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Reimer, A.

Publications and source records attributed to Reimer, A..

4 records
All sourcesNASA NTRSDOE OSTI
DOE OSTI2023

Angular Correlations in the β Decay of B 8 : First Tensor-Current Limits from a Mirror-Nucleus Pair

We present the first measurement of the α–β–ν angular correlation in the Gamow-Teller β + decay of 8 B. This was accomplished using the Beta-decay Paul Trap, expanding on our previous work on the β – decay of 8 Li. The 8 B result is consistent with the V – A electroweak interaction of the standard model and, on its own, provides a limit on the exotic right-handed tensor current relative to the axial-vector current of |C T /C A | 2 < 0.013 at the 95.5% confidence level. This represents the first high-precision angular correlation measurements in mirror decays and was made possible through the use of an ion trap. Here, by combining this 8 B result with our previous 8 Li results, we demonstrate a new pathway for increased precision in searches for exotic currents.

6 ≤ A ≤ 19↗
DOE OSTI2023

Limits on the non-thermal emission of the WR–WR system Apep

Colliding-wind binaries (CWBs) constitute an emerging class of γ-ray sources powered by strong, dense winds in massive stellar systems. The most powerful of them are those binaries hosting a Wolf-Rayet (WR) star. Following the recent discovery of Apep – the closest known Galactic WR–WR binary – we discuss the non-detection of its putative high-energy emission by the Fermi Large Area Telescope (Fermi-LAT) in this Letter. The limits reported in the GeV regime can be used to set a lower limit on the magnetic field pressure density within the shocked wind-collision region (WCR), and to exclude Apep as a bright γ-ray emitting binary. Given that this WR–WR system is the most luminous CWB identified until now at radio wavelengths, this result proves unambiguously that non-thermal synchrotron emission is not a suitable identifier for the subset of γ-ray emitters in this class of particle accelerators. Rather, Apep could be an interesting case of study for magnetic field amplification in shocked stellar winds.

79 ASTRONOMY AND ASTROPHYSICS↗
NASA NTRS2005

Neutrino Emission in the Hadronic Synchrotron Mirror Model: The "Orphan" Flare from 1ES 1959+650

A challenge to standard leptonic synchrotron self-Compton (SSC) models is the so-called orphan TeV flares, i.e., enhanced very high energy (VHE) gamma-ray emission without any contemporaneous X-ray flaring activity, that have recently been observed in TeV blazars (e.g., 1ES 1959+650). In order to explain the orphan TeV flare of 1 ES 1959+650 observed in 2002 June, the so-called hadronic synchrotron mirror model has been developed. Here relativistic protons are proposed to exist in the jet and interact with reflected electron synchrotron radiation of the precursor SSC flare. If the reflector is located in the cloud region, time shifts of several days are possible between the precursor and the orphan flare. The external photons, blue-shifted in the comoving jet frame, are able to excite the Delta(1232) resonance when interacting with protons of Lorentz factors gamma(sub p) approx. 10(exp 3)-10(exp 4). The decay products of this resonance include charged pions, which, on decay, give rise to neutrino production during the orphan flare. In this paper we calculate the expected neutrino emission for the 2002 June 4 orphan TeV flare of 1ES 1959+650. We compare our results with the recent observations of AMANDA-II of a neutrino event in spatial and temporal coincidence with the orphan flare of this blazar. We find that the expected neutrino signal from the hadronic synchrotron mirror model is insufficient to explain the claimed neutrino signal from the direction of 1ES 1959+650.

Reimer, A.↗