reveals observation of 2 PeV energy neutrino events. The second publication of the collaboration including more data has also confirmed main features of the former paper. In literature, various interpretations of the IceCube data have been proposed. In this study, it is shown that PeV energy neutrino events observed by the IceCube collaboration can be interpreted as resonance production of color octet neutrinos with masses in 500–800 GeV range.

Potential discovery, observation and exclusion limits of excited $u$ and $d$ quarks with gamma$+$jet final state are researched at the multi-TeV scale colliders, FCC and S$pp$C in this paper. Both colliders, FCC and S$pp$C, show that excited $u$ and $d$ quarks could be discovered up to 42.1 TeV and 55.2 TeV for $u^{\star }$, 30.3 TeV and 39.4 TeV for $d^{\star }$ and 42.3 TeV and 55.5 TeV mass values for degenerate case $(m_{u^{\star }}=m_{d^{\star }})$, respectively. The determination of the excited quarks compositeness scale is examined, which will be up to multi-PeV level. Besides these analyses, free parameters ($f_s$, $f$ and $f^{\prime }$) are scanned from around 0.1 up to 1 that show excited quark could be discovered at dozens of TeV with even coupling constants under 0.1.