A. Tyukin

Search at the Mainz Microtron for light massive gauge bosons relevant for the muon g-2 anomaly.

H. Merkel,1, ∗ P. Achenbach,1 C. Ayerbe Gayoso,1 T. Beranek,1 J. Beričič,2 J. C. Bernauer,1, † R. Böhm,1 D. Bosnar,3 L. Correa,1 L. Debenjak,2 A. Denig,1 M. O. Distler,1 A. Esser,1 H. Fonvieille,4 I. Friščić,3 M. Gómez Rodrı́guez de la Paz,1 M. Hoek,1 S. Kegel,1 Y. Kohl,1 D. G. Middleton,1 M. Mihovilovič,1 U. Müller,1 L. Nungesser,1 J. Pochodzalla,1 M. Rohrbeck,1 G. Ron,5 S. Sánchez Majos,1 B. S. Schlimme,1 M. Schoth,1 F. Schulz,1 C. Sfienti,1 S. Širca,2, 6 M. Thiel,1 A. Tyukin,1 A. Weber,1 and M. Weinriefer1 (A1 Collaboration) Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany‡ Jožef Stefan Institute, SI-1000 Ljubljana, Slovenia Department of Physics, University of Zagreb, HR-10002 Zagreb, Croatia Clermont Université, Université Blaise Pascal, CNRS/IN2P3, LPC, BP 10448, F-63000 Clermont-Ferrand, France Racah Institute of Physics, Hebrew University of Jerusalem, Jerusalem 91904, Israel Department of Physics, University of Ljubljana, SI-1000 Ljubljana, Slovenia (Dated: April 22, 2014)

First measurement of proton's charge form factor at very low Q2 with initial state radiation

Abstract We report on a new experimental method based on initial-state radiation (ISR) in e–p scattering, which exploits the radiative tail of the elastic peak to study the properties of electromagnetic processes and to extract the proton charge form factor ( G E p ) at extremely small Q 2 . The ISR technique was implemented in an experiment at the three-spectrometer facility of the Mainz Microtron (MAMI). This led to a precise validation of radiative corrections far away from elastic line and provided first measurements of G E p for 0.001 ≤ Q 2 ≤ 0.004 ( GeV / c ) 2 .

MuPix7—A fast monolithic HV-CMOS pixel chip for Mu3e

The MuPix7 chip is a monolithic HV-CMOS pixel chip, thinned down to 50 \mu m. It provides continuous self-triggered, non-shuttered readout at rates up to 30 Mhits/chip of 3x3 mm^2 active area and a pixel size of 103x80 \mu m^2. The hit efficiency depends on the chosen working point. Settings with a power consumption of 300 mW/cm^2 allow for a hit efficiency >99.5%. A time resolution of 14.2 ns (Gaussian sigma) is achieved. Latest results from 2016 test beam campaigns are shown.

Components of polarization-transfer to a bound proton in a deuteron measured by quasi-elastic electron scattering

Abstract We report the first measurements of the transverse ( P x and P y ) and longitudinal ( P z ) components of the polarization transfer to a bound proton in the deuteron via the H 2 ( e → , e ′ p → ) reaction, over a wide range of missing momentum. A precise determination of the electron beam polarization reduces the systematic uncertainties on the individual components to a level that enables a detailed comparison to a state-of-the-art calculation of the deuteron using free-proton electromagnetic form factors. We observe very good agreement between the measured and the calculated P x / P z ratios, but deviations of the individual components. Our results cannot be explained by medium modified electromagnetic form factors. They point to an incomplete description of the nuclear reaction mechanism in the calculation.

Vertical Beam Polarization at MAMI

For the first time a vertically polarized electron beam has been used for physics experiments at MAMI in the energy range between 180 and 855 MeV. The beam-normal single-spin asymmetry An, which is a direct probe of higher-order photon exchange beyond the first Born approximation, has been measured in the reaction C12(e→,e′)C12. Vertical polarization orientation was necessary to measure this asymmetry with the existing experimental setup. In this paper we describe the procedure to orient the electron polarization vector vertically, and the concept of determining both its magnitude and orientation with the available setup. A sophisticated method has been developed to overcome the lack of a polarimeter setup sensitive to the vertical polarization component.

Readout Electronics for the First Large HV-MAPS Chip for Mu3e

Mu3e is an upcoming experiment searching for charged lepton flavour violation in the rare decay μ+->e+e-e+. A silicon pixel tracker based on 50 μm thin High-Voltage Monolithic Active Pixel Sensors in a 1T magnetic field will deliver precise vertex and momentum information. The MuPix High-Voltage Monolithic Active Pixel Sensor combines pixel sensor cells with integrated analogue electronics and a complete digital readout. For the characterization of the first large MuPix system-on-chip a dedicated readout system was developed. The readout chain and the first results from the characterization of the large scale MuPix8 prototype are presented.

From deep inside to outer space: exploring neutron skins

M. Thiel∗1, S. Baunack1, D. Becker1, J. Diefenbach1, A.Esser1, M.I. Ferretti Bondy1, K.S. Kumar2,3, F.E. Maas1, H. Merkel1, U. Müller1, K.D. Paschke4, B.S. Schlimme1, C. Sfienti1, P.A. Souder5, and A. Tyukin1 1Institut für Kernphysik, Johannes Gutenberg-Universität Mainz, D-55099 Mainz, Germany 2Department of Physics, University of Massachusetts, MA 01003-9337, USA 3Department of Physics and Astronomy, Stony Brook University, NY 11794-3800, USA 4University of Virginia, Charlottesville, Virginia 22904, USA 5Syracuse University, Syracuse, New York 13244, USA E-mail: thiel@kph.uni-mainz.de