0000000001017632
AUTHOR
H. Merkel
Dark Sectors and New, Light, Weakly-Coupled Particles
Dark sectors, consisting of new, light, weakly-coupled particles that do not interact with the known strong, weak, or electromagnetic forces, are a particularly compelling possibility for new physics. Nature may contain numerous dark sectors, each with their own beautiful structure, distinct particles, and forces. This review summarizes the physics motivation for dark sectors and the exciting opportunities for experimental exploration. It is the summary of the Intensity Frontier subgroup "New, Light, Weakly-coupled Particles" of the Community Summer Study 2013 (Snowmass). We discuss axions, which solve the strong CP problem and are an excellent dark matter candidate, and their generalizatio…
Study of doubly strange systems using stored antiprotons
Bound nuclear systems with two units of strangeness are still poorly known despite their importance for many strong interaction phenomena. Stored antiprotons beams in the GeV range represent an unparalleled factory for various hyperon-antihyperon pairs. Their outstanding large production probability in antiproton collisions will open the floodgates for a series of new studies of systems which contain two or even more units of strangeness at the PANDA experiment at FAIR. For the first time, high resolution gamma-spectroscopy of doubly strange Lambda Lambda-hypernuclei will be performed, thus complementing measurements of ground state decays of Lambda Lambda-hypernuclei at J-PARC or possible …
Front-End Electronics for the KAOS Spectrometer at MAMI
A new front-end electronics system has been developed for the electron arm tracking detectors in the Kaos spectrometer at the Mainz microtron MAMI. The signals of multi-anode photomultipliers are collected by 96-channel front-end boards, digitized by double-threshold discriminators and the signal time is picked up by F1 TDC chips. The system was designed to process more than 4,000 channels and to cope with the high electron flux in the spectrometer and the high count rate requirement of the detectors. A subset of 288 channels was installed and successfully used in the 2008 data taking period of the Kaos spectrometer.
Beam-normal single spin asymmetry in elastic electron scattering off Si and Zr
We report on a new measurement of the beam-normal single spin asymmetry An in the elastic scattering of 570 MeV transversely polarized electrons off $^{28}$Si and $^{90}$Zr at Q2=0.04 GeV2/c2. The studied kinematics allow for a comprehensive comparison with former results on $^{12}$C. No significant mass dependence of the beam-normal single spin asymmetry is observed in the mass regime from $^{12}$C to $^{90}$Zr.
Pion Production at Threshold as Test of Chiral Perturbation Theory
An overview of recent results in threshold pion production is given. While the photoproduction data are in impressive agreement with calculations in the framework of Chiral Perturbation Theory, electroproduction data at low four-momentum transfer show severe deviations from these calculations.
"Table 1" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."
Measured value of SIG(C=T) + EPS*SIG(C=L) as a function of the pion angle relative to the virtual photon direction.
"Table 1" of "Virtual Compton scattering under pi0 threshold at Q**2 = 0.33-GeV**2: Preliminary results."
No description provided.
"Table 2" of "Polarization transfer in the He-4(e(pol.),e' p(pol.)H-3 reaction."
No description provided.
"Table 5" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."
Unpolarized cross sections as a function of the azimuthal pion angle relative to the virtual photon direction from which the extracted results were taken (to be published).
"Table 1" of "Polarization transfer in the He-4(e(pol.),e' p(pol.)H-3 reaction."
No description provided.
"Table 3" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."
Measured value of SIG(C=LT) as a function of the pion angle relative to thevirtual photon direction.
"Table 4" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."
Measured value of SIG(C=LTP) as a function of the pion angle relative to the virtual photon direction.
"Table 2" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."
Measured value of SIG(C=TT) as a function of the pion angle relative to thevirtual photon direction.
"Table 7" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."
Unpolarized cross sections as a function of the azimuthal pion angle relative to the virtual photon direction from which the extracted results were taken (to be published).
"Table 6" of "Lowest Q**2 measurement of the gamma* p --> delta reaction: Probing the pionic contribution."
Unpolarized cross sections as a function of the azimuthal pion angle relative to the virtual photon direction from which the extracted results were taken (to be published).