相关论文: Sensitivity to the KARMEN Timing Anomaly at MiniBo…
Recent resuls from experiments at Fermilab and the Paul Scherrer Institute have constrained the parameter space available for a hypothetical particle $Q^0$ produced in the decay $\pi^+ \to \mu^+ Q^0$. This decay has been invoked to explain…
The KARMEN experiment observes a time anomaly in events induced by pion decay at rest. This anomaly can be ascribed to the production of a new weakly interacting particle X with mass m_X\sim 34 MeV. We show that a recently proposed…
We have searched for the pion decay pi^+ --> mu^+ X, where X is a neutral particle of mass 33.905 MeV. This process was suggested by the KARMEN Collaboration to explain an anomaly in their observed time distribution of neutrino induced…
A recently reported anomaly in the time structure of signals in the KARMEN neutrino detector suggests the decay of a new particle $x$, produced in $\pi^+ \to \mu^+ x$ with mass $m_x=33.9$ MeV. We discuss the constraints and difficulties in…
We consider the hypothesis that the recently reported anomaly in the time structure of signals in the KARMEN experiment is due to the production of a light photino (or Zino) which decays radiatively due to violation of $R$-parity. Such a…
An anomaly in time distribution of neutrinos from the ISIS pulsed beam stop source observed by the KARMEN collaboration is discussed. We show that the anomaly can be interpreted as a superposition of two exponentials, both having time…
Recently, it has been proposed that the observed anomaly in the time distribution of neutrino induced reactions, reported by the KARMEN collaboration, can be interpreted as a signal from an exotic muon decay branch mu+ to e+ X. It has been…
We suggest that the decay modes of kaons with a pion and a pionium ($\pi^+\pi^-$ atom) in the final state can constitute a not yet considered background to the very rare decay $K\to\pi\nu\bar\nu$. In fact, a part of pioniums may escape the…
A solution to the MiniBooNE excess invoking rare three-body decays of the charged pions and kaons to new states in the MeV mass scale was recently proposed as a dark-sector explanation. This class of solution illuminates the fact that,…
Recent results on rare kaon and pion decays are reviewed and prospects for future experiments are discussed
In this paper I will describe the search for rare kaon decay processes $K^+\to \pi^+ \nu \bar\nu$ and $K^0_L \to \pi^0 \nu \bar\nu$. The small decay rate for these processes is considered a key prediction of the standard model. We searched…
The E815 (NuTeV) neutrino experiment has performed a search for a 33.9 MeV/c^2 weakly-interacting neutral particle produced in pion decay. Such a particle may be responsible for an anomaly in the timing distribution of neutrino interactions…
A next-generation rare pion decay experiment, PIONEER, is strongly motivated by several inconsistencies between Standard Model (SM) predictions and data pointing towards the potential violation of lepton flavor universality. It will probe…
The time anomaly of neutrino events observed in the KARMEN detector at the ISIS facility is discussed. We show that beam-correlated neutron events are not completely suppressed by the KARMEN lower energy cut and could cause the observed…
Motivated by the anomaly in the KARMEN experiment, we study new possibilities for brane-world models of neutrino masses. We show that the KARMEN anomaly can be understood in the context of a six-dimensional brane-world model. The…
The excess of electron-like events measured by MiniBooNE challenges our understanding of neutrinos and their interactions. We review the status of this open problem and ongoing efforts to resolve it. After introducing the experiment and its…
The Karmen anomaly can be interpreted as being due to a heavy neutrino of mass around 137 MeV produced in $\pi_{e 2}$ decays. This interpretation is consistent with the present limits on the couplings of such an object.
The KTeV/E799 experiment at Fermilab has searched for the rare kaon decay KL--> pi0ee. This mode is expected to have a significant CP violating component. The measurement of its branching ratio could support the Standard Model or could…
Current results of the MiniBooNE experiment show excess events that indicate neutrino oscillations, but only if one goes beyond the standard 3 family scenario. Recently a different explanation of the events has been given, not in terms of…
We have observed 1 event consistent with the signature expected of the rare decay of a positive kaon to a positive pion and a neutrino anti-neutrino pair. In the examined momentum region of 211 to 230 MeV/c in the center of mass of the kaon…