The ANITA collaboration recently reported the detection of two anomalous upward-propagating extensive air showers exiting the Earth with relatively large emergence angles and energies in the range $\mathcal{O}(0.5\!-\!1)~\mathrm{EeV}$. We interpret these two events as coming from the decay of a massive dark-matter candidate ($m_\text{DM}\!\gtrsim\! 10^{9}~\mathrm{GeV}$) decaying into a pair of right-handed neutrinos. While propagating through the Earth, these extremely boosted decay products convert eventually to $τ$-leptons which loose energy during their propagation and produce showers in the atmosphere detectable by ANITA at emergence angles larger than what Standard-Model neutrinos could ever produce. We performed Monte Carlo simulations to estimate the propagation and energy loss effects and derived differential effective areas and number of events for the ANITA and the IceCube detectors. Interestingly, the expected number of events for IceCube is of the very same order of magnitude than the number of events observed by ANITA but at larger emergence angles, and energies $\lesssim 0.1~\mathrm{EeV}$. Such features match perfectly with the presence of the two upward-going events IceCube-140109 and IceCube-121205 that have been exhibited from a recent re-analysis of IceCube data samples.
Tau neutrinos are unique cosmic messengers, especially at extreme energies. When they undergo a charged-current interaction, the short lifetime of the produced tau gives rise to secondary tau neutrinos that carry a significant fraction of the primary neutrino energy. This effect, known as tau neutrino regeneration, has not been applied to its full potential in current generation neutrino experiments. In this work, we present an updated calculation of tau neutrino regeneration, and explore its implications for two scenarios: the recent anomalous ANITA events and the cosmogenic neutrino flux. Fo…
The ANITA balloon experiment was designed to detect radio signals initiated by neutrinos and cosmic ray air showers. These signals are typically discriminated by the polarization and phase inversions of the radio signal. The reflected signal from cosmic rays suffer phase inversion compared to a direct tau neutrino event. In this paper we study sub-surface reflection, which can occur without phase inversion, in the context of the two anomalous up-going events reported by ANITA. We find that subsurface layers and firn density inversions may plausibly account for the events, while ice fabric laye…
Two unusual neutrino events in the Antarctic Impulse Transient Antenna (ANITA) appear to have been generated by air showers from a particle emerging from the Earth at angles 25-35 degrees above the horizon. We evaluate the effective aperture for ANITA with a simplified detection model to illustrate the features of the angular dependence of expected events for incident standard model tau neutrinos and for sterile neutrinos that mix with tau neutrinos. We apply our sterile neutrino aperture results to a dark matter scenario with long-lived supermassive dark matter that decay to sterile neutrino-…
The ANITA collaboration has observed two ultra-high-energy upgoing air shower events that cannot originate from Standard Model neutrinos that have traversed the Earth. Several beyond-the-standard-model physics scenarios have been proposed as explanations for these events. In this paper we present some general arguments making it challenging for new physics to explain the events. One exceptional class of models that could work is pointed out, in which metastable dark matter decays to a highly boosted lighter dark matter particle, that can interact in the Earth to produce the observed events.
The ANITA experiment, which is designed to detect ultra-high energy neutrinos, has reported the observation of two anomalous events, directed at angles of $27^{\circ}$ and $35^{\circ}$ with respect to the horizontal. At these angles, the Earth is expected to efficiently absorb ultra-high energy neutrinos, making the origin of these events unclear and motivating explanations involving physics beyond the Standard Model. In this study, we consider the possibility that ANITA's anomalous events are the result of Askaryan emission produced by exotic weakly interacting particles scattering elasticall…
The most recent measurement of the fine structure constant leads to a 2.4 $σ$ deviation in the electron anomalous magnetic moment $g_{e}$-2, while the muon anomalous magnetic moment $g_μ$-2 has a long standing 3.7 $σ$ deviation in the opposite direction. We show that these deviations can be explained in a three-loop neutrino mass model based on an $E_6$ Grand Unified Theory. We also study the impact such a model can have on the anomalous events observed by the ANITA experiment and find an insufficient enhancement of the event rate.
