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A new measurement of $B_{pi e2}$, the $pi^+ to e^+ u(gamma)$ decay branching ratio, is currently under way at the Paul Scherrer Institute. The present experimental result on $B_{pi e2}$ constitutes the most accurate test of lepton universality available. The accuracy, however, still lags behind the theoretical precision by over an order of magnitude. Thanks to the large helicity suppression of $pi_{e2}$ decay, the branching ratio is susceptible to significant contributions from new physics, making this decay a particularly suitable subject of study.
With few open channels and uncomplicated theoretical description, charged pion decays are uniquely sensitive to certain standard model (SM) symmetries, the universality of weak fermion couplings, and to aspects of pion structure and chiral dynamics.
Allowed charged $pi$ meson decays are characterized by simple dynamics, few available decay channels, mainly into leptons, and extremely well controlled radiative and loop corrections. In that sense, pion decays represent a veritable triumph of the s
The realm of strong classical gravity and perhaps even quantum gravity are waiting to be explored. In this letter we consider the recently detected triple system composed of two stars and a non-accreting black hole. Using published observations of th
In this paper a new method is presented for particles in storage rings which could reach a statistical sensitivity of 10**(-27) e cm for the deuteron EDM. This implies an improvement of two orders of magnitude over the present best limits on the T-odd nuclear forces ksi parameter.
NEWAGE is a direction-sensitive dark matter search using a low-pressure gaseous time projection chamber. A low alpha-ray emission rate micro pixel chamber had been developed in order to reduce background for dark matter search. We conducted the dark