The ANITA balloon experiment has observed two EeV-energy, upgoing events originating from well below the horizon. This is puzzling, because (i) no Standard Model (SM) particle is expected to survive passage through Earth at such energies and incident angles, and (ii) no such events were reported by IceCube. In this paper, we address both these issues by invoking a beyond SM interpretation of the EeV events as due to the decay of a long-lived bino in the R-parity violating (RPV) supersymmetry. In particular, a TeV-scale slepton/squark can be resonantly produced through the interaction of the Ee…
The ANITA collaboration have reported observation of two anomalous events that appear to be $\varepsilon_{\rm cr} \approx 0.6$ EeV cosmic ray showers emerging from the Earth with exit angles of $27^\circ$ and $35^\circ$, respectively. While EeV-scale upgoing showers have been anticipated as a result of astrophysical tau neutrinos converting to tau leptons during Earth passage, the observed exit angles are much steeper than expected in Standard Model (SM) scenarios. Indeed, under conservative extrapolations of the SM interactions, there is no particle that can propagate through the Earth with p…
The Antarctic Impulse Transient Antenna (\textsc{ANITA}) collaboration [1-3] has reported two anomalous events with noninverted polarity. These events are hard to explain in terms of conventional cosmic rays (CRs). We explore a new possible explanation for these anomalous events by suggesting that these events can be related to the dark matter (DM) annihilations within the so-called axion quark nugget (AQN) DM model. This model was initially invented for a completely different purpose to explain the observed similarity between the dark and the visible components in the Universe, i.e. $Ω_{\rm D…
The ANITA experiment has registered two anomalous events that can be interpreted as $ν_τ$ or $\barν_τ$ with a very high energy of $\mathcal{O}(0.6)$~EeV emerging from deep inside the Earth. At such high energies, the Earth is opaque to neutrinos so the emergence of these neutrinos at such large zenith angles is a mystery. In our paper, we present a model that explains the two anomalous events through a $L_e -L_τ$ gauge interaction involving two new Weyl fermions charged under the new gauge symmetry. We find that, as a bonus of the model, the lighter Weyl fermion can be a dark matter component.…
The Antarctic Impulsive Transient Antenna (ANITA) experiment has observed two air shower events with energy $\sim 500~{\rm PeV}$ emerging from the Earth with exit angles $\sim 30^\circ$ above the horizon. As was immediately noted by the ANITA Collaboration, these events (in principle) could originate in the atmospheric decay of an upgoing $τ$-lepton produced through a charged current interaction of a $ν_τ$ inside the Earth. However, the relatively steep arrival angles of these perplexing events create tension with the standard model (SM) neutrino-nucleon interaction cross section. Deepening th…
The ANITA experiment has recently observed two anomalous events emerging from well below the horizon. Even though they are consistent with tau cascades, a high energy Standard Model or Beyond the Standard Model explanation is challenging and in tension with other experiments. We study under which conditions the reflection of generic radio pulses can reproduce these signals. We propose that these pulses can be resonantly produced in the ionosphere via axion-photon conversion. This naturally explains the direction and polarization of the events and avoids other experimental bounds.
The ANtarctic Impulsive Transient Antenna (ANITA) collaboration has observed two EeV-energy, upward going events originating from below the horizon. As no standard model (SM) particles, propagating through the earth at such energy and exit angles, can give rise to the required survival probability for the observed events, several beyond standard model (BSM) proposals have come up. We propose a scenario where a $Z_2$ odd sector is responsible for such anomalous events. The next to lightest $Z_2$ odd particle or the next to lightest stable particle (NLSP), created from ultra high energy neutrino…
We develop a general formalism to treat reflection of spherical electromagnetic waves from a spherical surface. Our main objective is interpretation of radio wave signals produced by cosmic ray interactions with Earth's atmosphere which are observed by the Antarctica based ANITA detector after reflection off the ice surface. The incident wave is decomposed into plane waves and each plane wave is reflected off the surface using the standard Fresnel formalism. For each plane wave the reflected wave is assumed to be locally a plane wave. This is a very reasonable assumption and there are no uncon…
Driven by the recent experimental hints of lepton-flavor-universality violation in the bottom-quark sector, we consider a simple extension of the Standard Model (SM) with an additional vector leptoquark $V_{\rm LQ}({\bf 3},{\bf 1},2/3)$ and a scalar diquark $S_{\rm DQ}({\bf 6},{\bf 1},4/3)$ under the SM gauge group $SU(3)_c\times SU(2)_L\times U(1)_Y$, in order to simultaneously explain the $b \to s \ell^+ \ell^-$ (with $\ell=e,μ$) and $b \to c l^- \bar ν_l$ (with $l=e,μ,τ$) flavor anomalies, as well as to generate small neutrino masses through a two-loop radiative mechanism. We perform a glob…
The ANITA balloon experiment has recently observed several ~EeV cascade events at an angle below the horizon that renders any Standard Model (SM) interpretation unlikely as the Earth is significantly opaque to all SM particles at such energies. In this paper, we study a sterile neutrino interpretation of these events, calculating the angular acceptance of cascades and the relative sensitivities of several experiments to a cascade initiated by an EeV sterile neutrino. We find that ANITA is uniquely sensitive to this type of upward directed cascade signal over a wide portion of the sky and from …
The ANITA experiment has observed two unusual upgoing air shower events which are consistent with the $τ$-lepton decay origin. However, these events are in contradiction with the standard neutrino-matter interaction models as well as the $\rm EeV$ diffuse neutrino flux limits set by the IceCube and the cosmic ray facilities like AUGER. In this paper, we have reinvestigated the possibility of using sterile neutrino hypothesis to explain the ANITA anomalous events. The diffuse flux of the sterile neutrinos is less constrained by the IceCube and AUGER experiments due to the small active-sterile m…
We propose a new physics scenario in which the decay of a very heavy dark-matter candidate which does not interact with the neutrino sector could explain the two anomalous events recently reported by ANITA. The model is composed of two components of dark matter, an unstable dark-sector state, and a massive dark gauge boson. We assume that the heavier dark-matter particle of EeV-range mass is distributed over the galactic halo and disintegrates into a pair of lighter -- highly boosted -- dark-matter states in the present universe which reach and penetrate the Earth. The latter scatters {\it in}…
The CMS Collaboration has recently reported some excess events in final states with electrons and jets, in searches for leptoquarks and $W'$ bosons. Although these excesses may be due to some yet-to-be-understood background mismodeling, it is useful to seek realistic interpretations involving new particles that could generate such events. We show that resonant pair production of vector-like leptons that decay to an electron and two jets leads to kinematic distributions consistent with the CMS data.
$W$ boson pair production processes at $e^+e^-$ and $pp$ colliders have been conventionally interpreted as measurements of $WWZ$ and $WWγ$ triple gauge couplings (TGCs). Such interpretation is based on the assumption that new physics effects other than anomalous TGCs are negligible. While this "TGC dominance assumption" was well-motivated and useful at LEP2 thanks to precision electroweak constraints, it is already challenged by recent LHC data. In fact, contributions from anomalous $Z$ boson couplings that are allowed by electroweak precision data but neglected in LHC analyses, being enhanced…
During the first three flights of the Antarctic Impulsive Transient Antenna (ANITA) experiment, the collaboration detected several neutrino candidates. Two of these candidate events were consistent with an ultra-high-energy up-going air shower and compatible with a tau neutrino interpretation. A third neutrino candidate event was detected in a search for Askaryan radiation in the Antarctic ice, although it is also consistent with the background expectation. The inferred emergence angle of the first two events is in tension with IceCube and ANITA limits on isotropic cosmogenic neutrino fluxes. …
We analyze the Belle data [K. F. Chen {\it et al.} (Belle Collaboration), Phys.\ Rev.\ Lett.\ {\bf 100}, 112001 (2008); I. Adachi {\it et al.} (Belle Collaboration), arXiv:0808.2445] on the processes $e^+ e^- \to Υ(1S)\; π^+π^-, Υ(2S)\; π^+π^-$ near the peak of the $Υ(5S)$ resonance, which are found to be anomalously large in rates compared to similar dipion transitions between the lower $Υ$ resonances. Assuming these final states arise from the production and decays of the $J^{PC}=1^{--}$ state $Y_b(10890)$, which we interpret as a bound (diquark-antidiquark) tetraquark state $[bq][\bar{b}\ba…
The long-standing Galactic center gamma-ray excess could be explained by GeV dark matter (DM) annihilation, while the DM interpretation seems in tension with recent joint limits from different astronomical scale observations, such as dwarf spheroidal galaxies, the Milky Way halo and galaxy groups/clusters. Motivated by $^8$Be and $^4$He anomalous transitions with possible new interactions mediated by a vector boson $X$, we consider a small fraction of DM mainly annihilating into a pair of on-shell vector boson $X X$ followed by $X \to e^+ e^-$ in this paper. The Galactic center gamma-ray exces…
We discuss the leptoquark interpretation of the anomalous HERA positron-jet events in the context of the YFS exponentiated Monte Carlo event generator treatment of the attendant multiple photon radiative effects for both the would-be signal and the SM background, wherein finite-$p_T$ photon effects are properly taken into account and wherein infrared singularities are cancelled to all orders in $α$. We show that H1 and ZEUS data are consistent with such an interpretation for a leptoquark coupling $\lesssim 0.3g_W$, mass $\sim 200$ GeV, and width $\lesssim 2$GeV. Possible future tests are propo…
We discuss the allowed parameter regime in the coupling-mass plane implied by the existing LEP2 data on e+ e- -> hadrons at 172.3 GeV for the leptoquark interpretation of the anomalous DESY positron-jet events for four different models of the leptoquark charges and chiral couplings to quarks, for both a loose cut on s'/s and a tight cut on s'/s. We find that this interpretation of the DESY phenomenon is still consistent with the LEP2 data although, for vector leptoquarks, a significant regime of the relevant parameter space is already excluded.
We suggest that the anomalous 4-jet events recently reported by ALEPH may be the first indication of low scale technicolour. According to our interpretation about half of the events are due to resonantly enhanced pair production of charged technipions, of mass around 55 GeV, each decaying into a pair of jets, the other half being due to standard processes. The resonant enhancement is due to a nearby technirho resonance in the mass range 150-200 GeV, leading to hugely enhanced signals at the forthcoming LEP run at $\sqrt{s}=160$ GeV since the CM energy would be closer to the peak of the resonan…
Recently reported diboson and diphoton excesses at LHC are interpreted to be connected with heavy $WW$ zero spin resonances. The resonances appears due to the wouldbe anomalous triple interaction of the weak bosons, which is defined by well-known coupling constant $λ$. The $2\, TeV$ anomaly tentatively corresponds to weak isotopic spin 2 scalar state and the $γγ\,\,750\, GeV$ anomaly corresponds to weak isotopic spin 0 pseudoscalar state. We obtain estimates for the effect, which qualitatively agree with ATLAS data. Effects are predicted in a production of $W^+ W^-, (Z,γ) (Z,γ)$ via resonance …
Contrary to what has been often claimed in the literature, we clarify that the hard photon-gluon cross section $\gg_{\rm hard}(x)$ in polarized deep inelastic scattering calculated in the gauge-invariant factorization scheme does {\it not} involve any soft contributions and hence it is genuinely {\it hard}. We show that the polarized proton structure function $g_1^p(x)$ up to the next-to-leading order of $α_s$ is independent of the factorization convention, e.g., the gauge-invariant or chiral-invariant scheme, chosen in defining $\gg_{\rm hard}(x)$ and the quark spin density. Thereby, it is no…
I discuss the scope and naturalness of the proton mass decomposition (or sum rule) published in PRL74, 1071 (1995) and answer a few criticisms that appeared recently in the literature, focusing particularly on its interpretation and the quantum anomalous energy contribution. I comment on the so-called frame-independent or invariant-mass decomposition from the trace of the energy-momentum tensor. I stress the importance of measuring the quantum anomalous energy through experiments. Finally, I point out a large discrepancy in the scalar radius of the nucleon extracted from vector-meson productio…
The $e^{+}\,e^{-}\,\rightarrow\,l^{+}\, ł^{-}\,γ\,γ$ anomalous events, regis\-te\-red at $L3$ de\-tec\-tor at $e^+ e^-$ $CERN-LEP$ collider have been analysed. It has been shown that the interpretation of such events as a manifestation of scalar (pseudoscalar) resonance with the mass of 60 GeV contradicts other experimental data.
For the purpose of minimizing the number of sample model evaluations, we propose and study algorithms that utilize (sequential) versions of likelihood-to-evidence ratio neural estimation.We apply our algorithms to a supersymmetric interpretation of the anomalous muon magnetic dipole moment in the context of a phenomenological minimal supersymmetric extension of the standard model, and recover non-trivial models in an experimentally-constrained theory space. Finally we summarize further potential possible uses of these algorithms in future studies.
The strong "anomalous" J/Psi suppression observed recently by the NA50 Collaboration at CERN SPS has attracted considerable attention. Is it the first signature of a long-awaited quark-gluon plasma, or just a peculiar combination of "conventional" effects acting together to produce the puzzling pattern observed experimentally? This talk is an attempt to summarize the theoretical explanations proposed during the last two years.
The recent developments in theory and experiment related to the anomalous magnetic moment of the muon are applied to supersymmetry. We follow a very cautious course, demanding that the supersymmetric contributions fit within five standard deviations of the difference between experiment and the standard model prediction. Arbitrarily small supersymmetric contributions are then allowed, so no upper bounds on superpartner masses result. Nevertheless, non-trivial exclusions are found. We characterize the substantial region of parameter space ruled out by this analysis that has not been probed by an…
There exist about $3.7σ$ positive and $2.4σ$ negative deviations in the muon and electron anomalous magnetic moments ($g-2$). Also, some ratios for lepton universality in $τ$ decays have almost $2σ$ deviations from the Standard Model. In this paper, we propose a lepton-specific inert two-Higgs-doublet model. After imposing all the relevant theoretical and experimental constraints, we show that these lepton anomalies can be explained simultaneously in many parameter spaces with $m_H > 200$ GeV and $m_A~(m_{H^\pm})> 500$ GeV for appropriate Yukawa couplings between leptons and inert Higgs. The k…
In theories with anomalous fermion number nonconservation, the level crossing picture is considered a faithful representation of the fermionic quantum number variation. It represents each created fermion by an energy level that crosses the zero-energy line from below. If several fermions of various masses are created, the level crossing picture contains several levels that cross the zero-energy line and cross each other. However, we know from quantum mechanics that the corresponding levels cannot cross if the different fermions are mixed via some interaction potential. The simultaneous applica…
Chiral Magnetic Effect (CME) is the macroscopic manifestation of the fundamental chiral anomaly in a many-body system of chiral fermions, and emerges as anomalous transport current in hydrodynamic framework. Experimental observation of CME is of great interest and significant efforts have been made to look for its signals in heavy ion collisions. Encouraging evidence of CME-induced charge separation has been reported from both RHIC and LHC, albeit with ambiguity due to potential background contributions. Crucial for addressing such issue, is the need of quantitative predictions for both CME si…
